GENETICS

Question 1

DNA TO RNA

Answer 1

Transcription

Question 2

RNA to DNA

Answer 2

Reverse Transcription

Question 3

RNA to Proteins

Answer 3

Translation

Question 4

Histones have a high content of what AA.

Answer 4

arginine and lysine

Question 5

The process of disrupting the double helix is called

Answer 5

denaturation

Question 6

Thymine = Adenine has how many Hydrgen bonds?

Answer 6

2

Question 7

Cytosine = Guanine has how many hydrogen bonds

Answer 7

3 (stronger)

*Note that there are three hydrogen bonds between GC and just two

hydrogen bonds between AT. Thus, DNA strands with a greater

proportion of GC nucleotide pairs will be more difficult to separate.

Question 8

Copies genetic information from DNA and serves as the template for protein synthesis

Answer 8

MESSENGER RNA (mRNA)

Question 9

Prokaryotes have _______ subunits, made up of 3 types of rRNA: 16S, 23S, and 5S

Answer 9

50S and 30S

Question 10

Differentiate DNA and RNA

Answer 10

Question 11

MESSENGER RNA (mRNA) structure

Answer 11

• In eukaryotes
  
  • Methylguanosine cap at the 5’-end
  • Poly(A) tail at the 3’-end
• The primary transcript undergoes splicing prior to protein synthesis

Question 12

Contribute to the formation and function of ribosomes, which act as the site for protein synthesis

Answer 12

RIBOSOMAL RNA (rRNA)

Question 13

Eukaryotes have ______ subunitis, made up of four types of cytosolic rRNA: 18S, 28S, 5S, 5.8 S

Answer 13

60S and 40S

Question 14

Adapter molecules that translate the nucleotide sequence of mRNA into specific amino acids

Answer 14

TRANSFER RNA (tRNA)

Question 15

DNA REPLICATION occurs during what phase of the cell cycle?

Answer 15

S phase

Question 16

The origin of replication (ori) is recognized by a group of proteins called ____

Answer 16

origin recognition complex (ORC)

Question 17

___unwinds the double helix, in a process that is driven by ATP

Answer 17

Helicase

Question 18

maintain the separation of the parent strands

Answer 18

Single-stranded DNA-binding proteins

Question 19

relieve torsional strain that results from helicase-induced unwinding

Answer 19

Topoisomerases

o Type I (Swivelase)

o Type II (Gyrase), inhibited by fluoroquinolones

Question 20

synthesizes short segments of complementary RNA primers

Answer 20

Primase

Question 21

elongates the DNA strand by adding new deoxyribonucleotides

Answer 21

DNA polymerase III

• Synthesis proceeds in the 5’ to 3’ direction only
• Leading strand is synthesized continuously
• Lagging strand consists of Okazaki fragments
• Mismatched nucleotides are removed using the enzyme’s 3’→5’ exonuclease (proofreading)

Question 22

When another primer is reached, _____ removes the ribonucleotides using its 5’→3’ exonuclease

Answer 22

DNA polymerase I

*fills the gap with deoxyribonucleotides

Question 23

seals the nick by catalyzing the formation of the last phosphodiester (joins 2 nucleotides) bond, requiring hydrolysis of ATP

Answer 23

DNA ligase

Question 24

DNA Lesion: Mismatched Strand

Answer 24

Question 25

DNA lesion: Pyrimidine dimers (Usually thymine)

Answer 25

Question 26

DNA Lesion: Base alterations (e.g., cytosine to uracil, or guanine to xanthine)

Answer 26

Question 27

DNA Lesion: DOuble strand breaks

Answer 27

Question 28

inhibits topoisomerase

Answer 28

Etoposide

Question 29

Enzyme for Transcription (DNA to RNA)

Answer 29

Enzyme: DNA-dependent RNA polymerase * No primer needed, no proofreading activity * In eukaryotes, the polymerases synthesize specific RNA molecules:

Question 30

o \_\_\_\_\_\_are DNA sequences that stimulate transcription rate o _______ inhibit transcription

Answer 30

Enhancers Silencers

Question 31

What are the 3 stop codons that terminate translation

Answer 31

**(UAG, UAA, UGA)**

Question 32

Start or initiating codon in eukaryotes

Answer 32

(AUG) methionine

Question 33

Start or initiating codon in prokaryotes

Answer 33

formylmethionine

Question 34

* The poisonous mushroom Amanita phalloides (“death cap”) contains the peptide toxin **α-amanitin** which inbitits the **RNA polymerase II** * Presents with gastrointestinal symptoms, acute liver failurea, and may be fatal

Answer 34

AMANITA MUSHROOM POISONING

Question 35

o Inactivates the eukaryotic elongation factor EF-2, preventing translocation

Answer 35

Exotoxin of Corynebacterium diphtheriae

Question 36

• Binds to the β subunit of bacterial DNAdependent RNA polymerase

Answer 36

Rifampicin

Question 37

Binds to the DNA template and interferes with the movement of RNA polymerase during transcription

Answer 37

Dactinomycin

Question 38

Bind to the 30S subunit and interferes with initiation

Answer 38

aminoglycosides and streptomycin

Question 39

Prevents binding of aminoacyl-tRNA to the A site

Answer 39

Tetracycline

Question 40

Inhibits peptidyltransferase prokaryotic

Answer 40

Chloramphenicol

Question 41

Inhibits **eukaryotic peptidyltransferase**

Answer 41

Cycloheximide

Question 42

purine to purine or pyrimidine to pyrimidine

Answer 42

Transition

Question 43

purine to pyrimidine or pyrimidine to purine

Answer 43

Transversion

Question 44

* New codon codes for same amino acid * No effect on protein

Answer 44

Silent Mutation

Question 45

* New codon codes for different amino acid (conservative if new amino acid is similar in chemical structure) * Variable effects on protein

Answer 45

Missense Mutation

Question 46

* New codon is a stop codon * Shorter than normal, usually non-functional protein

Answer 46

Nonsense Mutation

Question 47

* Deletion or addition of bases that should not be multiples of three * Shorter than normal, usually non-functional protein

Answer 47

FRAME SHIFT MUTATION

Question 48

* Loss of large areas of chromosomes during unequal crossover in meiosis * Loss of function * Protein shorter than normal or entirely missing

Answer 48

LARGE SEGMENT DELETION

Question 49

* Splice site is lost * Variable effects ranging from addition or deletion of a few amino acids to deletion of an entire exon * Examples: Tay-Sachs, Gaucher, β-thalassemia

Answer 49

SPLICE DONOR OR ACCEPTOR

Question 50

* Expansions in coding regions cause protein product to be longer than normal and unstable * Diseases often show anticipation in pedigree

Answer 50

TRIPLE REPEAT EXPANSION

Question 51

CAG repeats

Answer 51

Huntington Disease

Question 52

CGG repeats

Answer 52

Fragile X Syndrome

Question 53

CTG repeats

Answer 53

Myotonic Dystrophy