Genetics Exam 4 Review Part 2

Question 1

Forward Mutation

Answer 1

Changes from wildtype genotype

Question 2

Reversion Mutation

Answer 2

Back to wildtyoe

Question 3

Deleterious Mutations

Answer 3

decrease chance of survival

Question 4

Beneficial Mutations

Answer 4

increase chance of survival

Question 5

Conditional Mutations

Answer 5

affects phenotype under certain conditions

Question 6

Germline Mutations

Answer 6

occur directly in sperm or egg cell

Question 7

Germline Mutations are passed down from parent to offspring

Answer 7

true
on average, passed to half of gametes in next generation

Question 8

Germline Mutations effect the entire body

Answer 8

true

Question 9

Somatic Mutations

Answer 9

mutations not in egg or sperm cells

do not effect entire body/ occurs in patches that can grow over time

Question 10

Genetic Mosaic

Answer 10

individual that has somatic mutation regions that differ from rest of body

Question 11

Types of Spontaneous Mutation

Answer 11

• errors in DNA replication
• induced mutations (caused by enviornmental agents)

Question 12

Spontaneous Mutation: ROS converts Guanine → 8-oxoG (pairs with A → G→T transversion Deamination of Cytosine and 5-methylcytosine

Answer 12

5-methylcytosine is deaminated into thymine and repair enzymes cant determine incorrect base

Question 13

Spontaneous Mutation:
Oxidative Damage

Answer 13

ROS converts Guanine → 8-oxoG (pairs with A → G→T transversion

Question 14

Induced Mutations

Answer 14

include mutagens (agents that alter DNA structure and cause mutations)

chemical/physical mutagens

Question 15

Chemical Mutagens

Answer 15

chemicals that interact with bases, changing their structure, making them act weird

Question 16

Types of chemical mutagens

Answer 16

• base modifiers
• intercalating agents
• base analogues (bases are added during DNA replication)

Question 17

Physical Mutagens

Answer 17

ionizing
nonionizing

Question 18

Ionizing Physical Mutagens

Answer 18

-xrays, gamma rays
- penetrate molecules (breaking/damaging DNA)

Question 19

Nonionizing Physical Mutagens

Answer 19

• uv light
• less strong effects dimers

Question 20

Covalent Modifications

Answer 20

Photolyase uses energy from light to repair thymine dimers

Alkyltransferase repairs alkylated bases

Question 21

Base Excision Repair

Answer 21

removes damaged bases

( BER: recognizes abnormal base and cleaves the bond between it and a sugar ) (uses DNA-N)glycloase)

Question 22

Nucleotide Excision Repair

Answer 22

removes damages DNA segments

(NER) repairs thymine dimers, modified bases, missing bases, crosslinks

Question 23

ECOLI DNA Repair

Answer 23

uses NER ( composed of uvRA, uvRB, uvRC, uvRD)

ultralight repairs dimers by recognizing damaged DNA which is than repaired by DNA polymerase/ligase

Question 24

Mismatch Repair Systems

Answer 24

recognize and correct base mismatches when proofreading fails

Question 25

Ecoli Mismatch Repair

Answer 25

Mutl,MutH,Muts detect mismatch and direct its removal Mutl/Muts bind to MutH which cleaves the site by recognizing parental/daughter strands

Question 26

How does MutH recognize daughter and parental strands

Answer 26

parental strands are methylated

Question 27

Double Stranded DNA Repair

Answer 27

Non homologous end joining homologous end joining

Question 28

Non homologous end joining

Answer 28

broken ends are recogonized by end binding proteins which then create a crossbridge - can delete small regions of DNA

Question 29

Gene Editing

Answer 29

experimentally altering a gene sequence

Question 30

Crispr-Cas Technology

Answer 30

- edit genes in a living cell - gene inactivation - creation of a point mutation

Question 31

Process

Answer 31

1, creation of sgRNA 2. spacer region of sgRNA is complementary to target gene 3. sgRNA binds with cas9 to locate gene 4. cas9 makes a double strand break 5. non homologous end joining repairs and regions spliced ends

Question 32

sgRNA

Answer 32

created signal guide RNA

Question 33

Genetic Diseases

Answer 33

1. direct result of mutation in 1 gene 2. can involve many genes

Question 34

Genetic Bases for Human Diseases

Answer 34

1. disease are more prevalent within family 2. monozygotic twins share diseases more often than dizygotic twins 3. disease does not spread to individuals in similar environments 4. different populations have different disease frequencies 5. disorders have an onset age 6. human disorders mirror disorders in other mammals 7. disease can be observed between mutation/chromosomal alteration

Question 35

Autosomal Recessive

Answer 35

- unaffected parents - 25% affected children for heterozygotes - affected parents have affected children - not discriminated by gender

Question 36

Autosomal Dominant

Answer 36

- affected offspring has affected parent - one affected parent = 50% chance of affected offspring - homozygote disadvantage

Question 37

x-linked recessive

Answer 37

- males more likely to have trait - affected males have other affected male relatives - Female offspring of affected males produce (on average) 50% affected male offspring

Question 38

x-linked dominant

Answer 38

- rare - males are def more affected - females express trait when lethal to males - affected females: 50% chance to pass to female offspring