Chapter 4 - DNA, RNA, and the flow of genetic material

Question 1

DNA and RNA are long linear polymers called

Answer 1

nucleic acids.

Question 2

mRNA

Answer 2

The information-carrying intermediates in protein synthesis.

Question 3

Introns

Answer 3

a segment of a DNA or RNA molecule which does not code for proteins and interrupts the sequence of genes.

Question 4

Exons

Answer 4

a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

Question 5

Each monomer unit within the polymer of DNA and RNA is a

Answer 5

nucleotide.

Question 6

A single nucleotide consists of three components:

Answer 6

A sugar, a phosphate, and one of four bases.

Question 7

RNA and DNA differ in

Answer 7

the sugar component and one of the bases.

Question 8

In deoxyribose, which carbon lacks an oxygen atom that is included in ribose?

Answer 8

2

Question 9

Sugar carbons are numbered with primes to

Answer 9

differentiate them from atoms in the bases.

Question 10

The sugars in both nucleic acids are linked to one another by

Answer 10

phophodiester bridges.

Question 11

DNA bases that are derivatives of purine.

Answer 11

adenine and guanine

Question 12

DNA bases that are derivatives of pyrimidine.

Answer 12

cytosine and thymine

Question 13

In RNA, one of the four major bases is ______ instead of ______.

Answer 13

uracil; thymine

Question 14

Each phosphodiester bridge has a ______ charge.

Answer 14

negative

Question 15

Nucleoside

Answer 15

A unit consisting of a base bonded to a sugar.

Question 16

4 nucleosides in RNA

Answer 16

adenosine, guanosine, cytidine, and uridine

Question 17

4 nucleosides in DNA

Answer 17

deoxyadenosine, deoxyguanosine, deoxycytidine, and thymidine

Question 18

A nucleotide is a

Answer 18

nucleoside joined to one or more phosphoryl groups by an ester linkage.

Question 19

The monomers linked together to form the building blocks in DNA and RNA are

Answer 19

nucleotide triphosphates.

Question 20

The four nucleotides that link to form DNA are monophosphates called

Answer 20

deoxyadenylate, deoxyguanylate, deoxycytidylate, and thymidylate.

Question 21

The four nucleotides that link to form RNA are monophosphates called

Answer 21

adenylate, guanylate, cytidylate, and uridylate.

Question 22

A DNA chain has directionality, commonly called

Answer 22

polarity.

Question 23

The human genome comprises approximately ________ nucleotides in each strand of DNA.

Answer 23

3 billion

Question 24

The nucleotides in the human genome are divided into distinct molecules of DNA called

Answer 24

chromosomes.

Question 25

The double helix in DNA is stabilized by

Answer 25

hydrogen bonds and van der Waals interactions.

Question 26

In DNA, adjacent bases are separated by approximately

Answer 26

3.4 Angstoms.

Question 27

In DNA, there are approximately _______ bases per turn.

Answer 27

10.4

Question 28

The diameter of the DNA helix is about

Answer 28

20 Angstroms.

Question 29

Stem-loops are created when

Answer 29

two complementary sequences within a single strand come together to form double-helical structures.

Question 30

The sequence of bases of one strand of the double helix in DNA precisely determines

Answer 30

the sequence of the other strand.

Question 31

Semiconservative replication

Answer 31

the process by which DNA makes copies of itself, each strand, as it separates, synthesizing a complementary strand.

Question 32

The dissociation of the double helix is called

Answer 32

melting.

Question 33

The melting temperature (T_m) of DNA is the temperature at which

Answer 33

half the helical structure is lost.

Question 34

Hypochromism

Answer 34

Stacked bases in nucleic acids absorb less ultraviolet light than do unstacked bases.

Question 35

Annealing

Answer 35

Separated complementary strands of nucleic acids spontaneously reassociate to form a double helix when the temperature is lowered below T_m

Question 36

DNA polymerases

Answer 36

catalyze the step-by-step addition of deoxyribonucleotide units to a DNA strand.

Question 37

DNA replication has an error rate of less than

Answer 37

10^-8 per base pair.

Question 38

The information stored in DNA becomes useful when it is expressed in

Answer 38

the production of RNA and proteins.

Question 39

Messenger RNA (mRNA) is

Answer 39

the template for protein synthesis or translation.

Question 40

Transfer RNA (tRNA)

Answer 40

carries amino acids in an activated form to the ribosome for peptide-bond formation.

Question 41

Ribosomal RNA (rRNA) is the major component of

Answer 41

ribosomes.

Question 42

In prokaryotes, there are three kinds of rRNA

Answer 42

23S, 16S, and 5S

Question 43

Abundance of types of RNA

Answer 43

rRNA > tRNA > mRNA

Question 44

All cellular RNA is synthesized by

Answer 44

RNA polymerases.

Question 45

Transcription

Answer 45

The synthesis of RNA from a DNA template.

Question 46

RNA polymerase requires what 3 components?

Answer 46

1. A template
2. Activated precursors
3. A divalent metal ion

Question 47

Transcription begins near

Answer 47

promoter sites.

Question 48

Transcription ends at

Answer 48

terminator sites.

Question 49

Discrete start and stop signals for transcription are encoded in

Answer 49

the DNA template.

Question 50

The adapters in protein synthesis are

Answer 50

transfer RNAs.

Question 51

tRNAs contain what two sites.

Answer 51

1. amino acid-attachment
2. template-recognition

Question 52

How many nucleotides encode an amino acid?

Answer 52

3

Question 53

Synonyms

Answer 53

Codons that specify the same amino acid.

Question 54

Degeneracy of the genetic code minimizes

Answer 54

the deleterious effects of mutations.

Question 55

Codons representing chain termination

Answer 55

UAA, UAG, and UGA

Question 56

Spliceosomes

Answer 56

Assemblies of proteins and small RNA molecules that carry out splicing.

Question 57

Nascent

Answer 57

having recently come into existence.

Question 58

Translation

Answer 58

The synthesis of a protein from an RNA template.