Lecture 3 Dr. Williams

Question 1

Define: Constitutive Gene

Answer 1

A gene that is transcribed continually compared to a facultative gene which is only transcribed when needed

Question 2

Define: Housekeeping Gene

Answer 2

Typically a constitutive gene that is transcribed at a relatively constant level. The houekeeping gene’s products are typically needed for maintenance of the cell. it is generally assumed that their expression is unaffected by experimental conditions.

Question 3

Examples of Housekeeping Genes

Answer 3

Actin
GAPDH
Ubiquitin

Question 4

Define: Facultative Gene

Answer 4

A gene which is only transcribed when needed, compared to a constitutive gene

Question 5

Define: Inducible Gene

Answer 5

A gene whose expression is either responsive to environmental change or dependent on the position of the cell cycle.

Question 6

Define: Tissue/Cell-Specific Gene

Answer 6

These genes are only expressed in a limited subset of cells or tissues, such as albumin in liver hepatocytes

Question 7

Name the 6 levels genes can be regulated at

Answer 7

1. Transcription
2. RNA Processing
3. RNA Transport
4. Translation
5. mRNA degradation
6. Protein modification or degradation

Question 8

Regulation of gene expression in Eukaryotes vs. Prokaryotes

Answer 8

More complex in prokaryotes.
Transcription and Translation are linked in prokaryotes, and are largely performed in separate compartments in eukaryotes

Question 9

Name That Polymerase: Actin mRNA

Answer 9

RNA Pol II(2)

Question 10

Name That Polymerase: Poly(A) tail

Answer 10

Poly(A) polymerase

Question 11

Name That Polymerase: Lagging Strand

Answer 11

DNA Pol III(3)

Question 12

Name That Polymerase: hnRNA

Answer 12

RNA Pol II(2)

Question 13

Name That Polymerase: Okazaki Fragment Primer

Answer 13

DNA Pol III(3)

Question 14

Name That Polymerase: miRNA

Answer 14

RNA Pol II(2)

Question 15

Name That Polymerase: 18S rRNA

Answer 15

RNA Pol I(1)

Question 16

Name That Polymerase: Any RNA that is capped

Answer 16

RNA Pol II(2)

Question 17

Name That Polymerase: tRNA

Answer 17

RNA Pol III(3)

Question 18

Name That Polymerase: Any RNA that disappears in the presence of alpha-amanitin

Answer 18

RNA Pol II(2)

Question 19

Which transcription factor has a phosphorylated C-terminal domain in eukaryotes?

Answer 19

RNA Pol II

Question 20

What are non-protein coding genes?

Answer 20

Genes that are not translated into protein (rRNA, tRNA)

Question 21

What does RNA Pol II Transcribe?

Answer 21

All protein-coding genes mRNAs and micro-RNAs

Question 22

What does RNA Pol I Transcribe?

Answer 22

rRNA

Question 23

What does RNA Pol III Transcribe?

Answer 23

tRNAs and snRNAs

Question 24

Define: Promotor

Answer 24

A genetic element, binding site, that can attract the DNA binding machinery.

Question 25

Sigma factor leaves when?

Answer 25

After attracting polymerase to promotor

Question 26

2 kinds of transcription termination in bacteria?

Answer 26

Rho-dependent - a molecule (rho) binds to the formed RNA and signals release of mRNA Rho-independent - stem-loop structure signals release of mRNA

Question 27

Location of Cis and Trans elements

Answer 27

Cis - on the DNA | Trans - a molecule floating about that binds to the cis-elements

Question 28

What does the sigma factor recognize?

Answer 28

Binding sites such as the -35 and -10 subunits respectively, away from the coding sequence

Question 29

Define: Core promotor

Answer 29

Location of binding with the initiation complex and polymerase. Defines where transcription starts and the direction of transcription

Question 30

Define: Regulatory Promotor

Answer 30

Site where additional proteins will bind and stabilize transcription

Question 31

Define: Enhancer

Answer 31

Talks to promotor in enzymatic and physical terms, alters the rate at which polymerase transcribes - amplify

Question 32

Define: Silencer

Answer 32

Talks to promotor in enzymatic and physical terms, alters the rate at which polymerase transcribes - restrict

Question 33

Largest Coded Gene?

Answer 33

Distrophin

Question 34

Define: Locus Control Region

Answer 34

Controls the enhancer

Question 35

Promotor Selectivity - Prokaryotes

Answer 35

-10/-35 signals are recognized by a family of sigma factors.

Question 36

Name some Prokaryote promotors:

Answer 36

Standard promotor Heat-Shock promotor Nitrogen-Starvation promotor

Question 37

Define: Promotor Strength

Answer 37

Is a critical determinant of the rate of transcription in prokaryotes

Question 38

What is TBP?

Answer 38

Tata Box Protein

Question 39

TAF

Answer 39

Transcription Accessory Factor - interact with Pol II and DNA