Chapters 3,4,5,6 Flashcards
Deoxyribonucleic acid DNA
molecule that encodes the genetic instructions used in the development and functioning of all known living organisms
chromosome
46 molecules of DNA (23 pairs); contain all genes
genes
the basic units for the transmission of heredity
allele
variation that makes a gene different from the other genes for the same characteristics
genome
full set of genes that are instructions to make and individual member of a certain species
gamete
sperm or ovum that can produce a being if it combines with a gamete from the opposite sex; makes zygote
zygote
single cell formed from 2 gametes; sperm & ovum
genotype
genetic inheritance
23rd pair
determines sex; all other 22 are inherited equally by males & female
stem cells
cells from whic any other specialized type of cell can form
monozygotic twins
twins who originate from one zygote that splits apart very early in development; identical
dizygotic twinnies
formed when 2 separate ova are fertilized by 2 seperate sperm; fraternal
assisted reproductive tech (ART)
helps infertile couples concieve and sustain pregnancy
in vitro fertilization
fertilization takes place outside a womans body, in a lab dish; if zygote is produced then implate into woman’s uterus and develop into a baby
phenotype
observable characteristics/ physical makeup such as apperance, personality and other traits
polygenic
a trait that is influenced by many genes
multifactorial
trait that is affected by many factors, both genetic and environmental, that enhance, halt, shape or alter the expression of genes , resulting in a phenotype that may differ from the genotype
epigenetic
environmental factors that affect genes and genetic expressions resulting in a phenotype that may differ from the genotype
Human genome project
international effort to map the complete human genetic code. effort essentially completed in 2001; though analysis is ongoing
dominant-recessive pattern
interation of heterozygous pair of alleles in such away phenotype reflects one allele more than the other
x linked
gene carried on the X chromosome; females are more likely to be carriers of x linked traits but are less likely to express them
copy # variations
genes with various repeats or deletion of base pairs
heritabillity
statistic that indicated what percentage of variation in a particular trait withion a particular population, context and era, can be traced to genes
down syndrome (trisomy 21)
condition where a person has 47 chromosomes instead of the usual 46; they have 3 rather than 2 chromosomes at the 21 site
Language difficulties, unusual appearances, heart abnormalities
fragile x syndrome
genetic disorder in which part of the x chromosome seems to be attached to the rest of it by a very thin string of molecules; the cause is asingle gene that has more that 200 repetitions of one triplet
phenlyketonuria (PKU)
genetic disorder in which a chids body is unable to metabolize an amino acid called phenylalanine. unless the infant immediately begins a special diet, the resulting buildup of phenylalanine in body fluids causes brain damage, progressive mental retardation and other symptoms
germinal period
first 2 weeks pf prenatal development after conception characterized by rapid cell division and the beginning of cell differentiation
embryonic period
stage of prenatal development from approximately 3rd-8th week after conception; during which all basic forms of all body structures including internal organs develop
fetal period
stage of prenatal development from 9th week after concepttion until birth during which the fetus gains about 7 lbs and organs become more mature, gradually able to function on their own