genetics

Question 1

Except for the sperm and oocytes (gametes), during development and afterwards, all body cells have _____ total chromosomes

Answer 1

46

Question 2

the cells in the body other than sperm and egg cells. replicated by mitosis

Answer 2

somatic cells

Question 3

gametes are produced through mitosis or meiosis

Answer 3

meiosis

Question 4

Meiosis ___ is a ______ from 2n to n
o The homologous chromosomes are segregated from each other, then two _____ cells are formed, each containing one of the segregates

Answer 4

I. reductive division. haploid

Question 5

Meiosis ____ consists of decoupling each chromosome’s sister strands (chromatids), then segregating the DNA into two sets (each set having one of each homologue)
o Two haploid cells with replicated sister chromatids go to form four _____ cells with single, unreplicated molecules of DNAs

Answer 5

II. haploid

Question 6

: How each pair of homologous chromosomes separates has NOTHING to do with each other pair

Answer 6

Independent assortment

Question 7

: a result of crossing over, it means that even
DNA on the same chromosome may go in different directions (part gets crossed over to the other homologous chromosome)… not all the time but occasionally.

Answer 7

Recombination

Question 8

Different forms of homologous genes

Answer 8

Alleles

Question 9

Locations of genes on a chromosomes (different alleles have the same locus on the homologous chromosome)

Answer 9

Locus

Question 10

both alleles identical

Answer 10

Homozygous

Question 11

alleles different

Answer 11

Heterozygous

Question 12

: complete set of genes and alleles

Answer 12

Genotype

Question 13

observed physical and functional traits (depends on interaction of alleles and environment)

Answer 13

Phenotype

Question 14

Genetics involves 2 basic things: determining where the alleles for a _____ come from, and then determining the ____ based on that _____

Answer 14

genotype. phenotype. genotype

Question 15

When the diploid number of chromosomes (2n) is reconstituted in a fertilized ovum, one chromosome in each pair came from the mother, and the other came from the father - these are called

Answer 15

homologous chromosome

Question 16

Each pair in this genetic sampling of a human cell is a

Answer 16

Homologous pair (look at pic)

Question 17

Each of the two homologues contains genes that control the ______ (make the ______), though they do so with individual variation characteristic of our species

Answer 17

same traits. same proteins

Question 18

Alternative forms of a gene that code for the same trait and are at the same location on homologous chromosomes are called

Answer 18

alleles

Question 19

: gene always expressed, even if heterozygous

Answer 19

Dominant alleles

Question 20

two copies of gene needed to be expressed,
must be homozygous

Answer 20

Recessive alleles

Question 21

: heterozygote is an intermediate phenotype

Answer 21

incomplete dominance. ex: white flower x red flower = pink flower

Question 22

: both phenotypes equally expressed

Answer 22

Codominance. ex: white cow x brown cow = cow with white and brown spots

Question 23

: more than 2 alleles involved

Answer 23

Multiallelic inheritance. ex: ABO blood type

Question 24

: multiple genes involved

Answer 24

Polygenic inheritance. ex: hair, eye, and skin color

Question 25

____ determines sex (presence of Y makes individual male)

Answer 25

Y

Question 26

Characteristics of what : mostly males with disease (recessive, they only have one X copy), passed to sons by mother, father cannot pass the gene

Answer 26

Sex-linked genes located on sex chromosomes:

Question 27

is the total collection of genes in a population at any one time. A xxx for a particular trait can be though of as all the cards in a
deck. Each diploid individual gets a 2 allele “hand

Answer 27

A gene pool

Question 28

is a change in the relative frequencies of
alleles in a gene pool over time

Answer 28

evolution

Question 29

_____ alone does not lead to evolutionary change in a population

Answer 29

sexual reproduction

Question 30

The causes of evolution

Answer 30

 Mutations (drawing on or erasing the cards)
 Genetic drift in small populations(odds, probability v. actual results)
 Gene flow between populations (adding/removing cards to/from the deck)
 Natural selection (throwing away some hands and not others)

Question 31

or changes in the nucleotide sequence of DNA, are rare and Random and have little effect on the total gene pool, but they are the Only ultimate source of new alleles

Answer 31

mutation

Question 32

Key facts on mutation
Direction=
speed=

Answer 32

-Random, can be Totally new
- Minimal (but it can provide a new allele that other mechanisms of microevolution can increase rapidly)

Question 33

The three main causes of significant change in allele frequencies over time are

Answer 33

– Genetic drift
– Gene flow
– Natural selection

Question 34

is a change in the gene pool of a population due to chance
– In a small population, chance events may lead to the loss of genetic diversity (10 coin flips v. 10,000 coin flips)

Answer 34

genetic drift

Question 35

Key facts on Genetic Drift:
direction=
speed=

Answer 35

-Random
- happens a lot faster with small numbers, large populations are usually closer to the actual odds, so they have minimal drift. Can happen suddenly when a population is separated

Question 36

is the movement of individuals or gametes/spores between populations and can alter allele frequencies in a population

Answer 36

Gene flow

Question 37

Key facts on Gene flow:
direction=
speed=

Answer 37

• Makes two populations Similar
• depends on how many barriers there are to mating between the two populations

Question 38

If individuals differ in their probable reproductive success, xxx will alter allele frequencies

Answer 38

natural selection

Question 39

Key facts on Natural Selection:
Direction=
speed=

Answer 39

• Increase in alleles that give a phenotype making more children on average in the current environment
• depends on how many more offspring
  that allele helps you get compared to others

Question 40

______ is the only mechanism that has a
“direction” that is not random or determined by other populations

Answer 40

Natural selection

Question 41

Natural selection
- That direction is an increase in alleles that
 produce a ______ that on Average
 produces more ______ in
 the current ______

Answer 41

Phenotype. Offspring. Environment