Exam 1 Review

Question 1

Genome

Answer 1

entire set of DNA instructions found in a cell–> mostly in nucleus (also in mitochondria and chloroplasts; haploid)

Question 2

Karyotype

Answer 2

an individual’s complete set of chromosomes, also an image of a person’s organized chromosomes

Question 3

Cytogeneticists

Answer 3

detect and interpret chromosomal abnormalities

Question 4

Cohesins

Answer 4

hold sister chromatids together during mitosis

Question 5

homologous chromosomes

Answer 5

one paternal, one maternal

Question 6

chromosome number

Answer 6

n = number of unique chromosomes in a “set”

Question 7

ploidy

Answer 7

number of complete sets of chromosomes

Question 8

C-value

Answer 8

amount of nuclear DNA in a gamete (haploid); irrespective of ploidy–> organismal complexity is NOT correlates with N, ploidy, or numbers of genes

Question 9

nucleoid

Answer 9

region that contains condensed DNA/protein complexes; attaches to inner membrane

Question 10

NAPs

Answer 10

nucleoid- assisted-proteins–> bind to repetitive sequences to form loops of supercoiled DNA

Question 11

Microdomains/Loop Domains

Answer 11

help condense bacterial chromosomes

Question 12

topoisomerases

Answer 12

enzymes that overwind and under wind dsDNA
-positive= spin DNA in same direction as double helix
negative= opposite direction of helix; unwinds DNA

Question 13

nucleosome

Answer 13

a single histone/DNA complex, the fundamental subunit of chromatin

Question 14

Histone H1

Answer 14

lies where DNA goes into/out of nucleosome and clamps it together
DNA wraps around histones

Question 15

Introns

Answer 15

parts of genes that are transcribed into mRNAs and then removed before translation
- members of same species tend to have same introns in same positions
- maintain ancestral positions

Question 16

exons

Answer 16

part of RNA that is read during translation; spliced together to form mature mRNA

Question 17

alternative splicing

Answer 17

alternate splicing can create different proteins

Question 18

Transposable elements

Answer 18

self-replicating, mobile DNA sequences
- “jumping genes”

Question 19

Single Nucleotide Polymorphisms (SNPs)

Answer 19

changes one base, could have no effect, could have major effect if in promoter/gene

Question 20

Variable Number Tandem Repeats (VNTRs)

Answer 20

some humans have 2 repeats, some have three, some have four… etc.

Question 21

Test Cross

Answer 21

cross an unkown to an individual with a known, recessive genotype
- offspring will have predictive phenotypic rations

Question 22

Independent Assortment

Answer 22

when homologous chromosomes separate during anaphase I of meiosis–> can go wherever they want in the cell

Question 23

Pleiotropy

Answer 23

one gene controlling multiple phenotypes
- one gene affects multiple different systems

Question 24

epistasis

Answer 24

dominant allele masks all other alleles

Question 25

Major effect Loci

Answer 25

ex: long hair in cats

Question 26

Modifier genes

Answer 26

how “short” the long hair will be

Question 27

codominant

Answer 27

show both phenotypes

Question 28

incomplete dominance

Answer 28

phenotype is in between both homozygotes

Question 29

law of dominance

Answer 29

some alleles are dominant, others are recessive, a heterozygous individual will display the dominant form

Question 30

law of segregation

Answer 30

only 1 allele is carried in a gamete

Question 31

Law of Independent Assortment

Answer 31

genes of different traits segregate independently into the gametes

Question 32

Chromosomal theory of heredity

Answer 32

genes are located on chromosomes

Question 33

hemizygous

Answer 33

males have one copy of the X chromosome; X-linked recessive traits will be expressed

Question 34

reciprocal cross

Answer 34

switch the phenotype associated with each parent

Question 35

nondisjunction

Answer 35

failure of chromosomes to separate during meiosis

Question 36

dosage compensation

Answer 36

mechanism to equalize gene expression due to difference in chromosome number

Question 37

Barr Body

Answer 37

one copy of X chromosome is randomly inactivated in females–> expression of X chromosome is equalized across sexes

Question 38

Why do we need pedigrees in humans

Answer 38

1, offspring number is too small
2. breeding takes place too infrequently
3. can’t be sure of genetic background of parents
4. controlled crosses can’t be made