MODEL PAPER 5 BIOLOGY - MODEL PAPER 5

Select the option that gives the correct description of the process of Natural Selection with respect to the length of the neck of giraffe.

The natural method of birth control in which the couples avoid coitus from day 10 to 17 of the menstrual cycle is called:

The diagram represents the Miller experiment. Choose the correct combination of labelling.

How much solar energy falling on the leaf of plant is converted into chemical energy?

Which of the following supports a dense population of planktons and littoral vegetation ?

Write the name of the bioactive molecules produced by the microbes listed below, and their role in the field of medical sciences.
a. Monascus purpureus
b. Trichoderma polysporum

i. Look at the above sequence and mention the event A, B and C.
ii. What does central dogma state in molecular biology? How does it differ in some viruses?

A patient who has undergone an organ transplant is put on immunosuppressant. Name the immunosuppressant and its source organism.

Given below is an incomplete chart showing the influence of hormones on gametogenesis in males. Observe the chart carefully and fill in the blanks A, B, C and D

a. Draw a neat diagram of a mature angiospermic embryo sac and label any four cellular components.
b. Write the function of filiform apparatus.

Given below is an equation describing the Species-Area relationship between species richness and area for a wide variety of taxa as angiosperm plants, birds, bats etc.
S = CA^Z
a. Give a graphical representation of the given equation showing Species-Area relationship.
b. What does S represent in the given equation?
c. What is the value of Z (regression coefficient) for frugivorous birds and mammals in the tropical forests of different continents?

Who proposed the term evolution? What is evolution? List the different evidences in support of evolution.

Forests provide intangible benefits to us. Explain by taking three different areas, how.

Study the table showing the population interaction between species Z and Y respectively. Assign the appropriate +/- signs for A, B, D, E and respective interactions for C and F.

Species 'Z'	Species 'Y'	Name of Interaction
A	B	Mutualism
-	-	C
D	E	Parasitism
+	O	F

Given below is a schematic representation of a lac operon. Answer the following questions:

i. Identify i and p.
ii. Name the inducer for this operon.
iii. Explain the function of inducer for this operon.

Answer the following questions with respect to recombinant DNA technology:
i. Why is plasmid considered to be an important tool in rDNA technology? From where can plasmids be isolated? (Any two sources)
ii. Explain the role of ori and selectable marker in a cloning vector.
iii. r-DNA technology cannot proceed without restriction endonuclease. Justify.

A vector is a way to take a sequence of DNA, usually, and introduce it into another place. So what vectors do is allow you to propagate the DNA you're interested in, in the organism you've chosen to propagate it in. So the simplest one is the origins of recombinant DNA technology: They made copies of RNAs, and they were able to insert these into what is known as plasmids.

Unless the vector and source DNA are cut, fragments separated and joined, the desired recombinant vector molecule cannot be created.
i. How are the desirable DNA sequences cut?
ii. Explain the technique used to separate the cut fragments.
iii. How are the resultant fragments joined to the vector DNA molecule?

a. Why did Hershey and Chase use radioactive ³²P and ³⁵S in their experiments? Explain.
b. Following the experiments conducted by them, write what conclusion did they arrive at and how.

i. Describe the arrangement of nuclei and cells in a mature embryo sac of a typical angiosperm.
ii. Explain the devices the flowering plants have developed to prevent the following types of pollination:
1. Prevents both autogamy and geitonogamy
2. Prevents autogamy, but not geitonogamy

Vivipary automatically limits the number of offsprings in a litter. How?

Assertion (A): Fossils are remains of dead organisms.
Reason (R): Palaeontology is helpful in study of evolution.

Assertion (A): Test-tube baby has raised several legal problems.
Reason (R): It involves in vitro fertilization followed by embryo transfer.

Assertion (A): Decomposition process is slower if detritus is rich in lignin and cutin.
Reason (R): Decomposition is largely an oxygen requiring process.

Assertion (A): Yeasts such as Saccharomyces cerevisiae are used in baking industry.
Reason (R): Carbon dioxide produced during fermentation causes bread dough to rise by thermal expansion.

Read the following text carefully and answer the questions that follow:
After implantation, finger-like projections appear on the trophoblast called chorionic villi which are surrounded by the uterine tissue and maternal blood. The chorionic villi and uterine tissue become interdigitated with each other and jointly form a structural and functional unit between the developing embryo (foetus) and the maternal body.

i. Name the hormone crucial in parturition. Does the parturition signal originate from the mother or the fetus?(1)
ii. When and where do chorionic villi appear in humans? (1)
iii. Woman has conceived and implantation has occurred. Discuss the impact of progesterone and estrogen. (2)
OR
Fetal ejection reflex leads to parturition. Justify (2)

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.