Chapter 3

Question 0

single cell formed from the union of 2 gametes, a sperm & an ovum

Answer 0

zygote

Question 1

reproductive cell; that is, a sperm or ovum that can produce a new individual if it combines w/ a gamete from the other sex to make a zygote

Answer 1

gamete

Question 2

chemical composition of the molecules that contain the genes, which are the chemical instructions for cells to manufacture various proteins

Answer 2

DNA

Question 3

one of the 46 molecules of DNA (in 23 pairs) that virtually each cell of the human body contains & that, together, contain all of the genes. other species have more of fewer chromosomes

Answer 3

chromosome

Question 4

small section of a chromosome; the basic unit for the transmission of heredity. a gene consists of a string of chemicals that provide instructions for the cell to manufacture certain proteins

Answer 4

gene

Question 5

a variation that makes a gene different in some way from other genes for the same characteristics. many genes never vary; others have several possible alleles

Answer 5

allele

Question 6

the full set of genes that are the instructions to make an individual member of a certain species

Answer 6

genome

Question 7

an organisms entire genetic inheritance, or genetic potential

Answer 7

genotype

Question 8

chromosome pair that, in humans, determines sex. the other 22 pairs are autosomes, inherited equally by males & females

Answer 8

23RD pair

Question 9

a 23rd chromosome pair that insists of two x-shaped chromosomes, one each from the mother & the father. XX a zygotes become females

Answer 9

XX

Question 10

a 23RD chromosome pair that consists of an x-shaped chromosome from the mother & a y-shaped chromosome from the father. XY zygotes become males

Answer 10

XY

Question 11

cells from which any other specialized type of cell can form

Answer 11

stem cells

Question 12

twins who originate from one zygote that splits part very early in development. (also called identical twins) other monozygotic mult. births (such as triplets & quadruplets) can occur as well

Answer 12

monozygotic (MZ) twins

Question 13

twins who are formed when 2 separate ora are fertilized by 2 separate sperm at roughly the same time (fraternal twins)

Answer 13

dizygotic (DZ) twins

Question 14

general term for the techniques designed to help infertile couples conceive & then sustain a pregnancy

Answer 14

assisted reproductive technology (ART)

Question 15

fertilization that takes place outside a woman’s body (as in a glass lab dish) the procedure involves mixing sperm w/ ova that have been surgically removed from the woman’s ovary. if a zygote is produced, it is inserted into a woman’s uterus, where it may implant & develop into a baby

Answer 15

in vitro fertilization (INF)

Question 16

observable characteristics of a person, including appearance, personality, intelligence, & all other traits

Answer 16

phenotype

Question 17

a condition in which a person has 47 chromosomes instead of the usual 46, w/ 3 rather than 2 chromosomes at the 21st site. people w/ Down Syndrome typically have distinctive characteristics, including unusual facial features, Hearst abnormalities, & language difficulties

Answer 17

down syndrome

Question 18

consultation & testing by trained experts that enable individuals to learn about their genetic heritage, including harmful conditions that they might pass along to any children they may conceive

Answer 18

genetic counseling