test 2 study guide

Question 1

Aneuploidy

Answer 1

Missing or extra chromosomes
Caused by nondisjunction
ex: Down (Trisomy 21), Turner (XO), Klinefelter (XXY)

Question 2

aneuploidy types

Answer 2

monosomy (2n–1)
trisomy (2n+1)

Question 3

Polyploidy

Answer 3

Whole extra sets of chromosomes

Question 4

Autopolyploidy

Answer 4

from same species

Question 5

Allopolyploidy

Answer 5

from hybridization between species

Question 6

Deletions

Answer 6

missing segment → severe effects

Question 7

Duplications

Answer 7

dosage imbalance → phenotypic change

Question 8

Inversions

Answer 8

segment reversed; affects meiosis, possible reduced fertility

Question 9

Translocations

Answer 9

segment moves chromosomes; can be Robertsonian

Question 10

Bacterial Defense Systems

Answer 10

Restriction enzymes
CRISPR-Cas immunity:

Question 11

restriction enzymes

Answer 11

cut foreign DNA

Question 12

CRISPR-Cas immunity

Answer 12

Adaptation

Expression

Interference

Question 13

Horizontal Gene Transfer

Answer 13

Conjugation
Transformation
Transduction

Question 14

Conjugation

Answer 14

plasmid transfer

Question 15

Transformation

Answer 15

uptake of naked DNA

Question 16

Transduction

Answer 16

phage-mediated DNA transfer

Question 17

Phage Mapping

Answer 17

Infect bacteria with phages that differ in 2+ traits
Count recombinant plaques → map distances

Question 18

Retrovirus

Answer 18

reverse transcriptase, integrates into host DNA

Question 19

HIV

Answer 19

infects helper T cells

Question 20

Influenza

Answer 20

RNA virus → antigenic shift via reassortment (major pandemics)

Question 21

Rhinovirus/Zika

Answer 21

RNA viruses, high mutation/recombination

Question 22

Properties of Genetic Material

Answer 22

Stores information

Replicated accurately

Can vary (mutations)

Question 23

Griffith

Answer 23

transformation (dead virulent → live nonvirulent become virulent)

Question 24

Avery/MacLeod/McCarty

Answer 24

DNA = transforming principle

Question 25

Hershey–Chase

Answer 25

DNA, not protein, enters phage-infected cells

Question 26

Chargaff

Answer 26

A=T, G=C → disproved tetranucleotide theory

Question 27

DNA Structure

Answer 27

Nucleotide = phosphate + sugar + base Bases: A/T (2 H-bonds), G/C (3 H-bonds) Antiparallel strands (5'→3' opposite 3'→5') Double helix with major/minor grooves

Question 28

Meselson–Stahl Experiment

Answer 28

Distinguished: conservative, dispersive, semiconservative Showed replication is semiconservative 1st generation: single intermediate band 2nd: light + intermediate bands

Question 29

Replication Models

Answer 29

Theta: circular DNA (E. coli) Rolling circle: viruses & plasmids Linear eukaryotic: many origins; bidirectional

Question 30

Key Rules

Answer 30

DNA synthesis occurs 5′ → 3′ only Template strands read 3′ → 5′ Leading = continuous Lagging = discontinuous (Okazaki fragments)

Question 31

DnaA

Answer 31

initiator (oriC)

Question 32

Helicase

Answer 32

unwinds DNA

Question 33

SSB proteins

Answer 33

keep strands open

Question 34

Gyrase (topoisomerase)

Answer 34

relieves supercoiling

Question 35

Primase

Answer 35

makes RNA primers

Question 36

DNA Pol III:

Answer 36

main replication enzyme

Question 37

DNA Pol I

Answer 37

removes RNA primers, fills gaps

Question 38

Ligase

Answer 38

seals nicks

Question 39

Eukaryotic Extras

Answer 39

Multiple origins + licensing Telomerase: extends chromosome ends Uses RNA template → reverse transcriptase activity Active in germ cells, cancer cells

Question 40

Recombination

Answer 40

Homologous recombination = exchange between homologs Holliday junction → resolution can produce: Non-crossover products Crossover products