Phytochrome is a bluish biliprotein pigment responsible for perception of light in photo physiological process. It was named by Butler et a1 and exists in two inter convertible forms - P_r (red . r light absorbing pigment)' and (P_fr - far red light absorbing pigment).

60 years old - Age of the Tree.
Reason:
(i) In the cross section of the tree trunk, the lighter (spring wood) and darker (Autumn wood) rings appear in the form of concentric circles.
(ii) One spring wood circle and one autumn wood circle together constitute an annual ring.
(iii) Thus one dark and one light ring would have been formed every year.
(iv) 60 dark and 60 light rings indicate the age of the tree as 60 years.

Human hair is made of protein. The more the distance between the sulphur atoms, the more the proteins bend; the more the hair curls.

1. Marginal (i) It is with the placentae along the margin of a unicarpellate ovary. (ii) Eg: Fabaceae.	4. Axile (i) The placentae arises from the column in a compound ovary with septa. (ii) Eg: Hibiscus, tomato lemon
2. Superficial (i) Ovules arise from the surface of the septa. (ii) Eg: Nymphaeaceae	5. Parietal (i) It is the placentae on the ovary walls or upon intruding partitions of a unilocular, compound Ovary. (ii) Eg: Mustard, Argemone, cucumber.
3. Free-central (i) It is with the placentae along the column in a compound ovary without septa. (ii) Eg: Caryophyllaceae, Dianthus, Primrose	6. Basal (i) It is the placenta at the base of the ovary. (ii) Eg: Sunflower(Asteraceae) Marigold

1. Among these 'Phycomycetes' include fungal species of Oomycetes, Chytridiomycetes and Zygomycetes which are considered as lower fungi indicatlng algal origin of fungi.
2. Constantine J. Alexopoulos and Charles W. Mims in the year 1979 proposed the classification of fungi in the book entitled 'Introductory Mycology'.
3. They classified fungi into three divisions namely Gymnomycota, Mastigomycota and Amastigomycota. There are 8 subdivisions, 11 classes, 1 form class and 3 form subclasses in the classification proposed by them.
4. The salient features of some of the classes - Oomycetes, Zygomycetes, Ascomycetes, Basidiomycetes and Form class Deuteromycetes are discussed below.
5. With the advent of molecular methods, fungi traditionally studied by mycologists at present fall into 3 kingdom of Eukaryota.
6. The Eumycota include only fungi and protozoa and chromista which accommodates (myxomycetes, Oomycetes) formerly placed in fungi.

Physiological effect:
1) Cytokinin promotes cell division in the presence of auxin (IAA).
2) Induces cell enlargement associated with IAA and gibberellins
3) Cytokinin can break the dormancy of certain light-sensitive seeds like tobacco and induces seed germination.
4) Cytokinin promotes the growth of lateral bud in the presence of apical bud.
5) Application of cytokinin delays the process of aging by nutrient mobilization.
6) It is known as Richmond Lang effect.
7) Cytokinin
(i) increases rate protein synthesis
(ii) induces the formation of inter-fascicular cambium
(iii) overcomes apical dominance
(iv) induces formation of new leaves, chloroplast and lateral shoots.
8) Plants accumulate solutes very actively with the help of cytokinins.

(i) Nitrogen fixation process requires Nitrogenase enzyme complex, Minerals (Mo, Fe and S), anaerobic condition, ATP, electron and glucose 6 phosphate as H⁺ donor.
(ii) Nitrogenase enzyme is active only in anaerobic condition.
(iii) To create this anaerobic condition a pigment known as leghaemoglobin is synthesized in the nodules which acts as oxygen scavenger and removes the oxygen.

Melanocytes are the cells responsible for-producing the skin pigment, melanin, which gives skin its colour and protects it from the sun's UV rays.

Nutritive values of fishes:
1. Fishes farm a rich source of protein food and provide a good staple food to tide over the nutritional needs of man.
2. Fish species such as sardines, mackerel, tuna, herrings have high amino acids concentrations particularly histidine which is responsible for the meaty flavor of the flesh.
3. It is rich in fat such as omega 3 fatty acids. Minerals such as calcium, magnesium, phosphorus, potassium, iron, manganese, iodine and copper.
4. Some of the by-products are fish oil, fish meal, Isinglass.

1. The intestinal tract is more prone to bacterial, viral and parasitic worm infections.
2. This infection may cause inflammation of the inner lining of the colon called colitis.
3. The most common symptoms of colitis are rectal bleeding, abdominal cramps, and diarrhoea.

Yes. The antheridia produce biflagellate antherozoids which swim in thin film of water and reach the archegonium and fuse with the egg to form diploid Zygote. Hence they need water for completing their life cycle.

In Dicot stem, a few layers of sclerenchyma cells occur in patches outside the phloem in each vascular bundle. This patch of sclerenchyma is called Bundle cap or Hard bast.

Absence of light may lead to yellowish colour in plants. This is called etiolation. Light is important for photosynthesis.

Cell wall, Chloroplast

If too much of protein is consumed, the body cannot store the excess amino acids formed from the digestion of proteins. The liver breaks down the excess amino acids and produces urea. Blood in the hepatic vein has a high concentration of urea than the blood in other vessels namely, hepatic portal vein and hepatic artery.

1. Queen bee
2. Nuptial flight

Actin, myosin, meromyosin, tropomyosin and troponin.

Excessive stretch of cardiac atrial cells cause an increase in blood flow to the auricles of the heart and release ANF (Atrial natriuretic peptide or factor) which stimulates the increase Na⁺ excretion. Chemoreceptors like carotid bodies formed in the heart.

(i) Blood supply to kidney's is reduced.
(ii) Disposal of blood from the kidney's is reduced.
(iii) Auto regulation of micturition is disturbed.

(i) The head is small, triangular and lies at right angle to the longitudinal axis of the body.
(ii) The mouth parts are directed downwards so it is hypognathous.

Male frog attracts female frog by amplifying its croaking sound during breeding season.

Protostomia:
It includes the eumetazoans in which the embryonic blastopore develops into mouth.
Deuterostomia:
a. Eumetazoans in which anus is formed from or near the blastopore and the mouth is formed away from the blastopore.
b. They have a true coelom called enterocoel, formed from the archenteron.

1. In the multicarpellary ovary, when the carpels are free, it is called Apocarpous ovary. Eg: Polyalthia.
2. When the carpels are united, it is called Syncarpous ovary, Eg: Hibiscus.

Chemiosmotic theory was proposed by P. Mitchell (1966)
1) ATP synthesis is linked to development of proton gradient a cross the membranes thylakoids.
2) Electrons are transported along the membrane through PS I and PS II and connected by cytochrome b₆ - f complex.
3) Splitting of water molecule takes place inside of the membrane. Protons or H+ ions accumulate within the lumen of the thylakoid (1000-2000 times) Protons are less in number in strong. A proton gradient is formed.
4) These protons move across the membrane because the primary acceptor of electron is located outside the membrane.
5) The proton gradient is broken down due to the movement of proton across the membrane to the strong through CF₆ of the ATP synthase enzyme.
This proton motive force created in the lumen of thylakoid or chemical stimulates ATP generation.

The evolution of one oxygen molecule (4 electrons required) requires 8 quanta of light. C₃ plants utilise 3 ATPs and 2 NADPH + H⁺ to evolve one Oxygen molecule. To evolve 6 molecules of Oxygen 18 ATPs and 12 NADPH + H⁺ are utili sed. C₄ plants utilise 5 ATPs and 2 ADPH + H⁺ to evolve one oxygen molecule. To evolve 6 molecules of Oxygen, 30 ATPs and 12 NADPH + H⁺ are utilised.

Viruses are ultramicroscopic particles. They are smaller than bacteria and their diameter range from 20 to 300 nm (lnm = 1O-9'metres). Bacteriophage measures about 10 - 100 nm in size.
The size ofTMV is 300 x 20 nm.
Generally viruses are ofthree typesbased on shape and symmetry.
(i) Cuboid symmetry - ego Adenovirus, Herpes virus.
(ii) Helical symmetry - ego Influenza virus, TMV.
(iii) Complex or Atypical - ego Bacteriophage, Vaccinia virus

(i) A pair of adrenal glands are located at the anterior end of the kidneys. The outer region is the cortex and the inner region is the medulla.
(ii) The adrenal cortex has three distinct zones, they are 1. Zona glomerulosa 2. Zona fasciculata and 3. Zona reticularis.
(iii) Zona glomerulosa an outer thin layer constitutes about 15% of adrenal cortex and its secretes mineralocorticoids.
(iv) Zona fasiculata, the middle layer constitutes about 75% of adrenal cortex and secretes glucocorticoids such as cortisol, corticosterone and trace amounts of adrenal androgen and oestrogen.
(v) Zona Reticularis, an inner zone of adrenal cortex constitute about 10% of adrenal cortex and secretes the adrenal cortex androgen, trace amount of oestrogen and glycocorticoids.

(a) Some nephrons, have very long loop of Henle that run deep into the medulla are called juxtamedullary nephrons which aid in filtration from glomerulus.
(b) Podocytes are the filtration slits.
(c) Sphincters of urinary bladder are internal paired (involuntary) and external paired (Voluntary) control micturition.

Structure of human heart (L.S)

(i) Raymond de viessens in 1706 described the structure of heart.
(ii) Heart is made up of cardiac muscles.
(iii) Heart lies in the thoracic cavity (mediastinum) the space between the two lungs).
(iv) Its apex part is slightly tilted towards left.
(v) In adult human it weighs about 300g.
(vi) Its size is roughly equal to a closed fist of fore limb.
(vii) Heart is divisible into 4 chambers upper two small atria and lower two large ventricles.
(viii) Atria are separated by interauricular septum.
(ix) Ventricles are separated by inter ventricular septum.
(x) Due to the presence of these septae mixing of blood is prevented.
(xi) The walls of ventricles are thicker than atria.
(xi) The thickness of ventricles is due to the presence of papillary muscles.
(xii) The heart is enveloped by three layers an outer epicardium, middle myocardium and an inner endocardium.
(xiii) Over all the heart is enveloped by double membranous peritoneum called pericardium.
(xiv) The space between the two membranes is inter pericardial space filled by pericardial fluid.
(xv) Atria communicate with the ventricles by atrio ventricular apertures.
(i) Such apertures are guarded by atrio ventricular valves
(a) Tricuspid valve between right atrium and right ventricle
(b) Bicuspid or mitral valve between left atrium and left ventricle
(ii) Atrio-ventricular valves prevent the backward flow of blood from ventricles to atria.
(iii) Semi lunar valves in ventricles prevent the backward flow of blood into ventricles and direct the flow of blood into aorta and pulmonary artery in the left ventricle and right ventricle respectively.
(iv) Each semilunar valve is made up of three half moon shaped cusps.
(v) The middle myocardium shows an irregular muscular ridges called trabeculae corneae.
(vi) The modified trabeculae corneae are called chordae tendineae.
(vii) The chordae tendineae hold the valves in the heart under fixed position.
(viii) The chordae tendineae are attached to the lower end of the heart by papillary muscles.
(ix) The main venous blood vessels like Inferior vena cava and superior vena cava and a small coronary sinus collect deoxygenated blood from entire body and transport such deoxygenated into right atrium.
(x) Pulmonary veins from the lungs bring oxygenated to the left atrium.

Economic importance	Binomial	Useful part	Uses
Pulses	Cajanus cajan (Pigeon Pea) Phaseolus vulgaris (French bean)	Seeds	Sources of protein and starch of our food
Food plants	Sesbania grandiflora (agathi, vegetable humming bird) Cyamopsis tetragonoloba (cluster bean)	Leaves Tender fruits	Greens Vegetable
Oil Plants	Arachis hypogaea (Ground nut) Pongamia pinnata (Pungam)	Seeds Seeds	Oil extracted from the seeds is edible and used for cooking. Pongam oil has medicinal value and is used in the preparation of soap
Timber Plants	Dalbergia latifolia (rose wood) Pterocarpus santalinus (red sandalwood)	Timber	Timber is used for making furniture, cabinet articles and as building materials.
Medicinal Plants	Crotalaria albida Mucuna pruriens	Roots Seeds	Used as purgative Neurological remedy
Fibre Plants	Crotalaria juncea (sunhemp), Sesbania aegyptiaca (sesban)	Stem fibres (Bast)	Used for making ropes
Dye Plants	Indigofera tinctoria (Avuri)	Leaves	Indigo dye obtained from leaves is used to colour printing and in paints. Blue dye is obtained.
Green Manuring	Indigofera tinctoria Tephrosea purpurea Gliricidia sepium	Entire plant	Used as green manure because of the presence of nitrogen fixing bacteria in the lateral roots.
Ornamental Plants	Butea frondosa (Flame of the forest), Clitoria ternatea,  Lathyrus odoratus (Sweet pea) and Lupinus hirsutus (Lupin)	Entire plant	Grown as ornamental plants