Cell Bio - Unit 2 - Gene Expression

Front 1

What are sequences of DNA that code for different RNA's?

Back 1

Genes

Front 2

What kind of experiments prove that adult cells contain the entire set of genes needed to form the whole organism?

Back 2

Cloning experiments.

Front 3

Differences between cell types depend on the precise control of ____ _____.

Back 3

Gene expression.

Front 4

Differences in gene expression between different cell types are illustrated by the ____ _________.

Back 4

Protein composition.

Front 5

What is the general name for proteins common to almost all cells of an organism?

Back 5

Housekeeping proteins.

Front 6

What is the general name for proteins responsible for the distinctive properties of different cell types.

Back 6

Specialized proteins.

Front 7

What are the 6 housekeeping proteins listed in the notes?

Back 7

•Structural proteins of chromosomes
•DNA and RNA polymerases
•DNA repair enzymes
•Ribosomal proteins
•Enzymes of glycolysis
•Cytoskeletal proteins

Front 8

What is the most important form of gene regulation?

Back 8

Transcriptional Control.

Front 9

List 2 regulatory proteins that bind to a genes DNA sequence.

Back 9

•Gene activator proteins.
•Gene repressor proteins.

Front 10

T/F?
Most often gene regulatory proteins insert into the MINOR groove of the DNA helix and make multiple hydrogen and ionic bonds, and hydrophobic interactions with the edges of base pairs exposed in the grooves of double helix without disrupting bonds between bases.

Back 10

False: major.

Front 11

What is one of the strongest and most specific interactions known in biology?

Back 11

DNA-protein interactions.

Front 12

What are some common structural motifs?

Back 12

*Homeodomain motif
*Zinc finger motif
*Leucine zipper motif

Front 13

In all motifs, one or more ____-____ from the protein bind to bases in the major groove of the DNA double helix

Back 13

Alpha-helices.

Front 14

What are two ways to turn genes on or off?

Back 14

Negative regulation & Positive regulation.

Front 15

What are molecules that bind to a specific region of DNA to prevent transcription of an adjacent gene?

Back 15

Repressors.

Front 16

What turns a gene off?

Back 16

Binding of a repressor protein to DNA.

Front 17

What molecules bind to the promoter and enhance the binding of RNA polymerase to the DNA (often require a binding of another molecule before it can bind to DNA)?

Back 17

Activators.

Front 18

List 2 operons that were used to study gene regulatory mechanisms in bacteria.

Back 18

• Lac operon
• Tryptophan operon

Front 19

Tryptophan operon is an example of ____ regulation.

Back 19

Negative.

Front 20

What is a set of genes transcribed into a single mRNA?

Back 20

Operon.

Front 21

What are short DNA sequence in a bacterial chromosome within (or adjacent to) the promoter to which the repressor binds and prevents binding of RNA polymerase.

Back 21

Operator.

Front 22

What is regulated by the presence or absence of tryptophan molecules in the bacterial environment (can bind to DNA only when it has also tryptophan molecules bound to it)

Back 22

Tryptophan repressor.

Front 23

Fact:
Activity of a single promoter can be controlled by two different signals - example: E. coli lac operon.
What are the two signals?

Back 23

The lac repressor and lac activator protein CAP (Catabolite Activator Protein).

Front 24

Eucaryotic RNA polymerases require assembly of general transcription factors at the ____ before polymerase can bind to DNA and begin transcription.

Back 24

Promoter.

Front 25

What are the same set of proteins for all promoters transcribed by RNA polymerase II?

Back 25

General TFs.

Front 26

What distorts the DNA and initiates binding of other factors?

Back 26

Binding of TFIID to the TATA promoter sequence (TATA box).

Front 27

What is the key component of almost all promoters used by RNA polymerase II (located 25 nucleotides upstream from transcription start site)?

Back 27

TATA box.

Front 28

What are Post-transcriptional Controls?

Back 28

Controls of gene expression that occur after RNA polymerase begins transcription.

Front 29

List the 8 post transcriptional controls listed in the notes.

Back 29

*transcription attenuation > aborts transcription
*alternative RNA splicing > produces different mRNA's
*control of RNA transport
*cytoplasmic localization of mRNA's
*RNA editing
*initiation of translation
*repression of translation
*mRNA stabilization/degradation

Front 30

What phosphorylates RNA polymerase II after TFIID binds to TATA box?

Back 30

TFIIH.

Front 31

Activator proteins used to help assembly of TFs and RNA polymerase on chromosomal DNA bind at specific sites on DNA called ___ sites.

Back 31

Enhancer.

Front 32

Often additional proteins called _____, serve as a link between activator protein/s and RNA polymerase-TFs assembly.

Back 32

Mediators.

Front 33

What kind of control can lead to cell differentiation?

Back 33

Combinatorial control.

Front 34

Formation of an entire organ can be triggered by what?
Give an example.

Back 34

A single regulatory protein.

Examples: Ey or Pax-6 gene regulatory protein - responsible for the eye formation.

Front 35

What must be moved out of the way (or disassembled) for control proteins and RNA polymerase to gain access to the control sequences and the promoter?

Back 35

Nucleosomes.

Front 36

Define: Combinatorial Control.

Back 36

The collective effect of gene regulatory proteins controlling the level of gene expression.

Front 37

T/F?:
In eucaryotes - although each gene is regulated individually by multiple gene regulatory proteins (combinatorial control), the effect of a single gene regulatory protein (completing the combination needed to activate or repress the gene) can be decisive in turning gene on or off.

Back 37

True.

Front 38

What is an example of the same protein being able to regulate the expression of multiple genes?

Back 38

Example: glucocorticoid receptor protein.

Front 39

T/F?
In bacteria - genes are clustered together in an operon under the control of MULTIPLE promoters.

Back 39

False: Same promotor.