Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

Microbes are useful in household products. Explain this with suitable examples

Read the following text carefully and answer the questions that follow:
The process of formation of a mature female gamete is called oogenesis which is markedly different from spermatogenesis. A schematic representation of Oogenesis is shown below study the flow chart carefully.

i. How is a primary oocyte different from a secondary oocyte? (1)
i. Mention the changes taking place during the transition of a secondary follicle to Graafian follicle in the oogonia. (1)
iii. How many primary follicles are left in each ovary in a human female at puberty? (2)
OR
What happen to graafuan follicle after ovulation? (2)

Discuss the important measures that are useful in preventing and controlling the use of alcohol and drugs in youth.

Read the following and answer any four questions from (i) to (v) given below:

Ananya is a biologist, her research guide assigned project, i.e., to determine the effect ofin tra-specific competition on the growth of sapling of Eucalyptus. For this, she designed an experiment in which two sets of pots were used. ln the first set (set A) only I sapling was planted per pot and in the other set (set B) 16 saplings were planted per pot. To check for the effect of intra-specific competition on allocation of resources, a decreasing amount of water was added to each set. The results have been graphically indicated. Which of the following conclusions can indicated as follows:

1. Which of the following statements can be concluded from the given study?

1. More resources are allocated to the root during low water conditions.
2. Competition for water among individuals of a population causes more root growth as compared to individuals who are growing alone.
3. Lesser leaves are formed under low water conditions.
4. Root growth is higher in individual grown singly as compared to individuals in populations.

2. Which of the following associations is an example of competitions?

1. Cuscuta and hedge plant.
2. Balanus and Cathamalus.
3. Cactus and moth.
4. Orchid and mango.

3. If '+' sign is assigned to beneficial interaction, '-' sign to detrimental and O sign to neutral interaction, then the population interaction of competition refers to:

1. +, +
2. -, -
3. +, -
4. +, 0

4. lntraspecific competition is more severe due to:

1. similar needs.
2. similar adaptations.
3. common resources.
4. all of these.

5. Assertion: Two members of a competing species may co-exist.

Reason: Different individuals of a species have different resource requirements.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Given below is the pattern of temperature in a person suffering from a non-viral disease transmitted by mosquitoes. Study the graph and answer the questions that follow:

A. Explain the factor(s) responsible for this pattern of temperature.
B. How does this pathogen multiply in the human body?
C. How is this infection transmitted to humans?
OR
D. Which stages of the life cycle of this pathogen are completed in the mosquito's gut?

Read the following and answer any four questions from (i) to (v) given below:
Villagers in a place near Chambur started planning to make power supply for agricultural purposes from cow dung. 'Tiley have started a biogas plant for the purpose. Study the flow chart for biogas production given below and answer the following questions.

1. Biagas is composed of majorly:

1. Methane, CO₂ and O₂
2. CO₂, H₂S and H
3. Methane, CO₂
4.  H₂S, H and O₂

2. In the given flow chart, 'A' denotes:

1. Aerobic bacteria.
2. Methanogenic bacteria.
3. Cellulose degrading bacteria.
4. Yeast and protozoa.

3. What is represented by 'B' in the flow chart?

1. Carbohydrates.
2. Protein polymers.
3. Organic acids.
4. Fat globules.

4. 'C' in the given flow chart causes:

1. Aerobic breakdown of complex organic compounds.
2. Anaerobic digestion of complex organic compounds.
3. Fermentation of organic compounds.
4. Fermentation of monomers.

5.  If 'A' is not added in the procedure.

1. Methane will not be formed.
2. CO₂ will not be formed.
3. Organic compounds will not be converted to H₂S
4. O₂ will not be formed.

Read the following and answer any four questions from (i) to (v) given below:

X and Y are communicable diseases, whereas Wand Z are non-communicable diseases.X is transmitted through vectors whereas Y is transmitted through droplet infection. Wis caused due to a hormone deficiency, whereas Z is a degenerative disease. Based on the above information, answer the following questions.

1. Identify W, X, Y and Z.

	W	X	Y	Z
(a)	Coronary artery disease	Cholera	Chikungunya	Chikungunya
(b)	Diabetes	Malaria	Rhinitis	Alzheimer's disease
(c)	Alzheimer's disease	AIDS	Shigella	Plague
(d)	Gonorrhea	Diphtheria	Pertussis	Anthrax

2. Select the correct statement.

1. If X is sleeping sickness then its vector is Leishrnania.
2. If Y is diphtheria then it is caused by Bacillus anthracis.
3. If W is hypothyroidism then it is caused by deficiency of thyroxine hormone.
4. If Z is myocardial infarction then patient develops acute rheumatic fever, joint pain and throat infection.

3. If X and Y both are usual diseases then which of the following holds true?

1. X could be dengue caused by flavivirus and Y could be AIDS caused by HIV.
2. X could be chikungunya whereas Y could be rhinitis.
3. X could be hepatitis whereas Y could be rabies.
4. X could be chicken pox caused by Va rice/la zoster virus whereas Y could be yellow fever caused by flavivirus

4. If X and Y both are bacterial diseases then select the correct match from the following.

1. X- Bubonic plague-Yersinia pestis
2. Y-Leprosy- Mycobacteriurn leprae
3. X-Whooping cough-Bordetella pertussis
4. Y-Botulism-Clostridiurn botulinum

5. Assertion: Communicable diseases could be contagious or non-contagious.

Reason: Diseases that spread through vectors are non-contagious disease.

1. Both assertion and reason are true, and reason is the correct explanation of assertion.
2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
3. Assertion is true, but reason is false.
4. Both assertion and reason are false.

Nematode specific genes were introduced into the tobacco host plant using a vector:

1. pBR 322.
2. Plasmid.
3. Bacteriophage.
4. Agrobacterium.

Write a short note on pollination by wind.

Read the following text carefully and answer the questions that follow:
The image below shows the menstrual cycle of a human female. On the basis of this cycle:

i. Explain the menstrual phase in a human female. State the level of ovarian and pituitary hormones during this phase. (1)
ii. Why is follicular phase in the menstrual cycle also referred as proliferative phase? Explain. (1)
iii. Explain the events that occur in a Graafian follicle at the time of ovulation and thereafter. (2)
OR
Draw a Graafian follicle and label antrum and secondary oocyte. (2)