Biology

Question 1

Importance of primer synthesis?

Answer 1

RNA primer critical for DNA polymerase to bind

The RNA primer is 8-12 nucleotides long and will later be replaced by DNA

Question 2

Purpose of DNA ligase?

Answer 2

To join fragments together

Question 3

Replication forks grow away from the origin in both directions and each contains which two types of strands?

Answer 3

Lagging and Leading

Replication of leading strand is continuous and leads into the replication fork. Replication of the lagging strand is discontinuous, resulting in Okazaki fragments

Question 4

Types of DNA Polymerase in Eukaryotes

Answer 4

DNA pol III: Elongation of the leading strand; proofreading capabilities just when replicating

DNA pol I: Starts adding nucleotides at the RNA primer; removes the RNA primer and leaving behind new DNA ; important for excision repair

Question 5

Excision repair

Answer 5

Removing defective bases or nucleotides and replacing them

Question 6

Mismatch repair system

Answer 6

Targets mismatched base pairs that were not repaired by DNA polymerase proofreading during replication

This is a post replication repair

Question 7

Is heterogenous nuclear RNA found in prokaryotes?

Answer 7

No processing events (such as addition of cap and tail, and splicing) are required for hnRNA to become mRNA and since prokaryotes do not process their transcripts, they do not have hnRNA

Question 8

Types of non-coding RNA

Answer 8

Transfer RNA and ribosomal RNA

Question 9

Can errors be corrected in transcription?

Answer 9

No RNA polymerase lacks exonuclease activity

Question 10

Which strands will have the same sequence?

Answer 10

The CODING strand and the mRNA

Coding strand is “sense” strand

mRNA gets made off of the template strand (antisense)

Question 11

Endoderm

Answer 11

GI tract tube (forms esophagus, small intestine, large intestine)+ lungs + liver + pancreas

Question 12

Mesoderm

Answer 12

form inner layers of skin, muscles, bones, cardiac muscles, kidneys, and bladder, ovaries/testes

Question 13

Ectoderm

Answer 13

Outer layer of skin, sweat glands, hair skin, nervous system

Question 14

Eukaryotic RNA polymerases

Answer 14

I - transcribes most rRNA
II - transcribes hnRNA (so ultimately mRNA), most snRNA, and some miRNA
III - tRNA, siRNA

Question 15

+ RNA Virus

Answer 15

must encode RNA dependent RNA pol (and do not have to carry it)

Their genome just directly acts like mRNA

Question 16

• RNA Virus

Answer 16

Must carry RNA dependent RNA pol (and of course encode it too)

Serves as template for viral mRNA production; immediately upon entering must create a + strand

Question 17

Retroviruses

Answer 17

Must encode reverse transcriptase

These are + RNA viruses which undergo lysogeny and so they integrate into the host genome as proviruses

Reverse transcription makes DNA from an RNA template

Question 18

Double stranded DNA Viruses

Answer 18

often encode enzymes required for dNTP synthesis and DNA replication

Question 19

SIster chromatids

Answer 19

Sister chromatids are identical copies of a chromosome, attached to each other at the centromere. Necessary for mitosis

Homologous chromosomes are equivalent but nonidentical and do not come anywhere near each other during mitosis.

Question 20

Incomplete dominance

Answer 20

phenotype of a heterozygote is a blended mix of both alleles

Question 21

Codominance

Answer 21

Both alleles are expressed but not blended (think blood type)

Question 22

Penetrance

Answer 22

likelihood that a person with a given genotype will express the expected phenotype