Lecture 16

Question 1

What is 90% of cells DNA and proteins dedicated to?

Answer 1

regulation

Question 2

What are examples of signals?

Answer 2

intracellular or extracellular signals

Question 3

What are examples of sensors?

Answer 3

Surface receptor enzymes

Question 4

What is an examples of analysis of a cell?

Answer 4

coincidence detectors

Question 5

What is the final response of the cell?

Answer 5

Transcription, enzymatic activity, protein stability, protein localization, cellular programs

Question 6

What are cellular programs?

Answer 6

cell differentiation, enter or exit cell cycle, apoptosis

Question 7

When is feedback regulation mainly used

Answer 7

Mainly used to regulate non-reversible reaction and to regulate key steps in metabolic pathways

Question 8

What enzyme is involved in the synthesis of the nucleotides CTP, UTP and TTP?

Answer 8

aspartate transcarbamoylase

Question 9

What helps regulate enzyme activity?

Answer 9

phosphorylation

Question 10

What happens during acetylation?

Answer 10

removes the positive charge of the lysine and therefore modification affects interactions of the protein with other proteins or molecules (histones)

Question 11

What helps with protein acetylation on lysine sidechains?

Answer 11

Acetyl-CoA

Question 12

What is the ultimate “turn off” mechanisms

Answer 12

Degradation

Question 13

What is the most common result of ubiquitination?

Answer 13

Degradation:
- proteasome
- lysosome
- autophagosome

Question 14

What is the most complex regulation systems containing many phosphorylation, acetylation and ubiquitination sites?

Answer 14

p53

Question 15

What drives vesicle formation on the ER membrane?

Answer 15

Sar 1

Question 16

The assembly of what drives vesicle formation?

Answer 16

assembly of coat proteins

Question 17

What is regulated by assembly/disassembly?

Answer 17

actin

Question 18

What are transcription factors?

Answer 18

are DNA binding proteins that regulate transcriptioninitiation

Question 19

What do transcription factors contain?

Answer 19

• DNA binding domains
• Transcription regulatory domains

Question 20

Homeodomains form what?

Answer 20

form hydrogen bonds with nucleobases mostly via the major groove of the DNA

Question 21

What do leucine zipper transcription factors form?

Answer 21

dimers

Question 22

What does the term leucine zipper refer to?

Answer 22

the facts that the two helixes are dimerizing because of leucine side chains that form hydrophobic interface

Question 23

What is the promoter?

Answer 23

transcription start site

Question 24

What can be far upstream or downstream of transcriptional start site?

Answer 24

Enhancers

Question 25

What interacts with seceral transcription factors/ regulators to regulate transcription initiation of a gene?

Answer 25

the mediator complex

Question 26

What are repressors?

Answer 26

repressors are either physically competing for the DNA binding site or are suppressing transcription via the mediator complex

Question 27

What is the transcription factor or regulator?

Answer 27

DNA binding protein that affects transcription initiation

Question 28

What is the transcription activator?

Answer 28

DNA binding protein that increases transcription of a gene

Question 29

what is a Transcription repressor?

Answer 29

DNA biding protein decreases transcriptionof a gene

Question 30

What is an enhancer?

Answer 30

DNA sequence that is recognized by a transcription activator

Question 31

silencer

Answer 31

DNA sequence that is recognized by a transcription repressor

Question 32

What is a promoter?

Answer 32

DNA region usually upstream of the transcription start site that contains enhancer/silencer sequences and RNA polymerase binding site

Question 33

What are the three different states of a gal promoter?

Answer 33

repressed, de-repressed and active

Question 34

What state does inhibitor proteins keep the promoter in?

Answer 34

repressed state

Question 35

What happens in the absence of glucose and galactose?

Answer 35

the repressors are not binding but the activator is blocked by Gal 80

Question 36

What happens in the presence of galactose and absence of glucose?

Answer 36

The gal80 repressor is removed by the galactose binding protein Gal3 and the promoter is active