Genes & Environment

Question 1

The genetic endowment that members of a particular species have in common; a contributor to universal species traits and patterns of maturation.

Answer 1

species heredity

Question 2

The evolutionary principle that individuals who have characteristics advantageous for survival in a particular environment are most likely to survive and reproduce. Over many generations, this process of “survival of the fittest” will lead to changes in a species and the development of new species.

Answer 2

natural selection

Question 3

Change in a species achieved not through biological evolution but through learning and passing on from one generation to the next new ways of adapting to the environment.

Answer 3

cultural evolution

Question 4

The moment of fertilization, when a sperm penetrates an ovum, forming a zygote.

Answer 4

conception

Question 5

A single cell formed at conception from the union of a sperm and an ovum.

Answer 5

zygote

Question 6

A threadlike structure made up of genes; in humans, there are ?

Answer 6

chromosome

46 in the nucleus of each cell

Question 7

The process in which a germ cell divides, producing sperm or ova; in humans, the products of meiosis normally contain ?.

Answer 7

meiosis

23 chromosomes

Question 8

The process in which a cell duplicates its chromosomes and then divides into two genetically
identical daughter cells.

Answer 8

mitosis

Question 9

Molecule whose chemical code makes up chromosomes and serves as our genetic endowment; it is made up of sequences of the chemicals ?

Answer 9

DNA Deoxyribonucleic acid
A (adenine), C (cytosine), G (guanine), and
T (thymine).

Question 10

One of the possible variants of a particular gene.

Answer 10

allele

Question 11

A massive, government-sponsored effort to decipher

the human genetic code.

Answer 11

Human Genome Project

Question 12

A process in which genetic material is exchanged between pairs of chromosomes during meiosis.

Answer 12

crossing over

Question 13

A chromosomal portrait created by staining chromosomes, photographing them under a high-power microscope, and arranging them into a predetermined pattern.

Answer 13

karyotype

Question 14

The genetic endowment that an individual inherits.

Answer 14

genotype

Question 15

The way in which a person’s genotype is expressed in observable or measurable characteristics.

Answer 15

phenotype

Question 16

The activation of particular genes in particular cells of the body at particular times in life.

Answer 16

gene expression

Question 17

The genetic mechanism through which a characteristic is influenced by only one pair of genes, one gene from the mother and its partner from the father.

Answer 17

single gene-pair inheritance

Question 18

A condition in which a stronger gene fails to mask all the effects of a weaker partner gene; a phenotype results that is similar but not identical to the effect of the stronger gene.

Answer 18

incomplete dominance

Question 19

In genetics, an instance in which two different but equally powerful genes produce a phenotype in which both genes are expressed.

Answer 19

codominance

Question 20

An attribute determined by a gene that appears on one of the two types of sex chromosomes, usually the X chromosome.

Answer 20

sex-linked characteristic

Question 21

A deficiency in the blood’s ability to clot. It is more common among males than females because it is associated with a sex-linked gene on the X chromosome.

Answer 21

hemophilia

Question 22

A characteristic influenced by the action of many gene pairs rather than a single pair.

Answer 22

polygenic trait

Question 23

A change in the structure or arrangement of one or more genes that produces a new phenotype.

Answer 23

mutation

Question 24

A genetic blood disease in which red blood cells assume an unusual sickle shape and become inefficient at distributing oxygen throughout the body.

Answer 24

sickle-cell disease

Question 25

Conditions in which a child has too few, too many, or incomplete chromosomes because of errors in the formation of sperm or ova.

Answer 25

chromosome abnormalities

Question 26

A chromosomal abnormality in which the child has inherited an extra 21st chromosome and is, as a result, mentally retarded; also called trisomy 21.

Answer 26

Down syndrome

Question 27

A sex chromosome abnormality in which females inherit only one X chromosome (XO); they remain small in stature, fail to develop secondary sex characteristics, and may show some mental deficiencies.

Answer 27

Turner syndrome

Question 28

A sex chromosome abnormality in which males inherit two or more X chromosomes; these males fail to develop secondary sex characteristics and often show deficiencies on tests of verbal abilities.

Answer 28

Klinefelter syndrome

Question 29

A chromosome abnormality in which one arm of the X chromosome is only barely connected to the rest of the chromosome; the most common hereditary cause of mental retardation.

Answer 29

fragile X syndrome

Question 30

A service designed to inform people about genetic conditions they or their unborn children are at risk of inheriting.

Answer 30

genetic counseling

Question 31

In genetics, individuals who possesses a recessive gene associated with a disease and who, although they do not have the disease, can transmit the gene for it to offspring.

Answer 31

carrier

Question 32

A genetic disease caused by a single, dominant gene that strikes in middle age to produce a deterioration of physical and mental abilities and premature death.

Answer 32

Huntington’s disease

Question 33

Method of examining physical organs by scanning them with sound waves—for example, scanning the womb and thereby producing a visual outline of the fetus to detect gross abnormalities.

Answer 33

ultrasound

Question 34

A method of extracting amniotic fluid from a pregnant woman so that fetal body cells within the fluid can be tested for chromosomal abnormalities and other genetic defects.

Answer 34

amniocentesis

Question 35

An alternative to amniocentesis in which a catheter is inserted through the cervix to withdraw fetal cells from the chorion for prenatal testing to detect genetic defects.

Answer 35

chorionic villus sampling (CVS)

Question 36

A noninvasive method of prenatal diagnosis involving testing for substances in maternal blood; more recently, analysis of fetal cells that have slipped through the placenta into the mother’s blood.

Answer 36

maternal blood sampling

Question 37

Prenatal diagnostic procedure in which a mother’s eggs are fertilized in the laboratory using in vitro fertilization techniques, DNA tests are conducted on the first cells that result from mitosis of each fertilized egg, and only eggs that do not have chromosome abnormalities or genes associated with disorders are implanted in the uterus.

Answer 37

preimplantation genetic diagnosis

Question 38

The scientific study of the extent to which genetic and environmental differences among individuals are responsible for differences among them in traits such as intelligence and personality.

Answer 38

behavioral genetics

Question 39

The amount of variability in a population on some trait dimension that is attributable to genetic differences among those individuals.

Answer 39

heritability

Question 40

A method of studying genetic influence that involves deliberately determining whether a trait can be bred in animals through selective mating.

Answer 40

selective breeding

Question 41

Method of studying genetic and environmental influence in which the similarity of identical twins is compared to that of fraternal twins, often in studies involving both twins reared together and twins reared apart.

Answer 41

twin study

Question 42

Method of studying genetic and environmental influence that involves determining whether adopted children are more similar to their biological parents or adoptive parents.

Answer 42

adoption study

Question 43

The percentage of cases in which a particular attribute is present for both members of a pair of people (e.g. twins) if it is present for one member.

Answer 43

concordance rate

Question 44

Experiences that individuals living in the same home environment share and that work to make them similar.

Answer 44

shared environmental influences

Question 45

Experiences unique to the individual that are not shared by other members of the family and that tend to make members of the same family different.

Answer 45

nonshared environmental influences

Question 46

The analysis of particular genes and their effects, including the identification of specific genes that influence particular traits and the comparison of animals or humans who have these specific genes and those who do not.

Answer 46

molecular genetics

Question 47

A genetically based pattern of tendencies to respond in predictable ways; building blocks of personality such as activity level, sociability, and emotionality.

Answer 47

temperament

Question 48

The phenomenon in which the effects of people’s genes depend on the kind of environment they experience and in which the effects of the environment depend on their genetic endowment.

Answer 48

gene–environment interaction

Question 49

A systematic interrelationship between an individual’s genes and that individual’s environment; ways in which genes influence the kind of home environment provided by parents (passive gene– environment correlation), the social reactions to the individual (evocative gene–environment correlation), and the types of experiences the individual seeks (active gene–environment correlation).

Answer 49

gene–environment correlation

Question 50

A genetic disease in which the child is unable to metabolize phenylalanine; if left untreated, it soon causes hyperactivity and mental retardation.

Answer 50

phenylketonuria (PKU)

Question 51

Interventions that involve substituting normal genes for the genes associated with a disease or disorder; otherwise altering a person’s genetic makeup.

Answer 51

gene therapy

Question 52

Undifferentiated, primitive cells that have the ability both to multiply and to differentiate into a variety of specific cells.

Answer 52

stem cell