1. Basic Cell Structure

Question 1

Function of the Nucleus (2)

Answer 1

1. Contains genetic information (23 chromosomes)

2. Transcription (RNA synthesis)

Question 2

What are the functions of the plasmalemma/plasma membrane? (4)

Answer 2

1. Selective permeability
2. Endo/excocytosis
3. Transport of material along cell surface
4. Signal transduction

Question 3

Function of the Rough Endoplasmic Reticulum? (1)

Answer 3

(Translation) Synthesis of proteins for export, membrane insertion and lysosome/peroxisome

Question 4

What is the function of the smooth endoplasmic reticulum? (2)

Answer 4

1. Synthesis of lipids (for liver, mammary gland)

2. Synthesis of steroids (ovary, testes, adrenal gland)

Question 5

What is the function of the golgi apparatus?

Answer 5

1. Sorting, concentrating, modifying and packaging of proteins and lipids that have come from the ER
2. … destined for secretion, insertion into membrane or lysosome.
3. Proteins move through from cis face to trans face

Question 6

What is the function (and the main function) of the inner membrane of the mitochondria? (2)

Answer 6

1. Electron transport chain and oxidative phosphorylation

2. production of ATP and heat (thermogenin).

Question 7

What is the function of the intermembrane space? (2)

Answer 7

1. Acidic

2. allows ATP synthesis to occur

Question 8

What is the function of the matrix in the mitochondria?

Answer 8

1. Krebbs cycle for metabolism

2. Contains mitochondrial DNA

Question 9

How does the mitochondria divide? (3)

Answer 9

1. Binary Fission - Like a prokaryote would
2. Circular genetic DNA replicates
3. Then cell splits

Note- independent to rest of cell due to endosymbiosis

Question 10

What colour are tissues that have lots of mitochondria in them and why? (2)

Answer 10

1. Brown

2. Because mitochondria have a brown tinge

Question 11

What is endosymbiosis ?

Answer 11

1. Evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms.
2. Prokaryotic cell engulfed another
3. Both cells benefited and now live harmoniously :)

Question 12

How is mitochondrial DNA inherited?

Answer 12

1. Female lineage

I.e only from mother not father!

Question 13

What is the function of the peroxisome?

Answer 13

Detoxification of harmful chemicals in the liver and kidneys

Question 14

What is the function of the primary and secondary lysosome? (3)

Answer 14

1. Primary - just been formed by the golgi
2. Secondary - have joined with whatever they are engulfing
3. Contain hydrolytic enzymes for digestion of harmful pathogens/unwanted proteins

Question 15

Name some hydrolytic enzymes (7)

Answer 15

1. Nucleases
2. Proteases
3. Glycosidases
4. Lipases
5. Phosphatases
6. Sulfatases
7. Phospholipases

Question 16

What is the function of the nucleolus?

Answer 16

Assembly of ribosomes from rRNA and proteins

Question 17

What is the function of the nuclear envelope?

Answer 17

Double membrane containing pores for entry and exit of proteins and RNA

Question 18

What is the function of secretory vesicleS?

Answer 18

Membrane bound sacs for transport

Question 19

What does the cytoskeleton consist of and what are their relative functions? (3)

Answer 19

1. Microfilaments (actin) at periphery of cell control cell morphology and movement
2. Intermediate filaments (keratin) form a supportive mesh work in cytoplasm (abundant in skin epithelial cell)
3. Microtubules are long hollow cylinders made of protein tubulin. Found at sites where structures are moved e.g. Cilia, flagella

Question 20

Describe the structure of a microtubule in a cilium or flagellum.

Answer 20

1. Cross section is circular
2. 9+2 arrangement - 9 fused pairs of microtubules (doublet) on outside of cylinder, and 2 unfused in the centre
3. Dynein arms attach to microtubules and act as molecular motors (movement)

Question 21

Explain briefly why a phospholipid molecules is amphipatic (2)

Answer 21

1. Has a hydrophilic head (water loving) - choline, phosphate, glycerol
2. Has a hydrophobic tail (water hating) - fatty acid chain

Question 22

What is the glycocalyx made of, where is it positioned and what is its function?

Answer 22

1. Oligosaccharide/polysaccharide side chains
2. External of plasma membrane
3. Signalling and adhesion functions

Question 23

What is the difference between cytoplasm and cytosol?

Answer 23

Cytoplasm is everything contained within the plasma membrane except the nucleus

Cytosol is just the fluid surrounding the nucleus and the organelles

Question 24

What is the difference between a lysosomes and peroxisome on a TEM?

Answer 24

Peroxisomes are darker

Question 25

What is the difference between eukaryotic and prokaryotic ribosomes?

Answer 25

Eu - 80S - 60S + 40S | Pro - 70S - 50S + 30S

Question 26

Name a few differences between prokaryotes and eukaryotes. (6)

Answer 26

1. Eu compartmentalised by internal membranes 2. Pro - free circular DNA called nucleoid, eu - nucleus membrane bound 3. Pro - cell wall (peptidoglycan) + plasma membrane, eu - just plasma membrane 4. Pro - capsule - allows easier entry into cells 5. Pro - pili - allows attachment 6. Pro - 70s ribosomes, eu - 80s ribosomes

Question 27

If you were making a drug for a prokaryote, what would you target so that our eukaryotic cells weren't harmed? (2)

Answer 27

1. Cell wall of prokaryote | 2. 70S ribosome