Test 3: Fill in the Blanks

Question 1

During initiation of translation, the initiator tRNA associates after the ___________ has been bound to the small subunit.

Answer 1

mRNA transcript

Question 2

Intact ribosomes must be dissociated by _____ in order for _________ to occur.

Answer 2

IF-3, initiation

Question 3

Gene families appear to be built by cycles of ________ followed by ___________.

Answer 3

duplication, mutation

Question 4

All members of a gene family will share a high degree of sequence homology, even the unexpressed ___________.

Answer 4

pseudogenes

Question 5

The predominant form of guanine in DNA is the ____, but it can undergo _____________ to produce the ____ form.

Answer 5

keto, tautomerization, enol

Question 6

In eukaryotic genes, there are often many non-coding regions called ______, interspersed between the coding _____ sequences.

Answer 6

introns, exons

Question 7

Post transcriptionally all eukaryotic mRNAs receive a _______, but only some also receive a __________.

Answer 7

5’ cap, poly-A tail

Question 8

Primary damage of DNA caused by exposure to ultraviolet light is ___________ of bases.

Answer 8

dimerization

Question 9

The most common cause of spontaneous mutations is _____________.

Answer 9

tautomerization

Question 10

Associated with eukaryotic chromatin are octamers if ________ proteins that ultimately are involved in the formation of ____________.

Answer 10

histone, nucleosomes

Question 11

Very high levels of DNA damage can lead to the activation of the ____ response.

Answer 11

SOS

Question 12

During Interphase, most eukaryotic chromatin is organized either at the ______________ or the _______________.

Answer 12

nucleosome (100 Angstrom), solenoid (300 Angstrom) level

Question 13

During translation, each new charged tRNA is brought into the A site with the assistance of ______.

Answer 13

EF-Tu

Question 14

Ribosomes serve as the __________ workbench for translation.

Answer 14

non-specific

Question 15

Transcriptional units with two or more separate coding sequences are called _____________.

Answer 15

polycistronic

Question 16

The main damage caused by UV exposure is the formation of ________, and the two categories of repair processes that exist are ___________ and ______________.

Answer 16

dimers, light dependent, light independent

Question 17

Effector molecules in regulation can either be ______ or _______, depending on the effect they have on ________________ activity.

Answer 17

positive, negative, regulatory transcriptional

Question 18

If a purine is substituted for a pyrimidine, a __________ mutation has occurred.

Answer 18

transversion

Question 19

Hydrophobic mutagens that interact physically with DNA molecules are called _________ agents, and are particularly harmful because they may cause ___________ mutations.

Answer 19

intercalating, frameshift

Question 20

A unique feature of bacterial genome function is that ____________ and ____________ can occur simultaneously.

Answer 20

transcription, translation

Question 21

Exposure to nitrous acid leads to __________________ and adenine will become ___________.

Answer 21

oxidative deamination, hypoxanthine

Question 22

All tRNA molecules will have at least 4 ______________ regions formed by _____________.

Answer 22

double stranded, inverted repeats

Question 23

Point mutations are the result of ____________ of one base for another in a DNA sequence.

Answer 23

substitution

Question 24

In an inducible system the _________ of the regulated pathway is involved in transcribing the required genes.

Answer 24

promoter

Question 25

Class I eukaryotic genes are most like ________ genes because the transcripts are ___________.

Answer 25

bacterial, short/primitive

Question 26

The repressor proteins of both inducible and repressible systems are produced ___________, but only that of ________ operons, by ______ binds to the promoter.

Answer 26

continuously, inducible, itself

Question 27

In a re-association kinetics study, the A260 will _________ as more DNA becomes ___________.

Answer 27

decrease, re-associated

Question 28

Movement of DNA within a genome, often with mutagenic consequences, is the result of ____________.

Answer 28

transposons

Question 29

The basic unit of organization in eukaryotic chromatin is the __________, which consists of an octamer of 4 histone proteins associated with ______________ of DNA, combined with __________.

Answer 29

nucleosome, 146 base pairs, linker DNA

Question 30

The activation of the SOS response is caused by the action of the protein ______.

Answer 30

Rec A

Question 31

After termination of translation, ____ binds the ribosome and causes dissociation of the subunits, and then also aids in the binding of the ______ to the small sub-unit in the next initiation event.

Answer 31

IF3, mRNA

Question 32

Most inducible operons are associated with _______ pathways.

Answer 32

catabolic

Question 33

In classifying mutations on the basis of ultimate causes, they can be either __________ or ________.

Answer 33

spontaneous, induced

Question 34

The -imino form of cytosine is complementary to _________.

Answer 34

adenine

Question 35

Induction of the lac operon occurs when _______ interacts with the repressor protein.

Answer 35

lactose

Question 36

Additions or deletions of nucleotides into a DNA sequence can cause __________ mutations.

Answer 36

frameshift

Question 37

Simultaneous transcription and translation allows for the ____________ of repressible operons.

Answer 37

attenuation

Question 38

Two general types of causative agents for induced mutations are __________ and ____________.

Answer 38

chemicals, UV radiation

Question 39

Digesting the ends of nucleic acids can be accomplished with ____________.

Answer 39

exonucleases

Question 40

The repressor protein in a repressible operon binds to the DNA only when first bound by the ___________, which causes the __________ of transcription.

Answer 40

co-repressor, inhibition

Question 41

In a transversion mutation, ________ is substituted for a _________.

Answer 41

purine, pyrimidine

Question 42

In initiation of translation, ____ aids in the binding of mRNA with the small ribosomal sub-unit and ___ aids in the binding of the initiator tRNA.

Answer 42

IF3, IF2

Question 43

The most important types of mutation from the long term perspective of populations are _________.

Answer 43

germinal

Question 44

Of the histones, ___ occurs in half the concentration of the other ____ proteins.

Answer 44

one, four

Question 45

Addition of the 5’ cap to mRNA is catalyzed by the enzyme _______________ and involves the addition of guanine by a _________ bond.

Answer 45

guaninyl transferase, phosphate

Question 46

The initial discovery of middle repetitive DNA came from studies of __________________.

Answer 46

Reassociation Kinetics

Question 47

In eukaryotic gene organization, the nucleosome is a unit composed of an octamer of histones that associates with ___.

Answer 47

DNA

Question 48

In order for the lac operon to be expressed, ________ must be present to remove the repressor protein and enough _______ must have formed to bind and promote transcription.

Answer 48

lactose, cAMP

Question 49

A higher T-melt temperature is seen with ___ rich DNA.

Answer 49

G-C

Question 50

Permanent inactivation of genes such as is seen in Barr bodies formed from X chromosomes involves packaging of DNA into ______________.

Answer 50

looped domains

Question 51

The _____ form of thymine is complementary with adenine but the ______ form complements guanine.

Answer 51

keto, enol

Question 52

The ability of bacteria exposed to UV to recover in the dark was evidence of ___________ repair and this was confirmed by the presence of tritiated _____ in the buffer.

Answer 52

base excision, H3-T

Question 53

Because so much of DNA is non-coding in eukaryotes, the ___________ is much lower than that of prokaryotic genomes.

Answer 53

gene density

Question 54

Directionality of translation in prokaryotes is established by __________ because the _________ of the amino acid has been chemically altered to methionine.

Answer 54

initiator tRNA, N-terminus

Question 55

By the end of condensation, there is a _______ fold reduction in length of the genetic material.

Answer 55

10,000

Question 56

The final gene that codes for immunoglobin includes components from both the ________ and _______ gene libraries.

Answer 56

constant, variable

Question 57

Two types of post-transcriptional processing in eukaryotes that help slow the degradation of mRNAs are _____ and _________.

Answer 57

5’ cap, poly-A tail

Question 58

Removal of non-coding regions from a primary transcript can be ____________ or by way of the ____________.

Answer 58

autocatalytic, spliceosome

Question 59

Two general types of substitutional mutations are __________ and ___________.

Answer 59

transitions, transversions

Question 60

Excessive DNA damage that leads to high amounts of single-strandedness tends to activate the ___ system, and repair that occurs will be ______________.

Answer 60

SOS, highly erroneous

Question 61

A large ribosomal sub-unit in eukaryotes consists of _______ separate RNA molecules.

Answer 61

three

Question 62

In bacterial gene expression, it is not uncommon for ___________, _____________, and __________ to occur simultaneously.

Answer 62

transcription, translation, and degradation

Question 63

Deamination of adenine produces the base ___________, which is complementary to __________.

Answer 63

hypoxanthine, cytosine

Question 64

The “cut and paste” repair method for dimers encountered during replication is called __________________, but the dimer is not _________.

Answer 64

recombinational repair, removed

Question 65

The consequence of exposure to nitrous acid is oxidative deamination, and can lead to ___________.

Answer 65

point mutations

Question 66

The first step in activating the lac operon involves the removal of the ___________ by the binding of ________.

Answer 66

I-protein, lactose

Question 67

One bad thing about alkylating agents is they can lead to the activation of ___ repair.

Answer 67

SOS

Question 68

The basic level of chromatin organization involves _____ wrapped around the __________.

Answer 68

DNA, platysome

Question 69

In an attenuated operon (tryp), the rate of successful transcription will increase if the amino acid concentration is ____ because translation of the leader polypeptide will _____.

Answer 69

low, stall

Question 70

Class III genes are transcribed by RNA polymerase III and include genes coding for ______, _______, and __________.

Answer 70

tRNA, snRNA, and 5S rRNA.

Question 71

The eukaryotic equivalent of the prokaryotic Pribnow is the __________.

Answer 71

TATA box

Question 72

The _________ represents the sum total of all transcriptional activity in a given nucleus.

Answer 72

HnRNA

Question 73

An antibody is coded for by a gene, which is custom built with sequences taken from the ________ and ________ libraries.

Answer 73

constant. variable

Question 74

Alternative spicing options lead to the formation of _________ products.

Answer 74

isoform

Question 75

Exposure to nitrous acid causes ____________, and cytosine becomes complementary to ________.

Answer 75

point mutations, adenine

Question 76

On average, DNA is a double stranded molecule, but _______ leads to the equilibrium occurrence of single stranded regions.

Answer 76

breathing

Question 77

During translocation of translation, the energy of _____ is utilized by the ribosome as it moves _______ down the message.

Answer 77

GTP, 1 codon

Question 78

A ribosomal sub-unit is composed of _______ and a set of ________.

Answer 78

rRNA, proteins

Question 79

If oxidative deamination of cytosine occurs, the product is _______, which is complementary to _________.

Answer 79

uracil, adenine

Question 80

Translocation of the ribosome is aided by the accessory protein ______.

Answer 80

EF-G

Question 81

Enzymatic activity in the ribosome by _____________ leads to the linking of amino acids.

Answer 81

peptidyl transferase