Cells

Question 1

Cell Membrane

Answer 1

Structure: Partially permeable membrane.
Function: Controls substances leaving or entering the cell.

Question 2

Cytoplasm

Answer 2

Structure: Protoplasm between the cell membrane and the nucleus.
Function:
1. Location where most cell activities occur.
2. Contains organelles.

Question 3

Nucleus

Answer 3

Structure: Contains a small round mass of denser protoplasm called the nucleoplasm and is surrounded by the nuclear envelope.
Function:
1. Controls cell activities such as cell growth and repair.
2. Responsible for cell division.

Question 4

Cell Wall

Answer 4

Structure: Encloses the entire plant cell and is made of cellulose.
Function:
1. Protects the cell from injury
2. Gives the plant cell its fixed shape.

Question 5

Nuclear Envelope

Answer 5

Separates the contents of the nucleus from the rest of the cytoplasm.

Question 6

Nucleoplasm

Answer 6

Dense material within the nucleus.

Question 7

Nucleolus

Answer 7

Plays a part in making the proteins in the cell.

Question 8

Rough Endoplasmic Reticulum

Answer 8

Structure: Network of flattened spaces lined with a membrane. Ribosomes attached to its outer surface.

Question 9

Smooth Endoplasmic Reticulum

Answer 9

Structure: More tubular than RER. Does not have ribosomes attached to its membrane.
Function:
1. Synthesises substances such as fats and steroids.
2. Converts harmful substances into harmless substances (Detoxification).

Question 10

Golgi apparatus

Answer 10

Structure: A stack of flattened spaces surrounded by membranes. Vesicles can be seen fusing with one side of the Golgi apparatus and pinching off from the other side.
Function:
1. Chemically modifies substances made by the ER
2. Stores and packages these substances in vesicles for secretion out of the cell.

Question 11

How are substances made by the ER get secreted out of the cell?

Answer 11

1. Vesicles containing substances made by the ER are pinched off the ER
2. These vesicles then fuse with the golgi apparatus. The substances made by the ER may be modified inside the golgi apparatus.
3. Secretory vesicles containing the modified substances are pinched off the golgi apparatus. They then move to the cell membrane.
4. The secretory vesicles fuse with the cell membrane and their contents are released outside the cell.

Question 12

Mitochondria

Answer 12

Structure: Small sausage-shaped organelles.
Function: Site of aerobic respiration.

Question 13

Chloroplasts

Answer 13

Structure: Oval shaped organelles, contain chlorophyll.
Function: Site of photosynthesis.

Question 14

Vacuoles

Answer 14

Structure: Fluid-filled space enclosed by a membrane. Enclosed by the tonoplast.
Function:
Store substances (animal: food and water substances / plant cell: cell sap - sugars, mineral salts, amino acids) within the cell.

Question 15

What are the differences between plant and animal cells.

Answer 15

1. Presence of cell wall
2. Presence of chloroplasts.
3. Presence of centrioles
4. Presence of large central vacuole