Chapter 20

Question 1

What are genes made of?

Answer 1

DNA

Question 2

What is the Frederick Griffith experiment?

Answer 2

it was comparing two strands of Streptococcus there was an S strain is virulent and a
R strain is nonvirulent. when a variant was dead the mouse lived but with a cocktail of live and dead cells the animal died.

Question 3

what did Avery, MacLeod, & McCarty process of the experiment?

Answer 3

first they repeated Griffith’s experiment, then they found out that Removal of all protein from the transforming material did not destroy its ability to transform R strain cells, DNA-digesting enzymes destroyed all transforming ability, and lastly Supported DNA as the genetic material, at least in bacteria

Question 4

what was the Hershey & Chase experiment?

Answer 4

they were able to separate the phages into radioactive sulfur-containing protein ghosts and radioactive phosphorus-containing DNA. They found that the radioactive sulfur protein ghosts could attach to bacterial membranes while the radioactive phosphorus DNA could not

Question 5

How are monomers linked?

Answer 5

monomers are linked by Phosphodiester bonds

Question 6

how are phosphodiester bonds formed

Answer 6

Formed between the phosphate group of one nucleotide and the 3′ —OH of the next nucleotide

Question 7

what is the Structure of a single strand of DNA?

Answer 7

Phosphodiester backbone and a 5’ to 3’

Question 8

Erwin Chargaff determined that:

Answer 8

Always an equal proportion of two-ringed purines (A and G) and single-ringed pyrimidines (C and T) Amount of adenine = amount of thymine amount of cytosine = amount of guanine The ratio of A-T and G-C varies by species

Question 9

what did Rosalind Franklin discover?

Answer 9

she discovered that the molecule has a diameter of 2 nm and makes a complete turn of the helix every 3.4 nm she used Maurice Wilkins’

Question 10

James Watson and Francis Crick discover?

Answer 10

Deduced the structure of D N A using evidence from Chargaff, Franklin, and others, Strands
connected via hydrogen bonds between bases on opposite strands, Result is specific base-pairs: A-T and G-C, Helix has a consistent diameter, is stable because of additive property of thousands of low-energy hydrogen bonds

Question 11

Pattern of base-paring is

Answer 11

complementary

Question 12

Two strands of single DNA molecule are _____ identical

Answer 12

not

Question 13

each strand specifies the other by ____

Answer 13

base-pair complementarity

Question 14

Conservative DNA is

Question 15

semiconservative DNA is

Question 16

dispersive DNA is

Question 17

what was the Meselson and Stahl experiment for round 1?

Answer 17

Round 1 = 1 density band
Conservative model rejected
Dispersive & Semiconservative supported

Question 18

what was the Meselson and Stahl experiment for round 2?

Answer 18

Round 2 = 2 bands
Semiconservative supported
Dispersive rejected

Question 19

what are the stages of DNA replication?

Answer 19

Initiation, Elongation, Termination,

Question 20

central dogma steps

Answer 20

Transcription = D N A → R N A (both nucleic acids)

Translation = R N A → protein (from nucleic acid to protein)

Retroviruses violate this order using reverse transcriptase to convert their R N A genome into DNA

Question 21

Transcription = D N A-directed synthesis of _____

Answer 21

RNA

Question 22

the template strand is:

Answer 22

Only one strand of DNA copied as RNA

Question 23

the coding strand is:

Answer 23

Strand of DNA not used as template

Question 24

mRNA used to direct _____ of polypeptides

Answer 24

synthesis

Question 25

Messenger RNA

Answer 25

intermediate form of information from nucleus to cytoplasm for processing

Question 26

Ribosomal RNA

Answer 26

class of R N A found in ribosomes, is essential for their function in protein production

Question 27

Transfer RNA

Answer 27

intermediary adapter molecule between mRNA and amino acids during protein synthesis

Question 28

Small nuclear RNA

Answer 28

part of machinery involved in processing of “pre-mRNA” in splicing

Question 29

Signal recognition particle RNA

Answer 29

mediator for proteins synthesized on the rough endoplasmic reticulum

Question 30

Small RNAs

Answer 30

– involved in control of gene expression

Question 31

Start codon Codon ______ used to signify the start of translation

Answer 31

AUG

Question 32

Stop codons Three codons used to terminate translation

Answer 32

UAA, UGA, UAG

Question 33

Many eukaryotic genes contain sequences that are ___represented in mRNA

Answer 33

Not

Question 34

Introns

Answer 34

non-coding sequences

Question 35

Exons

Answer 35

sequences that will be translated

Question 36

exon shuffling

Answer 36

introns suggests exons are functional domains and intron-exon arrangements represent shuffling of those domains over evolutionary timescale

Question 37

Some support from genetic data, but _____

Answer 37

not universal

Question 38

Promoter

Answer 38

forms recognition and binding site for RNA polymerase( where start site is located)

Question 39

Start site

Answer 39

actual site where RNA synthesis begins

Question 40

All RNA is synthesized from a DNA template by _____

Answer 40

transcription

Question 41

Sequences the “stop” signal to RNA polymerase

Answer 41

RNA–DNA hybrid within the transcription bubble dissociates R N A polymerase releases the DNA DNA rewinds

Question 42

_______ bonds are weakest bonds, results in dissociation of RNA from DNA in transcription bubble

Answer 42

A-U

Question 43

Can form a hairpin, which causes RNA polymerase to pause at ______

Answer 43

uracil

Question 44

what are the differences of Procaryotes and eukaryotes replication

Answer 44

procaryotes: Prokaryotes have operons,

Question 45

Operon

Answer 45

A single mRNA may contain multiple genes

Question 46

RNA polymerase I transcribes what?

Answer 46

rRNA

Question 47

RNA polymerase II transcribes what?

Answer 47

mRNA and some snRNA

Question 48

RNA polymerase III transcribes what?

Answer 48

tRNA and some other small RNAs

Question 49

Each R N A polymerase recognizes its own_____

Answer 49

promoter

Question 50

RNA Pol II promoters:

Answer 50

Consist of a “core promoter” that can be composed of a number of elements, including the TATA box (TATA sequence upstream of start site)

Question 51

RNA Pol III promoters

Answer 51

Most are found within the gene itself

Question 52

Elongation complex factors coordinated by structural feature called

Answer 52

carboxyl terminal domain

Question 53

explain Eukaryotic initiation complex

Answer 53

proteins or protein complexes involved in the initiation phase of eukaryotic translation. These proteins help stabilize the formation of ribosomal preinitiation complexes around the start codon and are an important input for post-transcription gene regulation.

Question 54

_____ is added to 5′ end, with GTP modified by addition of _______ group, called methyl-G cap Involved in ________ initiation, RNA stability, and further processing

Answer 54

GTP, methyl, translation

Question 55

Transcriptome

Answer 55

all the RNAs produced from a genome

Question 56

Proteome

Answer 56

all the proteins produced from a genome

Question 57

How is it possible for one gene to produce multiple transcripts or proteins?

Answer 57

Alternative splicing, processes of a single primary transcript being spliced into different mRNAs by including different sets of exons, can account for deviation from balanced ratio