Human Development Ch2

a. DNA:Long, double-stranded molecules that make up chromosomes.

b. Chromosomes: rodlike structures in the cell nucleus that transmits and stores

genetic information.

c. Autosomes: the 22 matching pairs of chromosomes in each human cell

d. Allele: each 2 forms of a gene located at the same place on corresponding pairs

of chromosomes.

e. Gene: a segment of dna along the length of the chromosome containing

instructions for making proteins that contribute to body growth and functioning.

f. Gamites: sex cells or sperm and ovum, which contain half as many

chromosomes as normal cells.

g. Meiosis: the process of cell division through which gametes are formed in which

the chromosomes normally present in each cell is halved.

h. Zygote: the newly fertilized cell when the sperm meets the ovum at conception

i. Genotypes: an individual's genetic makeup, distinguished from phenotype

j. Phenotypes: a person's directly observable physical and behavioral

characteristics, which are determined by both genetic and environmental factors.

Distinguished from genotype.

a. fraternal : Twins resulting from the release and fertilization of two ova. They are

genetically no more alike than ordinary siblings. Distinguished from identical, or

monozygotic, twins.

b. Identical : Twins that result when a zygote that has started to duplicate

separates into two clusters of cells with the same genetic makeup, which develop

into two individuals. Distinguished from fraternal, or dizygotic, twins.

3. Dominant Recessive Inheritance:

a. Homozygous=Having two identical alleles at the same place on a pair of

chromosomes. Distinguished from heterozygous.

b. Heterozygous=Having two different alleles at the same place on a pair of

chromosomes. Distinguished from homozygous

4. Dominant and recessive diseases:

a. Cystic fibrosis=Lungs, liver, and pancreas secrete large amounts of thick mucus,

leading to breathing and digestive difficulties. (recessive)

b. Tay-Sachs disease=Central nervous system degeneration, with onset at about 6

months, leads to poor muscle tone, blindness, deafness, and

convulsions.(Recessive)

c. PKU=Inability to metabolize the amino acid phenylalanine, contained in many

proteins, causes severe central nervous system damage in the first year of

life.(recessive)

d. Sickle cell anemia=Abnormal sickling of red blood cells causes oxygen

deprivation, pain, swelling, and tissue damage. Anemia and susceptibility to

infections, especially pneumonia, occur. (recessive)

5. What causes mutations?=Some mutations occur spontaneously, simply by chance. Others

are caused by hazardous environmental agents.

6. Risk factor for carrying babies with down syndrome= The older the maternal age, the

higher the likelihood the child will have abnormalities or down syndrome.

7. Genetic Counseling= is a communication process designed to help couples assess their

chances of giving birth to a baby with a hereditary disorder and choose the best course of

action in view of risks and family goals.

8. Prenatal diagnosis and fetal medicine (prenatal diagnostic methods)=

a. Amniocentesis= Small risk of miscarriage.

b. Chorionic villus sampling= Entails a slightly greater risk of miscarriage than

amniocentesis. Also associated with a small risk of limb deformities,

c. Fetoscopy=Entails some risk of miscarriage

d. Ultrasound= When used five or more times, may increase the chances of low birth

weight.

e. Maternal blood analysis

f. Ultrafast magnetic resonance imaging (MRI)=no evidence of adverse effects

g. Preimplantation genetic diagnosis

9. Poverty=not having enough money to meet basic needs including food, clothing and

shelter

10. What practices can parents do to help kids be more successful?= Always be supportive,

nurturing towards the child, and be gentle. Also dinner with parents and maintain a happy

marriage.

11. Environmental influences on gene expression=

a. epigenesis= development from ongoing, bi-directional changes

b. methylation= A biochemical process triggered by certain experiences, in which a

set of chemical compounds (called a methyl group) lands on top of a gene and

changes its impact, reducing or silencing its expression.

c. niche-picking= A type of gene–environment correlation in which individuals

actively choose environments that complement their heredity.