Chapter 14 - Mendel

Question 0

The mating, or crossing, of two true-breeding varieties in genetics

Answer 0

Hybridization

Question 1

An observable hereditary feature that may vary among individuals

Answer 1

Character

Question 2

The true-breeding (homozygous) parent individuals from which F1 hybrid offspring are derived in studies of inheritance (P stands for parental)

Answer 2

P generation

Question 3

The first filial, hybrid (heterozygous) offspring arising from a parental cross

Answer 3

F1 generation

Question 4

The offspring resulting from interbreeding (or self-pollination) of the hybrid F1 generation

Answer 4

F2 generation

Question 5

Any of the alternative versions of a gene that may produce distinguishable phenotypic effects

Answer 5

Allele

Question 6

An allele that is fully expressed in the phenotype of a heterozygote, determines the organism’s appearance

Answer 6

Dominant allele

Question 7

An allele whose phenotypic effect is not observed in a heterozygote

Answer 7

Recessive allele

Question 8

Mendel’s first law, states 2 alleles in a pair segregate into different gametes during gamete formation

Answer 8

Law of Segregation

Question 9

A diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of known genotype

Answer 9

Punnett square

Question 10

Having two identical alleles for a given gene

Answer 10

Homozygous

Question 11

Having two different alleles for a given gene

Answer 11

Heterozygous

Question 12

The observable physical and physiological traits of an organism which are determined by its genetic makeup

Answer 12

Phenotype

Question 13

The genetic makeup, or set of alleles, of an organism

Answer 13

Genotype

Question 14

Breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype; the ratio of phenotypes in the offspring reveals the unknown genotype

Answer 14

Testcross

Question 15

An organism that is heterozygous with respect to a single gene of interest; all offspring from a cross between parents homozygous for different alleles are this; for example, parents of genotypes AA and aa produce a genotype Aa

Answer 15

Monohybrids

Question 16

A cross between 2 organisms that are heterozygous for the character being followed (or the self-pollination of a heterozygous plant).

Answer 16

Monohybrid cross

Question 17

An organism that is heterozygous with respect to 2 genes of interest; all the offspring from a cross between parents doubly homozygous for different alleles are this; for example, parents of genotypes AABB and aabb produce a genotype AaBb.

Answer 17

Dihybrids

Question 18

A cross between 2 organisms that are each heterozygous for both of the characters being followed (or the self-pollination of a plant that is heterozygous for both characters)

Answer 18

Dihybrid cross

Question 19

Mendel’s 2nd law, states each pair of alleles segregates independently of each other pair during gamete formation; applies when genes for 2 characters are located on different pairs of homologs or when they are far enough apart on the same chromosome to behave as though they are on different chromosomes

Answer 19

Law of Independent Assortment

Question 20

A rule of probability stating that the probability of 2 or more independent events occurring together can be determined by multiplying their individual probabilities

Answer 20

Multiplication rule

Question 21

A rule of probability stating that the probability of any one of two or more mutually exclusive events occurring can be determined by adding their individual probabilities

Answer 21

Addition rule

Question 22

The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable

Answer 22

Complete dominance

Question 23

The situation in which the phenotypes of heterozygotes is intermediate between the phenotype of individuals homozygous for either allele

Answer 23

Incomplete dominance

Question 24

The situation in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate distinguishable ways

Answer 24

Codominance

Question 25

A human genetic disease caused by a recessive allele for a dysfunctional enzyme, leading to accumulation of certain lipids in the brain; seizures, blindness, and degeneration of motor and mental skills usually manifest a few months after birth, followed by death in a few years

Answer 25

Tay-Sachs Disease

Question 26

Ability of a single gene to have multiple effects

Answer 26

Pleiotropy

Question 27

A type of gene interaction in which the phenotypic expression of one gene alters that of another independently inherited gene

Answer 27

Epistasis

Question 28

Heritable features that vary continuously over a range rather than in an either-or fashion

Answer 28

Quantitative characters

Question 29

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

Answer 29

Polygenic inheritance

Question 30

A diagram of a family tree with conventional symbols showing the occurrence of heritable characters in parents and offspring over multiple generations

Answer 30

Pedigree

Question 31

An individual who is heterozygous at a given genetic locus for a recessively inherited disorder. The heterozygote is usually phenotypically normal for the disorder but can pass on the recessive allele to the offspring

Answer 31

Carriers

Question 32

A human genetic disorder caused by a recessive allele for a chloride channel protein; characterized by excessive secretion of mucus and consequent vulnerability to infection; fatal if untreated

Answer 32

Cystic Fibrosis

Question 33

A recessively inherited human blood disorder in which a single nucleotide change in the gene causes hemoglobin to aggregate, changing RBC shape and causing multiple symptoms in afflicted individuals

Answer 33

Sickle-Cell Disease

Question 34

A human genetic disorder caused by a dominant allele, characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10-20 years after onset of symptoms

Answer 34

Huntington’s Disease

Question 35

A technique used for prenatal diagnosis in which amniotic fluid is obtained from aspiration of a needle inserted into the uterus; fluid is analyzed to detect certain genetic and congenital defects in the fetus

Answer 35

Amniocentesis

Question 36

Technique for prenatal diagnosis in which a small sample of the fetal portion of the placenta is removed for analysis to detect certain genetic and congenital defects in the fetus

Answer 36

Chorionic Villus Sampling (CVS)