Molecular Genetics/DNA

Question 1

What does DNA polymerase III do?

Answer 1

Adds nucleotides from primers

Question 2

What does ligase do?

Answer 2

Links all fragments together (known as “glue”)
- Okazaki fragments
- New DNA strand

Question 3

Which direction does polymerase III add DNA?

Answer 3

Only 5’ to 3’

Question 4

What is the replication fork?

Answer 4

Opening of the unwinding DNA

Question 5

2 stages of protein synthesis?

Answer 5

1. Transcription (in nucleus)
2. Translation (In ribosome)

Question 6

What does tRNA stand for?

Answer 6

Transfer RNA

Question 7

What are ribosomal subunits?

Answer 7

2 units that make up the ribosome
- Lower/smaller
- Higher/larger

Question 8

What does a restriction enzyme do?

Answer 8

Cuts the DNA

Question 9

What were Griffith’s experiments and findings? (1928)

Answer 9

Tested pneumonia strains on mice
- 2 strains of bacteria, 1 camouflages bacteria so immune system cannot attack it, 2nd is non-pathogenic
- Transforming principle

Question 10

Define transforming principle

Answer 10

Virulent and non-virulent bacteria exchange smth

Question 11

What was hammerling’s experiments? (1943)

Answer 11

Showed that hereditary material was in nucleus
- Algae regrew after top was cut off cuz nucleus is in roots

Question 12

What was Hershey-Chase experiment? (1952)

Answer 12

Used viruses to determine if DNA or protein (histone) was genetic material

Question 13

What were Levene and Chargaff 1952 experiment?

Answer 13

Discovered nucleotides

Question 14

What did Watson and crick find out? (1953)

Answer 14

Structure of NDA
(Used Franklin’s X-ray pic)

Question 15

T/F: G and C are triple bonded, A and T are double

Answer 15

True

Question 16

What did Meselson and Stahl show?

Answer 16

Semi conservative replication
- Radioactively labelled nitrogen from the 4 bases

Question 17

What do single stranded binding proteins (SSBP) do?

Answer 17

Attached to Unwinded dna strand and stops them from rebinding

Question 18

What does primase do?

Answer 18

Attach RNA primer to single strand

Question 19

What are nucleosidases?

Answer 19

Break down food from dna

Question 20

What does DNA polymerase 1 and exonuclease do?

Answer 20

Exo + Poly 1: cut out RNA primers
Poly 1: replaces it with DNA

Question 21

Define leading strand and lagging strand

Answer 21

Leading: continuously replicate DNA (Poly 3)
Lagging: Okazaki fragments

Question 22

Review: 5 main enzymes for replication

Answer 22

1. Helicase
2. primase
3. Poly 3
4. Poly 1
5. Ligase

Question 23

Define rRNA

Answer 23

Ribosomal RNA

Question 24

What does RNA polymerase do?

Answer 24

Like ligase + RNA polymerase together (creates mRNA starting with promoter sequence)

Question 25

Define elongation

Answer 25

Building mRNA from 5’ to 3’ using DNA as template

Question 26

What is the antisense strand?

Answer 26

Template DNA strand

Question 27

Types of sites in a ribosome

Answer 27

P site: binding E site: exit A site: tRNA binding

Question 28

What is a release factor?

Answer 28

Protein that helps remove ribosome from RNA

Question 29

Define introns

Answer 29

Non-coding DNA sections (OPP of exons) - splices out by spliceosome before mRNA translated

Question 30

Causes of mutations

Answer 30

1. Spontaneous (mistakes by poly 3 or 1) 2. Induced (mutagens)

Question 31

Categories of mutations

Answer 31

Point Frameshift

Question 32

Define missense mutation

Answer 32

Changes AA sequence and change function of protein (OPP of silent) - Point mutation

Question 33

Define nonsense mutation

Answer 33

Pre-mature stop, protein is not translated - point mutation

Question 34

T/F: Deletion and insertion mutations are frameshift mutations

Answer 34

True

Question 35

T/F: Sequence of AA determine structure and function of proteins

Answer 35

True

Question 36

What is Polymerase Chain reaction?

Answer 36

Multiple copies of a DNA sequence (DNA amplification)

Question 37

Define STRs

Answer 37

Short tandem repeats (repeating sequences of DNA)

Question 38

What is used in dna fingerprinting/profiling?

Answer 38

Introns (unique to individual) they have variable number tandem repeats (VNTR) or STRs.

Question 39

Difference between GMO and genetic engineering?

Answer 39

GMO: result organism GE: process

Question 40

Ways to make GMOs

Answer 40

1. Transgenic (not closely related exchange) 2. Cisgenic/intragenic (same species exchange) 3. Subgenic (edited gene)

Question 41

Define the gene wanted

Answer 41

Insert

Question 42

Define vectors

Answer 42

DNA used to carry foreign genetic material to other cells - cut using restriction enzyme (endonucleases) and insert replaces cut out part

Question 43

Difference between Endo and exo nucleases

Answer 43

Endo: anywhere cut (basically) Exo: ends (5’ or 3’)

Question 44

What does CRISPR use?

Answer 44

Cas9 enzyme (can cut DNA after guide RNA attaches to viral genome) -codes the gene using guide RNA (match virus DNA) -replacement DNA pairs with cut ends - Target many genes at once