MODEL PAPER 7 BIOLOGY - MODEL PAPER 7

Represented below is the inheritance pattern of a certain type of trait in humans. Which one of the following conditions could be an example of this pattern?

The specialized procedure to form an embryo in a laboratory in which a sperm is directly injected into the ovum is called:

The most important feature in a plasmid to serve as a vector in gene cloning experiment is:

Given below is a highly simplified representation of human sex chromosomes from a karyotype. The genes a and b could be of:

Which one among the following regions is not a hotspot of biodiversity?

Mention the common bacterium found in the anaerobic sludge during sewage treatment and also in the rumen of cattle. How is this bacterium commercially useful?

a. Give an example of viral biocontrol agent.
b. Why are they considered to be desirable when an ecologically sensitive area is being treated?

In the given figure, give the name and functions of parts labelled A and B.

Differentiate between perisperm and endosperm giving one example of each.

The process of termination during transcription in a prokaryotic cell is being represented here. Name the label a, b, c and d.

Bio-diversification of life started to occur almost 3 billion years ago. Since then new species have been evolving and then disappearing en masse from earth.
a. How many episodes of mass extinctions of species have already taken place and which one is in progress in the current era?
b. How is current episode in progress different from the previous episodes and why? Explain.

Explain the concept of co-extinction by taking two examples.

Answer the following questions with reference to opioids, the commonly abused drug :
a. Where in our body are the specific opioid receptors present?
b. What is heroin chemically known as?
c. Write the scientific name of the plant from which opioids are extracted.

While creation and presence of variation are directionless, natural selection is directional as it is in the context of adaptation. Comment.

This image highlights the process of Gene Therapy of ADA-SCID.

i. Mention the cause of ADA deficiency in humans.
ii. How has genetic engineering helped patients suffering from it?

Write any four ways used to introduce a desired DNA segment into a bacterial cell in recombinant technology experiments.

Explain the two complexities that are observed in the process of transcription in eukaryotes and not in prokaryotes.

a. Describe aminoacylation of tRNA.
b. Explain the process that takes place in the ribosomes when mRNA makes its entry into it in a prokaryote.
c. Due to transcription error, ATG codon of DNA is transcribed into UAG in mRNA which translates a nonfunctional polypeptide chain in the ribosome. Justify the statement.

i. How are the characteristic features of pollen, anther and stigma of a maize plant suited for pollination by wind?
ii. How do you justify that:
1. Pollen grains are recovered from fossils?
2. Micropyle remains as a small pore in the seed coat of a fully developed seed?

Bioreactors are the containment vehicles of any biotechnology-based production process. For large scale production and for economic reasons the final success of biotechnological process depends on the efficiency of the bioreactor.
Answer the following questions w.r.t. the given paragraph:
i. List the operational guidelines that must be adhered to so as to achieve optimisation of the bioreactor system. Enlist any four.
ii. Mention the phase of the growth we refer to in the statement Optimisation of growth and metabolic activity of the cells.
iii. Is the biological product formed in the bioreactor suitable for the intended use immediate? Give reason in support of your answer.

Assertion (A): Homologous organs have common ancestry and similar functions.
Reason (R): Analogous organs have unlike origin and dissimilar function.

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

Assertion: Penicillin was the first antibiotic to be discovered, and it was a chance discovery.
Reason: Alexander Fleming discovered Penicillin while working on Staphylococci bacteria.

Assertion (A): Zero population growth should be achieved as early as possible to control the human population.
Reason (R): This requires not two children per couple but a little more.

Read the following text carefully and answer the questions that follow:
A pathogen is defined as an organism causing disease to its host, with the severity of the disease symptoms referred to as virulence. Pathogens are taxonomically widely diverse and comprise viruses and bacteria as well as unicellular and multicellular eukaryotes. The immune system of a person is suppressed. He was found positive for a pathogen in the diagnostic test ELISA.

i. Name the disease, the patient is suffering from. (1)
ii. Which pathogen is identified by ELISA test? (1)
iii. Which cells of the body are attacked by the pathogen? (2)
OR
Suggest preventive measures of the infection. (2)

Read the following text carefully and answer the questions that follow:
Cleavage is the series of rapid mitotic divisions in zygote and forms blastula. The 2, 4, 8, 16 daughter cells are called blastomeres. Embryo with 64 blastomeres is known as blastocyst and has blastocoel cavity. Blastocyst gets implanted in uterine wall and leads to pregnancy.
i. Why the cells of the inner cell mass of blastocyst are called stem cells? (1)
ii. At which stage of embryonic development trophoectoderm develops? (1)
iii. What is the site of implantation? (2)
OR
What is the correct sequence of various structures formed during embryonic development? (2)