Why does milk appear white?

Why does milk appear white?

The normal milk ranges in colour from yellowish creamy white (cow milk) to creamy white (buffalo milk). The colour of milk is due to the combined effect of colloidal casein particles and the dispersed fat globules, both of which scatter light and carotene and to some extent xanthophylls, which impart a yellowish tint to milk. The intensity of yellow colour of cow milk is dependent upon factors such as breed, feed, size of fat globule present in milk, fat percentage.

Photorespiration

Pentose phosphate pathway-2

Active Absorption

Active Absorption

Movement of ions from the outer space of the cell to the inner space is generally against the concentration gradient and hence requires energy. This energy is obtained through metabolism either directly or indirectly. Various evidences indicate the active uptake of ions by carrier mechanism.

Sub Topics

• Carrier mechanism

• Ion traffic into the root

• Translocation of solutes

• Goldacre's Theory

• Cytochrome Pump Salt Respiration or Electron Transport Theory

Carrier mechanism

In carrier mechanism, activated ions combine with carrier proteins and from ion carrier complex. This complex moves across the membrane and reaches the inner space by the expenditure of energy.



Within the cytoplasm, the complex breaks to release the ions. The carrier moves out of the cytoplasm and is again ready to attach another ion to from a complex.

Ion traffic into the root

Mineral nutrients absorbed from the root has to be carried to the xylem. This transport follows two pathways namely apoplastic pathway and symplastic pathway.

In apoplastic pathway, mineral nutrients along with water moves from cell to cell through spaces between cell wall by diffusion. The ions, which enter the cell wall of the epidermis move across cell wall of cortex, cytoplasm of endodermis, cell walls of pericycle and finally reach the xylem.

In symplastic pathway, mineral nutrients entering the cytoplasm of the epidermis move across the cytoplasm of the cortex, endodermis of pericycle through plasmodesmata and finally reach the xylem.



Translocation of solutes

P.R. Stout and Dr. Hoagland have proved that mineral nutrients absorbed by the roots are translocated through the xylem vessel. Mineral salts dissolved in water moves up along the xylem vessel to be transported to all the parts of the plant body. Translocation is aided, by transpiration. As water is continuously lost by transpiration on the upper surfaces of the plant, it creates a transpirational pull, by which water along with mineral salts is pulled up along the xylem vessel.

Active absorption of energy can be achieved only by an input of energy. Following evidences show the involvement of metabolic energy in the absorption of mineral salts.

• Higher rate of respiration increases the salt accumulation inside the cell.

• Respiratory inhibitors check the process of salt uptake.

• By decreasing oxygen content in the medium, the salt absorption is also decreased.

These evidences indicate that salt absorption is directly connected with respiratory rate and energy level in the plant body, as active absorption requires utilization of energy.

Goldacre's Theory

Contractile proteins of membrane show their existence in folded or unfolded condition. Proteins in unfolded conditions are able to bind ions by free valencies exposed at membrane surface. Proteins in folded (contracted) condition release ions as free valencies of proteins get satisfied in folded condition. In this theory role of carrier has been emphasised with utilisation of ATP energy. This theory however has not been proved.



Diagrammatic Representation of the Goldacre Concept

Cytochrome Pump Salt Respiration or Electron Transport Theory

This theory was proposed by H. Lundegardh, who suggested that anions could be transported across the membrane by cytochrome system. Energy is supplied by direct oxidation of respiratory intermediates.



Diagrammatic representation of cytochrome pump hypothesis On salt absorption, anions (A^-) are actively absorbed via a cytochrome pump and cations (M⁺) are passively absorbed.

The rate of respiration, which is solely due to anion absorption, is called as anion respiration or salt respiration. The original rate of respiration (without anion respiration) can be observed in distilled water and is called ground respiration.

Total respiration (R₁) = Ground respiration (R_g) + Salt or anion respiration (R_a).

Krebs Cycle

Krebs Cycle

 After the glycolysis takes place in the cell's cytoplasm, the pyruvic acid molecules travel into the interior of the mitochondrion. Once the pyruvic acid is inside, carbon dioxide is enzymatically removed from each three-carbon pyruvic acid molecule to form acetic acid. The enzyme then combines the acetic acid with an enzyme, coenzyme A, to produce acetyl coenzyme A, also known as acetyl CoA.

Once acetyl CoA is formed, the Krebs cycle begins. The cycle is split into eight steps, each of which will be explained below.

Diagram of Krebs Cycle

Step 1

The acetic acid subunit of acetyl CoA is combined with oxaloacetate to form a molecule of citrate. The acetyl coenzyme A acts only as a transporter of acetic acid from one enzyme to another. After Step 1, the coenzyme is released by hydrolysis so that it may combine with another acetic acid molecule to begin the Krebs cycle again.

Step 2

The citric acid molecule undergoes an isomerization. A hydroxyl group and a hydrogen molecule are removed from the citrate structure in the form of water. The two carbons form a double bond until the water molecule is added back. Only now, the hydroxyl group and hydrogen molecule are reversed with respect to the original structure of the citrate molecule. Thus, isocitrate is formed.

Step 3

In this step, the isocitrate molecule is oxidized by a NAD molecule. The NAD molecule is reduced by the hydrogen atom and the hydroxyl group. The NAD binds with a hydrogen atom and carries off the other hydrogen atom leaving a carbonyl group. This structure is very unstable, so a molecule of CO₂ is released creating alpha-ketoglutarate.

Step 4

In this step, our friend, coenzyme A, returns to oxidize the alpha-ketoglutarate molecule. A molecule of NAD is reduced again to form NADH and leaves with another hydrogen. This instability causes a carbonyl group to be released as carbon dioxide and a thioester bond is formed in its place between the former alpha-ketoglutarate and coenzyme A to create a molecule of succinyl-coenzyme A complex.

Step 5

A water molecule sheds its hydrogen atoms to coenzyme A. Then, a free-floating phosphate group displaces coenzyme A and forms a bond with the succinyl complex. The phosphate is then transferred to a molecule of GDP to produce an energy molecule of GTP. It leaves behind a molecule of succinate.

Step 6

In this step, succinate is oxidized by a molecule of FAD (Flavin adenine dinucleotide). The FAD removes two hydrogen atoms from the succinate and forces a double bond to form between the two carbon atoms, thus creating fumarate.

Step 7

An enzyme adds water to the fumarate molecule to form malate. The malate is created by adding one hydrogen atom to a carbon atom and then adding a hydroxyl group to a carbon next to a terminal carbonyl group.

Step 8

In this final step, the malate molecule is oxidized by a NAD molecule. The carbon that carried the hydroxyl group is now converted into a carbonyl group. The end product is oxaloacetate which can then combine with acetyl-coenzyme A and begin the Krebs cycle all over again.

Summary

In summary, three major events occur during the Krebs cycle. One GTP (guanosine triphosphate) is produced which eventually donates a phosphate group to ADP to form one ATP; three molecules of NAD are reduced; and one molecule of FAD is reduced. Although one molecule of GTP leads to the production of one ATP, the production of the reduced NAD and FAD are far more significant in the cell's energy-generating process. This is because NADH and FADH₂ donate their electrons to an electron transport system that generates large amounts of energy by forming many molecules of ATP.

आप सभी को नवरात्रि व दशहरा की हार्दिक शुभकामनायें

आप सभी को नवरात्रि व दशहरा की हार्दिक शुभकामनायें

 

TIME TABLE FOR B.Sc. (Bio. & Math.)

BOTANY B.Sc. Part III 2012-13

 

 

 

VBS Purvanchal University ,Jaunpur

BOTANY

B.Sc. Part III

Paper- I MICROBIOLOGY AND PLANT PATHOLOGY AND PLANT PROTECTION

Unit-I

1. Introduction and significance Microbiology.

2. Methods of isolation and culturing of microbes.

3. An elementary study of immunology and serology.

4. Classification and distribution of microorganism in nature.

Unit-II

1. Decomposition of organic matter is soil, Role of microorganism in the

cycle of carbon and nitrogen.

2. Industrial utilization of microorganisms. Elementary idea of microbiology

of milk, alcohol, antibiotics, vitamins and organic acids.

Unit-III Plant Pathology

1. History and scope of plant pathology.

2. General symptoms of fungal, bacterial and viral diseases.

3. Mode of infection, disease resistance and control.

Unit-IV

1. A study of following diseases with reference to symptoms, causal

organisms, diseases cycle and control. Late blight of Potato, Powdary

mildew of pea. Tikka disease of ground nut, yellow vein mosaic of bhindi,

Bacterial blight of rice, Red rot of sugar cave, Little leaf.

Practical

1. Isolation of microorganisms from natural resources.

2. Staining and measurement of microbial cells.

3. Study of host parasite relationship of plant diseases listed above.

PAPER-II ECOLOGY, ENVIRONMENTAL POLLUTION, CONSERVATION

AND FORESTRY:

Unit-I

1. Basis principles of ecology

2. Ecological factors: climate, edaphic, biotic and topographic factors.

3. Biotic communities and developments of vegetation, Halophytes and

Epiphytes.

Unit-II Ecosystem Ecology

1. Ecosystem with reference to grass land, forest and pond, idea of food

chain, pyramids of number and biomass.

2. Energy flow and productivity.

3. Biogeochemical cycles, C.N.P. and Hydrological cycle.

Unit-III Atmospheric Pollution

1. Brief idea of Lithosphere, hydrosphere and atmosphere.

2. Brief idea of biospheric pollution causes and effects, water pollution air

pollution, noise pollution.

3. Techniques and devices to control different types of pollutions.

Unit-IV Conservation

1. Conservation of soil and renewable resources.

2. Major forest types of India and their characteristic features.

3. Afforestation, Agro forestry ad social forestry in India.

Practical

Study of communities by quadrat method to workout frequency, density and

abundance.

Biomass estimation

Determination of physical and chemical characteristics of water and air.

Determination of sound levels at different places.

Study of acute symptoms in the plants growing along road sides.

PAPER-III PLANT ANATOMY & EMBRYOLOGY

Unit-I Plant Anatomy

1. Meristems.

2. Leaf anatomy.

3. Origin, structure and function of the vascular cambium including

anamolous behaviour.

4. Structure of Xylem and Phloem.

Unit-II

1. Cork cambium activity and its products.

2. Structure and characteristics of wood.

Unit-III Embryology

1. Structure of anther, microspogenesis and development of the male

gametophyte.

2. Structure of ovule, megasporogenesis and development of the female

gametophyte with particular reference to polygonum type.

Unit-IV

1. Fertilization, Endosperm and embryo development (onagrad type)

2. Apomixis, Polyembryony and Parthenocarpy.

PRACTICAL

1. Plant Anatomy, Anatomy of normal Dicot and Monocot roots and stems.

Anatomy of anamolous structure of stems of: Bignonia, Nyctanthes,

Achyranthes, Boerhaavia, Dracaena.

Paper-IV GENETIC ENGINEERING AND BIOTECHNIQUE

Unit-I

1. Elementary idea of gene synthesis.

2. Tools and techniques of recombinant DNA Technology, Vectors and

restriction enzymes.

3. General principles of gene cloning.

Unit-II

Characterization and analysis of clone, blotting techniques, PCR and it application

in DNA finger printing.

Application of genetic engineering to human welfare.

Transgenic plants and gene transfer technology in them.

Unit-III

Elementary idea of cell culture and its nutrient media, protoplast fusion and

hybridomas.

Practical application of tissues and organ culture.

Micropropogation : auxilary bud, short tip and meristem culture, factors affecting

the micropropogation.

Haploid production and their application.

Unit-IV

Spectrophotometry, Biosensor, Cryoelectron microscopy.

Application of X-ray crystellography and NMR (Biology) spectroscopy.

Separation techniques – chromatography.

Practicals

Preparation of various nutrient media for tissue culture.

Estimation of DNA, RNA from plant samples.

Demonstration of photographs of

DNA Structure and replication

Gene cloning

Cellus

Micropropagation

Demonstration of cellus formation from pith of carrot root.

Separation of cell constituents by using chromatography techniques.

Practical Examination Scheme Based on Paper I, II, III and IV

Microbiology experiment

Plant pathology (i) Host parasite relationship

Experiment on Ecology/Environmental Biology/Forestry.

Temporary mounting of a double stained section of material for anatomical

studies. Identification of material with suitable comments and sketch.

Embryo dissection.

Experiments on Genetic Engineering and instrumentation.

Identify and comment upon spots (1 to 8).

Viva-Voce.

Records

Collection/Model/Charts.

List of Holliday 202

PSP

Admission form

DownloaddAddmissiondform

PSP

 

Progressive study point………..Handia branch

Progressive study point………..Handia branch

Progressive study point………..Handia branch

Progressive study point………..Handia branch

.

   A Complete Solution for

B.Sc.(Bio. & Math.), TET, NET, PMT, TGT/PGT, SSC, Civil Services & Oneday Exam.

By Our Expert Allahabad team

(Dr. S.N. Pathak, Santosh Sir, Rajendra Sir, PS Sir, Ravi Sir,  & Other)

Main Branch: 304/60-A, Indrapuri Coloney, New Bairahana, Allahabad

Contact : 9415690511, 9452694602, 9335710342 santapoonu@gmail.com www.botanyias.blogspot.com