Exam 1 Genetics Questions

What is a test cross

A test cross is used to determine genotypes of individuals with a dominant phenotype that may be heterozygous or homozygous for a dominant allele. The unknown genotypes are revealed by crossing the dominant individual to a "tester" that is known to be homozygous for the recessive allele in question.

Variants of the same genetic locus due to different DNA sequences are said to be

alleles

Female bees are diploid, and male bees are haploid. The haploid males produce sperm and can successfully mate with diploid females. Fertilized eggs develop into females and unfertilized eggs develop into males. How do you think the process of sperm production in male bees differs from sperm production in other animals?

Male bees go through Mitosis

Human Skin cells are ___________, produced by _____.

somatic diploid, Mitosis

Diploid cells have

two sets of chromosomes

List the three elements of eukaryotic chromosome anatomy. What are their purposes?

• Centromere (hold sister chromatids) • Telomere (seals the ends of chromosomes) • Origin of replication (initiation of dna replication)

List the three checkpoints of the cell cycle. What are their purposes?

• G1/S DNA is ready to replicate • G2/M. Check that the replication is correct/ No mutation • Spindle Assembly checkpoint (Makes sure that each chromosome is properly attached to the spindle)

If the genotypes of two parents are AaBbCcDdand AaBbCcDd,what is the probability that a daughter will be homozygous recessive for each of the four genes?

1/256

Beginning with a monohybrid cross of two true-breeding parents (AAX aa), what proportion of the F2generation will be homozygous recessive?

1/4

DNA synthesis in eukaryotic cells occurs

During Interphase in the time between G1 and G2

Which of the following essential structural elements of a eukaryotic chromosome are incorrectly paired with their function? A. Kinetochore—> serves as the point of attachment for the spindle fibers (microtubules). B. Telomeres —> serve to stabilize the ends of the chromosome and may have a role in controlling cell division. C. Origins of replication—> serve as the starting place for DNA synthesis. D. Select this answer if only two of choices A-C are correct E. Select this answer if choices A-C are correct

E.Select this answer if choices A-C are correct

The difference between dominance and epistasisis

Epistasis masks genes at different loci

Apis Melifera

honey bee

A. tall plant with blue flowers (TtBb) is crossed with a tall plant with white flowers (TT bb). What is the probability of obtaining progeny with genotype TTbb?

1/4 or 0.25

What percentage of the F1 generation will be tall if the genotype of the parent is TT? (TT x tt)

100%

A cell in prophase II of meiosis contains 12 chromosomes. How many chromosomes would be present in a cell from the same organism if it were in Prophase I of meiosis?

24

A secondary spermatocyte has 12 chromosomes. How many chromosomes will be found in the primary spermatocyte that gave rise to it?

24

Assume. that attachedearlobes are a recessive traitwith 70% penetrance. One parent is hetero and the other is homo recessive. for the attatchment gene. What is the probability that their child will have attached earlobes?

35%

Hemophilia is associated with sex-linked recessive. genetic mutation. Assume that a man with hemophilia marries a woman with no blood disorder whose father had hemophillia. What % of the sons will have hemophilia?

50%

Mating a beardless male (B+Bb) goat. with a bearded female (BbBb) goat would produce

50% of males with beards

Gametes are ______ and produced my ______.

Haploid, Meiosis

What is the principle of independent assortment.

The principle of independent assortment involves the random assortment of alleles from different homologs into separate daughter cells during meiosis I. This principle can only be demonstrated using two or more pairs of homologous chromosomes.

What is Mendel's principle of segregation

The principle of segregation involves segregation (separation) of the alleles of a gene pair as the paired homologs on which they reside separate during anaphase I of meiosis. This principle can be demonstrated using a single pair of homologous chromosomes.

What kind oof dominance does. the following example demonstrate? Individuals with the genotype HH have healthy levels of cholesterol, those. with Hh have higher levels of cholesterol, and those with hh have dangerous levels that lead to heart attacks.

incomplete dominance

In the ABO blood groups, a person with the Aantigen on the surface of their red blood cells would have antibodies against which antigen(s)?

B

Which of the following pairs are mismatched? A.nondisjunction->a pair of homologous chromosomes fails to segregate during meiosis. B.hemizygous ->the X-chromosome in female cells of most species. C.autosomes ->all of the chromosomes other than the sex chromosomes D.test-cross ->a cross involving an individual that is known to have recessive alleles for all of the genes being tested.

B

One form of color blindness in humans results from an X-linked recessive gene. Which of the statements below regarding the inheritance of the trait is FALSE?

Color blindness can only occur in males.

How does epistasis differ from Mendel's principle of dominance?

Epistasis involves interaction among alleles located at different gene loci. This is in contrast to dominance, which involves interaction between alleles located at the same gene locus.

Saccharomyces cerevisiae

Eukaryotic fungus (yeast)

True or False: Viruses are both eukaryotic and prokaryotic:

F (not true cells)

Explain how a phenotype like height in a tree can be due to the influence of both genes and environment.

The height reached by a tree at maturity is a phenotype that is strongly influenced by environmental factors, such as the availability of water, sunlight, and nutrients. Nevertheless, the tree's genotype still imposes some limits on its height: an oak tree will never grow to be 300 meters tall no matter how much sunlight, water, and fertilizer are provided.

Which of the following is false concerning dosage compensation in mammalian females?

The mechanism is similar to that in Dropsophila where expression of the X-linked genes in males is hyperactivated.

A human with an XXY sex chromosome karyotype appears female. Somatic cells contain 1 Barr body. What might. explain why this person does not look to be male?

This persoon has a mutated SRY gene

In some plant species, a single pair of alleles is involved in both flower color and stem color. For example, a plant with red flowers may also have red stems, whereas white-flowered varieties of the same species have green stems. How would you explain this observation?

This phenomenon, called pleiotropy, is the condition where a single gene affects multiple, apparently unrelated, phenotypic traits. In many other cases of pleiotropy, a single gene affects more than two phenotypic traits. For example, a mutant white-eye gene in Drosophila (fruit fly) also affects the structure and color of internal organs, causes reduced fertility, and decreases life expectancy. Another example involves sickle-cell anemia in humans (caused by a single nucleotide change in a hemoglobin gene), which has adverse affects on different organs and tissues.

Junior scientist crossed a female Drosophila with genotype Zz with a male Drosophila having genotype ZZ. The Z gene encodes an enzyme that is essential for the earliest stages of development. To determine whether mutations of the Z gene are dominant or recessive, she should

To determine whether mutations of the Z gene are dominant or recessive, she would perform a Test cross

How did Mendel obtain a true-breeding P1 generation in his pea plants?

True-breeding pea plants are produced by allowing plants to self-fertilize for many generations Offspring show only one form of a trait Pure Purple or Pure White

What evidence is there that viruses evolved after, not before, cells?

Viruses can reproduce only within host cells. Thus, they must have evolved after cells.

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: a. An AB gamete from an AaBb individual?

a. 1/4

List two similarities between mitosis and meiosis

a. Both involve the separation of replicated chromosomes during cell division. b. Both are processes to ensure that daughter cells in cell division receive a complete set of chromosomes.

What three fundamental events must take place for a cell to reproduce successfully?

a. Genetic info must be copied b. The copies must be separated c. The cell must divide

List two differences between mitosis and meiosis

a. Mitosis occurs in somatic (nonsex) cells; meiosis occurs in sex cells to produce gametes. b. Meiosis involves chromosome pairing (of homologous chromosomes); mitosis does not.

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: f. An AB phenotype from a cross AaBb × AaBb?

f. 9/16

You discover a new amphibian and name the sex chromosomes A and B. If the female is heterogametic and the male is homogametic, then what could be the chromosome arrangement of sex chromosomes in the adult?

female AB and male BB

Drosophila melanogaster

fruit fly

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: g. An AB phenotype from a cross aabb × AABB?

g. 1 (100%)

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: h. An aB phenotype from a cross AaBb × AaBB?

h. 1/4

A child whos blood type O has a mother whos type A.In a paternity suit a manis. accused of being the father. He is blood type B.Is he the father?

he cannot be excluded as the father

Mus Musculus

house mouse

In which type(s) of inheritance does the genotypic ratio match the phenotypic ratio?

incomplete and codominance

Jr. scientist found a fruit fly that had three sex chromosomes (XXY) and three copies of each autosome. The. sex of this fruit fly was _______

inter-sex because it has an X:A ratio between 0.5 and 1

The DNA sequence that specifies where the _______ will form is called the ______

kinetochore, centromere

Mechanisms that ensure a high degree of accuracy in DNA replication.

molecular

Examination of the nucleotide sequences found at the ends of chromosomes.

molecular genetics

Jr. scientist is examining a population of cells of various ages. Which of the following is. flase?

more than one of. the following is false

While studying fish, a researcher isolates a gene mutation. that produces a shorter stem-height phenotype. Intrestingly, when this gene is not mutated (wild-type plant) and the seedling is germinated at a lower temperature than the other phenotype. This phenomenon is known as

phenocopy

Which of the following statements is false?

phenotype is only determined by genotype

Effect of nonrandom mating on the distribution of genotypes among a group of animals.

population genetics

Study of people on a small island to determine why a genetic form of asthma is prevalent on the island.

population genetics

Analysis of pedigrees to determine the probability of someone inheriting a trait.

transmission genetics

Study of how the inheritance of traits encoded by genes on sex chromosomes differs from the inheritance of traits encoded by genes on non-sex chromosomes.

transmission genetics

a female with a single x chromosome will develop _____ syndrome

turner

Escherichia coli

E. coli

Caenorhabditis elegans

Nematode

danio rerio

Zebrafish

List three different mechanisms for generating sexes in dioecious species.

(1) Chromosomal sex determination (XX-XO, XX-XY, or ZZ-ZW) (2) Genetic sex determination (3) Environmental sex determination

What events during sexual reproduction are significant in contributing to genetic diversity?

(1) Crossing over changes allele combinations on chromosomes, so, after meiosis I, even sister chromatids are not genetically identical. (2) Independent assortment of non-homologous chromosomes ensures each gamete has a different combination of alleles for genes on nonhomologs. (3) Two genetically unique gametes from each parent combine during fertilization to form a novel, genetically unique individual.

Discuss "cytoplasmic inheritance"

(1) In cytoplasmic inheritance, the genes controlling a given trait are inherited exclusively from the mother (through cytoplasmic organelles such as mitochondria) and can be expressed in both male and female progeny.

List two dosage compensation strategies for equalizing the amount of sex chromosome gene products

(1) Inactivation of one sex chromosome in the homogametic sex (2) Increasing the activity of genes on the sex chromosome in the heterogametic sex

List at least four phenomena that can alter expected Mendelian phenotypic ratios in genetic crosses.

(1) Linkage (2) Epistasis (3) X-linked genes (4) Lethal recessive alleles (5) Environmental effects (6) Continuous traits (7) Variable expressivity

List five different sex determination systems and a representative organism for each.

(1) XX-XO grasshoppers (2) XX-XY humans (3) ZZ-ZW birds (4) Genic balance Drosophila (5) Environmental mollusks; many turtles, crocodiles, and alligators

Assume one parent is heterozygous while the other is homozygous dominant at all. 5 loci. What is the probability that the genotype of the child will be; AaBBCcDDEE?

(1/2)(1/2)(1/2)(1/2)(1/2)=1/32

Discuss "genetic maternal effect."

) In the genetic maternal effect, each individual's phenotype is determined by the genotype of the mother. Typically, the offspring's phenotype is determined by mRNA or protein factors loaded into the oocyte and encoded by the mother's genome. So while genes related to the trait are inherited from both parents (not so for the cytoplasmic inheritance), in a given generation, phenotype is determined exclusively by the mother's, not the offspring's, genotype.

Differences in Prokaryotes and Eukaryotes:

-Eukaryotic cells have a membrane -bound nucleus -Eukaryotic cells have linear DNA, prokaryotic DNA is circular-Prokaryotes are unicellular. Eukaryotes can be multicellular or unicellular (example: Saccharomyces cerevisiae) -Transcription and translation occur in the cytoplasm for prokaryotes. In eukaryotes, transcription occurs in the nucleus, translation occurs in the cytoplasm.

Differentiate the following: Haploid vs Diploid

-Haploid: 1 set of chromosomes -Diploid: 2 sets of chromosomes

Differentiate the following: RNA vs DNA

-Ribonucleic acid vs deoxy ribonucleic acid (lacks one oxygen atom) -RNA has Uracil instead of Thymine. -DNA is more stable than RNA.

What makes these organisms so suitable for genetic research?

-Short generation time- Adapt well to environment -Sequenced Genomes -Significant number of offspring -Easy and cheap to take care of

Similarities in Prokaryotes and Eukaryotes:

-They both have a plasma membrane -Both have DNA and RNA

What is the difference between a prokaryotic cell and a eukaryotic cell?

1) Eukaryotic cells have a membrane-bound nucleus 2) Eukaryotic cells have linear DNA, prokaryotic DNA is circular 3) Prokaryotes are unicellular. Eukaryotes can be multicellular or unicellular (example: Saccharomyces cerevisiae)

What. isa backcross?

A backcross is the mating of F1 progeny back to one of their parents. A backcross can also be a testcross if the original parent is homozygous for the recessive allele. Backcrosses are typically used to introgress an allele of interest back into the genetic background of one of the original parents.

What is the difference between: centromere and kinetochore

A centromere is the physical location on a chromosome where the kinetochore and spindle microtubules attach. The kinetochore is composed of proteins that assemble on the centromere to provide a site for the spindle microtubules to attach.

What is a dominant epistatic gene?

A dominant allele that, if present, determines the phenotype of a given trait regardless of which alleles at other loci are present.

Why is mitosis important within the cell cycle?

A single cell and all its genetic information is duplicated. Each cell contains a full complement of chromosomes.

Explain the genders of human and Drosophila XO individuals.

An XO human is female. In the absence of SRY from a Y chromosome, the person will develop as a female, in spite of having only one X chromosome. An XO Drosophila is male. Drosophila is diploid, so there are two of each autosome. If there is a single X chromosome, the X:A ratio is ½, or 0.5, which is a male.

Explain the genders of human and Drosophila XXY individuals.

An XXY human is male. The SRY on the Y chromosome determines maleness, in spite of the two X chromosomes. An XXY Drosophila is female. Drosophila is diploid, so there are two of each autosome. If there are two X chromosomes, the X:A ratio is 1.0, which is a female.

Which of the following is an example of pleiotropism? A.Gene A controlling eye color. B.Gene B affecting both eye color and eye shape. C.Gene A and Gene B interact to influence eye color. D.Gene C controls eye color while Gene D affects eye shape. E.More than one of the above can be considered pleiotropism.

B.Gene B affecting both eye color and eye shape.

You are studying body color in an African spider and have found that it is controlled by a single gene with four alleles: B (brown), br (red), bg (green), and by (yellow). B is dominant to all the other alleles, and by is recessive to all the other alleles. The bg allele is dominant to by but recessive to br (c) You cross the progeny from parts (a) and (b), Diagram the cross and predict the genotype and phenotype of the progeny.

B/ br X B/ bg ->B/B (brown) Bbg (brown) Bbr (brown) br bg (red)

You are studying body color in an African spider and have found that it is controlled by a single gene with four alleles: B (brown), br (red), bg (green), and by (yellow). B is dominant to all the other alleles, and by is recessive to all the other alleles. The bg allele is dominant to by but recessive to br (b) You cross a pure-breeding brown spider with a pure-breeding green spider. Diagram the cross and predict the genotype and phenotype of the progeny.

B/B X bg / bg -> B/ bg (all brown)

You are studying body color in an African spider and have found that it is controlled by a single gene with four alleles: B (brown), br (red), bg (green), and by (yellow). B is dominant to all the other alleles, and by is recessive to all the other alleles. The bg allele is dominant to by but recessive to br . (a) You cross a pure-breeding brown spider with a pure-breeding red spider. Diagram the cross and predict the genotype and phenotype of the progeny.

B/B X br / br ->B/ br (all brown)

An individual with phenotype B is crossed to an individual with phenotype b. Bis. dominant to. b.All of the offspring have phenotype B. What are the genotypes of the individuals that were crossed?

BB and bb

A homozygous strain of corn that produces yellow kernels is crossed with another homozygous strain that produces purple kernels. When the F1 are interbred, 280 of the F2 are yellow and 70 are purple. a. If kernel color is controlled by a single gene pair with yellow dominant to purple, what would by the expected ratio of yellow to purple in the F2?

Because there are only two progeny classes, the simplest explanation is monohybrid inheritance with an expected ratio of 3 yellow:1 purple.

What is the process by which bacteria replicate called? How does cell reproduction differ in prokaryotes and eukaryotes?

Binary Fission (asexual reproduction)

A cell with a nucleus containing one member of each homologous chromosome pair is

Called a germline cell

During prophase I of meiosis, crossing over is indicated by what microscopically visible structure?

Chiasmata (chiasma) or the synaptonemal complex

telocentric chromosome

Chromosome in which the centromere is at or very near one end.

submetacentric chromosome

Chromosome in which the centromere is displaced toward one end, producing a short arm and a long arm

Explain continuous variation.

Continuous variation refers to phenotypic variation exhibited by quantitative traits that are overlapping and distributed from one extreme to another. The continuous variation of quantitative traits is usually controlled by several genes whose alleles have an additive effect on the phenotype.

What is one feature of meiosis that produces genetic variability in gametes? In two or three sentences, explain how this feature causes genetic uniqueness.

Crossing over. In meiosis I—prophase—portions of homologous chromosomes exchange, changing combinations of alleles of genes on a single chromosome, so not even sister chromatids are identical after crossing over. Each gamete has only one copy of each homolog, and each homolog now has a unique combination of alleles.

Draw out the Central Dogma of Biology. What is the exception to the rule?

DNA transcribed to RNA that is Translated to Proteins

In which oof the following would all daughters be colorblind ?

Father and mother are both colorblind

Who is Mendel and what did he contribute to the field of genetics?

Father of Modern Genetics-Will be going over his experiments with pea plants (chapter 3)

The effect of Barr body formation in mammals is that

Females are mosaics for heterozygous X-linked genes

The ability to curl one's tongue into a U-shape is a genetic trait. Curlers always have at least one curler parent but noncurlers can have one or both parents who are curlers. Using C and c to symbolize the alleles that control this trait, what is the genotype of a noncurler?

Following the convention that recessive traits are represented by lower case letters, we choose "c" to represent the noncurler allele. This means that the genotype of a noncurler must be "cc."

What is the difference between: G1 and G2 of the cell cycle

G1 occurs before S phase and G2 occurs after S phase. During G1, cells grow in size, chromosomes are composed of a single chromatid. During G1, cells pass a critical checkpoint (the G1/S checkpoint) after which they are committed to undergoing cell division. During G2, the chromosomes are composed of two chromatids. There is another checkpoint during G2 that ensures cells are prepared for mitosis. Cells typically spend more time in G1 than in G2.

which is. the proper order of stages in cell cycle

G1, S, prophase, metaphase, anaphase

Differentiate the following: Gene, Allele, and Chromosome

Gene: Basic unit of heredity (segments of DNA) Allele: Different versions of genes Chromosome: genes are arranged on a chromosome.

Differentiate the following: Genotype vs Phenotype

Genotype is the genetic makeup Phenotype is the physical appearance (observable characteristics)

What is the difference between: homologous chromosomes and sister chromatids

Homologous chromosomes can have different alleles. Sister chromatids are duplicates and (except for errors in replication) are identical in sequence

Which of the following events takes place in metaphase I?

Homologous pairs of chromosomes line up on the metaphase plate

What is the difference between: meiosis I and meiosis II

Homologs pair and segregate in meiosis I. Sister chromatids are paired and segregate in meiosis II. Crossing over occurs in meiosis I, but not in meiosis II.

Explain how dosage balance is achieved between X-linked genes and autosomal genes in mammals.

In both males and females only one X chromosome is fully active, potentially creating an imbalance in gene expression between genes on the X chromosome and autosomes. The imbalance is prevented by upregulation of genes on the X chromosome.

Explain incomplete dominance

In incomplete dominance, there will be three distinct phenotypes because the phenotype of a heterozygote is intermediate in appearance between the phenotypes of the two homozygotes. Incomplete dominance involves a single gene locus

Microscopy to look at a cell's chromosomes is often done when the cell is in mitotic metaphase. For example, karyotypes that extract chromosomes from a single cell and photograph them to look for abnormalities are done on metaphase, rather than interphase, cells. Why?

In metaphase, chromosomes are condensed and are more easily visualized

When a flower with yellow petals was crossed with another flower whose petals were red, all the F1heterozygotes displayed orange petals. The F2phenotypic ratio of the offspring produced by the self-fertilization of F1individuals was: 1yellow: 2 orange : 1 red. The alleles of this gene exhibit

Incomplete dominance

How do incomplete and co-dominance differ?

Incompletely dominant traits show an intermediate phenotype in the heterozygote, while co-dominant traits show both phenotypes in the heterozygote (e.g., AB alleles of blood type).

Beginning with a dihybrid cross of two-true breeding parents (AABB x aabb), you recover progeny in the F2 generation in the phenotypic ratio of 9:3:3:1. This indicates

Independent assortment Explanation: - Mendel's law of independent assortment states that alleles of two different genes get sorted into gametes independently of one another. - The independent assortment of genes can be illustrated by the dihybrid cross: a cross between two true breeding parents that express different traits for two characteristics.

Marsupials, like cats, achieve dosage compensation by X inactivation. You are working in a lab that has discovered a mutation on the X chromosome in marsupials in the same gene that causes the tortoiseshell fur color phenotype in cats. You cross an X+ Y black- furred male with an XOXO orange-furred female. You expect that the X+ XO female progeny will have tortoiseshell fur (like cats). Surprisingly, you find that all the females (n = 25) have solid orange fur. Offer a hypothesis to explain these results and describe a genetic test to support your hypothesis.

It appears that the X+ chromosome from the male was inactivated in every female offspring. So perhaps in marsupials, unlike in cats, X inactivation is not random. Instead, in marsupials only the paternal X chromosome is inactivated. If this is true (and, in fact, it is), then it may be tested genetically. Crossing an orange-furred XOY male to a X+ X+ black-furred female should produce only black-furred female progeny even though their genotype is X+ XO, the same as the orange-furred female progeny from the first cross.

Which statement is FALSEconcerning the use of a testcross?

It is only useful for determining whether an allele is dominant or recessive.

A couple has one girl and is expecting a second child. What is the probability that this child will be a boy? After several years and several births, this couple now has six daughters and is expecting a seventh. What is the probability that this child will be a boy?

Like flipping a fair coin, each birth is independent, so in both cases the probability is 1/2.

Which of the following distinguish meiosis from mitosis?

Mitosis has one cell division whereas meiosis involves two cell divisions

Explain why mitosis does not produce genetic variation and how meiosis leads to the production of tremendous genetic variation.

Mitosis produces cells that are genetically identical to the parent cell. Meiosis includes two distinct processes that contribute to the generation of genetic variation: crossing over shuffles alleles on the same chromosome into new combinations, whereas the random distribution of maternal and paternal chromosomes shuffles alleles on different chromosomes into new combinations.

Junior scientist mates two haploid histidine auxotrophic mutants of yeast. Neither strain is able to synthesize the amino acid histidine. The resulting diploid strain grows well on minimal nutrient medium (lacks added histidine). Which of the following can be confidently concluded from this experiment?

More than one of the choices is true

If both parents show the dominant phenotype, then 100% of the offspring will be _____ for the dominant allele

Not enough information provided

Which of the following aspects of the Central Dogma of Biology is incorrect?

One of the "unifying" theories of biology. -Information coded in molecules is stored, replicated, transcribed and translated for cellular machinery. -It describes a process of using "instructions"encoded in DNA to replicate itself for cell division, and express itself to produce machinery for cell functioning.

Sex in mammals is determined by the X and Y sex chromosomes: males are XY and females are XX. How do you explain the 50-50 sex ratio in mammalian progeny?

Sex ratio segregates like any other trait. By forming a Punnett square, you see that an XX mother and XY father form offspring in a 50-50 ratio of males and females.

Differentiate the following: Somatic cells vs Gametes

Somatic cells are diploid while gametes are haploid.

How did Sutton's chromosome theory of inheritance link Mendel's work with a more mechanistic understanding of heredity?

Sutton documented the fact that each homologous pair of chromosomes consists of one maternal chromosome and one paternal chromosome. Showing that these pairs segregate independently into gametes in meiosis, he concluded that this process is the biological basis for Mendel's principles of heredity.

True or False: Eukaryotic chromosomes have their DNA wrapped around a core of 8 proteins called histones to form a nucleosome:

T

True or False: Ploidy indicates how many sets of genetic information a cell possesses:

T

True or False: Viruses consist of a protein coat surrounding either DNA or RNA:

T

True or False: In prokaryotes, transcription and translation occur in the same compartment of the cell

T

Differentiate the following: Transmission genetics, Molecular genetics, and Population genetics

Tansmission genetics: How traits are passed from one generation to another. Molecular genetics: How the genome and genes function at a molecular level. Population Genetics: The study of variance of genes found within a group of individuals and how it changes over time.

What is a test cross?

Test cross refers to the cross of an organism with an unknown dominant genotype with an organism that is homozygous recessive for that trait. It can determine whether the individual being tested is homozygous dominant (pure bred) or heterozygous dominant (hybrid).

Which of the following statements about homologous chromosomes is true?

The chromosomes that make up a pair are called homologous chromosomes, and they carry genes controlling the same inherited characters.They contain the same genes

You cross a female rat with pink toe pads (T) and pointy ears (Xe ) to a male rat with black toe pads (t) and round ears (XE ). The t and e alleles are both recessive, and the ear-shaped gene is X-linked, while the toe pad color gene is autosomal. The F1 progeny all have pink toe pads. What is the genotype of parental generation? What is the genotype of the F1 progeny? If the F1 are crossed to produce F2 progeny, what proportion of the F2 will be black-padded, pointy-eared males?

The parental generation was T/T; Xe /Xe and t/t; XE /Y. The F1 were T/t; XE Xe and T/t;Xe Y. Black-padded, pointy-eared males are tt and Xe /Xe . One-quarter of the F2 progeny will be t/t, ¼ will be Xe Y. Therefore, 1/16 of the progeny will be black-padded, pointy-eared males.

Honey bees have a haplo-diploid sex determination system where females develop from a fertilized egg (they are diploid, having one allele from the female queen and 1 allele from the male), and males develop from unfertilized eggs (they are haploid, having only one allele from the queen). What is the probability that a daughter will inherit a particular allele from her mother? What is the probability that a son will inherit a particular allele from his mother?

The probability that a daughter will inherit a particular allele from her mother is 50%; the probability that a son will inherit a particular allele from his mother is 50%.

What is genetics

The study of genes and Inheritance.

Compare and contrast the patterns of inheritance expected for Y-linked and X-linked recessive inheritance in humans.

Y-linked inheritance is easy to recognize because the trait is passed from a father to all of his sons and none of his daughters, and continues to pass from fathers to sons in every generation. The trait does not affect females. An X-linked recessive trait is more common in males but can affect females as well. A son inherits the trait from his mother, who is typically a phenotypically normal carrier. Often, the trait will also be present in the mother's father or brothers or other male relatives. An affected female normally occurs from an affected father and a carrier mother.

What is the probability that in the cross Aa Bb X aaBb that progeny will be aaBB

aa (1/2) BB. (1/4) aaBB (1/2 x 1/4) = 1/8

Crosses of the two animals marked with circles will have progeny with _____ shells

all sinistral

A disease where offspring have a more severe phenotype than do their parents. could be explained by what. genetic phenomenon?

anticipation

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: b. An AB gamete from an AABb individual?

b. 1/2

You are studying body color in an African spider and have found that it is controlled by a single gene with four alleles: B (brown), br (red), bg (green), and by (yellow). B is dominant to all the other alleles, and by is recessive to all the other alleles. The bg allele is dominant to by but recessive to br (d) You cross the non-brown progeny from part (c) to a pure-breeding yellow spider. Diagram the cross and predict the genotype and phenotype of the progeny.

br bg X by by -> br by (red) bg by (green)

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: c. An AABB zygote from a cross AaBb × AaBb?

c. 1/16

Metacentric. Chromosome

centromere is in the middle

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: d. An AaBb zygote from a cross AaBb × AABB?

d. 1/4

Mendel. determined that for a given character, such as pea seed. shape, an individual has two factors and that these can exist in two forms(R or r). Today we would describeR and r as being:

different alleles of the seed shape gene

An allele is

different versions of a gene (Mendel's studies only involved two alleles of each gene encoding a trait)

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. Indicate the probabilities of producing the following: e. An Aabb zygote from a cross AaBb × AAbb?

e. 1/4