Biology today

MTMTBIOLOGY TODAYBIOLOGY TODAY || march ‘16march ‘16 3535

Assertion & reason

In each of the following questions, a statement of assertion (a)
is given and a corresponding statement of reason (r) is
given just below it. Of the statements, mark the correct
answer as :
(a) if both a and r are true and r is the correct explanation
of a
(b) if both a and r are true but r is not the correct explanation
of a
(c) if a is true but r is false
(d) if both a and r are false.

24. Assertion : hybrid seeds must be produced every

year to obtain maximum advantage of heterosis.
Reason : heterosis is lost by inbreeding.

25. Assertion : Virus-free plants can be produced from
    virus infected plants by means of meristem tissue
    culture.
    Reason : The virus fails to grow during the growth

of host tissue in the artificial medium.

26. Assertion : Somaclonal variations occur in tissue culture
    processes.
    Reason : Variations cannot occur in nature.


27. Assertion : Breeding, weeding, feeding and heeding
    are essential methods for livestock production.
    Reason : Livestock management deals with processes
    and systems that increase yield and improve quality of
    products.


28. Assertion : In mOET, hormones with progesterone-
    like activity are given to the cow for inducing super-
    ovulation.
    Reason : after mating, the embryos at 4 - 6 celled stage
    are recovered and transferred to surrogate mothers.

figure Based Questions

29. Study the following flow chart and answer the following
    questions.

Cow is administered with(1)hormone

(2)

6-8 eggs per cycle are derived

Artificially inseminated

Fertili ed eggs at 8-32 cells stages are recovereds

(3)

(a) Identify labels 1, 2 and 3.

(b) Describe briefly how the process is helpful in food

production.

30. refer to the given figure and answer the following
    questions.

Cell wall

Nucleus

Vacuole Plasmalemma

Plant cell

Parent I

PEG

Parent II

C

D

E

A

B

(a) Identify a, B, c, D and E in the given figure.

(b) Name any two plants obtained from the procedure

described in the above figure.

chAPTer-10 : mIcrOBes In humAn weLfAre

multiple choice Questions

1. Study the following statements regarding lactic acid
   bacteria (LaB) which are used to convert milk into curd.
   (i) They produce acids that coagulate and partially digest
   the milk proteins.
   (ii) a small amount of curd added to the fresh milk as an
   inoculum contains millions of LaB, which at suitable
   temperature, multiply and convert milk into curd.
   (iii) conversion of milk into curd improves its nutritional
   quality by increasing vitamin B 12.
   (iv) LaB may result in acidity in the stomach of human
   beings.
   Which of the given statements are correct?
   (a) (i) and (ii) (b) (ii) and (iii)
   (c) (i), (ii) and (iii) (d) (i), (ii), (iii) and (iv)