Chapters 11/12/13

Question 1

any eukaryotic chromosome that is not a sex chromosome; are present in the same number and kind in both males and females

Answer 1

autosome

Question 2

the fusion of two haploid gamete nuclei to form a diploid zygote nucleus

Answer 2

fertilization

Question 3

a haploid reproductive cell

Answer 3

gamete

Question 4

during zygote development, cells that are set aside from the somatic cells and that will eventually undergo meiosis to produce gametes

Answer 4

germ-line cells

Question 5

the morphology of the chromosomes of an organism as viewed with a light microscope

Answer 5

karyotype

Question 6

the position on a chromosome where a gene is located

Answer 6

locus

Question 7

any of the cells of a multicellular organism except those that are destined to form gametes (germ-line cells)

Answer 7

somatic (cell)

Question 8

the first round of cell division - referred to “reductive division” because homologous chromosomes separate

Answer 8

meiosis I

Question 9

the second round of cell division

Answer 9

meiosis II

Question 10

The diploid (2n) cell resulting from the fusion of male and female gametes (fertilization)

Answer 10

zygote

Question 11

The process of producing offspring through an alternation of fertilization (producing diploid cells) and meiotic reduction in chromosome number (producing haploid cells).

Answer 11

sexual reproduction

Question 12

A mechanism of genetic recombination that occurs only in eukaryotic organisms, in which two chromosomes trade segments; can occur between nonhomologous chromosomes as well as the more usual exchange between homologous chromosomes in meiosis.

Answer 12

recombination or crossing over

Question 13

One of two or more alternative states of a gene.

Answer 13

allele

Question 14

The genetic constitution underlying a single trait or set of traits.

Answer 14

genotype

Question 15

The realized expression of the genotype; the physical appearance or functional expression of a trait.

Answer 15

phenotype

Question 16

A single genetic cross involving two different traits, such as flower color and plant height.

Answer 16

dihybrid cross

Question 17

mendel’s second law of heredity, stating that genes located on nonhomologous chromosomes assort independently of one another

Answer 17

law of independent assortment

Question 18

Describes a case in which two or more alleles of a gene do not display clear dominance. The phenotype of a heterozygote is intermediate between the homozygous forms.

Answer 18

incomplete dominance

Question 19

Describes a case in which two or more alleles of a gene are each dominant to other alleles but not to each other. The phenotype of a heterozygote for codominant alleles exhibits characteristics of each of the homozygous forms.

Answer 19

codominance

Question 20

Interaction between two nonallelic genes in which one of them modifies the phenotypic expression of the other.

Answer 20

epistatsis

Question 21

an allele that is expressed when present in either heterozygous or the homozygous condition

Answer 21

dominant allele

Question 22

the offspring resulting from a cross between a parental generation - in experimental crosses, these parents usually have different phenotypes

Answer 22

first filial (f1) generation

Question 23

having two different alleles of the same gene

Answer 23

heterozygous

Question 24

having two identical alleles of the same gene

Answer 24

homozygous

Question 25

the mating of unlike parents

Answer 25

hybridization

Question 26

Mendel’s first law of heredity, stating that alternative alleles for the same gene segregate from each other in production of gametes

Answer 26

law of segregation

Question 27

condition in which an individual allele has more than one effect on production of the phenotype

Answer 27

pleiotrophy

Question 28

a diagrammatic way of showing the possible genotypes and phenotypes of genetic crosses

Answer 28

punnett square

Question 29

an allele that is expressed only when present in a homozygous condition, but is “hidden” by the expression of a dominant allele in the heterozygous condition

Answer 29

recessive allele

Question 30

in genetics, a characteristic that has alternative forms

Answer 30

trait

Question 31

The offspring resulting from a cross between members of the first filial (F1) generation

Answer 31

f2 generation

Question 32

describes a mode of inheritance in which more than one gene affects a trait

Answer 32

polygenic inheritance

Question 33

The theory stating that hereditary traits are carried on chromosomes.

Answer 33

chromosome theory of inheritance

Question 34

A trait determined by a gene carried on the X chromosome and absent on the Y chromosome.

Answer 34

sex-linked (x-linked) gene

Question 35

A phenomenon by which the expression of genes carried on sex chromosomes is kept the same in males and females, despite a different number of sex chromosomes

Answer 35

dosage compensation

Question 36

A deeply staining structure, seen in the interphase nucleus of a cell of an individual with more than one X chromosome, that is a condensed and inactivated X. Only one X remains active in each cell after early embryogenesis.

Answer 36

Barr body

Question 37

The failure of homologues or sister chromatids to separate during mitosis or meiosis, resulting in an aneuploid cell or gamete.

Answer 37

nondisjunction

Question 38

The condition in an organism whose cells have lost or gained a chromosome;

Answer 38

aneuploidy

Question 39

The process of evaluating the risk of genetic defects occurring in offspring, testing for these defects in unborn children, and providing the parents with information about these risks and conditions.

Answer 39

genetic counseling

Question 40

Genetic disease usually caused by presence of an additional chromosome 21 (trisomy 21). This can also be due to a translocation of material from chromosome 21 to another chromosome. The translocated chromosome combined with two normal copies of chromosome 21 produces the same effect as trisomy. The syndrome is characterized by growth reductions, characteristic facial structure, and mild to moderate intellectual disability.

Answer 40

down syndrome

Question 41

describes a condition in which a chromosome has been lost due to a nondisjunction during meiosis, producing a diploid embryo with only one of these autosomes

Answer 41

monosomic

Question 42

a chromosome that is related to sex

Answer 42

sex chromosome

Question 43

a permanent change in cell’s DNA; includes change in nucleotide sequence, alteration of gene position, gene loss or duplication, or insertion of foreign sequences

Answer 43

mutation

Question 44

describes the condition in which an additional chromosome has been gained due to a nondisjunction during meiosis, and the diploid embryo therefore has three autosomes.

Answer 44

triomic

Question 45

A cross in which only a single trait with two variations is considered is called a(n) ____
cross or single factor cross.

Answer 45

monohybrid