Intro to protein synthesis/translation -- Lecture 14 (exam 3)

Question 1

protein synthesis/translation:

translation (definition)

Answer 1

information in an mRNA is translated into a protein

Question 2

protein synthesis/translation:

necessary components:

Answer 2

ribosomes

transfer RNAs (tRNAs)

a mature mRNA that contains a genetic code

Question 3

the genetic code:

genetic code is a series of ___

Answer 3

codons

Question 4

the genetic code:

codon (definition)

Answer 4

a sequence of 3 nucleotide bases on an mRNA

Question 5

the genetic code:

codon functions:

Answer 5

some codons specify a particular amino acid

some codons signal where translation should ‘start or stop’ on the mRNA

Question 6

the genetic code:

how was the code deciphered?

Answer 6

Marshall Nirenberg (1960’s)

did a series of experiments:

1) generated & translated a series of mRNAs
2) examined the amino acid content of the proteins

Question 7

what did Nirenberg discover about genetic code?

Answer 7

codons are 3 bases in length

which amino acid each codon specifies

Question 8

nature of the genetic code:

universal:

Answer 8

the code is the same in virtually all organisms (rare exceptions exist)

Question 9

nature of the genetic code:

the genetic code is ___

Answer 9

redundant

Question 10

nature of the genetic code:

the genetic code is redundant (describe how)

Answer 10

61 codons encode 20 amino acids

more than 1 codon for some amino acids

Question 11

nature of the genetic code:

code has ___ translation START codon ___ (what is it)

Answer 11

1; (AUG, Met)

Question 12

nature of the genetic code:

code has ___ translation STOP codons

Answer 12

3

Question 13

nature of the genetic code:

is there any other punctuation besides ‘start’ and ‘stop’?

Answer 13

no other punctuation

Question 14

ribosomes:

ribosomes (what are they & what do they do)

Answer 14

enzyme complex that translate the information in mRNAs into proteins

Question 15

ribosomes:

ribosomes are made of 2 subunits:

Answer 15

large ribosomal subunit

small ribosomal subunit

Question 16

ribosomes:

each ribosomal subunit is made up of multiple ___ and ___

Answer 16

ribosomal proteins

ribosomal RNAs

Question 17

ribosome division of labor:

functions:

small subunit (what is it in charge of)

Answer 17

positioning of the mRNA

Question 18

ribosome division of labor:

functions:

both subunits (what are they in charge of)

Answer 18

binding tRNAs

Question 19

ribosome division of labor:

functions:

large subunit (what is it in charge of)

Answer 19

peptide bond formation

Question 20

ribosome division of labor:

functions:

large subunit, release factor (what are they in charge of)

Answer 20

recognition of the ‘stop’ codon and protein release

Question 21

ribosome division of labor:

functions:

what is in charge of the positioning of the mRNA?

Answer 21

small subunit

Question 22

ribosome division of labor:

functions:

what is in charge of binding tRNAs?

Answer 22

both subunits

Question 23

ribosome division of labor:

functions:

what is in charge of peptide bond formation?

Answer 23

large subunit

Question 24

ribosome division of labor:

functions:

what is in charge of recognition of the ‘stop’ codon and protein release?

Answer 24

large subunit, release factor

Question 25

ribosome division of labor:

functions:

rRNAs have ___

Answer 25

enzymatic function

Question 26

ribosome division of labor:

functions:

rRNAs have enzymatic function:

Answer 26

RNA molecules that catalyze reactions like enzymes are called Ribozymes

Question 27

ribosome division of labor:

functions:

ribozymes

Answer 27

RNA molecules that catalyze reactions like enzymes