Chapter 15 Prokaryotic Transcription

Question 1

Which of the following is an incorrect function of these enzymes in prokaryotic DNA replication?

A.Helicase—unwinds and separates parental double helix

B.Primase—forms DNA primer to start replication

C.Ligase—bonds together Okazaki fragment

D.None of the above—all are correct pairings

Answer 1

B

Question 2

The information in DNA is a triplet code. How many unique mRNA codons can be constructed from the four different RNA nucleotides?

Answer 2

64

Question 3

If the nucleotide sequence on the coding DNA strand is CAT, what is the corresponding codon on mRNA?

Answer 3

CAU

Question 4

=“turn a gene on”

Answer 4

Gene Expression

Question 5

Expressing different genes in a cell’s nucleus results in the

Answer 5

production of different proteins

Question 6

What gener located on chromosome 11 encodes the info to build up the protein hemoglobin?

Answer 6

HBB gene

Question 7

What causes the cells to be sickle shape?

Answer 7

The change in the DNA code causes ABNORMAL HEMOGLOBIN structure which results in sickled shaped blood cells

Question 8

•“black urine” disease

Answer 8

alkaptonuria

Question 9

Who studied alkaptonuria

Answer 9

Garrod

Question 10

–examined several generations of families with the “black urine” disease and determined that it is inherited via a recessive allele

Answer 10

Garrod

Question 11

What is important about Garrod?

Answer 11

Made observational inference, he did not conduct any research

Question 12

–hypothesized that patients with the disease lacked a particular enzyme to catalyze the breakdown of homogentisic acid and thus they had black urine.

Answer 12

Garrod

Question 13

–Inferred that a gene had something to do with enzyme production

Answer 13

Garrod

Question 14

Scientific data for explaining the function of genes came from studying

Answer 14

fungus

Question 15

–studied Neurospora crassa— Bread mold which can grow on a minimal medium

Answer 15

•George Beadle and Edward Tatum, 1941

Question 16

Neurospora cells that can grow on minimal media must be able to

Answer 16

•synthesize all their necessary biological molecules

Question 17

hypothesized that each gene in an organism is responsible for making a protein, most of which function as enzymes in biochemical pathways.

Answer 17

Beadle and Tatum

Question 18

–Used X-rays to intentionally damage the DNA in cells of Neurospora

Answer 18

Beadle and Tatum

Question 19

A GENE CONTAINS THE

ENCODED INFORMATION

USED TO BUILD A PROTEIN

Answer 19

Beadle and Tatum

Question 20

states that information flows in one direction:

Answer 20

central dogma

Question 21

is the flow of information from DNA to RNA.

Answer 21

transcription

Question 22

is the flow of information from RNA to protein.

Answer 22

Translation

Question 23

Exception(s) to central dogma

Answer 23

Some viruses have a RNA genome and first
do reverse transcription!

Question 24

“to copy”

Answer 24

Transcription

Question 25

3 important things to remember about RNA

Answer 25

1) is single stranded not double stranded, 2) has ribose sugar not deoxyribose sugar, and 3) has the base uracil NOT thymine.

Question 26

RNA) is involved in both transcription and translation

Answer 26

mRNA

Question 27

making an mRNA copy of a gene

Answer 27

Transcription

Question 28

The strand that is copied in transcription

Answer 28

template strand

Question 29

Template strand is identified by

Answer 29

3' to 5' sequence

Question 30

The other strand of DNA that is NOT used as a template is called the

Answer 30

Coding Strand

Question 31

•If DNA template strand reads 3’ ATACGATTA 5’ What would be the mRNA bases?

Answer 31

• 5’ UAUGCUAAU 3’

Question 32

converts base-pair code in mRNA a sequence of amino acids (a polypeptide) and involves all three types of RNA: mRNA, tRNA, and rRNA

Answer 32

Translation

Question 33

hypothesized that the DNA code is read in a series of blocks of information— each block consisting of 3 bases

Answer 33

Crick and Brenner

Question 34

set of 3 mRNA nucleotides that specifies a particular amino acid

Answer 34

codon

Question 35

the series of nucleotides read in sets of 3 (codon) with no punctuation

Answer 35

reading frame

Question 36

If a DNA triplet on the template strand reads CAT, the corresponding mRNA codon would be

Answer 36

GUA

Question 37

Alternative splicing

Answer 37

A.Occurs only in eukaryotes

Question 38

–Transcription: DNA→RNA “to copy” •Involves one primary type of RNA—

Answer 38

messenger RNA

Question 39

–Translation: RNA → protein •Involves three primary types of RNA:

Answer 39

–messenger RNA (mRNA) –transfer RNA (tRNA) –ribosomal RNA (rRNA)

Question 40

•is a single-stranded RNA copy of the DNA gene

Answer 40

messenger RNA

Question 41

are the molecules that transport the amino acids to the ribosomes

Answer 41

Transfer RNA

Question 42

along with proteins compose the ribosomes —the organelle that produces the polypeptide

Answer 42

ribosomal RNA

Question 43

was the primary individual who identified most of the codons that specify each amino acid (1961-1966). Used bacteria & artificial RNA

Answer 43

Nirenberg

Question 44

3 codons (UAA, UGA, UAG) in the genetic code are used to terminate translation

Answer 44

Stop codons

Question 45

List of Stop codons

Answer 45

3 codons (UAA, UGA, UAG) in the genetic code are used to terminate translation

Question 46

the codon (AUG) used to signify the start of translation; it also codes for amino acid methionine

Answer 46

start codon

Question 47

start codon

Answer 47

AUG, methionine

Question 48

The genetic code is DEGENERATE:

Answer 48

some amino acids are specified by more than one codon.

Question 49

The genetic code is also SPECIFIC:

Answer 49

Each codon never specifies more than one amino acid

Question 50

Differences between tanscription i eukaryotes versus prokaryotes

Answer 50

1) In eukaryotes, transcription occurs in nucleus and translation occurs in cytoplasm 2) RNA processing only in eukaryotes

Question 51

the key enzyme in transciption

Answer 51

RNA Polymerase

Question 52

•The enzyme that produces mRNA by transcribing the DNA of a gene

Answer 52

RNA Polymerase

Question 53

cells contain a single type of RNA polymerase

Answer 53

Prolkaryotic cells

Question 54

2 distince forms of RNA Ploymerase in prokaryotic cells

Answer 54

core enzymes and holoenzymes

Question 55

is composed of the core enzyme and the sigma factor which is required for transcription initiation

Answer 55

holoenzyme

Question 56

is capable of RNA synthesis from a DNA template but cannot initiate synthesis

Answer 56

core enzyme

Question 57

Prokaryotic Transcription: Step One:

Answer 57

Initiation

Question 58

Prokaryotic Transcription: Step One: Initiation

Answer 58

–RNA polymerase attaches and initiates transcription at the promoter segment of a gene, “upstream” of the information contained in the transcription unit.

Question 59

signals the beginning of transcription

Answer 59

promoter

Question 60

part of this region conains the info that specifies an amino acid sequence

Answer 60

Transcribed Region

Question 61

Signals the end of transcription

Answer 61

Terminator

Question 62

RNA polymerase binds to promoter and DNA unwinds

Answer 62

Step 1: Initiation in Prokaryotes

Question 63

Prokaryotic Transcription: Step Two:

Answer 63

Elongation

Question 64

Prokaryotic Transcription: Step Two: Elongation

Answer 64

During elongation, the transcription bubble moves down the DNA template at a rate of 50 nucleotides/sec.

Question 65

mRNA synthesis is in the ______ direction along the _____ template DNA strand

Answer 65

5’→3’ ,3’→5’

Question 66

The transcription bubble consists of:

Answer 66

1) RNA polymerase 2) DNA template 3) growing RNA transcript

Question 67

Sigma factor released—RNA polymerase moves along the template strand synthesizing mRNA in the 5’→3’ direction

Answer 67

Step 2: Elongation

Question 68

After transcription bubble passes, the now-transcribed DNA

Answer 68

DNA is rewound as it leaves the bubble.

Question 69

STEP 3 (Transcription):

Answer 69

Termination

Question 70

involves: 1) Phosphodiester bond formation ceases 2) RNA-DNA hybrid within the transcription bubble dissociates 3) RNA polymerase releases DNA 4) DNA within the transcription bubble rewinds

Answer 70

Prokaryotic Tanscription Step 3: Termination

Question 71

Prokaryotic Tanscription Step 3: Termination Involves:

Answer 71

1) Phosphodiester bond formation ceases 2) RNA-DNA hybrid within the transcription bubble dissociates 3) RNA polymerase releases DNA 4) DNA within the transcription bubble rewinds

Question 72

In prokaryotes ONLY,

Answer 72

transcription is coupled to immediate translation to produce protein ---- Translation of the mRNA message by the ribosomes is occurring before transcription is finished As soon as a 5’ end of mRNA becomes available, ribosomes are loaded onto this to begin translation.

Question 73

–RNA polymerase identifies where to begin transcription by binding to a promoter and DNA is unwound

Answer 73

Transcription Intitiation in Prokaryotes

Question 74

–RNA nucleotides are added to the 3’ end of the new RNA

Answer 74

Transcription Elongating in Prokaryotes

Question 75

–RNA polymerase stops transcription when it encounters terminators in the DNA sequence

Answer 75

Transcription termination in prokaryotes