Module 7

Question 1

True breeding

Answer 1

If an organism has a certain characteristic that is always passed on to its offspring, we say that this organism bred true with respect to that characteristic.

Question 2

Allele

Answer 2

One of a pair of genes that occupies the same position on homologous chromosomes

Question 3

Genotype

Answer 3

Two-letter set that represents the alleles an organism possesses for a certain trait

Question 4

Phenotype

Answer 4

The observable expression of an organism’s genes

Question 5

Homozygous genotype

Answer 5

A genotype in which both alleles are identical

Question 6

Heterozygous genotype

Answer 6

A genotype with two different alleles

Question 7

Dominant allele

Answer 7

An allele that will determine phenotype if just one is present in the genotype

Question 8

Recessive allele

Answer 8

An allele that will not determine the phenotype unless the genotype is homozygous in that allele

Question 9

Testcross

Answer 9

Breeding an organism displaying the dominant phenotype but unknown genotype with a homozygous recessive organism

Question 10

Pedigree

Answer 10

A diagram that follows a particular phenotype through several generations

Question 11

Monohybrid cross

Answer 11

A cross between two individuals, concentrating on only one definable trait

Question 12

Dihybrid cross

Answer 12

A cross between two individuals, concentrating on two definable traits

Question 13

Autosomes

Answer 13

Chromosomes that do not determine the sex of an individual

Question 14

Sex chromosomes

Answer 14

Chromosomes that determine the sex of an individual

Question 15

Carriers

Answer 15

Individuals who have one copy of an allele for a recessive trait but do not exhibit the trait

Question 16

Incomplete dominance

Answer 16

Inheritance pattern in which heterozygotes have a phenotype intermediate between the phenotypes of the homozygotes

Question 17

Codominance

Answer 17

Inheritance pattern in which heterozygotes express the distinct phenotypes of both alleles

Question 18

Antigen

Answer 18

A substance that, when introduced into the blood, triggers the production of an antibody

Question 19

Antibody

Answer 19

Specialized proteins in your immune system used to attack and destroy specific antigens

Question 20

Sex-linked inheritance

Answer 20

Inheritance of a genetic trait located on the sex chromosomes

Question 21

Gene mutation

Answer 21

A radical change in the DNA of one or more alleles

Question 22

Chromosomal mutations

Answer 22

Changes in the chromosome structure in which a chromosome loses or gains genes during meiosis

Question 23

Nondisjunction

Answer 23

A situation in which abnormal cellular events in meiosis lead to either none of a particular chromosome in the gamete or more than one of a particular chromosome in the gamete

Question 24

Genome

Answer 24

A complete set of an organism’s genetic information encoded in its DNA

Question 25

Short tandem repeats (STRs)

Answer 25

Short sequences of DNA (usually from two to six base pairs in length) that are repeated numerous times at various locations in the noncoding region of a chromosome

Question 26

Restriction enzyme

Answer 26

An enzyme that recognizes and cuts DNA only at a specific sequence of nucleotides

Question 27

Plasmid

Answer 27

A small, circular section of extra DNA that confers one or more traits to a bacterium and can be reproduced separately from the main bacterial genetic code

Question 28

Recombinant DNA

Answer 28

Taking DNA from two different species and combining them in one cell

Question 29

Genetically modified organism

Answer 29

An organism that has been genetically altered by humans

Question 30

Transgenic organism

Answer 30

An organism that carries one or more genes from a different species

Question 31

Transgenic organism

Answer 31

An organism that carries one or more genes from a different species