how many sperm does male ejaculation contain?
300-500 million
how many chromosomes does a gamete (sex cell) contain?
23
meiosis
cell division that results in gametes with 23 chromosomes
mitosis
cell division resulting in exact copies of cells
ectogenesis
fertilization of an egg outside the uterus
in-vitro fertilization
mixing egg and sperm and planting fertilized eggs inside mother
why does in-vitro fertilization result in an increased likelihood of twins or triplets?
because higher chance that more than 1 egg can attach to uterus
autosomes
first 22 pairs of chromosomes
which chromosome determines the sex of the child?
23 (sperm determines the sex)
DNA
molecule made up of chemical components; code for genes
gene
group of nucleotide bases that generate production of biological building blocks
alleles
specific forms of gene
heterozygous
different
homozygous
same
genotype
complete set of genes
phenotype
physical, behavioural, psychological features (all the characteristics we actually see)
dominant gene
chemical instructions are always followed
recessive gene
instructions are ignored when a dominant allele is present but expressed in the presence of another recessive allele
incomplete dominance
aspects of both heterozygous alleles are expressed; no one allele dominates
endogamy
tendency to preferentially mate with people of the same social/cultural group
clinical variation
geographical genetic variation
polygenic inheritance
contribution of many genes to a person's phenotypic expression
monozygotic twins
identical twins; single fertilized egg that splits into two
dizygotic twins
fraternal twins; two separate eggs fertilized by two separate sperm
what are the 3 strong areas of genetic influence?
intelligence, psychopathy, and personality
why are so few disorders associated with dominant alleles?
because if it is dominant then anyone who has an allele for it shows the condition and natural selection wouldn't allow for it (likely wouldn't live long enough)
what is an exception disease that is dominant and is able to persist?
Huntington's disease
why is Huntington's disease able to persist as a dominant allele?
because it isn't expressed until later in the lifespan
abnormal chromosomes
development is disrupted with extra, missing, or damaged chromosomes
which chromosome is effected in down syndrome?
extra 21st chromosome
mainstreaming
educational program to prepare children with developmental disabilities for school
abnormal sex chromosomes
disorders associated with atypical numbers of X and Y chromosomes
reaction range
extent to which full genetic expression can occur based on the limits of the environment
types of nature/nurture relationships
#NAME?
passive gene-environment relation
parents provide early environment for young children; infants are passive because they are not making active choices to control anything (it is all under parents' control)
evocative gene-environment relation
evoking or prompting people to respond in a certain way (taking a more active role in environment because enriched environment is encouraging certain things)
active gene-environment relation
individuals actively seek environments related to their genetic makeup; niche-picking, develops over childhood