Molecular Genetics

Question 1

mtDNA

Answer 1

Mitochondrial DNA

• found in mitochondria, but most other DNA is found in the cell nucleus
• inherited solely from mother

Question 2

Hershey and Chase

Answer 2

conducted experiments using bacteriophages to show that DNA was hereditary material that gets passed on from parent cell to daughter cell

Question 3

Watson and Crick

Answer 3

Determined structure of DNA

-DNA consists of 2 strands of nucleotides

Question 4

DNA Contains

Answer 4

Backbone: alternating deoxyribose sugars and phosphates

• nitrogenous bases stick out from the backbone connecting to the deoxyribose sugars
• nucleotides twist clockwise to form the double helix

Question 5

Purines

Answer 5

Double Ring Structure

• Adenine (A)
• Guanine (G)

Question 6

Pyramidine

Answer 6

Single Ring Structure

• Cytosine (C)
• Thymine (T) *only found in DNA
• Uracil (U) *only found in RNA

Question 7

Complementary Base Pairing

Answer 7

(A-T) by 2 hydrogen bonds
(C-G) by 3 hydrogen bonds
-causes helical shape

Question 8

Original Strand

Answer 8

Template Strand

Question 9

Replicated Strand

Answer 9

Complementary Strand

Question 10

Helicase

Answer 10

Unzips DNA strands (breaks H-bonds)

Question 11

Primase

Answer 11

Adds primers which attach to template strand. (act as starting point for nucleotide addition)

Question 12

DNA Polymerase III

Answer 12

attaches to primers and begins added nucleotide 5’ to 3’ direction
-proofreads

Question 13

DNA Polymerase I

Answer 13

Removes primers and replaces them with nucleotides.

-proofreads

Question 14

Ligase

Answer 14

Glues fragments together.

Question 15

Restriction Enzymes

Answer 15

Scissors

Question 16

DNA read/built in what direction

Answer 16

Reads in 3’ to 5’

Builds in 5’ to 3’

Question 17

Gel Electrophoresis

Answer 17

Used to separate DNA based on size and charge.

• DNA removed from organism, cut by restriction enzymes
• DNA put into wells in a sheet of gel
• Gel is attached to a battery with a positive and negative end
• Electric current is applied, negatively charged DNA moves to positive end
• large particles move slower than small particles
• MAKES DNA FINGERPRINT

Question 18

PCR

Answer 18

copies DNA

Question 19

Transformation

Answer 19

Taking foreign DNA, adding another DNA and using PCR to replicate it to clone.

Question 20

Transcription

Answer 20

Process of converting DNA into mRNA.

• RNA polymerase binds to DNA at the promoter region, opens double helix
• RNA polymerase builds from 5’ to 3’
• similar to DNA replication but does not need primers

Question 21

mRNA

Answer 21

Messenger RNA

• uracil instead of thymine
• mRNA sequence is complementary (opposite) to DNA
• codon codes for amino acid

Question 22

Translation

Answer 22

Synthesis of a protein which occurs under the direction of mRNA.

• mRNA is read in groups of 3 called codons
• codon = amino acid

Question 23

Start Codon

Answer 23

AUG (methionine) where translation begins

Question 24

Stop Codon

Answer 24

UAA, UAG, UGA do not code for amino acids, where translation ends.

Question 25

tRNA

Answer 25

Transfer RNA gets the ribosome the corresponding amino acid it is reading

• anticodon binds to complementary codon on mRNA
• other end has corresponding amino acid

Question 26

P site

Answer 26

Peptidyl Site - where first tRNA enters to attach to start codon

Question 27

Releasing Factor

Answer 27

Recognizes ribosome has stopped and helps release polypeptide chain.

Question 28

Silent Mutation

Answer 28

Nucleotide sequence changes but still codes for the same amino acid.

Question 29

Missense Mutation

Answer 29

Base substitution changes one amino acid in a sequence, resulting in a different protein.

Question 30

Nonsense Mutation

Answer 30

Normal codon is changed to a stop codon.

-often lethal

Question 31

Frameshift Mutation

Answer 31

Addition or deletion of codon causing reading frame of codons to change.