CMB 1

Question 1

What is the definition of a cell?

Answer 1

Fundamental unit of all living things

- take nutrients and free energy from their surroundings and make copies of themselves

Question 2

What are the 3 major domains of the living world?

Answer 2

• Bacteria (eubacteria)
• Archae (archaebacteria)
• Eucaryotes

Question 3

What is the role of ribosomes?

Answer 3

Site of protein synthesis

Question 4

What does the smooth endoplasmic reticulum do?

Answer 4

Regulates release of calcium ions and processes toxins

Question 5

What is the function of rough endoplasmic reticulum?

Answer 5

Aid protein synthesis due to presence of ribosomes on their surface

Question 6

What is the structure and role of the Golgi apparatus?

Answer 6

A series of complex vesicles and folded membranes that secrete and transport between cells

Question 7

What is the role of mitochondria in the cell?

Answer 7

Site of aerobic respiration and ATP production through Oxidative phosphorylation

Question 8

What is the significance of the cell nucleus?

Answer 8

Contains the cell’s genetic information, DNA and chromosomes

Question 9

What is the role of peroxisomes?

Answer 9

Break down long chain fatty acids through β oxidation

Question 10

Describe the structure of the cell membrane

Answer 10

Phospolipid bilayer
hydrophobic tails facing inwards
hydrophobic heads extracellularly placed

Question 11

What is the function of cholesterol in the cell membrane?

Answer 11

OH group interacts with the polar lipid heads reducing fluidity provides strength and rigidity

Question 12

What is the role of Glycolipids?

Answer 12

Act as recognition sites involved in intracellular communication

Question 13

What are the different types of protein associated with the cell membrane?

Answer 13

Membrane Proteins
- dependent on the type of cell

Structural Proteins

• attach cytoskeletal filaments to cell membrane
• adhesion molecules attach to extracellular matrix

Transport Proteins
- Channel proteins, carrier proteins and pumps carry molecules
across the membrane

Receptors
- Chemical signalling between cells

Question 14

Why does the cell turnover rate differ?

Answer 14

Different cells divide and die at different rates so molecules are continuously replaced

e. g.
- Gastrointestinal lining - 5 days
- Red Blood Cells - 120 days
- Cerebral cortex - persons age

Question 15

How is DNA replicated?

Answer 15

Through semi conservative replication

Question 16

What are the main features of Centrioles?

Answer 16

• Found in centrosome
• Only visible during cell division
• Formed from micro tubules

Question 17

What is the structure of a Centriole?

Answer 17

1 Centriole is made up of 9 sets of 13 micro tubules (117 in total)
occur in pairs arranged at right angles

Question 18

What are the main roles of Centrioles?

Answer 18

• Organising micro tubular network

- Development of micro tubules in cilia

Question 19

What are micro tubules ?

Answer 19

Hollow fibres in all cells (except RBCs) made from ɒ and β tubulin
joined alternatively forming protofilament chains

Question 20

What is the role of micro tubules?

Answer 20

• Intracellular transport
• Form cytoskeleton
• Form Centrioles and basal bodies “

Question 21

What is the percentage composition of a cell?

Answer 21

Water 70%
Inorganic ions 1%
Small organic molecules 3%
Macromolecules 26%