Unit 10- Genetics and Evolution

Question 1

(genetics) an organism or cell having two sets of chromosomes or twice the haploid number

Answer 1

diploid

Question 2

A haploid cell such as an egg or sperm. unite during sexual reproduction to produce a diploid zygote.

Answer 2

gametes

Question 3

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Answer 3

crossing over

Question 4

occurs when two haploids (an egg and sperm) join to form one zygote (first cell of life)

Answer 4

fusion of gametes

Question 5

meiosis in which there is a failure of paired homologous chromosomes to separate

Answer 5

non-disjunction

Question 6

(key difference piece of the villi)
Removes small piece of villi between 8-12 wks to test for genetic test; karyotype is completed to look for non-disjunction. Much earlier test than others

Answer 6

chorionic villi sampling

Question 7

(key difference amniotic fluid)
A technique of prenatal diagnosis in which amniotic fluid, obtained by aspiration from a needle inserted into the uterus, is analyzed to detect certain genetic and congenital defects in the fetus. Done at 15 weeks

Answer 7

amniocentesis

Question 8

the random position of each pair of chromosomes in the nucleus when the spindle microtubules become attached. Their random orientation will eventually result in which chromosomes end up where.

Answer 8

random orientation

Question 9

(genetics) an organism or cell having only one complete set of chromosomes

Answer 9

haploid

Question 10

A structure in which 2 pairs of homologous sister chromatids have synapsed with one another

Answer 10

bivalents

Question 11

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Answer 11

crossing over

Question 12

Male sex cell (sperm) unites with female sex cell into one cell (46 chromosomes – 23 from each).

Answer 12

fertilization

Question 13

Chromatids from opposite members of a homologous pair. These cross over at prophase I.

Answer 13

non-sister chromatids

Question 14

The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis.

Answer 14

chiasmata

Question 15

During crossing over, the switch of alleles for the same genes.

Answer 15

allele exchange

Question 16

the random distribution of the pairs of genes on different chromosomes to the gametes

Answer 16

independent assortment

Question 17

where cross over occurs between two non-sister chromatid to allow for cross-over

Answer 17

synaptomenal complex

Question 18

Genes located on the same chromosome that tend to be inherited together in genetic crosses

Answer 18

linked genes

Question 19

Inherited characteristic that have a limited number of variations, such as the ability or inability to roll one’s tongue

Answer 19

discrete variation

Question 20

An assemblage of measurements of a phenotypical characteristic which forms from a continuous spectrum of values, such as body height, skin color or hair curl

Answer 20

continuous variation

Question 21

An additive effect of two or more gene loci on a single phenotypic character

Answer 21

polygenic inheritance

Question 22

A statistical method used to calculate whether the observed and expected genotype frequencies of a population are significantly different.

Answer 22

chi-square test

Question 23

A cross between two individuals, concentrating on two definable traits, for example pea color and height of pea plant

Answer 23

dihybrid cross

Question 24

Offspring whose phenotype differs from that of the parents; also called recombinant types

Answer 24

recombinants

Question 25

The set of all genes, or genetic information, in any population, usually of a particular species.

Answer 25

Gene pool

Question 26

The percentage of all alleles at a given locus in a population gene pool represented by a particular allele.

Answer 26

allelic frequency

Question 27

Separation of species or populations so that they cannot interbreed and produce fertile offspring

Answer 27

reproductive isolation

Question 28

An evolutionary process in which one species splits into two or more species.

Answer 28

speciation

Question 29

A chromosomal alteration in which the organism possesses more than two complete chromosome sets. Found in plants

Answer 29

polyploidy

Question 30

Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.

Answer 30

directional selection

Question 31

Natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes.

Answer 31

stabilizing selection

Question 32

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

Answer 32

disruptive selection

Question 33

The onion genus comprises monocotyledonous flowering plants and includes the onion, garlic, chives, scallion, shallot, and the leek as well as hundreds of wild species

Answer 33

Genus: Allium

Question 34

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

Answer 34

punctuated equilibrium

Question 35

A proposed explanation in evolutionary biology stating that new species arise from the result of slight modifications (mutations and resulting phenotypic changes) over many generations.

Answer 35

gradualism

Question 36

the increased vigour (eg: growth, litter size, milk production) of crossbred animals

Answer 36

hybrid vigour