Genetics 2

Question 1

protein synthesis is

Answer 1

the process where information encoded in the genome is translated into specific cellular function in the cytoplasm

Question 2

genetic code=

Answer 2

sequence of adjacent bases ultimately determines the sequence of amino acids in the encoded poly peptide

Question 3

rRNA

Answer 3

ribosomal RNA supports structural unit of the ribosomes

Question 4

tRNA

Answer 4

transfer RNA is the link between code contained in base sequence of each mRNA and the AA sequence of the protein encoded

Question 5

non transcribed strand=

Answer 5

coding or sense strand

Question 6

transcribed strand=

Answer 6

non-coding or antisense strand

Question 7

additions to primary DNA modification

Answer 7

addition of a chemical “cap” structure to the 5’ end

-addition of polyA tail to 3’ end

Question 8

cleavage of ____ end in modification

Answer 8

cleavage of 3’ end at specific point downstream from the coding information

Question 9

polyA

Answer 9

location specified by sequence AAUAAA found in 3’ untranslated portion of RNA transcript
provides stability to mRNA

Question 10

prior to translation, how is RNA processed and spliced

Answer 10

-introns are removed
-exons are spliced together
(mRNA is then transported out of the nucleus and into the cytoplasm)

Question 11

in translation, what does tRNA do

Answer 11

it brings the correct amino acid sequence into position

Question 12

what are ribosomes

Answer 12

are macromolecular complexes made up of rRNA and are the sites of protein synthesis

Question 13

initiator codon

Answer 13

AUG- methionine- establishes the reading frame for all subsequent codons

Question 14

3 stop codons

Answer 14

UAA, UAG, UGA

Question 15

post translational processing of polypeptide chain

Answer 15

-fold, bind, form 3D structure, combine (2 or more polypeptide chains) to form protein complex

Question 16

what are transcription factors?

Answer 16

are specific proteins that regulate transcription

Question 17

promoter sequence does

Answer 17

interacts with transcription factors

Question 18

2 promoters found in tissue specific genes

Answer 18

TATA box

CAT

Question 19

TATA box

Answer 19

conserved region rich in adenines and thymines

-appears to be important for determining the position of the start of transcription

Question 20

CAT

Answer 20

conserved region

-involved in normal gene expression

Question 21

what is the role of promoters

Answer 21

• play a role in gene regulation

- can be site of mutation that can interfere with its normal expression and function

Question 22

house keeping genes (CG) are expressed where and contain what?

Answer 22

• expressed in most or all tissues that lack the CAT and TATA promoter boxes
• contain high proportion of cytosines and guanines

Question 23

what do CG (house keeping genes) rich sequence elements serve as

Answer 23

serve as binding sites for specific transcription factors

Question 24

what are house keeping genes associated with

Answer 24

repression of gene transcription

cancer, genomic imprinting, X chromosome inactivation

Question 25

what do enhancers do?

Answer 25

stimulate transcription

• establishing tissue specificity
• level of expression on many genes

Question 26

what is RNA splicing

Answer 26

splicing reactions guided by specific sequences in the primary RNA transcript at both 5’ and 3’
GT at 5’
AG at 3’

Question 27

how common are alternative transcripts

Answer 27

2 to 3 alternative transcripts per gene in the human genome

Question 28

what does alternative splicing lead to

Answer 28

the synthesis of multiple related but different mRNAs, each of which can be subsequently translated to generate different protein products