MolGen 4500 Final Compiled Quizlets(1)

Your TA for a class spent all night in the research lab on an experiment and in trying to review transcription and translation keeps interchanging the words during his lecture. which one(s) of these statements your TA has made is true?

-during translation, amino acids are brought to the ribosome by the tRNA molecule -DNA is transcribed to RNA

Genetic distances within a given linkage group...

-are measured in centimorgan -are dependent upon crossover frequencies b/w parred and non sister chromatids

In a germ-line cell from a human male that is dividing, when do the X and Y chromosomes segregate

during meiosis 1, anaphase

a chromosome with a centromere at the very end is called

telocentric

Human blood types are an example of codominance because

the A and B alleles both express equally in individuals with both alleles

what is a dominant epistatic gene?

the allele causing the epistasis is dominant. the dominant allele of one gene masks the expression of the alleles of another gene

In the G0 stage of the cell cycle, which of the following is true:

the cell exits the cell cycle

When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

the gene involved is on the X chromosome

difference between homogametic sex and heterogametic sex

the heterogametic sex determines the gender of the offspring

The primary structure of a protein is:

the linear chain of amino acids

how many barr bodies would you expect to see in an XXY individual?

1

Describe three different sex determination systems

1. XY determination: males (XY) and females (XX) 2. XO determination: males (XO) and females (XX) 3. ZW determination: males (ZZ) and females (ZW)

Describe 3 dosage compensations strategies for equalizing the amount of sex chromosome gene products

1. can double the activity of the gene of the X for males 2. can inactivate one of the X chromosomes on females 3. can reduce the activity of the genes on both X chromosomes by half

what are three characteristics of an autosomal dominant trait observed in a pedigree analysis?

1. equally likely in girls and boys 2. two unaffected parents can NOT have an affected child 3. does not skip generations 4. if one parent is affected and one is not the probability they will have an affected child is 50%

Meiosis involves 3 events that are unique and are not seen in mitosis. List these events and the stage of meiosis in which they occur

1. synapsis and crossing over- during prophase 1 2. homologous pairs at the metaphase plate- during metaphase 1 3. seperation of homologs- during anaphase 1

You are a viewing a pedigree and trying to determine the inheritance pattern of the trait. List 3 characteristics that, if observed, would indicate that the trait is autosomal recessive.

1. trait appears to skip generation 2. unaffected people with an affected parent will be carriers 3. both affected males and females with equal frequency from unaffected parents

Aility ot rol the tongue is caused by a dominant allele. A woman is a "roller", but one of her parents is not. The women is expecting a child with a man who is a "non roller". What is the probability that their child will be a "roller"?

1/2

If a couple with Sickle cell disease genotypes Ss and Ss mate and have one child with the disease, what is the chance the next child has the disease

1/4

In the following cross, what proportion of individuals will have the Bombay phenotype? Ab Hh x AB Hh

1/4

what is the probability of obtaining 3 heads in four flips of a fair coin?

1/4

In snapdragons, heterozygotes for one of the genes have pink flowers, whereas homozygotes have red or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring will have pink flowers?

100%

a homozygous dominant long haired cat is mated to a short haired cat. They produce a total of 13 kittens. What is the expected ratio phenotypes under monohybrid inheritance?

100% heterozygotes

If a typical somatic cell has 32 chromosomes, how many chromosomes are expected in each gamete of that organism?

16

If thymine makes up 15% of the bases in a certain DNA sample, what percentage of the bases must be cytosine?

35%

human gametogenesis from one oogonium and one spermatogonium results in how many mature gametes of each?

4 sperm, 1 ovum

how many different F2 genotypes would you expect in a cross with four heterozygous gene pairs?

81 (3^4)

Assuming Mendel's Second Law is correct, what is the expected segregation ratio for traits in a dihybrid cross?

9:3:3:1

A. A couple has one girl and is a expecting a second child. What is the probability that this child will be a boy? B. After several years and several births, this couple now has 4 daughter and is expecting a fifth. What is the probability that this child will be boy? C. What is the likelihood that the next two children will also be girls?

A. 1/2 B/ 1/2 C/ 1/4

A man has either an AaBB or AABb genotype with equal probability. Assume these genes are unlinked (i.e. assorting independently) a. what is the probability of the man producing an AB gamete? b. what is the overall probability that the man will produce an Ab gamete?

A. 25% B. 50%

Which of the following parental genotypes will produce only heterozygous F1 offspring?

AA x aa

Calvin Bridges crossed white-eyed females to red-eyed males and found rare red-eyed males and white-eyed females in the progeny. Explain how he used Drosophila sex determination system and nondisjunction to demonstrate that the gene for red/white eye color is on the X chromosome.

Bridges looked at the chromosomes of the rare flies under the microscope and showed that the rare white-eyed females had 2 X chromosomes and one Y, and the are red-eyed males had only one sex chromosome. The rare white-eyed females were XwXwY; they were white-eyed because they contained only recessive w alleles and female because there X:A ratio was 1:1. The rare red-eyed males were X+O; they were red-eyed because of the dominant + allele and male because their X:A ratio was 1:2 (0.5). This demonstrated that genes that confer phenotypes were located on chromosomes.

Interactions amount the human ABO blood group alleles involve _____ and ______

Co-dominance, complete dominance

Explain dominance and codominance with respect to the ABO blood groups. Which blood types are dominant, which are recessive, and which are codominant? What does it mean to say that two blood types are codominant?

Dominance: relationship between alleles of one gene, in which the effect on phenotype of one allele makes the contribution of a second allele at the same locus e.g. A and B are dominant over O Recessive: e.g. O is recessive Codominance: form of dominance in which the alleles of a gene pair in a heterozygote are fully expressed e.g. A and B are codominant to each other-- this means that when a person has both A and B alleles, they will have AB blood type

name one characteristic of X-linkage that is often used to identify X-lnked genes in pedigree analysis

If the father of a female has a trait, t he daughter will have have the trait too

Discuss the difference between "cytoplasmic inheritance" and "genetic maternal effect"

In cytoplasmic inheritance, the genes controlling a given trait are inherited exclusively from the mother. In genetic maternal effect, each individual's phenotype is determined by the genotype of the mother

what is one feature of meiosis that produces genetic variability in gametes? explain how this feature causes genetic uniqueness

In meiosis, there is the ability for chromosomes to experience crossing over, where genes switch chromosomes. Crossing over produces genetic variability. It created chromosomes that are not identical

Why are the progeny of the test cross generally used to map loci? Why not the F2 progeny from an F1 x F1 cross?

It is easier to classify recombinant and parental offspring of fa test cross than with the progeny of an F1 x F1 cross

Imagine that a human characteristic is determined by genotype only, with no environmental influence. Based on the amount of shared genetic information in MZ (monozygotic) and DZ (dizygotic) twins, would you expect concordance values to be the same or different in these two sets of twins?

MZ twins share 100% of genetic info whereas DZ twins share on average 50%. Therefore, if a trait is determined by genotype only, concordance values will be different in two types of twins. Values will be around 100% in MZ and 50% in DZ twins

Two and three factor test-cross can both be used to ___________ and ____________

Map gene loci, determine genotype

sister chromatids separate during what phase(s)?

Mitosis Anaphase and Meiosis 2 Anaphase

In deer mice, red eyes (r) is recessive to normal black eyes (R). Two mice with black eyes are crossed. They produce two offspring, one with red eyes and one with black eyes. Give the genotypes of parents and offspring of this cross.

Parents: Rr x Rr Offspring: rr(red eyed) and RR or Rr (black eyed)

Describe the difference between pluripotent and totipotent stem cells. Why are totipotent stem cells considered more valuable for research?

Pluripotent gives rise to cells that make up the body. Totipotent can form all the cell types in the body, this is why they are more valuable.

compare and contrast Mendel's principle of segregation and the principle of independent assortment

Principle of segregation- pairs of genes separate during gamete formation principle of independent assortment: each pari of alleles segregates independently during gamete formation

What are two features that distinguish a prokaryotic cell from a eukaryotic cell?

Prokaryotes lack a nucleus and they have less organelles

Phenotypically, what two general categories of offspring did Strutevant and Morgan observe in F2 generation of their fly crosses?

Red eyes and white eyes

while doing summer field work on a remote Indonesian island, you discover a new genus of lizard closely related to komodo dragons. You attempt to discover what sex determination system is uses by performing a series of controlled crosses on the island, using an isolate pair of lizards. Initially all of your crosses yield only males. As fall begins and you prepare to leave the island, you find that your test cross yielded only females. Suggest a mode of sex determination that explains this data.

Sex determination is influenced by temperature. Males are more likely to be produced in the summer when it is warmer while females are more likely to be produced during the fall when it is cooler.

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 ration in mammalian progeny?

Sex ratio segregates like any other trait. By forming a punnet square of XX vs XY you see a 50-50 ratio of males and females

What are sex-limited and sex-influenced traits and what is the difference between the two?

Sex-limited traits: phenotype is limited to one sex, e.g. tail and neck plumage in domestic fowl Sex-Influenced traits: sex of the individual influences the expression of the phenotype, e.g. male patterned baldness

Describe the differnce between homlogous chromosomes and sister chromatids.

Sister chromatids: identical, carry the same versions of all of their genes because one was produces as an exact copy of the other Homologous chromosomes: the 2 chromosomes of a homologous pair are individual chromosomes that were inherited from different parents; may contain different versions of the same gene

How do daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle?

The daughter cells have the same number of chromosomes and the same amount of DNA

You are trying to develop a new species of newt as an experimental model system. You know that in other species of newt, green (G) is dominant to brown (g) skin color and is determined by a sex-linked gene. You cross brown males to green females and see that in the F1 all the males are green and all the females are brown. Which is the heterogametic sex in your species of newt?

The females are Zg-W and the males are ZG-Zg We know this bc the F1 females have the recesive brown phentoype, so they must be hemizygous and inherit the brown allele from their father and not their mother. Nomenclautere for heterogamteic sex is ZW for females and ZZ for males

Two gene loci, A and B, are unlinked (and thus 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? b. An AB gamete from an AABb individual? c. An AABB zygote from a cross AaBb × AaBb? d. An AaBb zygote from a cross AaBb × AABB? e. An Aabb zygote from a cross AaBb × AAbb? f. An AB phenotype from a cross AaBb × AaBb? g. An AB phenotype from a cross aabb × AABB? h. An aB phenotype from a cross AaBb × AaBB?

a. 1/4 b. 1/2 c. 1/16 d. 1/4 e. 1/4 f. 9/16 g. 100% h. 1/4

what is the probability of drawing one card at random from a deck and obtaining the following a. queen of diamond b. any heart c. a 10 of any suit d. any even-numbered card e. an even-numbered spade

a. 1/52 b. 13/52 c. 4/52 d. 20/52 e. 4/52

What is the probability of rolling 2 six-sidled dice and obtaining the following numbers: a. 2 and 3? b. 6 and 6? c. at least one 6? d. two of the same number e. an even number on both dice f. an even number on at least one dice

a. 2/36 b. 1/36 c. 11/36 d. 1/6 e.9/36 f. 3/4

The following cross produced 125 progeny: aaBbCcDd × AaBbccDD. Assume all the genes are unlinked and that the uppercase letters represent dominant alleles. a. How many offspring are expected to express the dominant phenotype for each gene? b. How many offspring are expected to have the genotype aaBBccDd? c. How many offspring are expected to have the genotype AaBbCcDd?

a. ABCD phenotype= about 23.4 of the offspring (3/16) b. 1/32 of the offspring= about 3.9 c. 1/16 of the offspring= about 7.8

In the yawncat (a rare hypothetical animal), the dominant allele R causes solid tail color, and the recessive allele r results in white spots on a colored background. The black coat color allele B is dominant to the brown allele b, but these genes can only be expressed if the animal has an mm genotype at a third gene locus. Animals that are M- are yellow regardless of which allele from the B locus is present. A mating between a solid yellow-tailed male yawncat and a solid brown-tailed female yawncat produce 16 offspring with the following tail phenotypes: six solid yellow, two spotted yellow, three solid black, one spotted black, three solid brown, and one spotted brown. a. What are the most likely genotypes of the male and female parents? b. what is the probability of the next offspring from these same two parents having a spotted brown tail?

a. the genotypes: RrBbMm and Rrbbmm b. 1/16

Genes common different versions called:

alleles

Compare the inheritance of traits that re governed by genes on autosomal chromosomes with the inheritance of traits governed y mitochondrial genes.

autosomal genes are inherited form the mother and father; mitochondrial genes are usually inherited solely from the mother

Why are rare X-linked recessive diseases more common in males than in females?

because males have only one X allele

why is a karyotype done at metaphase of the cell cycle? Specifically, what is being observed at this point in the cell cycle?

because the chromosomes are condensed and more easily visualized during metaphase

The ability to curl ones tongue into a U Shape is a genetic trait that is inherited in a standard Mendelian fashion. Curlers always have at least one curler parent but non curlers can have one or both parents who are curlers. Using C and c to symbolize this trait, what is the genotype of a non curler.

cc

During prophase 1 of meiosis, crossing over is indicated by what microscopically visible structure? The ____

chiasmata

Within cells, DNA and genes are organized into structures called_____

chromosomes

within cells, DNA and genes are organized into structures called__________

chromosomes

Microscopy to look at a cell's chromosomes i often done when the cell is 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?

chromosomes are condensed and visible

linked genes _________

co-segregate

In order to determine if mutation from different organisms that exhibit the same phenotype are allelic, which test would you perform?

complementation test

which term refers to mating between closely related people?

consanguinity

The contribution of Gilbert and Sanger to modern genetic was to...

develop a method for DNA sequencing

Genetic information can be carried in which of the following biomolecules?

either DNA or RNA

Mice homozygous for mutation in one gene exhibit polydactyly while in another gene, homozygous for extra toes and limb deformity mutations will NOT exhibit polydactyly because it is missing distal limbs, where the toes are located. This type of genetic relationship is called.....

epistasis

_______ is the change in allele frequency in a population over time.

evolution

what is hemophilia and why can females, but not males, be carriers of hemophilia and other X-linker recessive characteristics?

hemophilia is a sex-linked recessive disorder that impairs the bodies ability to control blood clotting. Females can be carriers of hemophilia and other X linked recessive characteristics because females have 2 X chromosomes while males only have 1. Therefore the gene is guaranteed to show one a male with the single X chromosome that carries it.

how do incomplete and co-dominance differ?

incomplete dominance is an intermediate phenotype resulting from heterozygosity, whereas in co-dominance, the heterozygous expresses both traits in the phenotype simultaneously

during the cell cycle, chromosomal replication occurs in_______

interphase

what do kinase enzymes do, and why are they important to researchers of diseases such as cancer?

kinase enzymes add phosphate groups to other proteins. Deregulated kinase activity or mutated kinases are a frequent cause of disease, in particular cancer. Kinase enzymes regulate many aspects that control cell growth, movement, and death.

the attachment point on the chromosome for spindle microtubules is the_________

kinetochore

where on the chromatid are the microtubules attached?

kinetochore

explain why large recombination frequency values re less accurate measure of map distance than smaller ones.

multiple crossovers often lead to the parental arrangements of alleles and so these are not counted when measuring recombination frequencies. Multiple crossovers are expected more over long regions, so the problem is worse for larger recombination frequencies

multi-factorial traits are influenced by _____ and _______

multiple genes, environment

cytokinesis is....

none of the above

A rare dominant trait, when exhibited in men, is transmitted to half their sons and half their daughters. The gene for this trait is carried:

on an autosome

The DNA of a eukaryotic chromosome is:

one long double helix

In prokaryotes, replication usually begins at a specific place on the chromosome called the

origin of replication

how do penetrance and expressivity differ?

penetrance is the percentage of individuals that express the phenotype of the specific genotype. Variable expressivity is the degree to which the phenotype is expressed, so in other words how strong it is.

A measurable or observable trait or characteristic is called a(n)

phenotype

Which of the following is not a component within a single nucleotide of a nucleic acid?

polymerase

The contribution Charles Darwin made to genetics was to

propose that evolution occurs by natural selection

In eukaryotes., chromosomes do not contain:

proteases

Mendel's law of independent assortment has its physical basis in the:

random arrangement of chromosomes on the metaphase plate in meiosis 1

in what type of cell- in humans- would you expect to find meiosis occurring?

reproductive/ somatic

what is the mechanism that ensures Mendel's First Law of Segregation?

segregation of homologous chromosomes

Homologous chromosomes are those than can be matched by virtue of their similar structure ad function within a nucleus. What chromosomes making up the human genome do not follow the same characteristic of homology?

sex chromosomes

what does it mean if a human female oocyte is no longer arrested in metaphase 2 of meiosis?

she is pregnant

What conclusions did Mendel make from his monohybrid crosses?

there were four hypothesis

which of the following statements about homologous chromosomes are true?

they always contain the same genes, they occur together in diploid cells

Embryonic stem cells are the subject of a great deal of research.What characteristic of embryonic stem cells accounts for the this scientific interest?

they are potentially totipotent

What is the maximum recombination frequency observable from a cross? Why is it less than the true genetic distance in some cases?

this can be interpreted as unlinked genes or as genes that are 50 map units apart. Because gametes this far apart or more cant distinguish from gametes that are unlinked, its not possible to ever get a ratio of gametes produced that indicates a distance of greater than 50 map unites. Some genes that are farther apart but still on the same chromosomes may appear to be closer because the observed proportion of recombinant gametes neglects to count those double crossover events that occur between the genes. When a double crossover occurs, the parental gametes are formed again and it looks as if no crossovers have occurred at all.

how does epistasis differ from mender's principle of dominance?

when an epistatic gene is expressed, as the third trait, which is usually recessive is displayed and covers main dominant or recessive one at the first loci

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

when they make gametes in meiosis, the cells divide and get one chromosome from each mother and father. when the sperm and egg meet, you either get XX or XY depending on if there is an X or Y in the sperm