chpt 1 cell structure and organisation

Question 1

What is the role of the nucleus ?

Answer 1

1. contains hereditary material (DNA) in chromatin threads
2. controls and directs cell activities eg growing, repairing and reproduction of cells

Question 2

Function of vacuole ?

Answer 2

1. Provides support for plants when it is filled with water so it can maintain turgidity of cells (prevent bursting)
2. temporarily stores waste products and food reserves

Question 3

Function of ribosomes ?

Answer 3

1. ribosomes on rough ER are responsible for the synthesis of secretory protein
2. free ribosomes synthesise intracellular proteins

Question 4

Function of rough ER ?

Answer 4

1. covered with ribosomes
2. transports protein which are manufactured by ribosomes out of cell

Question 5

Function of smooth ER ?

Answer 5

1. no ribosomes
2. synthesis of fats and steroids (sex hormones in mammals are considered steroids)
3. detoxification of harmful substances into harmless materials (in liver -> detoxifies alcoholand skin)
4. gives rise to golgi body

Question 6

Function of golgi body ?

Answer 6

1. chemically modifies substances made by ERs (protein fats and steroids)
2. stores and packages substances in vesicles for secretion out of cells

Question 7

Features of muscle cell ?

Answer 7

1. elongated in shape
2. contains many mitochondrion for release of ATP during contraction
3. contains contractile protein fibres that contract and relax to bring movement