The duration of which of the following is constant in most cell types?
1. G1 phase, S phase and G2 phase
2. S phase, M phase and G1 phase
3. S phase, G2 phase and M phase
4. G1 phase, M phase and G2 phase

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

In animal cells steroidal hormones are synthesized in the:
1. Rough endoplasmic reticulum
2. Smooth endoplasmic reticulum
3. Golgi apparatus
4. Lysosomes

An important site of the formation of glycoproteins and glycolipids in a eukaryotic cell is the:
1. Rough endoplasmic reticulum
2. Smooth endoplasmic reticulum
3. Golgi apparatus
4. Lysosomes

A glycosidic bond connects :
1. two monosaccharides
2. two amino acids
3. two fatty acids
4. a fatty acid and a glycerol

Consider the following statements:
I. G₀ phase is viewed as either an extended G₁ phase where the cell is neither dividing nor preparing to divide and or as a distinct quiescent stage which occurs outside of the cell cycle.
II. In gamete production interphase is succeeded by meiosis.
III. In programmed cell death interphase is followed or preempted by apoptosis.
The correct statements include:

1. II and III
2. I and III
3. I, II, and III
4. I only

The most abundant enzyme is :
1. Carbonic anhydrase
2. Nitrogenase
3. Catalase
4. Rubisco

The concentrations of ions is significantly higher in the vacuoles than in the cytoplasm. The reason for this:
1. Facilitated diffusion of the ions by the tonoplast
2. Active transport of the ions by the tonoplast
3. Presence of porins for diffusion of the ions
4. Bulk transport across the tonoplast

All of the following are true of protein denaturation except that it
1. is a shape change
2. is always irreversible
3. may be caused by a pH change
4. could result from a temperature change

Cyclins and cyclin-dependent kinases (CDKs) are:
1. Two key classes of regulatory molecules that determine a cell's progress through the cell cycle
2. The products of the proto oncogenes in a eukaryotic cell
3. Two very important promoters that are involved in oncogenes
4. Mediators of apoptosis