Significance of pentose phosphate pathway:
1) HMP shunt is associated with the generation of two important products,NADPH and pentose sugars, which play a vital role in anabolic reactions.
2) Coenzyme NADPH generated is used for reductive biosynthesis and counter damaging the effects of oxygen free radicals
3) Ribose 5 phosphate and its derivatives are used in the synthesis of DNA, RNA, ATP, NAD+, FAD and coenzyme A.
4) Erythrose is used for synthesis of anthocyanin, lignin and other aromatic compounds.
5) It is characterized by the production of CO₂ and it is used for Carbon fixation in photosynthesis

There are 3 types of carrier proteins classified on the basis of handling of molecules and direction of transport in facilitated diffusion. They are,
i) Uniport
ii) Symport
iii) Antiport.
i) Uniport: In this molecule of a single type move across a membrane independent of other molecules in one direction
ii) symport or co-transport: The term symport is used to denote an integral membrane protein that simultaneously transports two types of molecules across the membrane in the same direction.
iii) Antiport or Counter Transport: An antiport is an integral membrane transport protein that simultaneously transports two different molecules, in opposite directions, across the membrane.

Elimination of nitrogenous waste and salt and water balance are performed by a well developed excretory system. It consists of a pair of kidneys, ureters, urinary bladder and cloaca. Kidneys are dark red, long, flat organs situated on either sides of the vertebral column in the body cavity. Kidneys are Mesonephric. Several nephrons are found in each kidney. They separate nitrogenous waste from the blood and excrete urea, so frogs are called ureotelic organisms. A pair of ureters emerges from the kidneys and opens into the cloaca. A thin walled unpaired urinary bladder is present ventral to the rectum and opens into the cloaca.

1) Plants follow different pathways in response to environment or phases of life to form different kinds of structures. This ability is called plasticity.
2) Example: Heterophylly in cotton and coriander. In such plants, the leaves of the juvenile plant are different in shape from those in mature plants.
3) On the other hand, the difference in shapes of leaves produced in air and those produced in water in buttercup also represent the heterophyllous development due to the environment. This phenomenon ofheterophylly is an example of plasticity.

(i) The log A will last longer for the merchant.
(ii) In any tree the outer part of the wood is pale in colour, is called Sap Wood, while the centre part is darker called Heart Wood.
(iii) Due to the presence of tyloses and their contents, the heartwood becomes coloured, dead and the hardest part of the wood.
(iv) The heartwood is more durable and more resistant to the attack of microorganisms and insects.

Reason : None of these functions can be carried out by RBC. Red Blood Cells (RBC) contain haemoglobin pigment and play a major role in transport of respiratory gases.

a. Sea anemone
b. Radial symmetry
c. Not cephalized
d. Two
e. A single
f. Yes

Plasmodesmata act as a channel between the protoplasm of adjacent cells through which many substances pass through.

Classification of enzymes:
Enzymes are classified into six groups based on their mode of action.

Yes, the shape of chloroplast is unique for algae.

1. Malfunctioning of the kidneys can lead to accumalation of urea and other toxic substances, leading to kidney failure. In such patients toxic urea can be removed from the blood by a process called haemodlalysis
2. A dialysing machine or an artificial kidney is connected to the patient's body. A dialysing machine consists of a long cellulose tube surrounded by the dialysing fluid in a water bath.
3. The patient's blood is drawn from a convenient artery and pumped into the dialysing unit after adding an anticoagulant like heparin.
4. The tiny pores in the dialysis tube allows small molecules such as glucose, salts and urea to enter into the water bath, whereas blood cells and protein molecules do not enter these pores.
5. This stage is similar to the filtration process in the glomerulus. The dialysing liquid in the water bath consists of solution of salt and sugar in correct proportion in order to prevent loss of glucose and essential salts from the blood.
6. The cleared blood is then llutnQed back. to the. body through a vein.

No. a defoliated plant will not respond to photoperiodic cycle because the hormonal substance responsible for flowering is found in the leaves of the plant.

1. Dense regular connective tissues primarily contain collagen fibres in rows. between many parallel bundles of tissues and a few elastic fibres. The major cell type is fibroblast. It attaches muscles and bones and withstands great tensile stress when pulling force is applied in one direction. This connective tissue is present in tendons, that attach skeletal muscles to bones and ligaments attach one bone to another.
2. Dense irregular connective tissues have bundles of thick collagen fibres and fibroblasts which are arranged irregularly. The major cell type is the fibroblast. It is able to withstand tension exerted in many directions and provides structural strength. Some elastic fibres are also present. It is found in the skin as the leathery dermis and forms fibrous capsules of organs such as kidneys, bones cartilages, muscles, nerves and joints. Elastic connective tissue contains high proportion of elastic fibres. It allows recoil of tissues following stretching. It maintains the pulsatile flow of blood through the arteries and the passive recoil of lungs following inspiration. It is found in the walls of large arteries; ligaments associated with vertebral column and within the walls of the bronchial tubes.

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) Valvate: Margins of sepals or petals do not overlap but just touch each other. eg. Calyx in members of Malvaceae, Calotropis, Annona.
(ii) Twisted or convolute or contorted: One margin of each petal or sepal overlapping on the other petal. ego Petals of chinarose.
(iii) Imbricate: Sepals and petals irregularly overlap on each other; one member of the whorl is exterior, one interior and rest of the three having one margin exterior and the other interior. ego Cassia, Delonix. There are three types: (i) Ascendingly imbricate, (ii) Quincuncial, (iii) Vexillary.
(iv) Quincuncial: It is a type of imbricate aestivation in which two petals are external and two internal and one petal with one margin internal and the other margin external. ego Guava,calyx of Ipomoea, Catharanthus.
(v) Vexillary: Large posterior petals both margins overlap lateral petals. Lateral petals other margin overlaps anterior petals. eg. Pea, bean.

(i) C₄ cycle/Di - carboxylic acid pathway/ Di - carboxylation pathway is an adaptive mechanism.
(ii) It takes place in two phases. First phase takes place in stroma of mesophyll cells, where the CO₂ acceptor molecule 3-Carbon compound, phosphoenol pyruvate (PEP) to form 4-carbon oxalo acetic acid (OAA). The first product is a 4-carbon and so it is named as C₄ cycle. Oxalo acetic acid is a dicarboxylic acid and hence this cycle is also known as dicarboxylic acid pathway.
(iii) Carbondioxide fixation takes place in two places one in mesophyll and another in bundle sheath cell.
(iv) C₄ plants requires 5 ATP and 2NADPH + H⁺ to fix one molecule of CO₂.

Stage: I Mesophyll Cells

(i) Oxaloacetic acid (OAA) is converted into malic acid or aspartic acid and is transported to the bundle sheath cells through plasmodesmata.
Stage: II Bundle Sheath Cells
(i) Malic acid undergoes decarboxylation and produces a 3 carbon compound Pyruvic acid and CO₂.
(ii) The released CO₂ combines with RUBP and follows the calvin cycle and finally sugar is released to the phloem.
(iii) Pyruvic acid is transported to the mesophyll cells.

1. The thin squamous epithelial cells of the alveoli are composed of Type I and Type II cells.
2. Type I cells are very thin so that gases can diffuse rapidly through them.
3. Type II cells are thicker, synthesize and secrete a substance called Surfactant.
4. Surfactants are the thin non-cellular films made of protein and phospholipids covering the alveolar membrane.
5. The surfactant lowers the surface tension in the alveoli and prevents the lungs from collapsing.
6. It also prevents pulmonary oedema.
7. Premature Babies have low levels of surfactant in the alveoli may develop the newborn respiratory distress syndrome (NRDS) because the synthesis of surfactants begins only after the 25th week of gestation.

Structure of Mitochondria
1. It was first observed by A. Kolliker (1880), 1897, 1898 and named as mitochondria.
2.T hey are ovoid, rounded, rod shape and pleomorphic structures.

3. Mitochondrion consists of double membrane, the outer and inner membrane. The outer membrane is smooth, highly permeable to small molecules and it contains proteins called Porins, which form channels that allows free diffusion of molecules smaller than about 1000 daltons.
4. The inner membrane divides the mitochondrion into two compartments, outer chamber between two membranes and the inner chamber filled with matrix.
5. The inner membrane is convoluted (infoldings), called crista (plural: cristae). Cristae contain most of the enzymes for electron transport system.
6. Inner chamber of the mitochondrion is filled with proteinaceous material called mitochondrial matrix.
7. The inner membrane consists of stalked particles called elementary particles or Fernandez Moran particles, FI particles or Oxysomes. Each particle consists of a base, stem and a round head.
8. In the head ATP synthase is present for oxidative phosphorylation.
9. Inner membrane is impermeable to most ions, small molecules and maintains the proton gradient that drives oxidative phosphorylation Mitochondria contain 73% of proteins, 25-30% of lipids, 5-7 % of RNA, DNA (in traces) and enzymes (about 60 types).
10. Mitochondria are called Power house of a cell, as they produce energy rich ATP. All the enzymes of Kreb's cycle are found in the matrix except succinate dehydrogenase.
11. Mitochondria consist of circular DNA and 70S ribosome. They multiply by fission and replicates by strand displacement model. Because of the presence of DNA it is semi-autonomous organelle.

the nucleus is the organising centre of the cell. The information in the nucleus is contained within structures called chromosomes. These uniquely:
(i) Control activities of the cell.
(ii) Genetic information copied from cell to cell while the cell divides.
Hereditary characters are passed onto new individuals when gametic cells fuse together in sexual reproduction.

1.Inflorescence: Solitary and axillary cyme.
2.Flower: Flowers are large, greenish white, bracteate, ebracteolate, pedicellate, complete, heterochlamydeous, pentamerous, regular, actinomorphic, bisexual and hypogynous.

1. Inflorescence present in the axile of the nearest vegetative leaf.
2. Example: Hibiscus rosa-sinensis

The cells of sclerenchyma & tracheids become dead because they lack protoplasm

At the junction of the sclera and the cornea, is a channel called 'canal of schlemm' which continuously drains out the excess of aqueous humour in the human eye.

Acromegaly is due to excessive secretion of growth hormone in adults.
Symptoms of acromegaly are :
Over growth of hand bones, feet bones, jawbones malfunctioning of gonads, enlargement of viscera, tongue, lungs, heart, liver, spleen, and also endocrine glands like thyroid, adrenal etc.

It is an agro-based industry comprising three main components:
1. Cultivation of food plants for the silkworms.
2. Rearing of silkworms.
3. Reeling and spinning of silk.