Molecules to Cells Exam 6

Question 1

In an ______ a single promoter serves a set of functionally related genes

Answer 1

Operon

Question 2

The regulatory “switch” is a segment of DNA called an _____ usually positioned within the promoter

Answer 2

Operator

Question 3

An operon is the entire stretch of DNA that includes what 3 components?

Answer 3

The operator, the promoter, and the genes they control

Question 4

The operon can be switched off by a protein ______

Answer 4

Repressor

Question 5

The repressor binds to the operator and blocks what?

Answer 5

The attachment of RNA polymerase

Question 6

The repressor is the product of a separate _______ which is not part of the operon

Answer 6

Regulatory gene

Question 7

A ____ is a molecule that cooperates with a repressor protein to switch an operon off

Answer 7

Corepressor

Question 8

The trp operon is an example of what?

Answer 8

A repressive operon

Question 9

When tryptophan is present it ____ to the trp ________, which then turns the operon _______.

Answer 9

Binds
Repressor protein
Off

Question 10

The trp repressor blocks transcription of the trp operon when the repressor _____.
A) is not bound to the operator
B) binds to tryptophan
C) is not bound to tryptophan
binds to tryptophan

Answer 10

B)

Question 11

A ______ operon is one that is usually on; binding of a repressor to the operator shuts off transcription.

Answer 11

Repressible

Question 12

An _____ operon is one that is usually off; a molecule called an inducer inactivates the repressor and turns on transcription.

Answer 12

Inducible

Question 13

The ____ operon is an inducible operon and contains genes that code for enzymes that function in the use of lactose.

Answer 13

Lac

Question 14

A molecule called an ____ inactivates the repressor to turn the lac operon on.

Answer 14

Inducer

Question 15

What is the inducer of lac operon

Answer 15

Allolactose

Question 16

Repressible enzymes usually function in _____ pathways.

Answer 16

Anabolic pathways

Question 17

______ enzymes usually function in catabolic pathways.

Answer 17

Inducible

Question 18

When glucose is scarce CRP acts as an _______ of transcription.

Answer 18

Activator

Question 19

Which of the following molecules when taken up by the cell, binds to the repressor that the repressor no longer binds to the operator?

A) promoter
B) repressor
C) inducer
D) co-repressor

Answer 19

C

Question 20

Using the table, identify a 3’ —> 5’ sequence of necleotides in the DNA template strand from mRNA coding for the polypeptide sequence
Phe-Pro-Lys
A) 3’ AAGGGAUUC 5’
B) 5’ AAGGGATTC 3’
C) 3’ AAGGGATTC 5’
D) 3’ TTCCCAAAG 5’
E) 5’ TTCCCAAAG 3’

Answer 20

C

Question 21

The production of a polypeptide based on the codon sequence of an mRNA

Answer 21

Translation

Question 22

Where and when does translation occur in eukaryotic cells

Answer 22

Cytoplasm after nuclear transcription of mRNA

Question 23

What is a major difference between eukaryotes and prokaryotes.

Answer 23

The coupling of transcription and translation

Question 24

The ____ synthesizes polypeptides based on the nucleotide sequence in mRNA

Answer 24

Ribosome

Question 25

A ribosome translates an mRNA message into protein with the help of ________

Answer 25

Transfer RNA(tRNA)

Question 26

Each ____enables the translation of a particular mRNA codon into a certain amino acid

Answer 26

tRNA

Question 27

The large and small ribosomal are made of what?

Answer 27

Proteins and ribosomal RNAs

Question 28

In ______, different mRNS molecules are produced from the same primary transcription depending on which RNA segments are treated es exons and which an introns

Answer 28

Alternative sRNS splicing

Question 29

How can genes of related function be “coordinated expressed” in eukaryotes?

Answer 29

The promoters of genes that need to be coordinators expressed have elements in common that bind to the same regulatory transcription factors

Question 30

Small single-stranded RNA molecules that can bind to complementary mRNA sequences

Answer 30

MicroRNAs(miRNAs)

Question 31

What can MicroRNAs do?

Answer 31

They can degrade the mRNA or block its translation

Question 32

How does acetylation affect the association of histones and DNA? A) acetylation loosens the association because it alters the charge of DNA B) acetylation tightens the association because it gives histones a positive charge C) acetylation loosens the association because it alters the charge of histones D) acetylation neutralizes the negative charge of acidic amino acids

Question 33

Diploid organisms have how many versions of every gene?

Answer 33

2

Question 34

The combination of alleles

Answer 34

Genotypes

Question 35

Having two of the same alleles

Answer 35

Homozygous

Question 36

Having two different alleles

Answer 36

Heterozygous

Question 37

A

Answer 37

Normal allele

Question 38

a

Answer 38

Mutant allele

Question 39

Both Rita and Joe have two alleles for the CFTR gene. One of the alleles is wild type and dominant and the other is a recessive mutant allele that causes cystic fibrosis. What is the probability that their second child has cystic fibrosis?

Answer 39

1/4

Question 40

Why do 3 out of 6 of Rita and Jose’s children have cystic fibrosis

Answer 40

Because probability does not equal predictability. Each kid had a 1/4 chance of having cystic fibrosis.

Question 41

The allele that produced melanin is ______(dominant or recessive) over the one that does not because as long as you have some, then you get the _______(blue or brown).

Answer 41

1) dominant 2) brown

Question 42

What is the probability of two people with Huntington’s disease will also hav Huntington’s disease

Answer 42

2/3 because one will die in child birth