Cell ultrastructure

Question 1

What is the role of the plasmalemma?

Answer 1

Cell membrane
Controls movement into/out of cell
Endo/exocytosis
Adhesion/recognition
Signal transduction

Question 2

What is the glycocalyx?

Answer 2

oligo/polysaccharide side chains on outside of membrane

Specific to cell interactions/functions

Question 3

What is the role of mitochondria?

Answer 3

Generation of ATP via oxidative phosphorylation
Thermogensis in brown adipocytes
TCA cycle

Question 4

Describe the structure of ribosomes?

Answer 4

40s (small) and 60s (large) subunits

Free ribosomes synthesis cytosolic proteins

Question 5

What is the difference between hetero and euchromatin?

Answer 5

Hetero = dense = not active
Eu = less packed = active

Question 6

Give examples of cells without a nucleus:

Answer 6

erethrocytes

cells in the stratum corneum

Question 7

What is the function of rER?

Answer 7

Has ribosomes

Synthesis of proteins destined for membrane, exterior, lysosomes

Question 8

What is the function of sER?

Answer 8

No ribosomes
Lipid synthesis
Steroid synthesis
Intracellular transport

Question 9

What is the role of the golgi apparatus?

Answer 9

Vesicles with rER fuse with convex face

Sorts, concentrates and modifies proteins

Question 10

What is the role of lysosomes?

Answer 10

Contain acid hydrolyses at pH 5 or so
Membranes are highly glycocylated for protection
Generated by golgi

Question 11

What is a residual body?

Answer 11

A lysosome that is full of digested contents

Question 12

What is the role of peroxisomes?

Answer 12

Site of beta oxidation
Contains oxidate enzymes e.g catalase
Present in all cells
But especially kidney and liver cells to detoxify substances from the blood

Question 13

What is the role of the cytoskeleton?

Answer 13

All cells have one
Maintains/changes shape
Allows movement of components within the cell
Allow ameboid movement of cell
Contractility in muscle cells