Final Review 2.0

Question 1

What rRNA’s and protein numbers make up the large and small subunits in prokaryotes?

Answer 1

50s–33 proteins–5s and 23s

30s–21 proteins–16s

Question 2

What rRNA’s and protein numbers make up the large and small subunits in eukaryotes?

Answer 2

60s–46 proteins–28s, 18s, 5.8s

40s–33 proteins–5s

Question 3

Which rRNA has ribozyme activity?

Answer 3

28s rRNA

Question 4

Which part of the small rRNA in prokaryotes base pairs with the Shine-Delgarno sequence?

Answer 4

16s

Question 5

What occurs at each temperature of PCR?

Answer 5

95 deg C–Denature DNA
55 deg C–Anneal Primers
72 deg C–Elongate DNA with free nucleotides

Question 6

What is the one base that Inosine cannot base pair with?

Answer 6

Guanosine (G)

Question 7

What terminates translation inside the ribosome?

Answer 7

Release Factor signaled by the stop codon

Question 8

What is epigenetic inheritance?

Answer 8

Epigenetic inheritance are things that are inherited that affect the expression of the genes without being changes in the actual genes themselves
• An example of this are histone modifications.
• Phosphorylation
• Methylation

Question 9

What is depurination?

Answer 9

The entire purine is removed, leaving an abasic site. The glycosidic bond was broken

Question 10

What makes up the Prokaryotic RNA polymerase core?

Answer 10

2 alpahs, 2 betas, 1 omega

–Called a holoenzyme when sigma factor binds to it

Question 11

What factor directs RNA polymerase to the correct binding site on the DNA template?

Answer 11

sigma D

Question 12

Explain the importance of the -10 and -35 regions in prokaryotes?

Answer 12

The -10 box (T and A rich) has fewer H bonds, which makes it easiest to open. The -35 box is the place a sequence the σ factor recognizes to bind and activate the RNA polymerase

Question 13

What is the difference between intrinsic termination and Rho dependent termination?

Answer 13

Intrinsic means the termination is caused by the mRNA itself (hairpin loops formed by C-G rich sequences followed by string of U’s)
–Rho dependent: Binds to the RUT sequence and slides along mRNA until it knocks off RNA polymerase

Question 14

What does each of the RNA polymerases transcribe?

Answer 14

Pol 1–Large rRNA
Pol2–mRNA
Pol 3–tRNA and small rRNA
(Remember, the bigger the number gets the smaller the RNA made gets)

Question 15

What two methods of transcription termination exist in eukaryotes?

Answer 15

Anti-termination: Pol 2 loses a positive EF or gains a negative EF decreasing processivity causing it to dissociate
Torpedo: A cut is made after the Poly A tail, and 5’-3’ exonuclease cuts up unneeded RNA until it runs into Pol 2 and kicks it off

Question 16

Which end of tRNA does the amino acid attach?

Answer 16

3’ end (sequence read 5’ to 3’ is CCA)

Question 17

What is degeneracy?

Answer 17

An amino acid being coded for by multiple codons

Question 18

What is wobble?

Answer 18

The 3rd nucleotide of the codon doesn’t have to match exactly for it to base pair with the anti-codon

Question 19

What is a missense mutation?

Answer 19

When a different amino acid is used in place of the correct one

Question 20

What does aminoacyl-tRNA synthetase do?

Answer 20

It combines an amino acid with the correct tRNA

Question 21

What does an IRES do?

Answer 21

It allows translation to begin in the middle of mRNA without the need of a 5’ cap

Question 22

What does ski7 do?

Answer 22

It allows a ribosome that is stalled on a non-stop mRNA (one without a stop codon) to dissociate

Question 23

What are the 7 levels at which gene expression can be regulated?

Answer 23

Transcription initiation
RNA processing
RNA stability
protein synthesis
protein modification
protein degradation
protein transport

Question 24

What does partial pairing of miRNA’s with mRNA do?

Answer 24

It represses translation

Question 25

What can defects in the ubiquitination pathway cause?

Answer 25

Tumors and cystic fibrosis

Question 26

What do architectural regulators do?

Answer 26

The bend and loop the DNA to bring regulatory proteins and RNA polymerase together

Question 27

What is the one difference between pluripotent and totipotent cells?

Answer 27

Pluripotent cells have differentiated once and cannot become the embryonic membrane

Question 28

What does TCA do?

Answer 28

It precipitates large molecules ONLY

Question 29

What is the function of the spliceosome, and what is it made of?

Answer 29

It removes most eukaryotic introns.

–Composed of 5 snRNP’s U1,U2,U4,U5,U6 (small nuclear ribonucleoproteins), and hundreds of additional proteins

Question 30

Where do repressors and activators bind?

Answer 30

Silencer and enhancer sequences respectively

Question 31

Where are the kinetichore proteins located?

Answer 31

On the centromere

Question 32

Which enzyme types are considered fast stop?

Answer 32

Those that work at the replication fork, or as tension relievers

Question 33

What are Variable Number Tandem Repeats (VNTR) used for?

Answer 33

Polymorphisms (specific gene sequences) that are unique for each person, but are more similar to related individuals

Question 34

What code is at the 5’ splice site of an intron?

Answer 34

GU

Question 35

What code is at the 3’ splice site of an intron?

Answer 35

AG

Question 36

Which groups don’t require other proteins to help splice?

Answer 36

Groups 1 and 2

Question 37

What is the start codon?

Answer 37

AUG (for methionine)

Question 38

What is one of the stop codons?

Answer 38

UAG