Biology

  • Books- Extracts. Reviews and some contents. Head Strong   by Dave Asprey.Chapter 1.   Head start.Figure from Google.Dr. Paul Mac Lian introduced the Triune brain model in 1960.Reptile brain controls ...
    Posted Jul 1, 2019, 9:29 PM by Upali Salpadoru
  • Genetics-ll. HeredityPrior to the study of this lesson it is essential to be familiar with these terms. Trait:- This is a characteristic of an individual such as hair colour, or ...
    Posted Aug 27, 2019, 2:41 PM by Upali Salpadoru
  • Biology terms M to Z. M..Meiosis This is the way cell divides to produce sex cells. The chromosome number gets halved, Ck\lick cell biology.MetabolismThis includes all the physical and chemical changes ...
    Posted Sep 16, 2017, 12:31 PM by Upali Salpadoru
  • Plant Kingdom Fig 1  The 5 kingdoms of  living things. Out of these, plant  kingdom, is the most mportant. Only PLANTS can synthesize food by photosynthesis.  Others have to directly or indirectly ...
    Posted Sep 3, 2017, 12:20 PM by Upali Salpadoru
  • Bacteriophages. “ Drinking water from the Holy Rivers like  Ganges & Yamuna,could cure cholera”, Fact or fiction? Fig.1. Phages landing on a bacterium.Courtsey:- Phages.org.Ernest Hankin (UK), in 1896 ...
    Posted Nov 5, 2017, 11:04 PM by Upali Salpadoru
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Books- Extracts.

posted Feb 14, 2018, 7:50 PM by Upali Salpadoru   [ updated Jul 1, 2019, 9:29 PM ]

Reviews and some contents.

Head Strong   by Dave Asprey.


Chapter 1.   Head start.Figure from Google.

Dr. Paul Mac Lian introduced the Triune brain model in 1960.

  1. Reptile brain controls temperature regulation and electrical systems.

2. Mammalian brain control instincts. Fear, Food and reproduction.

3. Human brain resist some of the reactions due to false alarms. Each decision requires a lot of energy. When u r tired, hungry or have already made a lot of decisions u run out of energy and make bad decisions.


Chapter 2.  Mighty mitochondria.

Earth was covered with warm seas. Atmosphere was oxygen. One type of bacteria learned to use oxygen to get  energy. They created ATP. A small purple bacterium entered became embedded in another type of cell. This combination evolved to form animals. These bacteria are the mitochondria in our cells.


Chapter 3. Become a neuromaster.

Researchers have found that progesterone , the female hormone, signals oligodendroglia to initiate remyelination.

Bioflavonoids  in citrus fruits and some veggies are essential to keep neurons alive. So are the Polyphenols in coffee, chocolate, blueberries and grapes.

Anything we do to avoid chronic stress will help to create more brain cells.exercise increases neurogenesis. A fun environment helps.

Tips.  

1, Eat saturated fat from grass fed butter, and meat,

2.    Avoid sugar

3. Manage your stress.

4. Have more sex.

Chapter 4. Inflammation.

The brain is the first part of the body to suffer when chronically inflamed.

When mitochondria are inflamed  electrons have to travel further to get to the same place.

Tips:-

Spend some time outdoors barefoot to soak up the earth’s negative charge.


Chapter 5. Brain fuel.

Polyphenols are antioxidants that protect your gut , increase your rate of neurogenesis, play a role in apoptosis. Mitochondria make energy more efficiently with ketones than with glucose.

Do these:-

Eat low sugar fruits and veggies with a healthy fat such as grass fed butter.

Eat more fish.

Restrict carbohydrates.

Chapter 6. Brain inhibiting foods.

Dairy protein, gluten, transfats and vegetable oils cause inlammation.

Mold toxins are particularly toxic.Healthy fats are damaged by high temperatures,

Tips:-

Stop using art sweeteners. They are toxic.

Never eat fried food. Toxic.

Buy organic.

Chapter 7. Avoid toxins and improve your body’s detox systems.

About 25% are genetically sensitive to mold.

Mold toxins , heavy metals, and some drugs are directly toxic.

Toxins are stored in fat. Breaking up fat detox your body.

Chapter 8 Your brain on light, air and cold.

LEd and CFL blbs have too much blue.which damages mitochondria.

Chapter 9

Focus on quality of sleep.

Meditate and exercjse.


            
                                                                      Your Body
       Extracted from 100 things you never knew.
            1. Tooth enamel is the toughest material in the body.

2.Skeletal muscle makes 40 - 50% of the mass of males and 30 - 40 % in females.

3. Women’s bodies have a lower centre of gravity.

4. Sweat glands releases 2 cups of water per day.

5. Oxytocin bolsters emotional bonding between individuals.

6. The brain can function up to 10 seconds after the blood supply is cut off.

7. Brain is only 2% of the body but it uses 20% of the O2 and glucose.

8. Sleep deprivation is connected to a loss in the no of immune cells.

9. Adults have about 4 -5 Litres of blood.

10. Anger and fear increases the heartbeat by 30 -49 beats a minute.

11. The heart muscles grown in a culture beats spontaneously.

12. normal resting heart rate for adults ranges from 60 to 100 beats per minute. .

13. Allergies decrease in elderly.


               
   

Genetics-ll.

posted Aug 15, 2016, 9:45 PM by Upali Salpadoru   [ updated Aug 27, 2019, 2:41 PM ]

Heredity



Prior to the study of this lesson it is essential to be familiar with these terms.


Trait:-

This is a characteristic of an individual such as hair colour, or an action such as the ability to roll the tongue.


Genotype :-

The functioning and dormant genetic material present in an organism.


Phenotype:-

The functioning or visible traits of that organism. The form that is shown.

Alleles:-
Different forms of a gene, which may give rise to different phenotypes,
(An individual gets two alleles from the two parents.)

Homozygous:-

Describes two of the same alleles at a specific locus.


Heterozygous:-

Describes two different alleles at a specific locus


All members in a specie are not the same. There are minor differences.

Such variations help the survival of the species. For example if a disease spreads, every individual will not be susceptible to the same extent. Even when a large percentage gets wiped out a few individuals at least will survive and continue the specie.

This is how the evolution takes place. The surviving individuals will be slightly different to the original stock.


The traits inherited are of two kinds.

1.Continuous traits.

Characteristics show a wide range of differences.  Eg. Size, skin colour, inteligence.

2. Discrete traits. (Discontinuous)

There are only two possibilities. A rabbit can be either white or black.

Eg. Ability to roll the tongue.


How alleles pass on  traits

The inheritance of a trait is governed by the 2 genes, which are termed alleles.

These two come from the two parents. In a pair one allele may be dominant while the other is recessive.

If a dominant allele is present it will always exhibit in the phenotype.

The recessive allele will only function in the absence of a dominant allele.


Three genotypes are possible with a pair of alleles.

We can illustrate this if we consider the dominant factor brown eyes as ‘R’ and the recessive factor as simple ‘r’ for blue eyes.


Description

Genotype

combination

Phenotype

1.Homozygous dominant.

R + R

Brown eyes.

2. Homozygous recessive.

r  + r.

Blue eyes.

3.Heterozygous

R + r.

Brown eyes.


Gregor Mendel discovered these rules of inheritance long before the discovery of the genes. According to the theory of Mendelian inheritance, variations in phenotype are due to variations in the genotype.

Mendel's Experiment.

He grew two varieties,  of the pea plants, having purple and white flowers,  allowing them to self pollinate so that he could obtain pure bred specimens. Then he systematically recorded the passing of seven characteristics (which we now call traits). Let us select one trait to show what he discovered.
In This case two pure bred varieties are taken and the flowers are cross pollinated. While capital B represents a dominant blue colour , simple w' is for a recessive gene. Combination of the plants shown in the punnet can produce only blue flowers.  This does not mean that the allele to produce white flowers has vanished. It will be there and exhibit it self when the daughter plants are crossed. 
Mendel's Law of Dominance.
.
All BLUE, 'cause that was the dominant in the two pure breds, Look at the Genotype. Recesive gene is there in every one.
After cross pollination of two pure forms having different discrete traits , only one form will appear in the first order of off springs.


Mendel's Law of segregation.
During reduction division to form gametes(Sex cells) two alleles coded for a trait separate.On fertilization they combine. The off springs always bear the ratio 3:1 for dominant:recessive alleles.

Sex determination



Out of the 46 genes of an individual 22 pairs would be identical in males and females. These are called autosomes.  The 23rd pair which is one that determines the sex would be different.  This diagram shows the difference.

In females sex cells are identical, X and X,  while males have two types, X and Y.

Gametes form after reduction division( meiosis) do not have a pair of chromosomes but only one. So the egg cells contain only X chromosomes while a male will have half the number  of  sperms with X and the other half with Y.

X-.chromosome. Has about 1098 genes.

Y chromosome, much smaller has only about 26 genes

X linked chromosomes are also responsible for some abnormalities such as haemophilia and a form of baldness.The Y chromosome has the genes for male characteristics. In the absence of Y, the embryo would produce a female.

As the males carry only one copy of X, they are more liable to get hereditary disorders such as haemophilia and colour blindness..

When  normal cells are stained , only in the case of female cells a stained body becomes visible. This is really the condensed form of an X chromosome. This has become invaluable in some legal cases.

Protein synthesis.

This is the process of making proteins according to the information coded in DNA..  The intermediary for the making of new protein is the RNA.( Ribonucleic acid.)

RNA.jpgFig.      Ribonucleic acid.

RNA varies from DNA from the following:

            1.They are single stranded.

            2. The base cell Thymine is changed to Uracil.

            3.Contains the sugar Ribose instead of deoxyribose.

Three bases in order is sufficient for a particular amino acid.  These are known as triplets or codons.

What are codons or Triplets ?

There are only 20 amino acids in human beings. They are listed here.

code

Amino acid

Possible codons

Order of Triplets

A

Ala

Alanine

GCA, GCC, GCG, GCT

B

Asx

Asparagine or Aspartic acid

AAC, AAT, GAC, GAT

C

Cys

Cysteine

TGC, TGT

D

Asp

Aspartic acid

GAC, GAT

E

Glu

Glutamic acid

GAA, GAG

F

Phe

Phenylalanine

TTC, TTT

G

Gly

Glycine

GGA, GGC, GGG, GGT

H

His

Histidine

CAC, CAT

I

Ile

Isoleucine

ATA, ATC, ATT

K

Lys

Lysine

AAA, AAG

L

Leu

Leucine

CTA, CTC, CTG, CTT, TTA, TTG

M

Met

Methionine

ATG

N

Asn

Asparagine

AAC, AAT

P

Pro

Proline

CCA, CCC, CCG, CCT

Q

Gln

Glutamine

CAA, CAG

R

Arg

Arginine

AGA, AGG, CGA, CGC, CGG, CGT

S

Ser

Serine

AGC, AGT, TCA, TCC, TCG, TCT

T

Thr

Threonine

ACA, ACC, ACG, ACT

V

Val

Valine

GTA, GTC, GTG, GTT

W

Trp

Tryptophan

TGG

X

X

any codon

NNN

Y

Tyr

Tyrosine

TAC, TAT

Z

Glx

Glutamine or Glutamic acid

CAA, CAG, GAA, GAG

*

*

stop codon

TAA, TAG, TGA



Step 1.Transcription.

For the genetic code to be active the two strands have to open up. This happens at different places at the same time catalyzed by an enzyme Helicase. Any one of these strands is used as a template to make a molecule of ribonucleic acid which would be known as mRNA. (‘m’ for messenger)Tr 2.jpg

This copy, called a messenger RNA (mRNA) molecule, leaves the cell nucleus and enters the cytoplasm, where it directs the synthesis of the protein, which it encodes.

This process is assisted by an enzyme called Polymerase .

One end of a DNA polymer contains an exposed hydroxyl group on the deoxyribose; this is known as the 3' end of the molecule. The other end contains an exposed phosphate group; this is the 5' end. So processes such as DNA replication occur in only one direction. All nucleic acid synthesis in a cell occurs in the 5' to 3' direction.
Step 2. Translation

This copy, called a messenger RNA (mRNA) molecule, leaves the cell nucleus and enters the cytoplasm, where it directs the synthesis of the protein, which it encodes.

Translation is the process of translating the sequence of a messenger RNA (mRNA) molecule to a sequence of amino acids during protein synthesis. The genetic code describes the relationship between the sequence of base pairs in a gene and the corresponding amino acid sequence that it encodes. In the cell cytoplasm, the ribosome reads the sequence of the mRNA in groups of three bases to assemble the protein.

A gene can be switched on and off. When a gene is active, the coding and non-coding sequences are copied in a process called transcription, producing an RNA copy of the gene's information. 

The mRNA then leaves the nucleus to the cytoplasm where it is translated via the use of tRNA and ribosomes and amino acids to translate the mRNA strand into a protein. 

When the gene is turned off, a repressor molecule is formed which stops protein synthesis as it covers the promoter site.

There are only 20 Amino acids among all living 

Gregor Mendel  first came across the idea of genes, in the 1860s. 

He studied inheritance in pea plants and hypothesized a factor that conveys traits from parent to offspring. Mendel was also the first to hypothesize independent assortment, the distinction between dominant and recessive traits, the distinction between a heterozygote (A person carrying two different forms of a gene inherited from father and the mother) and homozygote (A person having two similar genes inherited from the two parents), which is the genotype (the genetic material of an organism) and phenotype (the visible traits of that organism).

According to the theory of Mendelian inheritance, variations in phenotype are due to variations in genotype, or the organism's particular set of genes, each of which specifies a particular trait. Different forms of a gene, which may give rise to different phenotypes, are known as alleles. Organisms such as the pea plants Mendel worked on, along with many plants and animals, have two alleles for each trait, one inherited from each parent. Alleles may be dominant or recessive; dominant alleles give rise to their corresponding phenotypes when paired with any other allele for the same trait, whereas recessive alleles give rise to their corresponding phenotype only when paired with another copy of the same allele. But this is not always the case; in this situation the alleles are completely dominant. In other cases the alleles could be incompletely dominant or co-dominant. Incomplete dominance is when a characteristic in the heterozygote s intermediate in the degree between the two homozygotes. And co-dominance is when the heterozygote simultaneously expresses 2 alleles that have different kinds of effect.

 Chromosomes within cells are the carriers of genetic material, and they are made of DNA (deoxyribonucleic acid). DNA consists of a chain made from four types of nucleotide subunits: i.Adenine, ii.Cytosine, iii.Guanine, and iv.Thymine

Each nucleotide sub-unit consists of three components: i. a phosphate group,  ii. deoxyribose sugar ring, and a iii. base. (Adenine and guanine are purines, and cytosine and thymine are pyrimidines.)

 The DNA in a cell has double helix structure, in which two individual DNA strands twist around each other in a right-handed spiral. In this structure, the base pairing rules specify that guanine pairs with cytosine and adenine pairs with thymine (each pair contains one purine and one pyrimidine). 

The base pairing between guanine and cytosine forms three hydrogen bonds, whereas the base pairing between adenine and thymine forms two hydrogen bonds. The two strands in a double helix are complementary.

Q.1.0

Give a single word for these:

1.The functioning and dormant genetic material present in an organism.

2.The functioning or visible traits of that organism. The form that is shown.

3.Different forms of a gene, which may give rise to different phenotypes,

4. Two of the same alleles at a specific locus.

5. Two different alleles at a specific locus.

6. A characteristic showing a wide range of differences.

7. A trait showing only two variations.  

8. The process of making proteins according to the information coded in DNA.

9. The process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).

10. Synthesis of amino acids according to a an mRNA sequence.

3x10-30 marks.

Q. 2.0 MCQ.

  1. Two parents have had three female children. What are the chances of getting a male child next time?                              A. 1:3,  B. 3:1,  C.  2:1  D. 1:1.

  2. Which of these can you change?                       A.- Instincts. B.- Inherited traits. C-Acquired knowledge. D.-Inherited behaviors

  3. A rabbit, black (B-dominant) colour, was bred with a white one (b-recessive). There were 3 black off springs and 1 white. What could have been the genotype of the parents.  A.- BB and bb.  B.- Bb and Bb,  C-  bb and BB, D- Cannot be determined.

  4. The flowers of two plants, having white (W -dominant) and blue (b -recessive) were cross pollinated. This resulted in plants only with white flowers. What genotypes could have been possible  for the plant which had white flowers?

         A- WW or Wb,  B-  WW Only.   C-  Wb  only D- Cannot be determined.

  1. Which is not correct for the RNA molecule.                                                           A- It is a double helix. B-It is a single strand.   C- The base cell Thymine is changed to Uracil. D.-Contains the sugar Ribose instead of deoxyribose.

         4x5=20 marks.

Q.3.0

Recognize these cells and answer the questions below. There can be more than one letter to an answer.

cells.jpg

Name the following:-

  1. The somatic cells.     2.  The gamete cells.  3. Sperms     4. Egg cells. 5. A female somatic cell. 6. An abnormal cell.  7. A zygote  8. A fertilized cell that can produce a boy child.

3x8 = 24 maeks.

Q.4.0

Complete these punnets.and comment on the offsprings produced using the table given.

Bd = Black dominant.  Wr = White recessive.


No.

1 example

2

3

4

5

6

7

8

marks

Genotype

B w

7

Phenotype.

black

7

Ratio

Black; White.

F1 Hybrid.

F2 Hybrid.

2

=16 m.


pun.jpg

Q.5.0

Answer these.

  1. What is the molecule that escape from the nucleus to make proteins.

  2. How many amino acids are essential for living organisms?

  3. How many nucleotides are required for codons (triplets) in all amino acids required.

  4. Name the enzyme that helps to split up the DNA molecule.

  5. A molecule that binds to a gene in DNA to stop transcription.

2x5 =10 marks.

For answers click:- Answers-Bio.







Biology terms M to Z.

posted Jul 16, 2016, 2:03 PM by Upali Salpadoru   [ updated Sep 16, 2017, 12:31 PM ]

M..

  • Meiosis 

This is the way cell divides to produce sex cells. The chromosome number gets halved, Ck\lick cell biology.

  • Metabolism

This includes all the physical and chemical changes that occur inside a living being. There are two types. 

Anabolism:- This includes the formation of complex compounds present in the body.

Catabolism:the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy;

  • Mutation

Copying of proteins is a very reliable process, yet may one in a million a mistake can occur This would cause a mutation.  Most of the errors cause no harm.

The effect caused by the change of the structure in a gene. Only the mutations that may occur in the reproductive cells will be hereditary.

Mutations often lead to evolution. The process may produce an individual more suitable for the environment.

N

  • Nastic movements.

Non directional movements in plants due to stimuli such as temperature.

  • Nephron

The function of nephrons is to remove urea, uric acid, and creatinine, and also any excess sodium, chloride, and potassium ions. It can also re absorb water and useful materials such as glucose and maintain the fluid balance.







  • Nephritis
     This is the inflamation of kidneys  due to infection or immunity dis orders.

  • Niche

The place of an organism takes and the role it plays in a particular environment.

  • Nitrogen Cycle


  • Nucleus

  • Fig. Structure of the nucleus.

    This is the most important organelle in a cell.It contains genetic material, chromosomes.






    O

    • Oncogene

    A gene found in the chromosomes of tumor cells which is associated with the conversion of normal cells into cancer cells.

    • Organelle

    This is a structure with specialized functions, in the cytoplasm of an eukaryotic cell.

    • Osmosis

    This occurs when two solutions of un=equal concentration are separated by a semi permeable membrane. Water from the dilute solution diffuses into the more concentrated solution. Usually the solids dissolved cannot pass through the semi permeable membrane.  Plants are able absorb dissolved solids only when they are present in a very dilute form. If a plant root come in contact with a concentrated solution, reverse osmosis can occur.


  • This is an experiment to demonstrate diffusion. Take two yams carrots or beet root. Make a hole on top as shown Insert a straw and plug it so that water will not leak.
  • Add sugar solution to one and plain water to the other. Fill the first glass with water and the other with a sugar solution. Observe what happens after a few hours.



P

  • Parasites

These are organisms that live or get food from other organisms. There are the ecto parasites that rae found outside the body and endo parasites that live inside.

  • Phenotype

An off spring produced by the combination of hereditary factors as well as environmental conditions.

  • Photosynthesis.
  • Synthesis of primary food by the plants. The reaction is explained by this equation.Water +Carbon dioxide + (Energy from sun light)  =  Glucose + Oxygen.

  • 6CO2 + 6H2O   (Light energy)  = C6H12O6    + 6O2 
  • This reaction can only be performed by chlorophyll the green substance present in plants.
  • Polymerase 

an enzyme that can build long chains of DNA or RNA using the nucleotides

  • Plant

Parts of a dicot  plant.


  • Plantae

Seed.jpg

         Fig.   Structure of Maize (monocot) and Bean (dicot) seeds.


  • Polymerase chain reaction

A method developed to get copies of DNA very quickly. PCR was discovered in 1983 by K.B.Mullis.  He won the Nobel Prize for Chemistry in 1993.

·         Prebiotics

Prebiotics are carbohydrates in the intestines which cannot be digested. These help the healthy bacteria, probiotics to flourish.

.

  • Recessive allele.
These will become effective only if two copies of the allele are present in an individual. Cystic fibrosis is caused by a recessive allele.
  • Reflex action. An involuntary reaction such as the knee jerk.

  • Respiration

This process conforms to two important functions.

External respiration  - What happens outside the cells, described as breathing or ventilation.

Higher animals use lungs for breathing. Lung respiration

Insects use a system of air ducts.

The fish use gills.

Plants exchange gases through stomata.

Cellular respirationThis is the process by which food is oxidised to obtain

energy. There are two important ways of doing this.

1. Aerobic respiration This is the normal respiratory process using oxygen.

C6H12O6 + 6O2  = 6CO2 +6H2O +( energy, ATP)

Glucose + Oxygen = Carbon dioxide + Water + (Energy)

2. Anaerobic respiration. - This process does not use oxygen.This still takes place among some lower forms of life. Scientists believe that the earliest forms of life would have used this method as there was no oxygen in the atmosphere then. This does not produce as much energy as the other.

Fermantation by yeast is an example of anaerobic respiration.

Reproduction

The ability to make exact copies of oneself may be considered as the specific characteristic of living things. There are many ways of performing this most important task. Let us consider some of them.

A = Asexual Methods

1.    Fission – This is merely dividing a cell and its contents into two or more cells. This process is almost identical to growth. Spirogyra, an algae consists of a row of identical cells. When the cells divide yet they are attached to the filament we call it growth. If they separate and start life as new individuals it amounts to reproduction. In the case of amoeba, a protozoan, binary fission amounts to reproduction.

2.    Budding – This is very common in plants and yeast like specimens but rare among animals. Hydra is a fresh water animal that form new individuals by budding.

3.    Vegetative Propagation-This includes all types of producing new plants from a parent plant. Here are sme examples.

Runners in strawberry.   Leaves in Bryophillum and Begonia.   Suckers in Banana.   Bulbs in garlic   Stem cuttings in Roses.

B- Sexual Method

4.    This method involves the formation of gametes from two individuals and uniting them in a process called fertilization. Gametes contain only half the number of chromosomes which are formed by Reduction Division of cells. The process is also called meiosis. The gametes may be similar or differentiated as male and female. The individual formed by fertilization is called Zygote and would contain a diploid number of chromosomes.

Refer:- Cell division


  • Stem cells

These are the un specialised cells that are capable of dividing and becoming any kind of a specialised cell.

  • Stomata

These are the opening found on the surface of leaves. The gas exchange for respiration and photosynthesis take place through these openings. Each opening is controlled by two guard cells as it is a disadvantage to lose water, transpiration, through these in times of scarcity.






  • Stretch receptors

 These  are mechanoreceptors, that feel the extension  of various organs and muscles, They  are directly linked to the  brain stem via afferent nerve fibers. Examples include stretch receptors in the arm and leg muscles and tendons.

T

  • Tendril.


  • An appendage of a creeper to climb up a su[pport. Some times leaves or at times the axillary bud gets modified into a tendril that can search for a twijg and coil round it.

  •  Fig. shows an entire bud modified into a tendril.






  • Territory

The area which an animal or a group of a specie defend, to live and protect their young.

  • Tissue

A group of similar cells in a plant or an animal specialised for a purpose. Eg. Blood tissue. Epidermal tissue and vascular tissue in plants.

  • Tropism

The growth of a plant towards or away from a stimulus. Eg Phototropism growing towards light. Geo tropism and Hydrotropism are also examples.

  • Translation

Production of protein according to information in m RNA molecule.

Transpiration

This is the loss of water due to evaporation from plants, mainly from the leaves.

Turgor Pressure

Water enters the plant cells by osmosis. This causes the cell to swell keeping its shape. In the absence of this water cells can collapse.

Plant Kingdom

posted Jul 15, 2016, 12:41 PM by Upali Salpadoru   [ updated Sep 3, 2017, 12:20 PM ]


Fig 1  The 5 kingdoms of  living things.

 Out of these, plant  kingdom, is the most mportant.
 Only PLANTS can synthesize food by photosynthesis
 Others have to directly or indirectly get it from them.

   
Fig. The  food synthesizing system in the world. 99.9 % of the food is made this way.

Despite the fact all living things have had a common origin, plants have diversified to such an extent they hardly show any relationship to the specimens of the other kingdoms.  Let us examine the unique characteristics of this kingdom.that


 Fig.2  Parts of a flowering dicotyledonous plant.

 Only the standard parts, are shown . 

Flowers, thorns tendrils etc, are not included here as they are modifications of these parts . .

Parts of a normal plant.

1. Roots.

These are the parts that grow towards the earth (geotropic) unlike the shoots They also have a tendency to grow towards water. (hydrotropic)

As they do not have nodes and internodes leaves and buds are absent. 

Normal roots arise from the base of the stem but in certain species, roots arise from the shoots which are called adventitious roots.

When you uproot a plant, root hairs break off. Root hairs have only one cell.

Roots perform the following functions;

i.  Absorb water and nutrients from the soil.  
ii.  Holding the plant firmly to the soil against the forces of wind and water.
iii. Storing of food (starch) . Large reservoirs of food are known as yams.
iv. A few plants produce buds that grow into new plants. These are called adventitious buds.

2.Stem.

Fig.3  Sugar cane stem filled with sugary sap
The stem has nodes from which the leaves and buds arise.  These may be much branched as in most dicots.  or single as in palms. They generally grow towards light (phototropic) and  upwards.Some stems may remain underground and grow sideways. as in ginger. In that case only the leaves come above the soil.

Do you know? What of the plant is a potato tuber?  A fruit, root or a stem?

Functions;

Fig. A section of a typical stem showing a vascular bundle.
Vascular bundles contain vessels that conduct water. Xylem takes the water from the roots to the shoot while the sugar processed in the leaves is sent down through the phloem.
i. To spread the foliage and the flowers, in a way to get the maximum amount of light.

ii. Climbers, creepers and runners produce adventitious roots, tendrils or thorns  to hold on to a support.  

iii. Some stems store sugar or starch.
iv. Conducting water and nutrients from root to shoot. (xylem tubes)
v. Conducting food from leaves to roots.(Ohloem tubes)


3. Leaf

leaves are the food factories of the plants. 

They take in carbon dioxide from the air and combine with water to make sugar. This is the process known as photosynthesis. As the energy is obtained from sunlight the leaves are generally flat to capture the light.  They are also very thin exposing many stomata to the atmosphere for the exchange of gases.(Stomata are the opening on the leaf surface)

 

Fig.4  The trifoliate leaves of a leguminous plant. 

Functions of a leaf.

i.    Leaves manufacture food by photosynthesis.

ii. They exchange gases through stomata , the opening mostly found on the under surface of the leaf.

iii. They store water. which is used for photosynthesis and for cooling, when exposed to  direct sunlight.

iv.  In some plants they get modified into tendrils, or thorns.

v. In a few rare cases such as bryophillum and begonia the leaf margin can produce young plants.

                                            KINGDOM OF PLANTAE

 

Vascular Plants.

1. Ferns


    Reproduces by spores found on the under surface of leaves.
    Young leaves emerge rolled up from the bud.

eg. Bracken fern. Maiden hair fern (Adiantum). Tree fern.           

There are two main groups of tree ferns in New Zealand: Cyathea and Dicksonia.  They are easily distinguished since Cyathea is scaly and Dicksonia is hairy.

2. Gymnosperms

The ovules or seeds are not enclosed in an ovary.
The word "gymnosperm" comes from the Greek word gymnospermos, meaning "naked seeds". 
                                       
 CYCADS CONIFERS
 
 
The seeds are inside woody cones.                   eg. Pine family.


3. ANGIOSPERMS -Flowering plants.


 MONOCOTYLEDONS  DICOTYLEDONS
 Flower
Lily flower    6 petals and 6 stamens are visible.

eg. Grass, Palms,  

Seed

. One cotyledon in maize.

Leaf

Leaves are generally long and the veins are parallel. (Parallel venation.)

Flower
Hibiscus flower.
Usually pentamerous. (5 Petals,sepals stamens or a multiple of 5)


See
d.


 cotyledons of a bean seed.

Leaf



Reticulate venation.


        SUMMARY of two categories of flowering plants.





 Q.1.0 
    Classify the following into 3 groups. Flowering plants, and Non flowering and others.

  1.Grass.  2. Yeast 3. Silver fern, 4. Tea  5. X'mas tree,  6. Mush room . 7. Kiwi, 8. Ficus, 9. Bracken, 10. Bacteria, 11. Fur tree, 12. Spruce. 13. Centella asiatica (Gotu kola) 14. Moss. 15. Cactus.
2 x15 = 30 marks. 
 Q. 2.0
   Classify the following into 3 groups as  Dicotyledonous, Monocotyledonous and others.
1. Onion, 2. Sun flower,  3. Bean,  4. Bamboo,  5. Cashew nut, 6. Lily, 7. Orchid.      8. pineapple, 9. Lemon, 10. Cycads. 11. Fern.
2 x11 = 22

 Q.3.0
Mention the part of the plant mainly responsible for the respective functions.
 1. Synthesizing food.         2. Storing prepared food.
 3. Conducting the water to shoot.   4.  Bringing food for the roots.
 5. Reproduction.  6. Absorption of nutrients from soil.
3 x 6 = 18

 Q.4.0
Into which major part of a plant could these be assigned ?

3 x 10 =30











Bacteriophages.

posted May 29, 2016, 1:19 PM by Upali Salpadoru   [ updated Nov 5, 2017, 11:04 PM ]


Drinking water from the Holy Rivers like  Ganges & Yamuna,

could cure cholera”, Fact or fiction?


Phage -2.jpg


Fig.1. Phages landing on a bacterium.

Courtsey:- Phages.org.


Ernest Hankin (UK), in 1896 found that cholera bacteria that thrived in tap water had no success in Ganges water.

He found that even the filtered river water could destroy Vibrio cholerae bacteria, unless he boiled it.


The agent that killed bacteria was only discovered in 1916 by Felix d'Herelle (Can) from Pasteur Institute in Paris. These have been named as Bacteriophages as they destroy bacteria. They cannot even be classified as living things. They are described as ,’ Nano particles capable of self replicating”.


Phage-3.jpg
Fig.2 Three phages have landed on the surface of a Bacterium.
Courtsey:- Phages.org.

A baceriophage is very much smaller than a bacteria.  They are really viruses. Cousins of those that cause, flu, pox and ebola.No reason to worry; phages do not attack human cells.

The longest war in recorded history may be 100 yr war, but  there is a war that had been raging for millions of years.  The war between the phages and bacteria. It has been estimated that phages slaughter half the total number of bacteria in 2 days.


Then the question arises, “Why won’t the bacteria become extinct?.

There are two reasons for this.

  1. They propagate very fast.( So are the phages)

  2. They develop various defensive mechanisms against the evolving tactics of the phages.

While the war rages What shall we do ?




Fig.3 A phage attacking a bacteria.


The obvious thing we have to do is to take the side of the Phages. They do no harm to us unlike some bacteria who are infectious.

Phage Therapy


Phage therapy started before the discovery of antibiotics. The difficulty with phages is that they are highly specific.One kind of a phage can generally destroy only one type of bacteria. But now when some bacteria develop resistance even to the strongest antibiotics, the doctors are inclined to go back to phage therapy. Phages can change their mode of attack when the enemy changes unlike the antibiotics.



Bats

posted Mar 10, 2016, 8:56 PM by Upali Salpadoru   [ updated Mar 12, 2016, 7:37 PM ]


Flying foxes.

Fig.1 Indian flying fox. Courtsey:  batworlds.com


Bats were considered as,” Demon’s Angels”. They are unusual; flying at dusk and roosting upside down. Biologists have introduced sufficient evidence now for us to change that attitude.  

Bats carry deadly viruses including ebola,SARS etc. but they do not become sick. This has baffled  virologists.

Although colonies of bats have been destroyed in the recent years by man the scientists who have studied them say they cannot pass the disease causing viruses directly to man. On the other hand those who have studied viruses are of opinion that they are vital to our environment. They eat tons of agricultural pests in a single night. They pollinate flowers and help the plants by dispersing seeds and fruits.          

  • Bats do not have feathers.
  • They do not lay eggs,
  • They are the only mammals capable of powered flight.
  • Their wings show 5 ribs similar to our fingers.
Fig.2 Their ribs on the wings are similar to our fingers.
  • They are the only mammals along with whales and dolphins that have shown echo location. They can emit high frequency sound waves and hear the the echo if there are any objects in their path.


 

Anthony King writing an article in the New Scientist says, quotes the following scientists.


James Wood. University of Cambridge.

“ Bats carry rabies virus yet they have developed immunity”


Linfa Wang. University of Singapore.

“Injecting bacterial toxins to animals normally triggers a reaction.When bats are injected they don’t get even a fever.It is hard to make them sick. Trying to control emerging diseases by killing bats may be the worst thing we can do”



Reference.


CLICK HERE to wach a webcast "Project Edubat – Education Taking Flight” to learn more about these important animals.


Fungi

posted Feb 18, 2016, 2:13 PM by Upali Salpadoru   [ updated Sep 13, 2016, 1:00 AM ]


Kingdom Fungi


Largest Mushroom.jpg


             Fig.1 Largest Mushroom.              

Courtsey:  vyperlook.com

This is supposed to be the largest mushroom ever grown. Is it a Plant or something else. It is a Fungi; a different kingdom. The members of this Kingdom range from microscopic moulds and yeast cells to hyphae that grow hidden but exhibit as mush rooms.

They are not plants as they have no chlorophyll and cellulose in cell walls. They cannot be animals as they have cell walls. These cell walls are made of a poly-sacharide called chitin which happen to be present in some animals such as in the exo-skeleton of Arthropoda.




Structure

Most fungi are similar to icebergs as a greater part of it cannot be see. The mushroom canopies that we see are the fruiting bodies or sporophytes developed for asexual  reproduction. The main body is made up of fine threads called hyphae, that remain hidden to the naked eye. This part is called the mycelium.  

           


Fig.2. Diagram of septate hyphae. .(highly magnified)





Although in some fungi the hyphae are divided into compartments with a nucleus in each, in some fungi the whole filament looks a single cell with several nuclei.


Fungi live on some kind of food matter. They cannot synthesize or engulf food as some protists do. They secrete enzymes to digest the food externally and absorb the nutrition.



Fig.3. Non non septate hyphae. (Coenocytic)






Mould 2.jpg














Fig.4 some mould growing on a fruit.


Moulds.


Penicillin is a very well known antibiotic. Alexander Fleming obtained this from a mould that had the same name.These grow on moist bread and other food substances as invisible thread like structures called hyphae




What are the powdery stuff here?






Reproduction.


After the mycelium has grown for a few days they produce the reproductive structures. They are called sporangia.

Sporangium.jpgFig.5. Sporophyte of Mushroom.

Yeast Saccharomyces..


This is a uni cellular fungi. This had been of immense use to man from ancient times. It makes the dough rise in making bread.

Fig 6. Yeast producing buds.


Yeast is typically 3-4μm


Ali.jpg

Fungi

   

   Good !


Nelly.jpg

Fungi


  Bad!


1.    The most expensive food in the world is a fungi. It is known as ‘Black diamond’ Just a couple of shavings of black truffles from France - known as black diamonds - can cost hundreds of dollars in a restaurant in Paris. White truffles from Italy can cost more than three times as much.” A truffle is the sporophyte of a subterranean Ascomycete fungus that grow attached to the roots of oa trees.,


2.   .They decompose organic matter along with bacteria.


3.     The rising of dough for bread is performed by yeast.This is fermentation.   C6H12O6.[8] One glucose molecule is converted into two ethanol molecules and two carbon dioxide molecules:

C6H12O6 → 2 C2H5OH + 2 CO2

4. They are used in making medicines such as antibiotics and statins.

1.  Fungal spores if landed on moist food start growing spoiling the food.


2 Superficial fungal infections of the skin and nails are relatively common in normal individuals, Athletes foot

3.  Some fungi (mushroom) if eaten can cause immediate death.


4  The molds that grow especially  inside the house cause allergies and asthma on some people.


Normal building materials and furnishings provide ample nutrition for many species of molds, but they can grow and amplify indoors only when there i

s an adequate supply of moisture.   Courtsey. Pubmed.



Supplements


From the New Scientist  of 13th Feb 1916

Paul Stamets  says “We are sitting on a mould mine.”

Courtsey: Fungi Perfecti.

A bracket fungus off birch trees can arry fire.  When this is boiled and stretched you get a fabric . At present only the people in Tansylvania do this. As they are in the shape of a basket people make hats out of it.

The magic mushroom ( psilocybin) had been able to stop a stutter he had been having. Scientist have found that it can stimulate the growth of neurons. Us Defence department has found pharmaceuticals that can act on dangerous viruses and bacteria.

Bees such the juice of some fungi probably to de toxify the poisons they get from insecticides and herbicides.


Comparing Microbes



BACTERIA

FUNGI

VIRUS

1.Movability.

2 Sensitivity.




3.Nutrition.




4.Respiration.







5. Growth.





6.Cells.






7.Reproduction.




8.Excretion.

Some can crawl using pili or even swim using flagella.

They are sensitive to changes in heat, light, nutrients and chemicals.

They secrete enzymes into the food and absorb the nutrients selected by the cell membrane.

Some bacteria use Oxygen just like other organisms. There are others that derive energy  using other chemicals such as su;phur and iron. Some bacteria are capable of fermenting sugar.

As a result of taking in food and building up the body matter the cells grow in size.


Bacteria  cells are surrounded by a cell wall and a cell membrane. They carry nuclear material though not enclosed by a membrane.(Prokaryotic cell)

Matured bacteria reproduce by binary fission.(Asexual)

Some undergo conjugation.(Sexual)

They excrete waste produced due to reactions inside the cell mainly by diffusion.

Most fungi are incapable of any independent movement except for the growth movements.

They grow towards an area rich in nutrients and moisture..



They generally live inside the food. Digestive enzymes are secreted out and the nutrients are absorbed.

Fermentation is the general mode of respiration. Sugar is broken down to to produce alcohol and carbon dioxide giving energy.





The thallus makes body matter and elongates often producing branches.


The mycelium is surrounded by a cell wall made of chitin. In some species they are divided into units by septa.


Fragmentation is the norm.




Mainly by osmosis.

They do not show any movement except for their ability to push their DNA into a living cell.

They can sense the exact living cell in which they can grow.


A Viruses gets food from the host cell for reproduction.


As there are no metabolic activities, (reactions) without a host cell, there is no respiration outside.




These cells also increase in size.



The genetic material is covered with a protein coat called a capsid.





A virus has to enter a living cell to make copies of itself.



They pass any waste produced into the host cell.


(image courtesy of Jeff Benn)

wpe38.jpg (6660 bytes)


Another example is the 'Fairy Ring Toadstool' (Its scientific name is Marasmius oreades). This, in contrast to the Clouded Agaric, grows on grassy expanses such as lawns and golf courses. The fungus can be traced by the rings of dark green grass, with the mushrooms fruiting on the outer edge of the ring. The growth of the ring can be traced year on year. If there are no barriers, rings may grow outwards at up to 20 cm per year. This is a fungus which fruits early in the year, in the spring.




Living things.

posted Feb 15, 2016, 12:04 PM by Upali Salpadoru


Living Things


Ferns and Chicks are easy to recognise as living things while stones and ice are dead as door nails. But when it comes to micro organisms, the task is not that simple.

here is a lady by the name Mrs.C.Green, who can help you.

Let us take the letters of her name.

 M =  Movement.

Non living things too can move. Clouds can move, Planes can fly. These things do not move on their own will. Clouds are pushed by the wind a plane has to be piloted

In the case of plants although the movements are limited due to the presence of cell walls they show growth movements. Normal shoots grow towards light while the roots grow towards water. In certain climbers the tendrils coil round a stick.


R = Respiration.


This is a process similar to burning. Inside the cells, the food is burnt in a special way, at a low temperature,  to release energy. Normally sugar is burnt using oxygen producing carbon dioxide and water.


S= Sensitivity.

The organisms can respond to changes in the environment.

A TV can be sensitive to a remote control but this is not the same as responding to a stimulus. TV cannot decide what it has to do. It can only perform a task that has been programmed.

In the case of a dog if you hit it we cannot say how it will respond. It may bark, run away or bite you. It can decide what’s to be done.


C = Cells.

These are the building blocks of living things. Every cell of an organism has a copy of the DNA code of that individual.


G = Growth.

Growth here does not mean mere increase in size. Crystals can grow , which is due to the deposition of matter on the surface. Growth in living things result in the formation of body matter which occurs within the calls. When cells attain a certain size they divide by a process called cell division. Growth is the result of increasing the number of cells.


R= Respiration.

This is the method of obtaining energy by the organisms. The food such as glucose is oxidised at a low temperature with the help of enzymes.

There are two modes of respiration. Aerobic and anaerobic.  In anaerobic respiration other substances are used instead of oxygen.


E = Excretion.

This is the process of removing waste matter formed inside the cells. They include mainly urine (Or ammonia) , water and carbon dioxide in the case of animals.


N= Nutrition.

Taking in of substances for the purpose of growth and respiration is nutrition. Plants take in CO2 from the air water and mineral salts from the soil and synthesize food using light energy. (Photosynthesis) Animals fungi and most bacterie obtain food from other living organisms.

    


Mysteries.

posted Jan 4, 2016, 12:02 PM by Upali Salpadoru   [ updated Jan 6, 2016, 11:57 AM ]




An  octopus sat on her eggs for years.

 


A hen broods on her eggs for 21 days. 

Can you imagine any creature sitting on her eggs for 53 months; 1590 days? 

An octopus mother had just done that from may 2007 September 2011.  Bruce Robinson and his team has observed this by sending a submersible several times .  They found Graneledone boreopacifica clinging on to a cluster of about 160 olive sized eggs at a depth of 1400 m. in California’s Monterey Bay.

According to them she may never had eaten or moved out during this period. This is a mystery for the biologists. They think that the near freezing temperature may have ceased all metabolic activity.


More about Octopuses.


“ With its eight prehensile arms lined with suckers, camera-like eyes, elaborate repertoire of camouflage tricks and spooky intelligence, the octopus is like no other creature on Earth.

The independent computing power of the arms, which can execute cognitive tasks even when dismembered, have made octopuses an object of study for neurobiologists.   Alison Abbott   Nature.

Oct 2.jpgCourtsey: Marine Education Society of Australia.



Anatomy

An Octopus has 8 arms. Three hearts. A tiny piece of bone as skull and a rudiment of a shell.

Arms contain suckers of varying size all along. These are capable of grasping, feeling and tasting,

Each is capable of exerting a force of about 150 N.

At the base of an arm is the mouth. Food can pass from sucker to sucker.

It can change the colour and texture of the skin in a split second.

What colour is blood? Red ? The blood of an octopus is blue.

They use ' jet propulsion' for movement in water.


Behaviour

They often escape from aquariums as they are capable of creeping through small holes.

They seem to be as intelligent as some mammals.

They remember people. If they don’t like a person it can eject a stream of water from the funnel at the person.



Reference:
The Soul of an Octopus. by Sy Montgomery.


Digestive system

posted Dec 19, 2015, 12:56 PM by Upali Salpadoru   [ updated Dec 21, 2015, 1:06 AM ]


ali tract.jpg












The first attack, on whatever we eat, comes at the very start in the oral cavity / buccal cavity.

The 32 teeth will not spare a single hard morsel of food.



The digestive Process.

Buccal cavity.(Mouth)


Image

Name

Function



Teeth.jpg

1.Incisors




2.Canines.





3.Molars

1. Cut and chop.



2.Tear the food to shreds.


 


 3.Chewing and grinding.



Digestion is a two prong attack.

1. Physical - Pulverizes the food to obtain a bigger surface area.    

2. Chemical- Converts the insoluble food to soluble forms.

(Bigger molecules are broken down to smaller ones.) Example:- Starch to Glucose.     

These changes occur without the reagents (enzynes) being used up.  

So Enzymes are organic catalysts.


Name  

Image

Function

Remarks

Tongue


Tongue 2.jpg

“With a bitter back and sweet centre,

sour taste on the sides linger.

The tip takes the latest trend,

in licking a salty sweet blend.

Know how the buddies in the tongue,

taste the food of old and the young.”    

 This taste map, accepted earlier, does not seem to be right.

  Sensation of taste is not only from the tongue; the nose plays an important role.

Recognizes the food, mixes with saliva.

and is pushed to pharynx as  boluses.         

 

Salivary glands.

 





Deliver saliva. Saliva softens and lubricates the food . Physical change.

Saliva contains the enzyme Ptyalin (Amylase) that can chemically react with starch.

It also has a germicide, lysozyme.


1.5 L./day.

Nelly.jpg

Name

Image

Function / Properties.

Remarks

Esophagus Gullet.


Eso.jpg

A well lubricated tube.

Food is transported by the rhythmic contraction and relaxation of sphincter muscles.(circular muscles


Pushing the food is a reflex action. (in voluntary)

Chewing and gulping down are voluntary actions. (You can control them)  


Method of pushing food is peristalsis. This is involuntary.


Length= 25 to 30 cm.

Width 1.5 to 2 cm.

Epiglottis


This guards the trachea. (Windpipe)

If an attempt is made to speak while you swallow, epiglottis cannot function. 

One can get choked.

Stomach


Dilated part of the tract.



stomach 2.jpg


stomach 3.jpg

Three types of cells secrete gastric juice and mucus.


Only water, salts, alcohol and a little glucose are absorbed here.


Secretions

Pepsinogen-Reacts with HCl and forms Pepsin.


Pepsin acts on proteins.


Cardiac sphincters control the inflow while the Pyloric sphincters release the chyme in an orderly manner.

Capacity =  4 to 5 litres

Time:- Approximately 2 hrs.

This will vary according to the food and the emotional conditions of the person.




. Small Intestine. 1. Duodenum. 2. Jejunum, 3. Ileum.


  1. Duodenum

duodenum.jpg

This is is the first part of the small intestine.

Length;= 25 cm.

There are 2 glands pouring their secretions into the duodenum.

1. Pancreas:-  Gives Pancreatic juice. This contains 3 enzymes and bicarbonate ions.

Rate of flow 1.5 liters /day.

2. Gall bladder:- Releases bile which has been produced in the liver.

The alkaline salts in the bile emulsifies the lipids.

Bile is a greenish coloured liquid. The colour is due to the presence of degenerating matter from haemoglobin.

Capacity = approximately 30.cm3 .

                           Rate:-1 Litre//day.

2. Jejunum

Midsection of the small intestine, connecting the duodenum to the ileum.

Length about 2.5 m.

Contains villi.

3. Ileum


Highly enlarged view of the wall.

This is mainly responsible for the absorption;

The area of absorption is increased by a thousand fold due to tiny velvety like projections called villi.

The epithelial cells in these possess microvilli.

Crypt consists of younger cells which would replace the mature ones as they are discarded after a few days.


Length about 3.5m.

Absorption is not always passive. Often they have to be pushed against diffusion gradients. This has been termed active absorption

Absorption

Glucose and amino acids straight away pass on to the blood capillaries in the villi. These capillaries form the hepatic portal vein which takes the food into the liver. The liver may store or alter any of the digestive products. Some of the fatty acids and glycerol may enter the blood capillaries, but a large proportion enters the epithelium to be converted back to lipids.  These products then pass on to lacteals. The fluid in these joins the lymphatic system which will join the blood stream later.


Large Intestine.   (Colon)

Colon.jpg

Absorbs the water.

Some salts may also be absorbed here.

Usually there are beneficial bacteria which form vitamin B and K.

Rectum

The cellulose and vegetable fibres along with dead cells and the undigested matter form the faeces. or stool.

   
 Appendix This was earlier thought to be a vestgial organ. Now some researchers believe that it is a safe house for useful bacteria.


  Bio U test.jpg

1.0   Multiple Choice Questions..

1.1   Which answer describes the digestion in a meaningful manner.
        a. A physical change.  b. A chemical change. c. Converting food into a more nutritious form.
        d. Converting food into a form that can be absorbed by the blood.
1.2   In which organ does the chemical process of digestion start?
        a. Mouth.    b.  Gullet.   c. Stomach.  d. Small intestine.
1.3   Name the force that moves food along the food canal.
        a. Force of gravity. b. Peristalsis.  c Anti-peristalsis.  d. Support force.
1.4   Name the part that prevents food entering the windpipe.
        a. Tongue.  b. Epiglottis. c. Glottis. d. Larynx.
1.5   In which part of the tract, the chyme is most acidic.
        a.Mouth.  b. Esophagus. c. Stomach. d. Small intestine.

2.0 Supply short answers.

2.1  What is the advantage of having villi in the ileum, and how does it help?
2.2  What gastric juice neutralizes the Hydrochloric acid added to food.
2.3  What helps the release of partly digested food from the stomach? 
2.4  Why are the enzymes considered as catalysts?
2.5  Why does the stamach wall has 3 types of muscles?


3.0

Question

Part A

Part B


Q 3.2.jpg

3.1 Name the numbered parts.



3.2 

What enzymes are

present in the numbered regions.

5.

2 to 3.

3.3 

What is the function of ....

3.

2.


4.0   Fill in the blank spaces in this table.


Gland

A

Juice secreted

B

Enzymes present

C

Reaction on food

4.1 Salivary

4.2Gastric glands


4.3 Intestinal glands

Not required.




For the answers please CLICK :-  Answers-bio.

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