UNIT 3 Test: Molecular Genetics

Question 1

Biological Significance of DNA Gyrase

Answer 1

is necessary for the supercoiling of chromosomal DNA in bacteria to have efficient cell division

Question 2

Biological Significance of Primase and Primers

Answer 2

primers are synthesized by primase before DNA replication can occur

Primases possess the unique ability to utilize single-stranded (ss) DNA for the initiation of de novo RNA/DNA synthesis

Question 3

Biological Significance of DNA Ligase

Answer 3

DNA ligase fills the spaces between the different fragments to bridge together the gaps in DNA.

Question 4

Biological Significance of Template vs. Coding Strand

Answer 4

Template strand only serves as the template for transcription

whereas coding strand contains the exact same sequence of nucleotides in the mRNA except thymine

Question 5

Biological Significance of RNA polymerase

Answer 5

RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, during the process of transcription

Question 6

Biological Significance of Okazaki Fragments

Answer 6

Relatively short fragment of DNA synthesized on the lagging strand during DNA replication.

Question 7

Biological Significance of 3’ to 5’ template

Answer 7

RNA polymerase and transcription factors moves along the strand in a 3’ to 5’ direction and makes a new strand of mRNA with complementary base pairs

Question 8

Biological Significance of Anneal

Answer 8

the bonding of connecting of nitrogenous bases

Question 9

Biological Significance of SSB’s

Answer 9

single stranded binding protein blocks

Question 10

Biological Significance of DNA polymerase

Answer 10

enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA

Question 11

DNA molecule

Answer 11

• carries genetic instructions in all living things

- consist of two strands that wind around each other known as the double helix

Question 12

Hydrogen Bonds between bases

Answer 12

The two strands are held together by hydrogen bonds between the bases

Question 13

DNA helicase

Answer 13

Creates replication foil by removing bonds between bases

Question 14

DNA replication

Answer 14

double-stranded DNA molecule is copied to produce two identical DNA molecules.

Question 15

The genetic code and its UNIVERSALITY

Answer 15

universal genetic code because every known living organism has genes made of DNA.

Question 16

Order of protein synthesis

Answer 16

DNA -> RNA (Transcription) -> Protein (Translation)

Question 17

Types of mutations

Answer 17

Point Mutations:

• silent no change to aa sequence
• missense a change to another aa
• nonsense change from aa to a stop codon

Frameshift:

• Addition of one or more nitrogenous bases
• Deletion of one or more nitrogenous bases

Question 18

Itrons

Answer 18

Itrons are the portions of DNA molecules that do not contain the codes for proteins. However; they can be subtle genetic enhancers

Question 19

Leading vs. Lagging (4 marks)

Answer 19

A leading strand is the strand which is synthesized in the 5’-3’direction

lagging strand is the strand which is synthesized in the 3’-5’ direction. Also where the Okazaki fragments happen.