intracellular processes

Question 1

where does protein synthesis begin?

Answer 1

it starts in the cytosol on ribosomes

Question 2

how are proteins dispatched to different locations within the cell?

Answer 2

it is done according to their specific address labels contained in their amino acid sequence

Question 3

what are nuclear pores?

Answer 3

selective gates for nuclear proteins

Question 4

what are protein translocators?

Answer 4

for proteins moving from cytosol into ER, mitochondria , peroxisomes

Question 5

what are transport vesicles?

Answer 5

for proteins moving from the ER onwards

Question 6

where is the final destination for epidermal growth factor?

Answer 6

extracellular

Question 7

where is the final destination for DNA polymerase?

Answer 7

nucleus

Question 8

where is the final destination for keratin?

Answer 8

cytosol

Question 9

where is the final destination for melanin?

Answer 9

melanosomoes

Question 10

what is SRP?

Answer 10

signal-recognition particle is in the cytosol and binds to the ER signal peptide when its exposed on ribosome. The SRP receptor is embedded on the ER membrane (postman)

Question 11

what is the translocon?

Answer 11

protein channel in the ER membrane which it is threaded through (letterbox)

Question 12

what is the SRP receptor

Answer 12

it is in the ER membrane (name plate on door)

Question 13

what is the Golgi apparatus?

Answer 13

the sorting organelle of the cell located in the cytoplasm. proteins from the RER are sent to the Golgi. As they move through the Golgi they are modified and packaged into vesicles.

Question 14

what is the endosome?

Answer 14

an organelle that contains molecules to be degraded

Question 15

what is the cis cisterns

Answer 15

the cisterna nearest the ER which proteins pass through

Question 16

what is phosphorylation

Answer 16

addition of a phosphate which alters the activity of the protein

Question 17

what is acetylation

Answer 17

addition of an acetyl which regulates gene expression

Question 18

what is farnesylation

Answer 18

addition of a farnesyl group which targets proteins to cytoplasmic face of the plasma membrane

Question 19

what is ubiquitination

Answer 19

the addition of a ubiquitin chain which targets protein for degradation

Question 20

what are lysosomal enzymes

Answer 20

used for lysosomal degradation and are activated by an acidic environment

Question 21

what is proteasomal degradation?

Answer 21

it takes place in the cytosol at proteasomes which are cylindrical protein complexes . walls formed from protease enzymes and the active site is inside the cylinder. there are protein stoppers at either end which have to be open to allow the protein that is going to be degraded in.

Question 23

what is S?

Answer 23

Svedberg, a non linear measurement dependent on mass density and shape.

Question 24

what is sedimentation rate?

Answer 24

how quickly it will settle at the bottom after centrifugation

Question 25

what are nuclear pores?

Answer 25

selective gates for nuclear proteins

Question 26

what are protein translocators?

Answer 26

for proteins moving from the cytosol into the ER, mitochondria, peroxisomes

Question 27

what are transport vescicles?

Answer 27

for proteins moving from the ER onwards

Question 28

what is the signal peptide?

Answer 28

a specific sequence on the N-terminal amino acids

Question 28

how do proteins know to go to the ER?

Answer 28

because of the signal peptide on the protein being made

Question 29

what type of protein degradation would be used for a protein with a short half life?

Answer 29

proteasomal degradation

Question 30

what type of degradation would be used for a protein with a longer half life?

Answer 30

lysosomal degradation

Question 31

what are the subunits that make up a ribosome?

Answer 31

large - peptide transferase centre
small - decoding site

Question 32

How do proteins travel from ER to golgi?

Answer 32

Transport vesicles