Environmental Issues — BIOLOGY STD 12 Science — Question

1. How may codons code for amino acids and how many are unable to do so?
2. Why are codes said to be.

1. Degenerate.
2. Unambiguous.

OR

1. How many codons code for amino acids and how many do not?
2. Explain the following giving one example of each.

1. Unambiguous and specific codon.
2. Degeneration codon.
3. Universal codon.
4. Initiator codon.

'Predation is beneficial in long run'. Comment.

The diagram shows a part of the human female reproductive system.

1. Name the gamete cells that would be present in 'X', if taken from a newborn baby.
2. Name 'Y' and write its function.
3. Name 'Z' and write the events that take placehere.

Identify fish A, B, C and D in the given diagram.

Give the name and functions of ‘A’ and ‘B’ from the diagram given below

A woman has certain queries as listed below, before starting with contraceptive pills. Answer them.
What schedule should be followed for taking these pills?

1. Name the organism in which the vector shown is inserted to get the copies of the desired gene.
2. Mention the area labelled in the vector responsible for controlling the copy number of the inserted gene.
3. Name and explain the role of a selectable marker in the vector shown.

Define analogous organ. Give one example of analogous organ.

Give reasons : Expiration is called a passive process.

1. Differentiate between analogous and homologous structures.
2. Select and write analogous structures from the list given below:

1. Wings of butterfly and birds.
2. Vertebrate hearts.
3. Tendrils of bougainvillea and cucurbita.
4. Tubers of sweet potato and potato.