The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over is called:
1. Centromere

2. Centrosome

3. Chiasmata

4. Tetrad

Organisms prefer sexual mode of reproduction in adverse conditions because:
1. It leads to a rapid proliferation of numbers
2. It requires two individuals that can support the progeny
3. It is less energy consuming than the asexual mode of reproduction
4. It provides protection and increases variations that may help progeny to survive

A molecule of ATP is structurally most similar to :
1. RNA nucleotide

2. DNA nucleotide

3. amino acid

4. fatty acid

In feedback inhibition, a metabolic pathway is switched off by:
1. a rise in temperature
2. lack of a substrate
3. accumulation of the end product
4. competitive inhibition

The unique properties of each amino acid is determined by its particular :
1. R group
2. amino group
3. finds of peptide bond
4. number of bonds to other amino acids

If there were 4 chromosomes present during prophase I, how many chromosomes are there in each cell at the end of anaphase II?
1. 2

2. 4

3. 8

4. 16

In competitive inhibition, if the concentration of the substrate is increased :
1. the rate of the reaction is increased
2. the rate of the reaction is decreased
3. the rate of the reaction is not affected
4. the reaction direction is reversed

Place stages of Prophase I in correct order.
1. diakinesis, diplotene, leptotene, pachytene, zygotene.
2. diplotene, leptotene, pachytene, zygotene, diakinesis.
3. leptotene, pachytene, diakinesis, diplotene, zygotene.
4. leptotene, zygotene, pachytene, diplotene, diakinesis

Which of the following distinguishes the prophase1 of meiosis from the prophase of mitosis?
1. homologous chromosomes pair up
2. spindle forms
3. nuclear membrane breaks down
4. chromosomes become visible

Identify the structure of the amino acid that is a Zwitter ion :