Week 2

Question 1

What determines the function of a protein

Answer 1

It’s structure

Question 2

Where can protein structure be modified

Answer 2

The ER and the Golgi

Question 3

Order of the Central Dogma of molecular biology

Answer 3

Replication, Transcription, Translation

Question 4

Where does the golgi apparatus send out packaged proteins as vesicles to?

Answer 4

The endosome and cell exterior

Question 5

Why does Golgi receive vesicles from
endosomes and secretory vesicles?

Answer 5

because of its central role in processing, modifying, sorting, and trafficking proteins and lipids within the cell

Question 6

Co-Translational Translocation

Answer 6

Modification of a protein during translation

Question 7

Post-translational translocation

Answer 7

Modification of a protein after transcription

Question 8

What does this sequence do?
Lys-Lys-Lys-Arg-Lys

Answer 8

Import into the nucleus

Question 9

What is proteolysis

Answer 9

the breakdown of proteins or peptides into amino acids by the action of enzymes.

Question 10

Type of post-translational modification (not proteolysis)

Answer 10

covalent addition of molecules (e.g. acetyl group, methyl group, phosphate group, sugar moieties, small peptides)

Question 11

Reasons for covalent addition of molecules

Answer 11

to enhance/disrupt interaction with other proteins
to enhance stability or degradation
to enhance transportation

Question 12

Reasons for proteolysis

Answer 12

to make different variations of a protein from a single mRNA
to convert a protein to its active form
to enhance proper folding of the protein
to enhance insertion of protein to membranes or lumen of organelles

Question 13

Where is insulin made

Answer 13

The pancreas

Question 14

Histone Rings

Answer 14

• important for DNA packaging
• post-translation modification of them are essential for gene expression

Question 15

Acetylation nad methylation of histone cause-

Answer 15

relaxation or condensation of nucleosome

Question 16

Enzymes that add phosphate groups

Answer 16

Kinases

Question 17

Enzymes that remove phosphate groups

Answer 17

Phosphotase

Question 18

What is the process of activation of CDK through phosphorylation

Answer 18

• Cyclin partner binds to the CDK, inducing conformational changes, partially activates the kinase
• CDK-activating kinase (CAK) phosphorylates the CDK on a conserved threonine residue, greatly increasing kinase activity

Question 20

LRK2 is-

Answer 20

a super-kinase that plays an important role in the development of Parkinson’s disease (by not degrading itself and alpha-synuclein)

Question 21

Ubiquitylation

Answer 21

a post-translational modification (PTM) that attaches ubiquitin to a protein

Question 22

Glycoslylation

Answer 22

the addition of
sugars to the side chains of
certain amino acids

Question 23

N linked glycosylation is

Answer 23

the addition of sugar
moiety to the nitrogen atom of Asparagine

Question 24

O linked glycosylation is

Answer 24

the addition of sugar
moiety to the Oxygen atom of Serine and
Threonine

Question 25

N-linked glycosylation important for:

Answer 25

• protein folding
• protein targeting (mannose-6-phosphate targets lysosome)
• occurs initially in the ER, refined in the Golgi

Question 26

O-linked glycosylation importance

Answer 26

• complementary to phosphorylation and enhance protein-protein interaction
• mostly occurs in the cytoplasm

Question 27

Environmental changes must be sensed by the cell-

Answer 27

via the activation of cell surface and intracellular nuclear receptors

Question 28

In intracellular signalling, cells respond to environmental changes by

Answer 28

activating or inhibiting the activity of specific intracellular signalling pathways to change their biology

Question 29

Result of information passed through a metabolic enzyme:

Answer 29

altered metabolism

Question 30

Result of information passed through a transcription regulatory protein:

Answer 30

altered gene expression

Question 31

Result of information passed through a cytoskeletal protein:

Answer 31

altered cell shape or movement

Question 32

Non-active GPCR:

Answer 32

• G(alpha) subunit is bound to GDP, is complexed with GBy subunits and is inactive

Question 33

Ligand-bound GPCR:

Answer 33

• G(alpha) subunit releases GDP and binds GTP, this changes its conformation causing the GBy subunit to dissociate
• both of the free G(alpha) and GBy subunits are now active

Question 34

M-Phase cylclins are degraded-

Answer 34

at the spindle assembly checkpoint(SAC) by the APC/C ubiquitin ligase to promote chromosome segregation in anaphase

Question 35

The restriction checkpoint (R) is regulated by

Answer 35

G1 phase CDKs and Cyclins

Question 36

Regulatory subunits:

Answer 36

Expression levels controlled by rates of protein synthesis vs protein degradation

Question 37

Catalytic subunit:

Answer 37

Protein kinase activity controlled by cyclin binding AND protein phosphorylation

Question 38

• several Ca2+ handling proteins phosphorylated by active PKA catalytic subunits ->

Answer 38

muscle contraction/relaxation

Question 39

• PKA regulates activity of several metabolic enzymes

Answer 39

release of glucose from glycogen

Question 40

PKA regulates the _ of specific genes

Answer 40

Transcription

Question 41

How can the activity of signalling pathway be amplified?

Answer 41

• increase the amount of ligand available to a cell
• increase the numbers of available receptors expressed by a cell
• make use of enzymes
• use positive feedback loops