Question Set A

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Questions:

2 Marks

Answer the following:
(a) Which hormone is responsible for the changes noticed in females at puberty?
(b) Dwarfism results due to deficiency of which hormone?
(c) Blood sugar level rises due to deficiency of which hormone?
(d) Iodine is necessary for the synthesis of which hormone?

Match the terms in Column (A) with those in Column (B)

Column (A)	Column (B)
(a) Trypsin	(i) Pancreas
(b) Amylase	(ii) Liver
(c) Bile	(iii) Gastric glands
(d) Pepsin	(iv) Saliva

Which pancreatic enzyme is effective in digesting proteins?

Suggest any four activities in daily life which are eco-friendly.

Multiple Choice Question

Which organelle of the cell is known as powerhouse?

(a)

ATP

(b)

Golgi bodies

(c)

Mitochondria

(d)

Nucleus

A zygote which has an X - chromosome inherited from the father will develop into a

(a)

boy

(b)

girl

(c)

X - chromosome does not determine the sex of a child

(d)

either boy or girl

Name the artificial method for the removal of liquid nitrogenous waste from body

(a)

Excretion

(b)

Dialysis

(c)

Urination

(d)

All of these

What is the puberty age in human males?

(a)

8-10

(b)

10-12

(c)

12-14

(d)

14-16

Analogous organs have

(a)

Same structure, same function

(b)

Different structure, different function

(c)

Same structure, different function

(d)

Same function, different structure

10.

Given below is the diagram showing the role of different types of neuron in the reflex action mechanism.
Choose the correct label for A, B and C from the table below by identifying different neurons.

(a)

A	B	C
Sensory	Relay	Motor

(b)

A	B	C
Motor	Sensory	Relay

(c)

A	B	C
Motor	Relay	Sensory

(d)

A	B	C
Sensory	Motor	Relay

11.

Plants use completely different process for excretion as compared to animals. Which one of the following processes is not followed by plants for excretion?

(a)

They can get rid of excess water by transpiration

(b)

They selectively filter toxic substances through their leaves

(c)

Waste products are stored as resins and gums in old xylem

(d)

They excrete waste substances into the soil around them

Case Study Questions

12.

Mendel crossed tall and dwarf pea plants to study the inheritance of one gene. He collected the seeds produced as a result of this cross and grew them to generate plants of the first hybrid generation which is called the first filial progeny or F₁: Mendel then self pollinated the tall F₁ plants and he obtained F₂ generation.
(i) In garden pea, round shape of seeds is dominant over wrinkled shape. A pea plant heterozygous for round shape of seed is selfed and 1600 seeds produced during the cross are subsequently germinated. How many seedlings would have non-parental phenotype?

(a) 1600	(b) 1200
(c) 400	(d) 800

(ii) If 'A' represents the dominant gene and 'a' represents its recessive allele, which of the following would be the most likely result in the first generation offspring when Aa is crossed with aa ?
(a) All will exhibit dominant phenotype.
(b) All will exhibit recessive phenotype.
(c) Dominant and recessive phenotypes will be 50% each.
(d) Dominant phenotype will be 75%.
(iii) Which of the following crosses will give tall and dwarf pea plants in same proportions?

A)	B)
c)	D)

(iv) What result Mendel would have got, if he self pollinated a homozygous tall F₂ plant?
(a) TT and Tt
(b) All Tt
(c) All TT
(d) All tt
(v) In plant, tall phenotype is dominant over dwarf phenotype, and the alleles are designated as T and t, respectively. Upon crossing one tall and one dwarf plant, total 250 plants were obtained, out of which 124 displayed tall phenotype and rest were dwarf. Thus, the genotype of the parent plants were
(a) TT x TT
(b) TT x tt
(c) Tt x Tt
d) Tt x tt.

Assertion and reason

13.

Assertion: The large intestine is the largest part of the alimentary canal.
Reason: Tiger has a shorter small intestine, than herbivores.
Codes
(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.

14.

Assertion (A) A geneticist crossed a pea plant having violet flowers with a pea plant having white flowers, he got all violet flowers in first generation.
Reason (R) White colour gene is not passed on to next generation.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true

3 Marks

15.

(i) Define ecosystem.
(ii) Autotrophs are at the first level of food chain. Give reason.
(iii) In a food chain of frogs, grass, insects and snakes assign trophic level of frogs. To which category of consumers do they belong to?

16.

Two major forces help in the transport of water in a plant. Force A is the driving force In the movement of water during the day, whereas force B helps the movement of water in a plant during the night or during the day when humidity is very high.
(i) Identify force A and force В.
(ii) Describe how each of these forces helps in the movement of water in plant?

5 Marks

17.

(i) Study the diagram given below and name the parts marked as A, B and C. What happens when B reaches C in the ovary? Mention its significance.

(ii) Write the post fertilisation changes that occur in a flower.

18.

‘DNA copies generated will be similar, but may not be completely identical to the original.’ Explain the statement with reference to the asexually reproducing organisms.

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Answers Key:

2 Marks

(a) Oestrogen
(b) Growth hormone
(c) Insulin
(d) Thyroxine

(a) (i), (b) (iv), (c) (ii), (d) (iii)

Pancreatic trypsin

(a) Walking and cycling for commute.
(b) Using jute/cloth shopping bag.
(c) using public transport.
(d) Switching off light/fans in unoccupied rooms.

Multiple Choice Question

(b)
girl

(b)
Dialysis

(d)
Same function, different structure

10.

(d)

A B C

Sensory Motor Relay

11.

(b)
They selectively filter toxic substances through their leaves

Case Study Questions

12.

(i) (c): Since this pea plant is heterozygous for round shape, its genotype would be Rr.

Phenotypically, the ratio will be 3 : 1, i.e., only rr seedlings will show wrinkled seed phenotype, rest will show round seed shape.
1200 \(\Rightarrow\) Round shape (RR, Rr)
400 \(\Rightarrow\) Wrinkled (rr)
(ii) (c): 'A'. represents the dominant gene and 'a' represents its recessive allele. The most likely result in the first generation offspring when Aa is crossed with aa is:

Hence, Aa: aa
1 : 1
(iii) (b): This is an example of a test cross in which a cross is made between heterozygous tall and homozygous dwarf individuals and tall and dwarf plants are obtained in same proportion.

(iv) (c): Self pollination of homozygous tall F₂plant (TT) will give rise to all individuals of genotype TT.
(v) (d)

Assertion and reason

13.

(d): The small intestine is the largest part of the alimentary canal. It is about 6.5 metres long in an adult man. Though small intestine is very long, it is called small intestine because it is very narrow. The length of small intestine differs in various animals depending on the type of food they eat. Meat is a food which is easier to digest. So, tiger which is a carnivorous animal has a shorter small intestine than herbivores.

14.

(c) A is true, but R is false. R can be corrected as White colour flower shows its trait in the second generation, after the selfing of two plants of the first generation.

3 Marks

15.

(i) Ecosystem is the structural and functional unit of biosphere and is a stable ecological unit where regular input of energy and circulation of matter takes place
(ii) Autotrophs are the producers, i.e. green plants. They are the only ones that can make use of solar radiation for photosynthesis and prepare food materials for themselves and others.
(iii) In a food chain of frogs, grass, insects and snakes, frogs occupy third trophic level.
Grass → Insects → Frogs → Snakes
They belongs to the category of secondary consumers.

16.

(i) Force A: transpirational pull
Force B: root pressure
(ii) Evaporation of water from leaves of a plant is called transpiration. This results in reduced pressure at the top of the xylem vessels and creates a suction which pulls up water through the xylem cells of roots. Transpiration cannot occur at night/on a humid day when rate of evaporation is low.
Root pressure is a force or the osmotic pressure generated in the roots. It drives the fluids and other ions from the soil in upwards directions into the plant's vascular tissue. The effect of root pressure in transport of water is more important at night.

5 Marks

17.

(i) The parts marked as A, B and C are
A-Pollen grain (male gamete)
B-Pollen tube
C-Ovule
When part B (pollen tube) reaches the part C (ovule) the male gamete (pollen grain) enters into the ovule to fuse with the female gamete (egg) for fusion.
(ii) The post fertilisation changes that occurs in a flower are given below
(a) The ovule develops a tough coat and gets converted into a seed.
(b) The ovary grows rapidly and ripens into a fruit.
(c) All petals, stamens, style and stigma gets sherivel and fall off.

18.

In asexual reproduction there is involvement of only one parent, hence the offspring receives DNA from a single parent only. Now, this DNA divides or duplicates during the process of replication and cell division. During this division mostly what happens is there is the creation of clones because the similar DNA is being passed on to both daughter cells. However, DNA transferred is not identical because during replication there could be certain environmental factor or any other factors that caused certain changes in the DNA sequences of both.

CBSE 10th Science Our Environment Sample Question Papers Study Material - QB365 Set A

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Std: 10th Standard CBSE - Science

chapter: Our Environment - Sample Question Papers

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