Model Paper 5 — BIOLOGY STD 12 Science — Question

List the harmful effects of alcohol abuse.

Represent schematically the life cycle of a malarial parasite.

“Microbes play a dual role when used for sewage treatment as they not only help to retrieve usable water but also generate fuel”. Explain.

Name the law that states that the sum of allelic frequencies in a population remains constant. What are the five factors that influence these values?

Answer the following questions:
Explain the menstrual phase in a human female. State the levels of ovarian and pituitary hormones during this phase.

Explain the components of Ecosystem.###What do you understand by an ecosystem? Describe the structure and components of an ecosystem.

Give the term/ reason:
Role of oxytocin during expulsion of the baby out of uterus.

Explain insertional inactivation.

A true breeding pea plant homozygous for axial violet flowers is crossed with another pea plant with terminal white flowers (aavv).
Give the phenotypic ratio of F₂ generation.

Samya visited a zoo with her mother, on watching the cheetah, she wondered how he uses his forelimbs for running. While the same forelimbs in bats are used for flying. She wanted to know more about it and so asked her mother (a biology teacher) about it. Her mother explained her how forelimbs are modified in different animal groups for different functions.

1. What are such organs called?
2. Give an example of such organs from the plant world.
3. What led to the origin of such organs?
4. What are the values shown by Samya?