T2M3

Question 1

In prokaryotes assembly and translation occurs in the

Answer 1

cytoplasm

Question 2

Eukaryotic transcription occurs in

Answer 2

nucleus

Question 3

Eukaryotic translation occurs in the

Answer 3

cytoplasm

Question 4

Antibiotics work by

Answer 4

disrupting translation at site of the ribosome

Question 5

Translated polypeptide coded by insulin gene is how long?

Answer 5

110 amino acids

Question 6

Functional insulin protein 2 chains

Answer 6

Alpha - 21 aa’s
Beta - 30 aa’s

Question 7

preproinsulin to proinsulin

Answer 7

pre loses signal sequence, disulfide bonds

Question 8

proinsulin to insulin

Answer 8

C chain drops off

Question 9

What is alternative splicing?

Answer 9

primary transcripts from same gene can be spliced in different ways to yield different mRNAs and therefore different protein products

Question 10

George Beadle & Edward Tatum

Answer 10

• 1941 studied relationship of genes & enzymes
• examined three neurospora crassa mutants
• mutants created by UV or X-ray treatments

Question 11

Wild-type characteristics

Answer 11

• grows on minimal medium
• able to make all the amino acids and other substances that it needs to survive

Question 12

Minimal medium

Answer 12

support medium combined only with molecules that are necessary for the growth of wild-type individuals

Question 13

Srb & Horowitz hypothesis

Answer 13

certain genes were involved in making each of the 3 types of enzymes

Question 14

Conclusions of Srb & Horowitz

Answer 14

• for a mutant to grow on ornithine or citrulline it must be able to make arginine
• if a mutant is unable to grow with ornithine or citrulline added to medium (arg3) then it must have a defect in the enzyme that converts citrulline to arginine

Question 15

Ornithine is a precursor to

Answer 15

citrulline

Question 16

Citrulline is a precursor to

Answer 16

arginine

Question 17

the function of a gene is to

Answer 17

determine the production of a specific enzyme (one gene one enzyme - polypeptide - …)

Question 18

what does tRNA do?

Answer 18

enables the translation of the information in the mRNA genetic message to a polypeptide

Question 19

tRNA molecules are able to

Answer 19

transfer amino acids from a pool of cytoplasmically situated amino acids to a growing polypeptide strand in a ribosome

Question 20

tRNA is made up of

Answer 20

a single RNA strand ranging between 70-90 nucleotides in length

Question 21

complementarity along many stretches of a tRNA molecule results in

Answer 21

stretches of hydrogen bonding between complementary nucleotide bases for the formation of four double-helical segments and three characteristic loops seen in all tRNA molecules

Question 22

What is anticodon region of tRNA?

Answer 22

specific nucleotide triplet that forms complementary base-pairs with a specific mRNA codon that codes for a specific amino acid written in 3’ to 5’ direction

Question 23

3’ end of tRNA

Answer 23

protruding amino acid attachment site that is
made up of a single stranded CCA nucleotide

Question 24

terminal A point of attachment for ? when ?

Answer 24

an amino acid during tRNA molecule activation

Question 25

aminoacyl tRNA synthetase active site recognizes

Answer 25

the anticodon end of the tRNA and the region of the amino acid attachment site

Question 26

How many aminoacyl tRNA synthetase?

Answer 26

20, one for each amino acid

Question 27

For proper translation tRNA anticodon pairs with the

Answer 27

appropriate mRNA codon

Question 28

mRNA can code for

Answer 28

64 codons and 20 amino acids

Question 29

wobble

Answer 29

greater flexibility for base pairing between the third nucleotide of a codon and the corresponding base of a tRNA anticodon, explains redundancy in genetic code

Question 30

In eukaryotes, the initiation of translation occurs when

Answer 30

a translation initiation complex forms towards the 5’ cap of the mRNA and then scans the mRNA until an AUG start codon is encountered

Question 31

Where will prokaryotes translation initiation complex assemble?

Answer 31

at one or more ribosome binding sites called Shine-Dalgarno sequence because they have no 5' caps

Question 32

Shine-Dalgarno sequences located

Answer 32

a few bases upstream of the translation start codon (AUG)

Question 33

prokaryotes and eukaryotes basic machinery during translation

Answer 33

large and small subunits of the ribosome, an mRNA molecule, charged tRNA amino acids and initiation, elongation and termination factors