Chapter 17

Question 1

What is the link between genotype and phenotype?

Answer 1

Proteins

Question 2

What is gene expression?

Answer 2

The process by which dna directs the synthesis of proteins

Question 3

Transcription

Answer 3

The synthesis of RNA using information in DNA Occurs in the nucleus in Eukyartic cells

Question 4

Translation

Answer 4

the synthesis of a polypeptide using the information in the mRNA occurs in cytoplasm for Eukaryotic cells

Question 5

What are the ribosomes role in translation?

Answer 5

Site of translation, linking amino acids to polypeptide chains

Question 6

Primary transcript

Answer 6

RNA that is not translated into a protien

Question 7

Triplet code

Answer 7

The genetic instructions for polypeptide chain are written in the DNA as a series of non over lapping 2 nucleotide words

Question 8

Codons

Answer 8

mRNA nucleotide triplets … complementray to the template strand (opposite)

Question 9

What are the base pairing rules for DNA to RNA?

Answer 9

U pairs with A and C pairs with G

Question 10

Coding strand

Answer 10

the nontemplate DNA strand

Question 11

Reading frame

Answer 11

Correct groupings

Question 12

What direction is the mRNA read?

Answer 12

5’ to 3’ direction

Question 13

RNA polymerase

Answer 13

pries the 2 strands of DNA apart and joins together RNA nucloetides complementary to the DNA template strand Can start a chain from scratch only add in 5’-3’ direction

Question 14

Promoter

Answer 14

Where RNA polymerase attaches and initiates transcription

Question 15

Transcript unit

Answer 15

the stretch of DNA downstream from the promoter that is transcribed into an RNA molecule

Question 16

What are the 3 stages of transcription?

Answer 16

initiation, elongation adn termination

Question 17

Starting point

Answer 17

the necleotide where RNA polymerase actually begins synthesizing mRNA

Question 18

Transcription factors

Answer 18

a collection of protiens that help guide the binding of RNA polymerase and the initiation of transcription

Question 19

Transcription initiation complex

Answer 19

the whole complex of transcription factors and RNA polymerase 11 bound to the promotor

Question 20

How does the transcription terminate in bacteria?

Answer 20

through a terminator sequence in the DNA. .The transcribed terminator (an RNA sequence) functions as the temrination signal causing the polmerase to detach from DNA and release the transcript

Question 21

How does the transcription terminate in eukaryotes?

Answer 21

RNA polmerase 11 transcribes a sequence on the DNA called the polyadenylation signal sequence, which specifies a polydenylation signal int eh pre-mRNA, The protiens cut the RNA transcript free from the polymerase releasing the mRNA

Question 22

RNA processing

Answer 22

both ends of the primary transcript are altered.

Question 23

5’ cap

Answer 23

a modified form of guanine nucleotide added onto the 5’ end after transcription of the first 20-40 nucleotides have been transcribed

Question 24

poly-A tail

Answer 24

at the 3’ end an enzyme adds 50-250 more adenine nucleotides

Question 25

RNA splicing

Answer 25

large portions of RNA primary transcript molecules are removed and the remaining portions are reconnected

Question 26

Introns

Answer 26

the non coding segments of nucleic acid that lie between coding regions

Question 27

Exons

Answer 27

non introns regions that are usually expressed being translated into amino acid sequences

Question 28

Spliceosome

Answer 28

a large complex made of protiens and small RNAs Removes introns and joins together exons

Question 29

What is the purpose of the modifications 5’ cap and poly-A tail?

Answer 29

1. Aid in export of mRNA 2. protect from degradation 3. helps ribosomes attach during translation

Question 30

Where does translation happen in eukaryotic cells?

Answer 30

In cytoplasm

Question 31

Where does transcription happen in eukaryotic cells?

Answer 31

In nucleus

Question 32

Which codon has a code as a start signal?

Answer 32

AUG (MET or M)

Question 33

Which codons have a code to stop or terminate?

Answer 33

UAA UAG UGA

Question 34

Which direction does the RNA polymerase move in elongation?

Answer 34

Downstream

Question 35

What is the initiation of transcription process for Eukaryoitc cells?

Answer 35

1. Promotor includes a TATA about 25 nucleotides upstream from starting point 2. Several transcription facots recognize TATA box and bind to DNA 3. RNA polymerase and addtional transcription factors bind to DNA forming a transcription initation complex 4. RNA polymerase 11 unwinds the DNA and begins synthesizing RAN