Chapter 12

Question 1

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number

Answer 1

Aneuploidy

Question 2

A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome

Answer 2

Barr body

Question 3

A basic principle in biology stating that genes are located at specific positions (loci) on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns

Answer 3

Chromosome theory of inheritance

Question 4

The reciprocal exchange of genetic material between no sister chromatids during prophase 1 of meiosis

Answer 4

Crossing over

Question 5

A map of a chromosome that located genes with respect to chromosomal features distinguishable in a microscope

Answer 5

Cytogenetic map

Question 6

(1) A deficiency in a chromosomes resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene

Answer 6

Deletion

Question 7

A human genetic disease usually caused by the presence of an extra chromosome 21; characterized by developmental delays and heart and other defects that are generally treatable or non life threatening

Answer 7

Down syndrome

Question 8

A human genetic disease caused by a sex linked recessive allele; characterized by progressive weakening and a loss of muscle tissue

Answer 8

Duchenne muscular dystrophy

Question 9

An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicated

Answer 9

Duplication

Question 10

An ordered list of genetic loci (genes or other genetic markers) along a chromosome

Answer 10

Genetic map

Question 11

General term for the production of offspring with combination of traits that differ from those found in either parent

Answer 11

Genetic recombination

Question 12

A human genetic disease caused by a sex-linked recessive allele, resulting in the absence of one or more blood-clotting proteins; characterized by excessive bleeding following injury

Answer 12

Hemophilia

Question 13

An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated

Answer 13

Inversion

Question 14

A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes

Answer 14

Linkage map

Question 15

Genes located close enough together on a chromosome that they tend to be inherited together

Answer 15

Linkage genes

Question 16

A unit of measurement of the distance between genes. One map is equivalent to a 1% recombination frequency

Answer 16

Map unit

Question 17

Referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two

Answer 17

Monosomic

Question 18

An error in meiosis or mitosis in which members of a pair of homologous chromosomes or sister chromatids fail to separate properly from each other

Answer 18

Nondisjunction

Question 19

An offspring with a phenotype that matches one of the true-breeding parental (P generation) phenotypes; also refers to the phenotypes itself

Answer 19

Parental type

Question 20

A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division

Answer 20

Polyploidy

Question 21

An offspring whose phenotype differs from that of the true-breeding P generation parents; also refers the the phenotype itself

Answer 21

Recombinant type

Question 22

A gene located on either sex chromosome. Most sex-linked genes are on the X chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosome

Answer 22

Sex-linked gene

Question 23

(1) An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a non homologous chromosome (2) During protein synthesis, the third stage in the elongation cycle, when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrient in the phloem of vascular plants

Answer 23

Translocation

Question 24

Referring to a diploid cell that had three copies of a particular chromosome instead of the normal two

Answer 24

Trisomic

Question 25

The phenotype most commonly observed in natural populations; also refers to the individual with that phenotype

Answer 25

Wild type

Question 26

A gene located on the X chromosome; such genes show a distinctive pattern of inheritance

Answer 26

X-linked gene