Bio exam 5 slides 1

Question 1

Central dogma of molecular biology

Answer 1

-Flow of genetic information
-DNA, RNA, Protein
-Transcription, RNA processing, Translation

Question 2

Transcription

Answer 2

Information from a complementary DNA sequence is copied to a complementary RNA sequence

Question 3

RNA processing

Answer 3

-Eukaryotes
-Pre mRNA is processed to make mature RNA

Question 4

Translation

Answer 4

Ribosomes read information from mRNA sequence to make a chain of amino acids (polypeptide)

Question 5

mRNA

Answer 5

-DNA sequence is copied into mRNA
-Ribosomes read new mRNA strand and translate it into amino acids, link them together and its a polypeptide chain

Question 6

rRNA (ribosomal)

Answer 6

Along with proteins, makes up ribosomes; catalyzes peptide bond formation

Question 7

tRNA (transfer)

Answer 7

-Carries amino acid base pairs with mRNA
-Functions in translation

Question 8

Transcription initiation: Prokaryotes

Answer 8

-Cytoplasm
-Promoter

Question 9

Promoter

Answer 9

Sequence at front end of gene which RNA polymerase, sigma factors, and transcription factors bind for transcription initiation

Question 10

Transcription initiation: Eukaryotes

Answer 10

-Nucleus
-Transcription factors recognize the promoter
-RNA polymerase II binds and forms the transcription initiation complex

Question 11

Transcription elongation

Answer 11

-RNA polymerase moves along template strand
-Synthesizes from 5 to 3, adds matching base pairs
-DNA is unwound as it is read, then rewinds.
-In eukaryotes nucleosomes are assembled/unassembled

Question 12

Transcription termination

Answer 12

-Transcription ends when RNA polymerase reaches terminator region
-mRNA strand is released

Question 13

Transcription termination: Prokaryotes

Answer 13

mRNA can be translated by the ribosomes while it is being transcribed

Question 14

Transcription termination: Eukaryotes

Answer 14

-Pre mRNAs are processed in the nucleus to form mature mRNAs
-Then exported to cytoplasm, to be translated by ribosomes

Question 15

RNA processing: Eukaryotes

Answer 15

Converts pre mRNA into mature mRNA which can be translated

Question 16

RNA splicing

Answer 16

Removes introns and joins exons together

Question 17

5’ cap

Answer 17

-Added to the 5’ end
-Protects 5’ end of mRNA and facilitates translation initiation

Question 18

Poly A tail

Answer 18

-Added to 3’ end
-Tail stabilizes 3’ end of mRNA and facilitates mRNA export from nucleus to cytoplasm

Question 19

Mature RNA includes

Answer 19

Spliced RNA, 5’ cap, poly A tail

Question 20

Translation signals

Answer 20

Start: Start codon (AUG)
Stop: Stop codon (UGA, UAG, UAA)
Between: Coding sequence
Triplets of codons

Question 21

Translation initiation

Answer 21

1. Small subunit of ribosome attaches to mRNA
2. Initiator of tRNA with an anticodon attaches to comp. start codon
3. Large subunit of the ribosome attaches, 1st tRNA is in the p site

Question 22

Translation elongation

Answer 22

-“Charged” tRNA with anticodon complementary to 2nd codon enters ribosomes A site
-Peptidyl transferase makes peptide bond between first 2 amino acids
-Ribosome moves 1 codon to 3’ end of mRNA, 1st tRNA is moved to E site (exit)
-Next charged tRNA enters A site

Question 23

Charged tRNA

Answer 23

tRNA that is linked to its corresponding amino acid

Question 24

Translation termination

Answer 24

-Stop codon reaches ribosomes A site
-complex disassociates, frees amino acid chain

Question 25

Point mutations

Answer 25

Silent, missense, nonsense, frameshift

Question 26

Silent mutation

Answer 26

has no affect on protein sequence

Question 27

Misense mutation

Answer 27

results in amino acid substitution

Question 28

Nonsense mutation

Answer 28

Substitutes a stop codon for an amino acid

Question 29

Frameshift mutation

Answer 29

Insertions or deletions of nucleotides that results in a shift