Time : 1 Hour 30 Minute

STD 10 Science Total Marks : 50

Biology Unit test.

SECTION A

* Select and write one most appropriate option out of the four options given for each of the [8]
questions

1. The diagram shows a vertical section through the heart.

What are the functions of the numbered blood vessels?
Carri Carri Carrie Carri
es es s es
bloo bloo blood blood
d to d to from from
body lung lungs body
s
(a) 1 2 3 4
(b) 1 3 4 2
(c) 2 4 3 1
(d) 3 1 4 2

(A) (a) (B) (b) (C) (c) (D) (d)

2. Which of the following statements are true?

i. Sudden action in response to something in the environment is called reflex action.
ii. Sensory neurons carry electrical signals from spinal cord to muscles in a reflex
action.
iii. Motor neurons carry signals from receptors to spinal cord in a reflex action.
iv. The pathway of transmitting signals from a receptor to a muscle is a reflex action.
(A) (i) and (ii). (B) (i) and (iii). (C) (i) and (iv). (D) (i), (ii) and (iii).

3. In a synapse, chemical signal is transmitted from:

(A) Axon to cell body (B) Cell body to axon (C) Dendrite end of (D) Axon end of one
of the same neuron. end of the same one neuron to axon neuron to dendrite
neuron. end of adjacent end of adjacent
neuron. neuron.

4. The factors responsible for the rapid spreading of bread mould on slices of bread are:

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 i. Presence of large number of spores in air.
ii. Presence of large number of thread-like branched hyphae.
iii. Presence of moisture and nutrients.
iv. Formation of round shaped sporangia.
(A) (i) and (iii). (B) (ii) and (iv). (C) (i) and (ii). (D) (iii) and (iv).

5. A student while observing an embryo of a pea seed in the laboratory listed various parts
of the embryo as given below: Testa, Tegmen, Radicle, Plumule, Micropyle, Cotyledon.
On examining the list the teacher remarked that only three parts are correct. Select
three correct parts from the above list:
(A) Testa, Radicle, (B) Tegmen, Radicle, (C) Cotyledon, (D) Radicle,
Cotyledon. Micropyle. Plumule, Testa. Cotyledon, Plumule.

6. Height of a plant is regulated by :

(A) DNA which is directly influenced by growth hormone.
(B) Genes which regulate the proteins directly.
(C) Growth hormones under the influence of the enzymes coded by a gene.
(D) Growth hormones directly under the influence a gene.

7. Heterozygous purple-flowered plant was crossed with homozygous recessive white-

flowered plant.The observed phenotype is:
(A) All purple (B) All white (C) 50% purple, 50% (D) 75%
white

8. In the given food chain, suppose the amount of energy at fourth trophic level is 5kJ, what
will be the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk
(A) 5kJ. (B) 50kJ. (C) 500kJ. (D) 5000kJ.

* Question consist of two statements - Assertion (A) and Reason (R). Answer these [2]
questions by selecting the appropriate option given below:
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true

9. For two statements are given- one labelled Assertion (A) and the other labelled Reason
(R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as
given below:
a. Both A and R are true and R is correct explanation of the assertion.
b. Both A and R are true but R is not the correct explanation of the assertion.
c. A is true but R is false.
d. A is false but R is true.
Assertion: The movement of water and dissolved salts in xylem is always upwards.
Reason: The upward movement of water is due to low pressure created by transpiration.
10. For two statements are given- one labelled Assertion (A) and the other labelled Reason
(R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as
given below:

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 a. Both A and R are true and R is correct explanation of the assertion.
b. Both A and R are true but R is not the correct explanation of the assertion.
c. A is true but R is false.
d. A is false but R is true.
Assertion: A geneticist crossed two plants and got 50% tall and 50% dwarf progenies.
Reason: This cross follows Mendelian law as one of the parent plant might be
heterozygous.

SECTION B

* Answer the following question. : [ 2 marks each ] [10]

11. When a person breathes in air, the air enters into his body through an organ Ahaving two
holes B in it. The air then passes through pharynx and larynx and enters into a tube C.
The tube C divides into two smaller tubes D at its lower end. The two smaller tubes are
attached to two respiratory organs E. Each smaller tube divides inside the organs E to
form a large number of still smaller tubes called F. The smallest tubes F have air-sacs G at
their ends in which gaseous exchange takes place in the body of the person. What are A,
B, C, D, E, F and G?
12. a. Name one gustatory receptor and one olfactory receptor present in human
beings.
b. Write a and b in the given flow chart of neuron through which information travels
as an electrical impulse.

13. List four advantages of vegetative propagation.

14. ‘‘The chromosomal number of the sexually producing parents and their offspring is the
same.’’ Justify this statement.
15. Give reason to justify the following:
a. The existence of decomposers is essential in a biosphere.
b. Flow of energy in a food chain is unidirectional.

SECTION C

* Answer short answer questions. [3 Mark each] [12]

16. Draw a labelled diagram of stomata. List two functions of stomata.

17. Why is chemical communication better than electrical impulses as a means of
communication between cells in a multi-cellular organism?
18. List four methods of contraception used by humans.
Justify the following statement: ‘‘The use of contraceptive methods has a direct effect on
the health and prosperity of a family.’
19. If we cross pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant
will get pea plants of F1 generation. If we now self-cross the pea plant of F1 generation,
then we obtain pea plants of F2 generation.

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 i. What do the plants of F1 generation look like?
ii. State the ratio of tall plants to dwarf plants in F2 generation.
iii. State the type of plants not found F1 in generation but appeared in F2 generation,
mentioning the reason for the same.

SECTION D

* Long answer questions [5 Mark each] [10]

20. a. Mention any two components of blood.

b. Trace the movement of oxygenated blood in the body.
c. Write the function of valves present in between atria and ventricles.
d. Write one structural difference between the composition of artery and veins.
21. a. Draw a sectional view of human female reproductive system and label the part
where:
i. Eggs develop.
ii. Fertilisation take place.
iii. Fertilised egg gets implanted.
b. Describe, in brief, the changes the uterus undergoes:
i. To receive the zygote.
ii. If zygote is not formed.

SECTION E

* case - based/data -based questions [8]

22. Nastic movements in plants are not directional movements. They are not dependent on the
stimulus and are growth independent. For example, the leaves of a touch me not plant
(Mimosa pudica), fold up immediately when touched. These kinds of changes occur due to
the changes in the amount of water in the leaves. Depending on the quantity, they either
swell up or shrink. Plant hormones or phytohormones are responsible for the control and
coordination of plants. There are different types of hormones, which affect the growth of a
plant. Phytohormones are chemical compounds which are released by stimulated cells. These
hormones are diffused around the plant cells. They have a role in the cell division, cell
enlargement, cell differentiation, fruit growth, falling of leaves, ripening of fruits, ageing of
plants etc.
(i) Name the phenomenon called for the movement in growth of plants.
(ii) What do you mean by nastic movement?
(iii) What are the different types of harmonies of plants?
or
(iv) The plant harmone help in the cell growth at the shoot tips by elongating the cells and
help in the growth process is :
23. Read the following and answer any three questions from (i) to (iv).
In human, the allele for brown eyes (B) is dominant over that for blue eyes (b). A brown
eyed woman marries a blue eyed man, and they have six children. Four of the children
are brown eyed and two of them are blue eyed.
i. What is the genotype of blue eyed offspring?
 ii. What is the woman's genotype?

iii. a) The ovum, produced by the mother carries the gene regarding eye colour?
b) What is the gene carried by of the man's spenn regarding the eye colour?

OR

iv. The ratio of brown eyed children to blue eyed children in this family is 2 : I, which
deviates from typical phenotypic ratios for monohybrid inheritance. What might
be the reason?

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