Sexual Reproduction In Flowering Plants — BIOLOGY STD 12 Science — Question

Read the following text carefully and answer the questions that follow:
Malaria and dengue fever are major mosquito-borne public health problems in tropical countries. The authors report a malaria and dengue co-infection in an 11-year-old boy who presented with sustained fever for 10 days. The physical examination revealed a flushed face, injected conjunctivae and left submandibular lymphadenopathy. His peripheral blood smear showed few ring-form trophozoites of Plasmodium falciparum. His blood tests were positive for dengue NS-1 antigen and IgM antibody, and negative for IgG antibody. After the initiation of antimalarial treatment with artesunate and mefloquine, his clinical condition gradually improved. However, he still had low-grade fever that persisted for 6 days. Finally, he recovered well without fluid leakage, shock or severe bleeding.
i. Name the fish that help in eradication of mosquito larvae.
ii. What is the reason of symptoms of malaria?
iii. Name the body parts and host in which following events takes place in life cycle of plasmodium.
a. asexual reproduction
b. sexual reproduction.
OR
Name some vector borne diseases and their vector.

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

Ginkgo tree has been saved from extinction by selective breeding followed by channeling into trade of nature lovers. This is an ex-situ conservation, where endangered species are protected from all adverse factors. Offspring produced in captive breeding are released in natural habitat for acclimatisation.

1. What is the significance of offsite collections?

1. Restock depleted populations.
2. Protection of endangered species.
3. Reintroduce species in wild.
4. All of these.

2. Which of the following is not an ex-situ conservation?

1. Wetlands
2. Orchards
3. Aquaria
4. Botanical gardens.

3. Select the incorrect statements for ex-situ conservation.

1. It is conservation of species outside their natural habitats.
2. Endangered species are kept under human supervision and provided all the essentials.
3. The species population recovers in natural environment.
4. Both (b) and (c).

4. Conditions maintained in seed banks for orthodox seeds are:

1. Low moisture content.
2. Anaerobic conditions.
3. Low temperature.
4. All of these.

5. Assertion: Animal species which have become extinct in wild continue to be maintained in zoological parks.

Reason: Captive breeding is the conservation of those cases where these is no realistic chance of in-situ survival.

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.

Describe the process of DNA Fingerprinting in detail.

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

A desert lizard (an ectotherm) and a mouse (an endotherm) are placed inside a chamber at 15ºC and their body temperature [T(L) for the lizard and T(M) for the mouse] and metabolic rates [M(L) for lizard and M(M) for the mouse] are monitored.

1. Which of the following is correct regardingT(L), M(L), T(M) and M(M)?

1. T(L) and M(L) will fall while T(M) and M(M) will increase.
2. T(L) and M(L) will increase while T(M) and M(M) will fall.
3. T(L) and M(L) will fall, T(M) will remain same and M(M) will increase.
4. T(L) and M(L) will remain same, T(M) and M(M) will decrease.

2. It can be said that some animals in their evolutionary development preferred to be ectotherms than endotherms. Which of the following can be the best suited reason for it?

1. The metabolic reactions of these organisms can occur at a very wide range of temperature.
2. Maintaining homeostasis is an energetically expensive process.
3. The enzymes of these organisms are functional at high temperatures.
4. Both (b) and (c).

3. Organisms that can maintain a constant internal temperature are called.

1. Homoeothermic
2. Poikilothermic
3. Oligothennic
4. Heterothennic

4. An animal that survives at temperature of 10ºC and 40ºC both can be placed under the category of:

1. Ectotherm.
2. Endotherm.
3. Modifiers.
4. Migratory organisms.

5. Study the graph carefully and select the correct option.

1. X could be desert lizard.
2. Y could be mouse.
3. Z could be desert lizard.
4. Both (a) and (b).

Give a brief account of evolution of vertebrates.

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

The endosperm makes the main source of food for the embryo. Generally the endosperm nucleus divides after the division of the oospore, but in several cases the endosperm is formed to a great extent even before the first division of the oospore. There are three general types of endosperm formation: (a) nuclear type, (b) cellular type and (c) helobial type. The endosperm is usually triploid, but haploid endosperm is also found. Endosperm may either be completely consumed by the developing embryo before seed maturation, or it may persist in the mature seed.

1. Haploid endosperm is found in:

1. Pin us.
2. Cauliflower.
3. Sunflower.
4. Pea.

2. Persistent endosperm is found in:

P. Pea Q. Castor R. Bean S. Coconut T. Groundnut.

1. Q and S.
2. P and T.
3. R, S and T.
4. P, S and T.

3. Milk of tender coconut represents (A) and the surrounding white coconut meal represents (B).

S. No	A	B
(a)	Cellular endosperm	Free- nuclear endosperm
(b)	Free-nuclear endosperm	Cellular endosperm
(c)	Helobial endosperm	Cellular endosperm
(d)	Free-nuclear endosperm	Helobial endosperm

4. If an endosperm cell of a gymnosperm contains 12 chromosomes, the number of chromosomes in each cell of the root will be:

1. 4
2. 24
3. 16
4. 6

5. In angiosperms, normally after fertilization:

1. The zygote divides earlier than the primary endosperm nucleus.
2. The primary endosperm nucleus divides earlier than the zygote.
3. Both the zygote and primary endosperm nucleus divide simultaneously.
4. Both the zygote and primary endosperm nucleus undergo a resting period.

Read the following and answer any four questions from (i) to (v) given below:
A 23 year old Sahil has been diagnosed with an infection of reproductive tract caused by bacteria. He complains about burning sensation during urination, pus-containing discharge and pain around genitalia. This infection has incubation period of 2-5 days but can be cured.

1. From which disease is Sahil suffering?

1. Chlamydiasis.
2. Herpes.
3. Gonorrhoea.
4. Syphilis.

2. Which among the following reproductive tract infections is transmitted by bacteria?

1. Trichomoniasis.
2. Chancroid.
3. Genital warts.
4. Both (a) and (b).

3. Which mode of treatment would be useful for Sahil?

1. Cryosurgery.
2. Use of Podophyllum preparation.
3. Use of antibiotic ampicillin.
4. It cannot be treated.

4. What technique was used to diagnose Sahil's disease?

1. Gram staining of discharge and culture.
2. ELISA Test.
3. Antibody detection.
4. Antigen test.

5. Find the odd one out.

1. Treponema pallidum.
2. Neisseria gonorrhoeae.
3. Haernophilus ducreyi.
4. Trichomonas vaginalis.

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

Organism P has thick lips and tongue so that it can easily feed on the commonly available spiny plants. Organism Q has thick layer of insulating fat under the skin. It was strong hooves to walk steadily on steep surfaces and lives in burrows during winters. Organism R has bright colours and sticky pads on its fingers and toes. It lives on trees.

1. Which of the following is correct habitat for organisms P regarding its adaptation?

1. Grassland biome.
2. Desert biome.
3. Tropical rainforest.
4. Tropical deciduous forest.

2. Which of the following is correct match regarding organism Q and its habitat?

1. Tundra - Polar bear.
2. Tropical rain forest - Deer.
3. Grassland - Bighorn sheep.
4. Desert - Camel.

3. Which of the following is incorrect regarding organisms R's habitat?

1. The vegetation shows stratification.
2. Epiphytic growth is rich.
3. Standing crop is highest.
4. Deep rooted shrubs are common due to abundant sunlight.

4. The dominant plants in habitat where P lives could be:

1. Opuntia
2. Nymphaea
3. Deodar
4. both (a) and (c).

5. Organisms P, Q and R respectively most likely occur in:

1. F, B and A.
2. C, A, E.
3. A, F and C.
4. B, D and A.

What is chromosomal disorder? Explain any two aneuploidy with characters in humans.###Mention any two autosomal genetic disorders with their symptoms.