Unit 3

Question 1

How can bacteria regulate gene expression?

Answer 1

blocking transcription to then stopping translation

Question 2

What catabolic genes (in most cases)?

Answer 2

inducible (ex: breaking down sucrose which is not always in the cell)

Question 3

What are repressible genes (in most cases)?

Answer 3

anabolic (ex: cell always needs amino acids)

Question 4

In the trp operon, when tryptophan (trp) is low inside the cell:

Answer 4

without the co-repressor trp, the repressor is unable to bind to the DNA

Question 5

The functioning of enhancers is an example of:

Answer 5

transcriptional control of gene expression

Question 6

A co-repressor is:

Answer 6

proteins that regulate the process of gene expression indirectly by binding to the repressor protein

Question 7

Muscle cells differ from nerve cells mainly because they:

Answer 7

express different genes

Question 8

MicroRNAs can affect gene expression by:

Answer 8

tagging some mRNAs to degrade faster

Question 9

What is a constitutive gene?

Answer 9

genes that always need to be expressed

Question 10

What cell function uses the most ATP?

Answer 10

making proteins

Question 11

What are inducible genes?

Answer 11

normally off, can be turned on

Question 12

What are repressible genes?

Answer 12

normally on, can be turned off

Question 13

What is a sigma factor?

Answer 13

protein needed for initiation of transcription

Question 14

What is an operon?

Answer 14

set of genes mRNA that can encode multiple proteins in bacteria

Question 15

What is allosteric inhibition?

Answer 15

gene regulation where the regulatory molecule binds to an enzyme someplace other than the active site, which changes the shape

Question 16

What is feedback inhibition?

Answer 16

allosteric inhibition where the product binds to the enzyme and represses

Question 17

How is enzyme production regulated?

Answer 17

with regulatory molecules that can shut down synthesis in genes that encode enzymes

Question 18

Do bacteria cells prefer lactose or glucose?

Answer 18

lactose

Question 19

What happens if there is no glucose in the cell?

Answer 19

cAMP goes up, cAMP can bind to CRP
(CRP cannot bind if there is glucose around because there is no cAMP)

Question 20

What is a lactose operon?

Answer 20

disaccharide

Question 21

What allows lactose into a cell?

Answer 21

lactose permease

Question 22

What are the 3 enzymes that break down lactose?

Answer 22

beta-galactosidase, permease, trans

Question 23

What would happen if a repressor of an inducible operon were mutated so it could not bind the operator?

Answer 23

continuous transcription of the operon’s genes

Question 24

Which of the following molecules is a protein produced by a regulatory gene?
- operon
- inducer
- promoter
- repressor

Answer 24

repressor

Question 25

What molecules helps to "turn off" genes in a cell?

Answer 25

co-repressor

Question 26

When taken up by a cell, what molecule binds to a repressor so that the repressor no longer binds to the operator?

Answer 26

inducer

Question 27

Most repressor proteins are allosteric. What molecule binds with the repressor to alter its conformation and therefore affect its function?

Answer 27

inducer

Question 28

What is the difference between an inducer and a co-repressor?

Answer 28

an inducer binds to a repressor so it cannot bind to DNA, a co-repressor binds to a repressor to help it bind to DNA

Question 29

How does repressor shape affect lactose catabolism?

Answer 29

repressor can have a loop shape to grab and pull the DNA into a loop so polymerase cannot bind

Question 30

What are proximal control elements?

Answer 30

binding sites close to genes for transcription factors

Question 31

What are enhancer elements?

Answer 31

farther from genes, increase levels of transcription and are gene specific can allow some transcriptions and not others

Question 32

What results in an activator and an enhancer (being active?)

Answer 32

gene turns on, RNA polymerase is "trapped" in the right place

Question 33

What is MyoD?

Answer 33

can make MyoD proteins which bind to its own genes and transcribes itself when enough are made it binds to other genes to become muscle cells

Question 34

What is gene expression?

Answer 34

transcription and translation

Question 35

What is a basis for bacteria regulation of genes?

Answer 35

group genes- operons

Question 36

What stimulates transcription?

Answer 36

activator proteins

Question 37

What blocks transcription?

Answer 37

repressor proteins

Question 38

What are protein factors that are NOT proteins?

Answer 38

inducer molecules (like co-repressors)

Question 39

A DNA molecule that serves as a carrier molecule in DNA cloning is termed a

Answer 39

vector

Question 40

A restriction endonuclease is

Answer 40

cuts ds DNA at specific sequences.

Question 41

What comes from a bacterial anti-viral system?

Answer 41

Crispr-Cas

Question 42

In gel electrophoresis, DNA molecules move through the gel because they are

Answer 42

negatively charged

Question 43

What is the order of events in a PCR cycle?

Answer 43

Denaturing, Annealing, Extension

Question 44

Which enzyme is used to create a complementary copy of an RNA molecule?

Answer 44

reverse transcriptase

Question 45

Bacterial plasmid is

Answer 45

a small circular molecule of DNA separate from the chromosome.

Question 46

In gel electrophoresis, what function does the "ladder" carry out?

Answer 46

It serves a set of size standards for measuring the length of unknown DNA.

Question 47

With each cycle of the polymerase chain reaction, the gene of interest increases by a factor of

Answer 47

2

Question 48

Example of Crispr-cas9 working:

Answer 48

A small piece of RNA guides the Cas9 enzyme to a target DNA region and Cas9 makes cuts in the DNA.

Question 49

Dideoxynucleotides are used in

Answer 49

PCR

Question 50

Nodes on a phylogenetic tree represent..

Answer 50

a common ancestor

Question 51

What is needed for natural selection?

Answer 51

variety in a population, heritable traits, more offspring than environment can sustain, better adapted reproduce MORE

Question 52

What are the differences between a homologous structure, an analogous structure, and a vestigial structure?

Answer 52

vestigial structure- leftover traits from common ancestor (ex: pelvis in whale) analogous structure- similar trait but not related, ex: different pathway to same result homologous structure- similar trait from common ancestor

Question 53

List at least three categories of evidence that support the theory of “descent with modification?”

Question 54

How is artificial selection different from natural selection?

Answer 54

people choose traits in artificial selection (ex: dog breeding for certain look)

Question 55

What effects evolution other than "best fit"/adaptability?

Answer 55

CHECK NOTES sexual

Question 56

What is the mechanism behind descent with modification?

Answer 56

all organisms came from common ancestor, descendants moved to different environments, adaptable traits inherited

Question 57

What are the two levels of evolution?

Answer 57

microevolution - evolution of a population of species macroevolution - change on a large scale (extinction events, etc.)