BIO3: Control of Gene Expression: Biotechnology

Question 1

 polycistronic

Answer 1

Polycistronic mRNA can encode more than one polypeptide separately within the same RNA molecule (e.g. bacteria)

Question 2

Describe monocistronic

Answer 2

Monocistronic mRNA (primarily in eukaryotes) contain the coding sequence only for one polypeptide

Question 3

How do prokaryotes control gene expression?

Answer 3

Operons that result in multiple genes per mRNA (polycistronic mRNA) only exist in prokaryotes

Question 4

operons

Answer 4

Operons are a group of genes controled by a single promoter (all or nothing expression)

Question 5

How do eukaryotes control gene expression?

Answer 5

1. Transcription regulation
2. Changes in gene number
3. Translation regulation
4. Failure to control
5. DNA and chromatin structural modifications

Question 6

operator

Answer 6

Operators are regions of DNA which enables the regulation of genes on the operon

Question 7

What type of proteins bind regulate transcriptional activity in prokaryotes?

Answer 7

Activator and repressor proteins (decrease rate of transcription)

Question 8

Describe the lac operon

Answer 8

Lac operon plays a catabolic role where transcription of lac is induced by the presence of lac (the substrate) that the operon’s enzymes break down

Question 9

Describe the trp operon

Answer 9

Trp operon play an anabolic role where transcription of trp is represssed by the presence of trp (the product) of the operon’s enzymes

Question 10

What are the components of the Lac Operon?

Answer 10

1. Promoter region (P region) - RNA pol binds to begin transcription
2. Operator region (O region) - repressor binds to decrease transcription
3. Structural genes - lac Z, lac Y, lac A

Question 11

How is gene expression controlled in bacteria?

Answer 11

In prokaryotes, gene regulation occurs at the transcription level (since transcription and translation occur simultaneously); the stronger the affinity between RNA pol and the promoter, the higher the transcription rate

Question 12

Where does regulation of gene expression occur in bacteria?

Answer 12

Repressor proteins bind to the operator region of DNA; activator proteins bind to the enhancer region of DNA

Question 13

transcription factor (TF)

Answer 13

TFs are proteins that control the rate of transcription by activating/repressing the activity of RNA Pol and modulate the interaction of RNA Pol and the promoter

Question 14

RNA processing

Answer 14

The addition of a 5’ cap and 3’ poly-A tail that increases the stability of RNA, making it last longer in the cytosol

Question 15

How many times can RNA be translated?

Answer 15

mRNA can continuous be read to make proteins

Question 16

RNA interference

Answer 16

RNA molecules reduce translation by degrading some specific mRNA molecules

Question 17

What types of RNA are involved in RNA interference?

Answer 17

1. miRNA

2. siRNA

Question 18

miRNA

Answer 18

miRNA are single stranded RNA molecules that are complementary to the mRNA molecule, bind to it, and degrade it

Question 19

siRNA

Answer 19

siRNA are double stranded RNA that forms a complex with a protein, binds to a specific mRNA molecule, cleiving it

Question 20

gene amplification

Answer 20

Gene amplification (or gene duplication) is the duplication of a region of DNA resulting in an increase in the number of copies of a gene

Question 21

anueploidy

Answer 21

Having an abnormal # of chromosomes (an entire chromosome has been duplicated or lost)

Question 22

angiogenesis

Answer 22

Development of new blood vessels

Question 23

Describe the cancer growth process

Answer 23

Normal cells undergo apoptosis when DNA mutations occur but cancer cells avoid apoptosis. Cancer cells undergo angiogenesis which fuels tumor groups. Cancerous tissue invades and damages surrounding organs

Question 24

oncogenes

Answer 24

Genes that regulate cell growth, differentiation, and the process of apoptosis and can potentially cause cells to become cancerous

Question 25

proto-oncogenes

Answer 25

Normal genes involved in cell growth that get mutated

Question 26

tumor suppressor genes

Answer 26

Genes that have the potential to prevent cancer (trigger apoptosis, DNA repair, or decrease cell division)

Question 27

epigenetics

Answer 27

Changes in gene expression not due to change in DNA sequence (e.g. chromatin remodeling)

Question 28

chromatin remodeling

Answer 28

Changing arrangement of chromatin between heterochromatin/euchromatin that leads to changes in gene expression

Question 29

What types of covalent modifications occur to histone proteins in chromatin remodeling?

Answer 29

1. Acetylation/deacetylation 2. Methylation/demethylation 3. Phosphorylation

Question 30

rDNA

Answer 30

Recombinant DNA are DNA molecules made from combining DNA from 2 or more different sources

Question 31

restriction enzymes

Answer 31

endonucleases that recognize and cleave specific DNA sequences (producing "sticky ends" and rDNA when annealed)

Question 32

endonuclease

Answer 32

enzyme that cleaves a nucleotide chain in the middle of the chain

Question 33

exonuclease

Answer 33

enzyme that cleaves a nuscleoide from the end of a chain

Question 34

phosphodiester bonds

Answer 34

joins nucleotides

Question 35

FISH

Answer 35

Flourescent in situ hybridization - used to determine gene expression in a specific tissue

Question 36

What questions does FISH address?

Answer 36

Is a certain gene expressed? If so, how much and in what region of tissue?

Question 37

PCR

Answer 37

Polymerase chain reaction - used to amplify DNA to determine quantity of DNA present

Question 38

Describe the PCR process

Answer 38

Repeated cycles of heating and cooling (denature and anneal) and DNA extension

Question 39

Gel eletrophoresis

Answer 39

Used to separate macromoles of DNA and proteins by size and charge

Question 40

Describe the gel eletrophoresis process

Answer 40

Sample is placed at - (cathode) end of gel and electrical field is applied so negatively charged molecules migrate towards + (anode) opposite end of gel

Question 41

SDS-PAGE

Answer 41

Separate denatured proteins by their molecular weight

Question 42

Native-PAGE

Answer 42

Proteins separated by size in their native conformation

Question 43

Southern blot

Answer 43

Detect a certain fragment of DNA from a sample

Question 44

Northern blot

Answer 44

Detect a certain fragment of RNA from a sample

Question 45

Western blot

Answer 45

Detect a specific protein from sample

Question 46

Sanger sequencing

Answer 46

Method of DNA sequencing using ddNTP to terminate nucleotide chain elongation and generate various fragments to map to