chp 14: mendel and the gene idea

what disease’s symptoms don’t appear until the individual is 30-40 years old

what disease’s symptoms don’t appear until the individual is 30-40 years old

huntington’s

if Rhesus + dom or rec

dom

when 2+ alleles influence the phenotype resulting in a phenotype intermediate between the dom and rec

incomplete dominance

a diagram that predicts the genetic outcome of different types of crosses (provides probability of an outcome)

punnett square

the study of how characteristics are transmitted from parents to offspring

genetics

father of genetics

gregor mendel

a heterozygote that is phenotypically normal but carries a gene for some disorder

carrier

when 1 allele has complete dominance over another (ie: genotype is RR or Rr = red flower)

complete dominance

used to determine the genotype of an unknown individual

test cross

alternative form of a gene, an organism inherits 2, one from each parent

allele

offspring of F1 generation (2nd Pilial)

F2 generation

offspring of P gen (1st filial)

F1 generation

situation in which the phenotypes of both alleles are expressed in heterozygous offspring (co-captians)

codominance

to do a test cross, cross the unknown to a ___________ ___________

homozygous recessive

allele that is fully expressed in the organism’s appearance

dominant allele

allele that is masked and has no noticeable affect on the organism’s appearance

recessive allele

_________ _________ can separate genes on the same chromosome, the chance of this increases the ________ the genes are from each other

crossing over, further

traits controlled by 3+ alleles of the same gene (ie: blood type)

multiple allele traits

what makes sickle cell anemia good sometimes

prevents malaria

alleles behave as if they are on _________ chromosomes

different

is type O blood dom or rec

recessive

some genes are on the same chromosome and tend to be inherited together ( ie: _______ and ____ _____)

freckles and red hair

what does 2 different capital letters in a genotype mean

both traits are dom and expressed

parent generation

P generation

a cross between individuals that involves 2 pairs of contrasting trials (ie: AaBb x AaBb)

dihybrid cross

Mendel’s 1st law stating that allele pairs separate during meiosis and end up in different gametes

law of independent assortment

what is a cross between individuals that involves one pair of contrasting traits, give an example with rs

monohybrid cross, rr x Rr

physical appearance of an organism as a result of its genotype

phenotype

if you cross a homo red plant with a hetero red plant what is the genotypic ratio and the phenotypic ration

geno: 50% RR, 50% Rr pheno: 100% red

when 2 alleles of a pair are different

heterozygous

is Rh- dom or rec

rec

genetic makeup of an organism

genotype

flower colors and incomplete dominance: phenotype of RR

red

flower colors and incomplete dominance: phenotype of RR’

pink

flower colors and incomplete dominance: phenotype of R’R’

white

what will the phenotype of a RW flower

white and red areas

why are peas and fruit flies good for studying genetics

lots of offspring, quick generation time, easy to identify phenotypic traits

in pea plants is the color yellow or green dominant

yellow

in pea plants is the shape round or wrinkled recessive

wrinkled

in pea plants is the height short or tall dominant

tall

when both alleles of a pair are the same

homozygous

what are the types of homozygous

dom and rec

what is the ratio of a dihybrid cross and the ratio in As and Bs

9-3-3-1, AB-Ab-aB-ab

extracting amniotic fluid to test for genetic disorders

amniocentesis

extraction of placenta tissue, which has the same genotype as the fetus

chorionic villi sampling

chorionic villi sampling can give results ________ in the pregnancy than amniocentesis

earlier

chances of genetic disorders in a fetus increases with ____

age

chorionic villi sampling and amniocentesis have a __% chance of causing a miscarriage

<1

chorionic villi sampling and amniocentesis can both check for too many or too few _____________ as well as some gene _____________

chromosomes, abnormalities

what are the 3 x-linked recessive disorders we know

colorblindness, duchenne muscular dystrophy, hemophilia

can men be a carrier of a x-linked recessive disorder

no

can women be a carrier of a x-linked recessive disorder

yes

genes with multiple phenotypic effects

pleitrophy

a gene at 1 location alters the phenotypic expression of a gene at a 2nd location

epistasis

an additive effect of 2+ genes on a single phenotypic character

polygenic inheritance

a family record that shows how a trait is inherited over several generations

pedigree

what are the 3 autosomal recessive disorders

Cystic fibrosis, Tay-Sachs, phenylketonuria

what is the autosomal dominant disease

huntington’s

what is the autosomal co-dominant disease

sickle-cell anemia

what disease has the symptom(s) : excessive bleeding after injury

hemophilia

what disease has the symptom(s) : can’t break down the amino acid phenylalanine, which accumulates to toxic levels in the blood causing improper development of the brain

phenylketonuria (PKU)

what disease has the symptom(s) : uncontrollable body movements and degeneration of the nervous system

huntington’s

what disease has the symptom(s) : pain, physical weakness, organ damage, and even paralysis

sickle-cell anemia

what disease is caused by the substitution of the wrong amino acid in the hemoglobin protein, which causes the hemoglobin to be the improper shape and often clump together

sickle-cell anemia

what disease is caused by an enyzme that metabolizes lipids in the brain to not function properly so lipids accumulate in the brain

tay-sachs

what disease has the symptom(s) : seizures, blindness, degeneration of motor and mental performance

tay-sachs

what disease has the symptom(s) : mucus build up in the pancreas, lungs, digestive tract and other organs leading to poor absorption of nutrients, chronic bronchitis, and recurrent bacterial infections

cystic fibrosis

what disease is caused by a defective or absent membrane protein that functions in chloride ion transport, creating an unusually high concentration of extracellular chloride which causes a buildup of mucus

cystic fibrosis

what shape are females and males in a pedigree

f: circle, m: square

what does a half shaded circle/square mean

carrier

does a pedigree go oldest → youngest or youngest →oldest

oldest → youngest

T or F: polygenic traits follow a normal distribution (bell curve)

true

the more dom an allele the (darker/lighter) the skin

darker

T or F: in things like skin color dominate alleles have an additive affect

true