Lecture 1 and 2

Question 1

How much of the bilayer do phospholipids make up?

Answer 1

50%

Question 2

What type of layer do electron microscopes show of the plasma membrane?

Answer 2

Trilaminar layer

Question 3

Describe the appearance of the trilaminar layer.

Answer 3

Outer: electron dense
Central: electron lucent

Question 4

What three parts make up the polar head of a phospholipid

Answer 4

Nitrogenous compound
Phosphate bridge
glycerol

Question 5

How much of the nucleus does DNA make up?

Answer 5

20%

Question 6

What protein does the nucleus contain?

Answer 6

Nucleoprotein

RNA

Question 7

What are the two types of nucleoprotein?

Answer 7

Histone proteins

Non-histone proteins

Question 8

What are non-histone proteins found in the nucleus?

Answer 8

Enzymes for synthesis of DNA and RNA

Question 9

The nucleus is ____-genous

Answer 9

Heterogenous

Question 10

What name is given to the electron dense areas of the nucleus?

Answer 10

Heterochromatin (inactive coiled chromatin)

Question 11

What name is given to the electron lucent areas of the nucleus?

Answer 11

Euchromatin (DNA involved in RNA synthesis)

Question 12

Cells involved in highly active protein synthesis contain

Answer 12

Dense nucleoli

Question 13

What does the nucleolus consist of?

Answer 13

RIbosomes and ribosomal RNA

Question 14

Where is the nucleolus constructed? Where is it transported to?

Answer 14

Nucleolus

Cytoplasm

Question 15

What happens in the RER?

Answer 15

Proteins fold into their tertiary structure, proteins exported

Question 16

What is the RER?

Answer 16

System of flattened tubules covered with ribosomes

Question 17

What is the SER?

Answer 17

Continous with and similar to RER but no ribosomes

Question 18

What occurs in the SER?

Answer 18

Synthesis of lipids and membranes, membrane repair

Question 19

Where is the SER prominent?

Answer 19

Cells which discrete lipid/steroids: liver, steroid-secreting cells of adrenals/gonads

Question 20

What is the structure of the golgi?

Answer 20

4-6 saucer shaped stacked membrane bound cisternae

Question 21

What is the function of the golgi?

Answer 21

Modification of proteins (glycolisation of proteins, package proteins into secretory granules)

Question 22

What occurs in the mitochondria?

Answer 22

Energy production by oxidative phosphorylation

Question 23

What are the four compartments of the mitochondria?

Answer 23

Outer membrane, inner membrane, matrix, intermembranous space

Question 24

Why is the outermembrane of the mitochondria permeable?

Answer 24

Due to porin

Question 25

What does the inner membrane of the mitochondria fold into?

Answer 25

Christae (increases surface area for reactions to take place on)

Question 26

What does the mitochondrial matrix have?

Answer 26

Contains matrix granules | Binds Ca++

Question 27

What does the intermembranous space of the mitochondria contain?

Answer 27

Enzymes

Question 28

Why is the mitochondria unusual?

Answer 28

- Contains 1 or more strands of circular DNA | - Undergo self-replication

Question 29

What is the name of the theory that mitochondria are derived from bacteria?

Answer 29

Endosymbiotic theory of mitochondria

Question 30

How can the mitochondria be visualised under a microscope?

Answer 30

Cytochemical stain for cytochrome oxidase (involved in pathway)

Question 31

Where are fatty acids and triglycerides made?

Answer 31

Cytosol

Question 32

Where are cholesterol and phospholipids made?

Answer 32

sER

Question 33

How can lipids be stained?

Answer 33

Frozen, stained with osmium tetroxide (stains black)

Question 34

What is the diameter of microfilaments?

Answer 34

5-9nm

Question 35

What is the most abundant protein in eukaryotic cells?

Answer 35

Actin (5%)

Question 36

What is the structure of a microfilament?

Answer 36

Two-stranded helical polymer of G-actin protein

Question 37

How many types of actin do mammals have?

Answer 37

6

Question 38

What groups are mammals actin classified into?

Answer 38

Alpha (muscle cells/muscle differentiation) Beta Gamma

Question 39

What is the diameter of a microtubule?

Answer 39

25nm

Question 40

What is the shape of a microtubule?

Answer 40

Hollow cylinder

Question 41

What is tubulin made of?

Answer 41

Alpha and beta tubulin (heterodimer)

Question 42

Why do microtubules have a polar structure?

Answer 42

Each heterodimer is in the same orientation

Question 43

Where do mictotubules extend from?

Answer 43

The centrosome

Question 44

What motor proteins achieve movement along a microtubule?

Answer 44

Dynein and kinesin

Question 45

What is the diameter of intermediate filaments?

Answer 45

10nm

Question 46

What is the structure/shape of intermediate filaments?

Answer 46

Elongated rope-like fibrous molecules

Question 47

What do intermediate filaments form?

Answer 47

Extensive netwoek around nucleus and out to cell periphery, spanning cytoplasm from one cell-cell junction to another

Question 48

How many types of intermediate filaments are there?

Answer 48

More than 50

Question 49

What are the three classes of intermediate filament?

Answer 49

Keratin filaments (cytokeratins) Vimentin and vimentin related filaments Neurofilamets

Question 50

Where are cytokeratins found?

Answer 50

Epithelial cells

Question 51

Where is vimentin and vimentin-related filaments found?

Answer 51

Cells of mesodermal origin

Question 52

Where is the study of intermediate filament useful?

Answer 52

Diagnosis in histopathology