Biology

Question 1

What are the components of a nucleotide ?

Answer 1

a pentose, aromatic base and phosphates

Question 2

What is the point mutation that creates a STOP codon?

Answer 2

Nonsense

Question 3

How many types of RNA polymerases are used by eukaryotic cells?

Answer 3

Three

Question 4

Where is the START codon bound in a ribosome ?

Answer 4

P site

Question 5

What is the formula for determining ATP equivalents for amino acids ? Example how many ATP equivalents for 100 amino acids ?

Answer 5

ATP equivalents = number of amino acids x 4
ex: if have 100 aa X 4= 400 ATP equivalents

Question 6

What are similarities and differences for prokaryotes and eukaryotes for transcription ?

Answer 6

Similarites:
-both prokaryotic and eukaryotic RNA Polymerases require template
-
differences:
-transcription occurs in cytoplasm for prokaryotes, nucleus for eukaryotes
-only prokaryotes use shine-Dalgarno sequence to initiate translation
-Eukaryotes undergo post-translational modification (splicing, adding cap, poly A tails), prokaryotes don’t

Question 7

what are the three types of RNA polymerase that humans use? What are their roles ?

Answer 7

The three types of RNA polymerase in humans are RNA Polymerase I, II, and III
- RNA polymerase I is responsible for the transcription of most rRNA
-RNA polymerase II synthesizes mRNA, as well as snRNA (RNA polymerase III synthesizes mostly tRNA, some snRNA, and miRNA

Question 8

what is genetic penetrance?

Answer 8

when a certain genotype has the potential to lead to a phenotype

Question 9

What happens during Sanger sequencing ?

Answer 9

Sanger sequencing involves performing four different DNA replication reactions on one sample of DNA, where each reaction contains a different modified nucleotide that arrests synthesis on a certain template

Question 10

What are the different forms of DNA repair ?

Answer 10

Connecting broken ends of chromosomes, reversing UV damage, and removing defective bases are all forms of DNA repair.

Question 11

What are some features of prokaryotic translation? Which ribosome subunits are used?

Answer 11

In prokaryotes, the 30S and 50S subunits of the ribosome must come together for translation to occur but when they do they make a 70S ribosome. The Shine-Dalgarno sequence is the ribosome binding site in prokaryotes and without this the gene product cannot be translated.
fMet (formylmethionine) is a modified methionine used as the first amino acid in all prokaryotic proteins.

Question 12

What is the energy source used in prokaryotic transcription ?

Answer 12

GTP is used in prokaryotic transcription

Question 13

What is the role of DNA gyrase? Which kind of organisms is it seen in?

Answer 13

Gyrase is an enzyme specific to prokaryotes that maintains bacterial DNA in its supercoiled helical state.

Question 14

Which polymerases produce of stand od DNA in 5’ to 3’ direction ?

Answer 14

All three polymerases (polymerase I, III and Reverse transcriptase listed use a template strand to create a new strand of DNA. They do so by adding new nucleotides to the 3’ end of the new strand (hence, the strand grows in the 5’ to 3’ direction).

Question 15

How does reverse transcriptase differ from DNA polymerase?

Answer 15

Revere transcriptase differs from the DNA polymerase’s only that RNA template is made (instead of DNA template). but it too adds nucleotides in 5’ to 3’ direction

Question 16

What is the role of topoisomerase ?

Answer 16

Topoisomerase creates controlled cuts in DNA strands to manage the increased tension created by expanding replication bubbles

Question 17

What is the role of DNA ligase

Answer 17

RNA polymerase is used by eukaryotes and can be eliminated.and ligase links together the Okazaki fragments of the lagging strands

Question 18

What occurs in alternative splicing? which lab techniques would be useful?

Answer 18

Alternative splicing creates different mRNA sequences leading to different proteins, thus any technique that detects changes in mRNA transcripts or final protein products could be useful. Northern blotting is used to detect RNA and both Western blotting and ELISAs can be used to detect proteins. However, Southern blotting is used to detect DNA, and a if it says that genomes are the same (their is least useful technique).

Question 19

what are the chain of events that occur in the synthesis of a polypeptide?

Answer 19

DNA generates mRNA; mRNA moves to the ribosomes, where a tRNA anticodon binds to an mRNA codon, causing amino acids to join together in their appropriate order.

Question 20

When do translocations happen?

Answer 20

Translocations happen when recombination occurs between non-homologous chromosomes and previously unrelated genes are now placed together.

Question 21

What does a complex transposon contain?

Answer 21

A complex transposon contains an IS element (the transposase and its accompanying inverted repeat sequences) and one or more genes.

Question 22

what occurs in RNA splicing?

Answer 22

During RNA splicing, introns are removed and exons are connected together. This process occurs in the nucleus, and can be variable

Question 23

What is direct reversal ?

Answer 23

Direct reversal : a form of DNA repair , where visible light can trigger repair enzymes via photo reactivation when pyrimidine dimers appear (due to UV light)

Question 24

How do Eukaryotes and prokaryotes differ during translation ?

Answer 24

Eukaryotic and prokaryotic translation differ in the mechanism by which ribosomes recognize the 5’ end of mRNA.
Prokaryotic mRNA is recognized by the ribosome using the Shine-Dalgarno sequence (-10) while eukaryotic mRNA is recognized via the 5’ cap that is added during post-transcriptional modification.

Question 25

What are the similarities that eukaryotes and prokaryotes have in translation ?

Answer 25

Both eukaryotes and prokaryotes begin translation at an AUG; this specifies methionine in eukaryotes and formyl-methionine in prokaryotes.
Both utilize the codon UAA to signify a stop codon rather than an amino acid.
Both eukaryotes and prokaryotes can translate each mRNA transcript multiple times to generate more protein

Question 26

How can you lengthen Okazaki fragment during DNA replication ?

Answer 26

Decreasing the number of primers generated on the lagging strand would lengthen Okazaki fragments during replication. This would result in DNA polymerase III traveling uninterrupted for a longer period of time and generating longer Okazaki fragments.

Question 27

what happens when greater protein production is needed?

Answer 27

When greater protein production is needed a greater rate of translation occurs.
Translation: process through which the ribosome creates a protein by reading an mRNA transcript.