Genetics and Molecular Biology

Question 1

Nucleic Acid

Answer 1

Macromolecules that contain genetic information for protein synthesis.

Question 2

Nucleic acid structure

Answer 2

1.) Phosphate group- Neg charged oxygen atoms bonded to it
2.) Pentose molecule- Ribose or deoxyribose
3.) Nitrogen base- Can give molecules to carbon, hydrogen, and oxygen

Question 3

Who discovered nucleic acids?

Answer 3

Friedrich Miescher- From the white blood cells contained in pus he got from used hospital bandages.

Question 4

Gene expression

Answer 4

Process of using the information in a gene to create a protein inside a cell.

Question 5

Proteins

Answer 5

Macromolecules that direct all structures and functions of the cell, allowing gene regulation to be tightly controlled.

Question 6

Steps for gene expression

Answer 6

1. Transcription
2. mRNA processing
3. mRNA export
4. Translation
5. Protein folding
6. Protein translocation

Question 7

Splicing

Answer 7

Process where introns are removed from the transcript, and the remaining exons are attached back together.

Question 8

Introns

Answer 8

Non-coding sections of the mRNA

Question 9

Exons

Answer 9

The remaining coding sections of mRNA

Question 10

Alternative splicing

Answer 10

mRNA can be sliced in different ways to create different proteins

Question 11

Stop codon

Answer 11

Signals for translation to stop

Question 12

Ways that gene expression is regulated

Answer 12

• Transcription factors
• Stability of mRNA
• Alternative splicing
• Post-transcriptional regulation
• Post-translational modifications

Question 13

Ways to measure gene expression

Answer 13

-Western blot
-Immunofluorescence
- Microarray
- RT-PCR
- In situ hybridization

Question 14

Insertion mutation

Answer 14

Additional nucleotides are inserted into the DNA

Question 15

Complementary base pairs

Answer 15

Adenine–Thymine (RNA it is uracil)
Cytosine–Guanine

Question 16

Frameshift mutation

Answer 16

All of the codons downstream from the mutation are changed

Question 17

Causes of insertion mutation

Answer 17

• By chance during errors in DNA replication
• By chemicals or radiation

Question 18

Examples of insertion mutation

Answer 18

• Fragile X syndrome
• Huntington’s disease
  -Myotonic dystrophy
• Cystic fibrosis

Question 19

Deletion mutation

Answer 19

When a nucleobase is removed from the DNA sequence

Question 20

Substitution mutation

Answer 20

When a nucleobase is substituted for another nucleobase.

Question 21

Duplication mutation

Answer 21

When a section of the DNA sequence is repeated

Question 22

Causes of deletion mutation

Answer 22

• Translocation
• Unequal chromosome crossovers

Question 23

Types of deletion mutations

Answer 23

• Point mutation (affects a single nucleobase)
• Frameshift mutation (when one deletion shift all nucleobases in the reading frame)
• Chromosome deletion (An entire missing piece of a chromosome)

Question 24

Restriction enzymes (endonucleases)

Answer 24

Proteins that recognize and cleave specific DNA sequences. Found only in bacteria.

Question 25

Werner Arber

Answer 25

Discovered restriction enzymes in the 1960s

Question 26

Hamilton Smith

Answer 26

Reproduced Arber’s results, and named them

Question 27

Dan Nathans

Answer 27

Used the work of Arber and Smith to pioneer the field of molecular biology and genetics

Question 28

EcoR1 works by… (3 steps)

Answer 28

1.) EcoR1 (a restriction enzyme) recognizes DNA sequence GAATTC, and loosely binds to it.

2.) EcoR1 active site closes and binds more tightly forming a kink in the viral DNA.

3.) When kink is in right orientation, active site binds even more tightly until it cleaves the 5’ and 3’ DNA sequence between G and A.

Question 29

Restriction enzyme rules (3)

Answer 29

• Cleavage site sequences are usually palindromic (reads the same forward as backwards)
• After cleavage, restriction enzymes leave sticky ends
• Most restriction enzyme cleavage sequences are 4-6 bases long

Question 30

Main usage of restriction enzymes in molecular biology

Answer 30

Construct plasmids that can express specific gene products in a cell. After cutting the gene fragment, the gene can be amplified and then purified.

Question 31

5 types of restriction enzymes

Answer 31

I- Cut DNA far from the recognition sequences

II- Cut at specific positions closer to or within the restriction sites; most common type and used for DNA analysis and gene cloning

III- Multifunctional proteins with the subunits Res and Mod

IV- Know to cleave methylated DNA and use recognition sequences similar to II

V- Made up of dimers, require magnesium as a cofactor, and uses an RNA guide sequence instead of DNA. Used for CRISPR

Question 32

DNA polymerase

Answer 32

When DNA separates during replication, a special protein known as DNA polymerase comes in and adds in the new nucleotides.

Question 33

Polymerase Chain Reaction (PCR)

Answer 33

Used to make many copies of a DNA sample in the lab.

Question 34

Recombinant DNA

Answer 34

DNA that is cut and pasted together from multiple sources.

Question 35

Two-step process for recombinant DNA technology

Answer 35

1.) Restriction enzymes to cut through the double helix of bacteria.
2.) DNA ligase to paste the separate pieces of DNA back together.

Question 36

Applications of recombinant DNA

Answer 36

• GMOs
• Disease research

Question 37

Stanley Cohen and Herbert Boyer applied for a patent for…

Answer 37

Recombinant DNA technology