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Chapter 13

Explain why organisms only reproduce their own kind, and why offspring
more closely resemble their parents than unrelated individuals of the same
species.

Distinguish between asexual and sexual reproduction .

Diagram the human life cycle and indicate where in the human body that
mitosis and meiosis occur; which cells are the result of meiosis and
mitosis; and which cells are haploid.

Distinguish among the life cycle patterns of animals, fungi, and plants.

List the phases of meiosis I and meiosis II and describe the events
characteristic of each phase.

Recognize the phases of meiosis from diagrams or micrographs.

Describe the process of synapsis during prophase I, and explain how genetic
recombination occurs.
.

Describe key differences between mitosis and meiosis; explain how the
end result of meiosis differs from that of mitosis.

Explain how independent assortment, crossing over, and random
fertilization contribute to genetic variation in sexually reproducing
organisms.
Chapter 14

Use a Punnett square to predict the results of a monohybrid cross and
state the phenotypic and genotypic ratios of the F2 generation.
Phenotypic Ratio. 3:1; Genotypic Ratio: 1:2:1

Distinguish between genotype and phenotype; heterozygous and
homozygous; dominant and recessive.
Genotype is the genetic makeup of an organism, and phenotype is just the
appearance of it. Organisms having two different alleles for character are
heterozygous while an organism having a pair of identical alleles for a
character homozygous. A dominant allele in a heterozygote, is the allele
that is fully expressed in the phenotype, and the recessive allele is
completely masked in the phenotype.

Explain how a testcross can be used to determine if a dominant
phenotype is homozygous or heterozygous.
A testcross is designed to reveal the genotype of an organism that exhibits
a dominant trait, such as purple flowers in pea plants. Such an organism
could be either homozygous for the dominant allele or heterozygous. The
most efficient way to resolve the genotype is to cross the organism with an
individual; expressing the recessive trait. Since the genotype of the white
flowered parent must be homozygous, we can deduce the genotype of the
purple- flowered parent by observing the phenotypes of the offspring.

Define random event, and explain why it is significant that allele
segregation during meiosis and fusion of gametes at fertilization are
random events.
It is important that these are random events because then if it were not
like that then all the organisms would look the same

State, in your own words, Mendel's law of independent assortment.
Law of independent assortment is the independent segregation of
each pair of alleles during gamete formation.

Use a Punnett square to predict the results of a dihybrid cross and state
the phenotypic and genotypic ratios of the F2 generation.
Phenotypic Ratio: 9:3:3:1; Genotypic Ratio: 1:2:2:4:1:2:1:2:1

Give an example of incomplete dominance and explain why it is not
evidence for the blending theory of inheritance.
Incomplete dominance is when the F1 hybrids have an appearance
somewhere in between the phenotypes of the two parental varieties. For
instance, when red snapdragons are crossed with whit , all the F1 hybrids
have pink flowers. We should not regard incomplete dominance as
evidence of
the blending theory, which would predict that the red or white traits could
never be retrieved from the pink hybrids. The segregation of the red and
white alleles in the gametes produced by the color are heritable factors
that maintain their identity in the hybrids; that is, inheritance is
particulate.

Explain how the phenotypic expression of the heterozygote is affected by
complete dominance, incomplete dominance and codominance.
In complete dominance, the phenotypes of the heterozygote are
indistinguishable.. This represents one extrame of a spectrum in the
dominance/recessiveness relationship of alleles. At the other extreme is
codominance, in which both alleles are separately manifest in the
phenotype, and in incomplete dominace the F1 hybrids have an
appearance somewhere in between the phenotypes of the two parental
varieties.

Describe the inheritance of the ABO blood system and explain why the IA
and IB alleles are said to be codominant.
The ABO blood groups in humans are one example of multiple alleles of a
single gene.Four blood groups result from various combinations of three
different alleles of one gene, symbolized as IA (for the carbohydrate), IB
(for B), and I (giving rise to neither A nor B). Both the IA and the IB
alleles are dominant to the I allele. Thus, IAIAand IAi individuals have A
blood, and IBIB and IBi individuals have type B. Recessive homozygotes,
ii, have type O blood, because neither the A nor the B substance is
produced. The IA and IB alleles are codominant; both are expressed in the
phenotype of the IAIB heterozygote, who has type AB blood.

Define and give examples of pleiotropy.
Pleiotropy is the ablitity of a single gene to have multiple effects. For
example, alleles that are responsible for certain hereditary diseases in
humans, including sickle-cell disease, usually cause multiple symptoms.

Explain, in their own words, what is meant by "one gene is epistatic to another."
One gene affects the other by means that they are all connected to
each other in some which way or form.

Describe how environmental conditions can influence the phenotypic
expression of a character.
The Phenotype is the actual expression of a gene. The enviroment
may cause a mutation causing there to be change in the physical
appearance that isn’t considered “normal”

Given a simple family pedigree, deduce the genotypes for some of the
family members.
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wl/chapter14/medialib/1414.jpg
Chapter 15

Define linkage and explain why linkage interferes with independent assortment.
Linkage are genes that reside on the same chromosomes and thus cannot
segregate independently because that are physically connected. It interere
with independent assorment because homologous chromosomes, and the
genes they carry, segregate independtly of the segregation of other
chromosome pairs.

Explain how crossing over can unlink genes.
Because individual chromosomes that combine genes inherited from the
parents.

Describe sex determination in humans.
The determining factor for sex determination is of the last set of
chromosomes in the Karytype; XX=GIRL, XY=BOY; Males determine
the sex because they carry both the X and Y-chromosomes

. Describe the inheritance of a sex-linked gene such as color-blindness.
Sex linkage refers to a single gene residing specifically on a sex
chromosomes. A color-Blindness daughter may be born to a color-blind
father whose mate is a carrier. However, because the sex-linked allele for
color blindness rare, the probability that such a man and woman will come
together is very low.

Explain why a recessive sex-linked gene is always expressed in human males.
Because the X-Chromosomes is dominant because the Y-chromosomes is
too “little” compared to the X Chromosomes

Distinguish among nondisjunction, aneuploidy, and polyploidy; explain how these
major chromosomal changes occur and describe the consequences.
Nondisjuction- The Chromosomes do not properly separate.
Aneuploidy- A chromosomes aberration in which certain chromosomes
are present in extra copies or are deficient in number.
Polyploidy- A chromosomes alteration in which the organism possesses
more than two complete chromosomes sets.

Distinguish among deletions, duplications, translocations, and inversions.
Deletions- A deficiently in a chromosomes resulting from the loss of a
fragment through breakage.
Duplication- An aberration in chromosomes structure resulting from an
error in meiosis or mutagens.
Translocations- An aberration in chromosomes structure resulting from as
error in meiosis or from mutagens
Inversion- An abbrration in chromosomes structure resulting from as error
in meiosis or from mutagens