Chapter 11 Flashcards
Mendel discovered the basic principles of heredity by?
breeding pea plants in carefully planned experiments.
characters
overall personality of something
traits
specific characterisitc
true-breeding
plants that produce offspring of the same variety
hybridization
crossing of 2 contrasting true-breeding variants
true-breeding parents
P
F₁
hybrid offspring of P generation
F₂
hybrid offspring of F₁ generation
alleles account for?
variations in inherited characteristics
each gene resides at?
a specific locus on a specific chromosome
For each character a organism inherits?
2 alleles, each from 1 parent
2 alleles at a particular locus may?
differ
If 2 alleles at a locus differ then?
the dominant allele determines the organisms appearance
law of segregation
During gamete formation, each allele separates and end up in different gametes
homozygous
PP
heterozygous
Pp
Unlike homozygous, heterozygous are not?
true-breeding
pheonotype
physical appearance
genotype
genetic makeup
testcross
breeding an individual with a recessive homozygotes
A testcross can revel?
the genotype of a organism
monohybrids
individuals that are heterozygous for a character
monohybrid cross
cross between heterozygotes
dihybrids
heterozygous for both characteristics
A dihybrid cross can determine?
whether 2 characteristics are transmitted to offspring as a package or independently.
law of independent assortment
genes for one trait are not inherited together with another trait.
law of independent assortment applies to?
genes that are not homologous or far apart on a chromosome
genes located near each other on a chromosome tend to be?
inherited together
Mendel’s laws of segregation and independent assortment reflect?
rules of probability
rules of probablity
alleles of one gene segregate into gametes independently of another gene’s alleles
multiplication rule
the probability that 2 or more independent events will occur together is the product of their individual properties
The multiplication rule can be applied to?
F1 monohybrid cross
addition rule
the probability that any one or more exclusive events will occur is calculated by adding together their individual probabilities.
The addition rule can be applied to?
F2 plants from monohybrid cross.
The inheritance of a single gene may deviate from?
Mendelian patterns
When will the inheritance characters by a single gene deviate (3)
-alleles are not completely dominant or recessive
-when a gene has more than 2 alleles
-single gene produces multiple phenotypes
Complete dominance
phenotypes of heterozygote and dominant homozygote are indistinguishable.
incomplete dominance
phenotype of F1 hybrids is somewhere between the phenotypes of the two parental variations.
codominance
2 dominant alleles affect the phenotype separate distinguishable ways
alleles
variation in a gene’s nucleotide sequence
When does dominance and recessiveness come into play?
pathway from genotype to phenotype
Tay-Sachs disease
dysfunctional enzyme causes accumulation of lipids in the brain
Tay Sachs at organismal level
allele is recessive
Tay Sachs at biochemical level
phenotype is incompletely dominant
Tay Sachs at molecular level
alleles are codominant
Dominant alleles are not necessarily more?
more common in populations than recessive alleles.
Most genes exist in population in more than?
2 allele forms
Surface carbohydrates on type A blood
A carbohydrates
Surface carbohydrates on type B blood
B carbohydrates
Surface carbohydrates on type AB blood
A and B carbohydrates
Surface carbohydrates of type ii blood
none
pleiotrophy
genes have multiple phenotypic effects
Multiple genes could independently affect?
a single trait
epistasis
gene at one locus alters phenotypic expression of a gene at a second locus
Quantitative characters
vary in the population along a continuum
Quantitative variation usually indicates?
polygenic inheritance
polygenic inheritance
effect of 2 or more genes on a single phenotype
The phenotype for a character can depend on ______ as well of genotype.
environment
multifactorial characters
genetic and environmental factors that collectively influence phenotype
An organism’s phenotype includes?
-physical appearance
-internal anatomy and physiology
-behavior
Why are humans not good subjects for genetic research?
-generation time is too long
-parents produce relatively few offspring
-breeding experiments would be unethical
pedigree
family tree that contains a family’s history for a particular trait
pedigrees can be used to make predictions about?
future offspring
recessively inherited disorders only show up in ____ individuals.
homozygous
carriers
heterozygous individuals who carry recessive alleles but are phenotypically normal
people with recessive disorders are born to parents who are?
carriers of disorder
consanguineous
mating between close relatives increases the chance of mating between two carriers of the same rare allele
cystic fibrosis
mucus buildup in internal organs and abnormal absorption of nutrients in small intestines
the cystic fibrosis allele results in?
defective or absent chloride transport channels in plasma membranes.
sickle-cell disease
substitution of one amino acid in the hemoglobin protein in red blood cells
In homozygous individuals all ___ is abnormal (sickle cell disease).
hemoglobin
Heterozygotes that have sickle cell trait are usually healthy but?
may exhibit some symptoms
In regions where malaria is common you are less likely to get it if you are?
heterozygote
Achondroplasia
form of dwarfism caused by a rare dominant allele
Huntington’s disease
degenerative disease of the nervous system
What causes Huntington’s disease?
lethal dominant allele that shows no apparent phenotype until individual is 35-45
Lifestyle has a tremendous effect on?
phenotype for cardiovascular health and other multifactorial characters
Each child represents an _____ in the sense that its ____ is unaffected by the genotypreof older siblings.
independent events, genotype
