Week 6_Alternative splicing and translation

Question 1

what is alternative splicing?

Answer 1

when some exons are also spliced out

Question 2

alternative splicing allows:

Answer 2

multiple versions of a gene’s mRNA to be produced

multiple versions of the protein to be produced

Question 3

what is an example of alternative splicing?

Answer 3

dystrophin gene (79 exons), 19 different splice variants

Question 4

alternative splicing allows ~___ protein coding genes to produce ~___ different proteins

Answer 4

20,000 protein coding genes to produce 100,000 different proteins

Question 5

alternative splicing is regulated (in part) by…

each influences how…

Answer 5

splice site activator proteins

splice site repressor proteins

each influences how mRNAs will be spliced

Question 6

proper regulation of ___ is important to biological functions

Answer 6

alternative spliicng

Question 7

altered regulation of alternative splicing may be a factor in ___ and in ___

Answer 7

autism

cancer cell biology

Question 8

what is translation?

Answer 8

when information in an mRNA is translated into a protein

Question 9

what are the necessary components of protein synthesis/translation?

Answer 9

a mature mRNA that contains a genetic code

transfer RNAs (tRNAs)

ribosomes

Question 10

the genetic code is a series of ___

Answer 10

codons

Question 11

what is a codon?

Answer 11

a sequence of 3 nucleotide bases

Question 12

what are the functions of a codon?

Answer 12

specify a particular amino acid

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

Question 13

who deciphered the code?

Answer 13

Marshall Nirenberg

Question 14

what experiments did Marshall Nirenberg do to decipher the code?

Answer 14

(1) generated and translated mRNAs

(2) examined the amino acid content of the proteins

Question 15

how do you identify code?

Answer 15

(1) make synthetic mRNAs containing 1 repeated base
- translate the mRNAs using cytoplasmic extract
- determine the amino acid content of the resulting proteins

(2) make mRNAs with different combinations of RNA nucleotides
- test all possible codon sequences

Question 16

what is the universal nature of genetic code?

Answer 16

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

Question 17

the genetic code is ___

Answer 17

redundant

Question 18

how is the genetic code redundant?

Answer 18

61 codons encode 20 amino acids

more than 1 codon for some amino acids

Question 19

code has ___ translation START codon, which is…

Answer 19

1

AUG, Met

Question 20

there are ___ translation STOP codons

Answer 20

3

Question 21

what are ribosomes?

Answer 21

enzymes that translate information in mRNAs into proteins

Question 22

ribosomes are made of ___ subunits

they are…

Answer 22

2

large ribosomal subunit

small ribosomal subunit

Question 23

each ribosomal subunit is made up of multiple ___ and ___

Answer 23

ribosomal proteins

ribosomal RNAs

Question 24

function of small subunit of ribosome

Answer 24

positioning of the mRNA

Question 25

function of both subunits of ribosome

Answer 25

binding tRNAs

Question 26

function of large subunit and rRNA in ribosome

Answer 26

peptide bond formation

Question 27

function of large subunit, rRNA, release factor in ribosome

Answer 27

recognition of 'Stop' codon and protein release

Question 28

which ribosome subunit is in charge of positioning of the mRNA?

Answer 28

small subunit

Question 29

which ribosome subunit is in charge of binding tRNAs?

Answer 29

both subunits

Question 30

which ribosome subunit is in charge of peptide bond formation?

Answer 30

large subunit, rRNA

Question 31

which ribosome subunit is in charge of recognition of the 'Stop' codon and protein release?

Answer 31

large subunit rRNA release factor

Question 32

rRNAs have ___ function

Answer 32

enzymatic

Question 33

what are ribozymes?

Answer 33

RNA molecules that catalyze reactions, like protein enzymes

Question 34

what do tRNAs molecules do?

Answer 34

carry amino acids to the ribosome for incorporation into a protein

Question 35

what are the parts of a tRNA molecule?

Answer 35

amino acid acceptor stem anticodon loop anticodon

Question 36

the anticodon associated with the codon thru...

Answer 36

complementary base pairing

Question 37

what is a charged tRNA?

Answer 37

a tRNA with an amino acid attached

Question 38

how does a tRNA become charged?

Answer 38

aminoacyl-tRNA synthetase (aaRS) enzymes bind to: - an amino acid - an ATP - an 'uncharged' tRNA (not bound to an amino acid) using the energy from ATP hydrolysis, the amino acid is covalently bound to the tRNA

Question 39

there are ___ aaRS enzymes (___ for each amino acid)

Answer 39

20 1