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54 terms

biology 111 chapter 10

STUDY
PLAY
the person who made the most lasting impression on the science of genetics is
Gregor Mender
If a healthy young couple are both carriers of cystic fibrosis, the chance that each of their future children will inherit this serious illness is
25%
A portion of DNA that encodes a specific protein is
a gene
Alternate forms of the same gene are called
alleles
In humans, alleles are inherited from
males and females(two alleles from each parent)
All gametes contain
one set of chromosome
The pea plant (Pisum sativum) is a good choice for studying heredity because it
is easy to control which plants mate with each other
Mendel called a masking trait
dominant
Mendel called a trait that is masked
recessive
An allele that exerts its effects whenever it is present is
dominant
If the two alleles for a particular gene are identical the gene pair is
homozygous
If the two alleles for a particular gene are different the gene pair is
heterozygous
If an individual is heterozygous for a particular trait
each parent contributed a different allele for that trait
If an individual is homozygous for a particular trait
each parent contributed the same allele for that trait
Recessive alleles seem to vanish in some generations and reappear in later ones due to
they are masked by a dominant allele
Genotype means
the combination of alleles in an individual
Phenotype means
the observable expression of the genes in an individual
The most common or "normal" phenotype or allele for a gene in a population is the
a wild type
In the study of genetics the offspring of the P generation is referred to as the
F1 generation
A pea plant with (Tt) as its genotype should be referred to as
heterozygous
A monohybrid cross is a mating between two individuals that are both
heterozygous for one gene
Any monohybrid cross consisting of one dominant and one recessive allele for the trait studied should result in a ratio of ______________ dominant to __________________ recessive.
three, one
A test cross is a mating of an individual with an unknown genotype and an individual that
is homozygous recessive
Two alleles of each gene are packaged into separate gametes and they move apart from each other during gamete formation summarizes Mendel's
law of segregation
A dihybrid cross is a mating between two individuals that are each ______________ for ___________ gene (genes).
heterozygous, two
Segregation of alleles for a gene on one chromosome that does not influence the segregation of alleles for a gene on another chromosome during meiosis is Mendel's
law of independent assortment
In the ABO blood type system the alleles IA, IB and i produce
four phenotypes
In the ABO blood type system, the IA allele is _____ with the IB allele.
codominant
If the heterozygous phenotype is intermediate between the homozygotes, this is called
incomplete dominance
Autosomes
a non sex chromosome
Linked genes, by definition, are genes that
are found on the same chromosome
Crossing over is more likely to separate genes on a chromosome if they are
far apart
To inherit an autosomal dominant disorder a person could receive the disease causing allele from
the mother or the father
To inherit an autosomal recessive disorder requires the person receive the disease causing allele from
both parents
A person has a recessive allele for a disease but the allele is masked by the presence of a normal dominant allele in the person. This person
termed a carrier
Diagrams depicting family relationships and phenotypes for a genetic disorder are
pedigree charts
The chromosome that determines human gender is
the Y chromosomes
Hemophilia A is caused by
an X linked recessive disorder causing a defective blood clotting protein
Homologous chromosomes have
7 pairs of homologous chromosomes
A single chromosome has
a single gene with a single allele
Yellow peas are an example of
phenotypr
Having the alleles Tt is
a genotype
If a pea plant is heterozygous for yellow seeds (Yy), which gametes will it produce?
Y or y
If a pea plant is homozygous recessive for yellow seeds (yy), which gametes will it produce?
y only
If a pea plant is homozygous for yellow seeds (YY), which gametes will it produce?
Y only
If you cross two heterozygous (Yy) pea plants, what proportion of the offspring will be heterozygous?
50%
If you cross two heterozygous Yy pea plants, what proportion of the offspring will be the dominant color yellow?
75%
Which gametes can a RrYy plant produce?
RY, Ry,rY,ry
Which gametes can a RRyy plant produce?
RR or yy
In an inherited form of high cholesterol, (HH) individuals have a blood cholesterol level greater than 500mg/dL, (RH) individuals are near 300mg/dL, and normal (RR) cholesterol levels should be less than 200mg/dL. The H allele is ___ to the R allele.
codominant
In cystic fibrosis, two unaffected carriers can have a child with the disease. It is as common in boys as in girls. This disease is
autosomal recessive
The wide variation in skin color in humans is best explained by
skin color is a polygenic trait
Which has the following in order from smallest to largest
DNA nucleotides, gene, chromosome, cell
Which of the following is in the correct order?
meiosis of diploid cell, haploid gametes produced, fertilization, new diploid organism formed