Module 1 Part 1

Question 1

How are mutations classified

Answer 1

• heritability
  -how they arise
  -effects on gene function
  -mutation type

Question 2

define mutation

Answer 2

a change in the DNA sequence

Question 3

define germ line mutation

Answer 3

heritable mutation from egg and sperm

Question 4

define somatic mutation

Answer 4

mutation which is non heritable from the body cells

Question 5

define protein coding region

Answer 5

mutation will affect polypeptide sequence

Question 6

define non coding regions

Answer 6

mutation will affect gene regulatory regions; non coding RNA
- might still affect protein function during gene expression

Question 7

what is germline mosaicism

Answer 7

genetically non identical germline cells (sperm, oocytes)
- mutation causes differences in offspring

Question 8

what is somatic mosaicism

Answer 8

genetically non identical somatic cells
- post zygotic
- one mutated cell gives rise to daughter cells with same mutation

Question 9

Describe the case study of genetic mosaicism discussed in class

Answer 9

blaschkoid congenital ichthyosiform erythroderma
- linear erythematosquamous plaques
- no growth/developmental delays
- hair and teeth not affected
RECESSIVE MUTATION

Question 10

what gene is affected in blaschkoid congenital ichthyosiform erythroderma

Answer 10

gene ABCA12

Question 11

define allele

Answer 11

gene variants which CAN result in mutation

Question 12

define wildtype allele

Answer 12

the more abundant allele- present at greater frequencies

Question 13

define mutant allele

Answer 13

the more rare allele

Question 14

define spontaneous mutation

Answer 14

• occur randomly with no cause
• due to low level errors
• occur less frequently

Question 15

describe an induced mutation

Answer 15

-arise due to exposure to physical and chemical mutagenic agents (radiation)
- mutagenic agents increase mutation rates greatly

Question 16

describe loss of function mutation

Answer 16

reduces or abolishes protein function

Question 17

what are the two types of loss of function mutations

Answer 17

• null (amorphic); complete loss of function
  -hypomorphic; incomplete; reduced activity

Question 18

define haplo insufficient genes

Answer 18

dominant gene

Question 19

define haplo sufficient genes

Answer 19

recessive genes
- loss of function in which one normal allele is not enough for normal function
- more than 660 genes cause human disease as a result

Question 20

describe a gain of function mutation

Answer 20

increased activity or new function; also for expression in wrong place or time

Question 21

describe hypermorphic gain of function mutation

Answer 21

more protein or more efficient protein

Question 22

describe neomorphic gain of function

Answer 22

generates a novel function

Question 23

describe a dominant negative or anti morphic gain of function

Answer 23

prevents the normal protein from performing its homeostatic function

Question 24

what is TP53

Answer 24

a transcription factor that functions as the gatekeeper of cell cycle progression

Question 25

what does p53 do

Answer 25

arrests cell cycle progression if there is DNA damage- prevents it from proliferating

Question 26

where do most p53 loss of function mutations occur

Answer 26

in the dna binding domain

Question 27

what do some mutations in p53 result in

Answer 27

gain of function mutation

Question 28

what does p53 actively supress

Answer 28

WT p53

Question 29

what do mutant p53 cells exibit same phenotype as

Answer 29

p53 null cells

Question 30

what are the three categories of mutations

Answer 30

single nucleotide, chromosomal re arrangements, change in chromosome number

Question 31

what are the different types of nucleotide mutations

Answer 31

• substitution
• deletion
• insertion

Question 32

what ar the different type of chromosomal re arrangement mutations

Answer 32

• large deletions
• large insertions
• inversions
• translocations

Question 33

what is an example of changes in chromosome number

Answer 33

aneuploidy

Question 34

what is the central dogma

Answer 34

DNA to RNA to Protein

Question 35

define the genetic code

Answer 35

the set of nucleotide triplicates (codons) that code for amino acids or translation stop signal

Question 36

what are point mutations

Answer 36

single base pair substitutions

Question 37

what are three types of point mutations

Answer 37

nonsense: code for stop codon which can stop protein
missense: code for different amino acid, resulting in non functional or protein with different function
silent mutation: code for same or different amino acid but there is no functional change in protein