Genetics

Question 1

G1 phase

Answer 1

• period after cell division and before start of DNA replication
• cells grow and monitor environment to determine whether to initiate another round of cell division

Question 2

S phase

Answer 2

• period of DNA synthesis
• cells replicate chromosomes

Question 3

G2 phase

Answer 3

• period between end of DNA replication and start of cell division
• cells check to make sure DNA replicated successfully and make any necessary repairs

Question 4

M phase

Answer 4

• period of actual cell division
• prophase, metaphase, anaphase, telophase, and cytokinesis

Question 5

diploid

Answer 5

two copies of each chromosome

Question 6

haploid

Answer 6

one set of chromosomes

Question 7

autosomes

Answer 7

chromosomes that do not differ between males and females

Question 8

sex chromosomes

Answer 8

chromosomes that differ between males and females

Question 9

euploid

Answer 9

cells with complete number of chromosomes

Question 10

aneuploid

Answer 10

cells with missing or extra chromosomes

Question 11

homologous

Answer 11

two copies of a particular chromosome that can have different variants of the same gene

Question 12

unreplicated chromosome

Answer 12

chromosome with one long strand of DNA double helix

Question 13

replicated chromosome

Answer 13

chromosome that has been copied and consists of two identical chromatids, each containing one double helix and joined at the centromere

Question 14

sister chromatids

Answer 14

the two attached, identical copies of a replicated chromosome

Question 15

mitosis prophase

Answer 15

chromosomes condense; each chromosome consists of a pair of identical sister chromatids joined at the centromere

Question 16

mitosis metaphase

Answer 16

chromosomes line up at the middle of the cell, along the plane of cell division, pushed and pulled by microtubules of the spindle apparatus

Question 17

mitosis anaphase

Answer 17

sister chromatids separate and migrate towards opposite ends of the cell

Question 18

mitosis telophase

Answer 18

chromatids cluster at opposite ends of the cell and begin to decondense

Question 19

cytokinesis

Answer 19

the membrane pinches in to divide the two daughter cells

Question 20

Mendel’s Law of Independent Action

Answer 20

all possible combinations of maternal and paternal chromosomes are possible in the two daughter cells

Question 21

prokaryote genome

Answer 21

usually packed into one circular chromosome consisting of circular DNA molecule of few million base pairs (Mbp)

Question 22

eukaryote genome

Answer 22

packaged into multiple linear chromosomes, each consisting of a linear DNA molecule of tens or hundreds of Mbp

Question 23

chromosome number (N)

Answer 23

the number of chromosomes in a haploid cell, or gamete (sperm or egg cell)

Question 24

particulate inheritance

Answer 24

the idea that hereditary elements are passed on in discrete units rather than “blended” together at each new generation

Question 25

gene

Answer 25

- a hereditary factor that determines (or influences) a particular trait - comprised of a specific DNA sequence and is located on a specific region of a specific chromosome called genetic locus

Question 26

allele

Answer 26

a particular variant of a gene

Question 27

genotype

Answer 27

the particular collection of alleles found in its DNA

Question 28

homozygous

Answer 28

two of the same alleles for a particular gene

Question 29

heterozygous

Answer 29

two different alleles for a particular gene

Question 30

phenotype

Answer 30

- observable traits - can have a heterozygous at a particular locus but have a phenotype that looks like only one of the two alleles due to dominance/recessiveness

Question 31

dominant allele

Answer 31

produces its phenotype whether the organism is homozygous or heterozygous at that locus

Question 32

recessive allele

Answer 32

produces its phenotype only when homozygous at the locus; its phenotype is masked if the locus is heterozygous

Question 33

sex linkage

Answer 33

inheritance of genes of sex chromosomes (X and Y)

Question 34

genetic linkage

Answer 34

the genes controlling two different traits are located near each other on the same chromosome

Question 35

genetic recombination

Answer 35

new combinations of alleles on chromosome

Question 36

Mendelian traits

Answer 36

- single gene - dominant/recessive inheritance

Question 37

non-Mendelian traits

Answer 37

anything other than Mendelian traits

Question 38

differentiate

Answer 38

to become specialized by making different sets of proteins

Question 39

transcriptional control

Answer 39

whether and how much a gene is transcribed into mRNA

Question 40

translational control

Answer 40

whether and how much a gene is translated into protein

Question 41

post-translational control

Answer 41

whether the protein is in an active or inactive form, and whether the protein is stable or degraded

Question 42

positive regulation

Answer 42

turning on gene expression

Question 43

negative regulation

Answer 43

turning off gene regulation

Question 44

co-regulation

Answer 44

turning multiple genes on or off together

Question 45

promoters

Answer 45

- sites in DNA where RNA polymerase binds to initiate transcription - contain binding sites for transcription factors

Question 46

transcription factors

Answer 46

DNA-binding proteins that help recruit or repel DNA polymerase

Question 47

regulatory element

Answer 47

a DNA sequence that certain transcription factors recognize and bind to in order to recruit or repel RNA polymerase

Question 48

constitutively expressed

Answer 48

genes always transcribed

Question 49

operon

Answer 49

two or more functionally related genes transcribed together from single promoter into one long mRNA

Question 50

lacZ

Answer 50

encodes the enzyme beta-galactosidase, which cleaves lactose into glucose and galactose

Question 51

lacY

Answer 51

encodes permease, a membrane protein for facilitated diffusion of lactose into the cell

Question 52

lacA

Answer 52

encodes transacetylase, an enzyme that modifies lactose

Question 53

C-value paradox

Answer 53

the amount of DNA in a haploid genome (the 1C value) does not seem to correspond strongly to the complexity of an organism, and 1C values can be extremely variable

Question 54

introns

Answer 54

“intervening” sequences in genes that do not code for proteins

Question 55

exons

Answer 55

the sequence of DNA present in mature messenger RNA, some of which encodes the amino acids of a protein

Question 56

principle of segregation

Answer 56

two alleles for a particular trait are segregated into different gametes

Question 57

principle of independent assortment

Answer 57

alleles for different traits are segregated independently