Exam One - 1.8 Genetics Overview

Question 1

Genes x Environment = ?

Answer 1

Phenotype

Question 2

Genome

Answer 2

the DNA found within all of our chromosomes

Question 3

Genetics

Answer 3

the branch of biology that deals with heredity and variation

Question 4

Gene

Answer 4

segment of DMA that produces a function product, most often a peptide

Question 5

Traits

Answer 5

characteristics of an organism (morphological, physiological, and behavioral)

Question 6

Nucleic Acids

Answer 6

building blocks of nucleotides with made DNA and RNA

Question 7

Genetic Code

Answer 7

3 base pair sequence of DNA that specifies amino acid

Question 8

Chromosomes

Answer 8

structures containing DNA, 46 in humans (23 pairs)

Question 9

Gene expression

Answer 9

transcription -> translation -> traits

Question 10

Alleles

Answer 10

different forms of the same gene (ex - eye color)

Question 11

Polymorphisms

Answer 11

small DNA changes in >1% of population, examples include genes for eye, hair, and skin color

Question 12

SNPs

Answer 12

single nucleotide polymorphisms - responsible for much genetic variation

Question 13

Genome

Answer 13

the DNA found within all our chromosomes

Question 14

mutation

Answer 14

change in DNA, whether inherited or spontaneous

Question 15

Mutagen

Answer 15

cause DNA mutation

Question 16

Gain of function

Answer 16

mutation adds or increases peptide function

Question 17

Loss of function

Answer 17

mutation attenuates or stops peptide function, or translation at all

Question 18

upregulate

Answer 18

gene expression increases

Question 19

downregulate

Answer 19

gene expression decreases

Question 20

homozygous

Answer 20

both allels are the same for a given gene loci

Question 21

heterozygous

Answer 21

the alleles are different for a given gene loci

Question 22

dominant allele

Answer 22

promotes phenotype when heterozygous

Question 23

recessive allele

Answer 23

promotes phenotype only if homozygous

Question 24

Mendelian Genetic square results when crossing two heterozygous parents

Answer 24

RR, Rr, rR, and rr
3:1 ratio
(ex - 3 purple, 1 white flower)

Question 25

Complete dominance of one allele

Answer 25

heterozygous phenotype same as homozygous dominant phenotype

Question 26

incomplete dominance of either allele

Answer 26

heterozygous phenotype intermediate between the two homozygous phenotypes (ex. red flower + white flower = pink flower)

Question 27

codominance

Answer 27

both phenotypes expressed in heterozygotes (ex. blood types)

Question 28

multiple alleles

Answer 28

in the pop, some genes have more than two alleles

Question 29

Pleiotropy

Answer 29

one gene affects multiple different phenotypic characters (ex - sickle cell)

Question 30

Gene mutations have two classifications:

Answer 30

1 - Hereditary
2 - Acquired (somatic)

Question 31

Hereditary mutations

Answer 31

• inherited
• mutation present in every cell
• “germ line” mutations
  If germ line DNA is mutated, the child that grows from the fertilized egg will have the mutation in each of their cells

Question 32

Acquired (somatic) mutations

Answer 32

• occur only in life
• present only in certain cells
• caused by mutagens (or DNA copy error)
• acquired mutations in somatic cells cannot be passed down to children

Question 33

Types of DNA mutations

Answer 33

• Base substitutions (silent, missense, nonsense mutations)
• Frameshift (deletions, insertions)

can result in gain or loss of function

Question 34

What is the most common genetic disease?

Answer 34

cancer

Question 35

Point Mutation types

Answer 35

substitution
insertion
deletion

Question 36

Point mutation - substitution

Answer 36

one base is incorrectly added during replication and replaces the pair in the corresponding position on the complementary strand

Question 37

Point mutation - insertion

Answer 37

one or more extra nucleotides are inserted into replicating DNA, often resulting in frameshift

Question 38

Point mutation - deletion

Answer 38

one or more nucleotides is “skipped” during replication, often resulting in frameshift

Question 39

Types of chromosomal mutations

Answer 39

inversion
deletion
duplication
translocation

Question 40

chrom. mutation - inversion

Answer 40

one regions of a chromosome is flipped and reinserted

Question 41

chrom. mutation - deletion

Answer 41

a regions of a chromosome is lost, resulting in the absence of all the genes in that area

Question 42

chrom. mutation - duplication

Answer 42

a region of a chromosome is repeted, resulting in an increase in dosage from the genes in that region

Question 43

chrom. mutation - translocation

Answer 43

a region from one chromosome is aberrantly attached to another chromosome

Question 44

Types of Copy number variation

Answer 44

gene amplification
expanding trinucleotide repeat

Question 45

copy number v. - gene amplification

Answer 45

the number of tandem copies of a locus is increased

Question 46

copy number v. - expanding trinucleotide repeat

Answer 46

the normal number of repeated nucelotide sequences is expanded

Question 47

DNA mutation causes

Answer 47

environmental
spontaneous

Question 48

Environmental mutations from…

Answer 48

radiation (ionizing and non-ionizing)
chemical mutagens

Question 49

Spontaneous mutations from…

Answer 49

mistakes in DNA repair

Question 50

What type of mutation causes sickle cell anemia?

Answer 50

• base substitution
• single base = point mutation
• changes GAG to CTG, switching normal glutamic acid for valine
• loss of function mutation

Question 51

Prevalence of Sickle Cell

Answer 51

• more so in black births 1/365
• hispanic origin 1/16300
  thought to be protective against malaria

Question 52

Symptoms of Sickle Cell

Answer 52

anemia, pain, swelling (hands/feet), frequent infections, delayed growth/puberty, vision abnormality