Wednesday, October 28, 2020

2016 March | HSE +1 Exam | Botany - Answers

BOTANY (+1, 2016 MARCH)

ANSWERS

1.   Pasteur.

2.   Chlorophyll a.

3.   Rhodophyceae.

Flagella are not present in gamete and spores.

Red pigment r-phycoerythrin is present.

Stored food-floridean starch is present.

OR

Mycorrhiza- symbiotic association of algae and fungi.

Coralloid root-association of fungus with root.

4.   In active transport, transport proteins and energy are used.

In facilitated diffusion- transport protein only is used.

5.   Chlorosis, necrosis, delay flowering and inhibition of cell division.

6.   In amphibolic pathway, both catabolism and anabolism are involved.

In respiratory pathway, fat is breakdown into fatty acid and glycerol, fatty acid again splits into acetyl coA. If body require the synthesis of fat, acetyl coA withdraws from pathway and used in the synthesis of fat.

7.   In alcoholic fermentation, glucose undergoes incomplete oxidation in the presence of yeast and forms ethyl alcohol and CO2.

In lactic acid fermentation, glucose undergoes incomplete oxidation in the presence of lactobacillus and forms lactic acid.

8.   a) ABA

b) 1) GA3 increases the length of grapes stalks.

2)   Gibberellins elongate and improve the shape of fruits like apple.

3)   They delay senescence.

4)   GA3 is used to speed up the malting process in brewing industry.

9.   a) Kranz anatomy.

b) C4 plants are photosynthetically efficient than C3 plants because energy wasteful process photorespiration occurs in C3.

C4 plants can tolerate high temperature conditions than C3 plants.

10. a) Pachytene

b) 1)  Meiosis conserves the specific chromosome number of each species across generations in sexually reproducing organisms.

    2)  It results in reduction of chromosome number by half.

    3)  It increases the genetic variability from one generation to the next.

    4)  Variations are very important for the process of evolution.

11. a) Lilliaceae.

b) tepal six (3+3), often united into tube; valvate aestivation, stamen six, (3+3), tricarpellary, syncarpous, ovary superior, trilocular with many ovules; axile placentation.

12. It consists of lipid bilayer. They are arranged within the membrane with the polar head towards the outer sides and the hydrophobic tails towards the inner part. The peripheral proteins lie on the surface of membrane while the integral proteins are buried in the membrane.

13. Due to the activity of vascular cambium, girth of the stem increases. This results the breakdown of outer cortical and epidermis layers. So the new protective tissues are formed by another meristematic tissue called cork cambium or phellogen. Phellogen cuts off cells on both sides. The outer cells differentiate into cork or phellem while the inner cells differentiate into secondary cortex or phelloderm.

Phellogen, phellem, and phelloderm are collectively known as periderm.

OR

The cambial ring cut off new cells towards the inner (secondary xylem) and the outer sides (secondary phloem). The cambium is more active on the inner side than on the outer.

Amount of secondary xylem produced is more than secondary phloem. The primary and secondary phloems get gradually crushed due to the continued formation and accumulation of secondary xylem.

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