Chapter 1- Cell structure and function

Question 1

What are the types of cells that exist on Earth?

Answer 1

1. Eukaryotic (plants | animals | fungi)

2. Prokaryotic (bacteria | archaea)

Question 2

Name the parts of an eukaryotic cell.

Answer 2

Nucleus (nuclear envelope | nucleolus | nucleoplasm | chromatin), smooth ER, rough ER, golgi apparatus, mitochondrion, ribosomes, cytoplasm (protoplasm), cell surface membrane, vesicles, lysosomes, centriole, cell wall, vacuole, chloroplasts.

Question 3

Name the parts of a prokaryotic cell.

Answer 3

Cytoplasm (with chloroplasts), cell surface membrane, capsule, ribosomes, nucleoid (containing chromatin), flagellum.

Question 4

Describe the appearance and structure of the smooth ER.

Answer 4

Appearance:
1. Network of tubular spaces lined with a membrane.
2. Outer membrane is continuous with the rough ER.
Function:
1. Synthesizes fats and steroids.
2. Engaged in detoxification.

Question 5

Describe the appearance and function of the rough ER.

Answer 5

Appearance:
1. Ribosomes attached to outer surface.
2. Network of flattened spaces lined with a membrane continuous from the nuclear envelope.
Function:
1. Synthesizes and transports proteins made by ribosomes.

Question 6

Describe the appearance and function of the Golgi apparatus.

Answer 6

Appearance:
1. Disc shaped with stacks of flattened spaces lined with a membrane.
2. Vesicles can be seen fusing and pinching off at the ends.
Function:
1. Chemically modifies and temporarily stores proteins.
2. Packs and secretes them out of the cell (in secretory vesicles).

Question 7

Describe the appearance and function of the mitochondrion.

Answer 7

Appearance:
1. Oval shaped organelle with highly folded inner membranes.
Function:
1. Aerobic respiration occurs here, where glucose is oxidized to release energy.

Question 8

Describe the appearance and function of the lysosomes.

Answer 8

Appearance:
1. Rounded membrane bound sacs filled with digestive enzymes.
Function:
1. Autolysis (destruction of old organelles and damaged cells).
2. Destroys harmful bacteria by digesting it.
3. Helps digest organic waste produced by the cells.

Question 9

Describe the appearance and the function of the chloroplast.

Answer 9

Appearance:
1. Oval shaped organelle with stacks of inner membrane and thylakoids (which store excess chlorophyll).
Function:
1. Carries out photosynthesis; where light energy is converted into chemical energy in the presence of water and carbon dioxide.

Question 10

Describe the appearance and function of the nucleus.

Answer 10

Appearance:
1. Contains nuclear envelope, nucleoplasm, nucleolus and chromatin.
Function:
1. Essential for cell division, cell growth, reproduction and repair.
2. Contains DNA and RNA (genes | instructions for cell activities).
3. Synthesis of ribosomes and proteins.

Question 11

Describe the specialization of a root hair cell.

Answer 11

1. It has long and narrow root protrusions (increases surface area to volume ratio | faster intake of water and mineral salts).

Question 12

Describe the specialization of a red blood cell.

Answer 12

1. Contains haemoglobin (binds to oxygen).
2. Has no nucleus (more space for haemoglobin).
3. Oval and biconcave shape (increases surface area to volume ratio | efficient and faster distribution of oxygen).

Question 13

Describe the specialization of a xylem vessel.

Answer 13

1. No cross wall (unobstructed flow).
2. No protoplasm (no easier water flow).
3. Lignin deposited (thickens and strengthens).