Cell Structure and Organisation

Question 1

What are the functions of:

1. CSM
2. Cytoplasm
3. Nucleus

Answer 1

1. It is a partially permeable membrane. Hence, the cell surface membrane controls substances entering or leaving the cell.
2. It is where most cell activities occur.
3. It controls cell activities such as cell growth and the repair of worn-out parts.
   It is essential for cell division. Cells without a nucleus, for example, the red blood cells of a mammal are unable to divide.

Question 2

What are the functions of the ribosomes?

Answer 2

The ribosomes attached to the ER make proteins that are usually transported out of the cell.
The ribosomes lying freely in the cytoplasm make proteins that are used within the cytoplasm of that cell.

Question 3

What is the function of the RER/SER?

Answer 3

1. The RER transports proteins made by ribosomes to the Golgi apparatus for secretion out of the cell.
2. Synthesises substances such as fats and steroids. Sex hormones in mammals are steroids.
   Converts harmful substances into harmless materials. This process is called detoxification.

Question 4

Functions of the GA?

Answer 4

Chemically modifies substances made by the ER.

Stores and packages these substances in vesicles for secretion out of the cell.

Question 5

How do substances made by the endoplasmic reticulum enter the Golgi apparatus and are finally secreted out of the cell?

Answer 5

1. Vesicles transport substances within the cell. Small vesicles containing substances made by the ER are pinched off from the ER.
2. These vesicles then fuse with the Golgi apparatus and release their contents into the Golgi apparatus. The substances made by the ER may be modified inside the Golgi apparatus.
3. Secretory vesicles containing these modified substances are pinched off from the Golgi apparatus. They then move to the cell surface membrane.
4. The secretory vesicles fuse with the cell surface membrane and their contents are released outside the cell.

Question 6

What are the two types of tissues?

Answer 6

1. Cells of the same kind may group together to form a simple tissue.
2. Complex tissue contains more than one type of cells.

Question 7

What is an organ?

Answer 7

Organs contain more than one type of tissues grouped together to form a similar function.