Question

1. Define cell, its basic activities, and its three major regions. 2. Describe the composition and basic functions of the plasma membrane. 3. Explain the different processes used to move across the plasma membrane. 4. Describe the structure and cellular activity of each organelle: ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria, cytoskeleton, centrosome, and centrioles. 5. Explain the structure of glycosomes and lipid droplets. 6. Describe the role of each of the three parts of the nucleus in the control of cellular activities: the nuclear envelope, the nucleolus, and chromatin. 7. List the phases of the cell life cycle, and describe a key event of each phase. 8. Name specific cell types, and relate their overall shape to their specific functions. 9. Compare theories of cell differentiation and aging.

Answer 1

1. A cell is the structural and functional unit of living organisms. It is the fundamental unit of life.
Three regions of a cell
a. Cell envelope = Cell wall, cell membrane, and glycocalyx. They help in protection.
b. Cytoplasm = Liquid compart of the cell that contains all the cell organelles.
c. Nucleus = It contains genetic material.

2. According to the fluid mosaic model,
a. The plasma membrane is composed of phospholipids and proteins
b. It is a bilayer
c. It is predominantly non-polar
d. It exhibits semi-permeability
e. It exhibits asymmetric structure
f. It exhibits fluid nature
g. It exhibits dynamic composition

3. There are three different types of molecular transport across the membrane.
a. Simple diffusion:
Molecules move from high concentration to low concentration
Carrier is not required
Energy is not required
Non-specific

b. Facilitated diffusion:
Molecules move from high concentration to low concentration
Carrier is required
Energy is not required
Specific

c. Active transport:
Molecules move from low concentration to high concentration
Carrier is required
Energy is required
Specific