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131 Cards in this Set

  • Front
  • Back

In many species, there are two representatives of each chromosomes. In such species, the characteristic number of chromosomes is called the ________ number. It is usually symbolized as ______.

diploid, 2n.

Living organisms are categorized into two major groups based on the presence or absence of a nucleus. What group is defined by the presence of a nucleus?

Eukaryotic organism

In dihybrid crosses, the ratio 9:3:3:1

independent assortment

Choose the correct statement(s) about the packing of DNA in a chromosome.

Double stranded DNA folds around proteins at the lowest level of DNA compaction


compaction makes it easier for chromosomes to be transmitted in mitosis and meiosis

DNA stores the info needed for the synthesis of cellular


In many organisms, one set of chromosomes comes from the maternal parent, while the other set comes from the paternal parent. Similar chromosomes in these sets are said to be


Which of the following would contain genetic material that is 100% identical?

Sister chromatids

In the cross Aa Bb Cc Dd x Aa Bb Cc Dd, in which all genes undergo independent assortment, what proportion of offspring are expected to be homozygous recessive for all four genes?


In a cross of a round hybrid pea with a true breeding round parent (Ww x WW), what genotypic proportions would be observed in the offspring?

Half heterozygous, half homozygous dominant

A coin is flipped 100 times, with a result of 53 heads and 47 tails. The deviation between the observed numbers and the expected 50-50 results is called

Random sampling error

To determine if an organism with a dominant phenotype is heterozygous, one can perform a


Assuming independent assortment, how many different gametes can be formed by an organism that is homozygous for three and heterozygous for two genes?


The longitudinal halves of a chromosome that has undergone replication are known as


The portion of cell cycle during which the chromosomes are replicated is called


The mode of cell division that results in four daughter cells that are genetically different, with each cell containing one haploid set of chromosomes is known as


A genetically important even called crossing over occurs during

Prophase 1

Haploid chromosome number of 6. How many chromatids present in a diploid, somatic, metaphase cell?


Which of the following would represent ideal qualities of a research organism for genetic studies?

Short generation time, large numbers of offspring per mating, inexpensive to raise

Assuming no crossing over between the gene in question and the centromere, when do alleles segregate during meiosis?

Anaphase 1

RNA is formed by the process of


Cellular respiration (organism)

E. coli

Chloroplast function (organism)

Arabidopsis thaliana

Cell cycle regulation (organism)

S. cerevisiae

Cell differentiation

C. elegans

You would like to know whether the progeny of a pair of mated fruit flies are distributed among the resulting four phenotypic classes in a 1:1:1:1 ratio. You perform a chi-square test and obtain a p value of 0.04. Assuming you have done the test correctly, select the best interpretation of this result.

The differences between the observed and expected counts are too large to be attributed to chance.

Barney and Betty are about to have their first child. They both have normal feet but Barney's father has flat feet and Betty has a child from a previous marriage who has flat feet. What is the probability that they will have a boy with flat feet?


Polydactyly is expressed when an individual has extra fingers and/or toes. Assume that a man w six fingers on each hand and six toes on each foot marries a woman with a normal number of digits. Having extra digits is caused by a dominant allele. the couple has a son w normal hands and feet, but the couple's second child has extra digits. What is the probability that their next child will have polydactyly?


Mendel crossed peas w round, green seeds with peas having wrinkled, yellow seeds. All F1 plants had seeds that were round and yellow. Predict the results of testcrossing these F1 plants.

1/4 round, yellow; 1/4 round, green; 1/4 wrinkled yellow; 1/4 wrinkled green

A couple has a son with XYY syndrome, a condition in which an extra copy of the Y chromosome is present. This condition also results from nondisjunction. During which meiotic division, and in which parent, could nondisjunction have occurred to produce a child w this condition?

Meiosis II in the fatgher

Jill is heterozygous for gene A and is going to have a child with Jack, who is homozygous recessive for gene A. Which of the following offspring genotypes could NOT result from fertilization of a normal haploid sperm with an oocyte that had undergone nondisjunction in meiosis II?


Probability of obtaining an AbC gamete from an AaBbCc individual?


Probability of obtaining an AABB zygote from the cross AaBb x AaBb?


Probability of obtaining an aB phenotype from the cross AaBb x AaBB?


When homologous chromosomes pair in meiosis the structure is called a


A cell that makes up the body structure of an organism and is diploid is


Alternative forms of a gene are called


The monomer building blocks of DNA are known as


An organism produced by biotechnology that involves the transfer of hereditary traits across species is known as a _________ organism.


Name an organelle other than the nucleus that contains its own DNA


List four terms used to describe the normal morphologies w respect to arm ratio and centromere location of eukaryotic chromosomes

telocentric, metacentric, acrocentric, submetacentric

A fundamental Mendelian process that involves the separation of contrasting genetic elements at the same locus would be called


According to Mendel's model because of ________________ of chromosomes during meiosis, all possible combinations of gametes will be formed in equal frequency

independent assortment

Proteins are made in cellular structures called


Identical twins are produced from the same sperm and egg (which splits after the first mitotic division), whereas fraternal twins are produced from separate sperm and separate egg cells. If two parents w brown eyes (dominant) produce one twin boy w blue eyes what is the probability of the other fraternal twin having blue eyes?


Identical twins are produced from the same sperm and egg (which splits after the first mitotic division), whereas fraternal twins are produced from separate sperm and separate egg cells. If two parents w brown eyes (dominant) produce one twin boy w blue eyes what is the probability of the other fraternal transmitting the blue eye allele to his/her offspring?


In cocker spaniels, solid coat color is dominant over spotted coat color. If two heterozygous dogs were crossed to each other, what would be the probability of having a first litter of five pups, the firstborn w solid fur, then among the next four, three w solid fur and one with spotted fur, and then a second litter of seven pups in which the firstborn is spotted, the second born is spotted, and the remaining five are composed of four solid and one spotted animal

0.78% chance

An individual wi type A blood and an individual w type B blood mate and have offspring. What blood type is not possible in their offspring?

All blood types are possible

Two parents with blood types A and B have a child who has O blood type. What is the chance that their next child will be A?


Which of the following types of inheritance have the feature that an affected male could have all affected daughters but no effected sons?

X-linked dominant.

Common red-green color blindness is an X-linked trait. A woman whose father is colorblind married a normal man and they have one son. What is the probability that he is colorblind?


Which of the following is not correct concerning epistatic interactions?

They always result in a 9:7 ratio of a dihybrid cross

In a cross between homozygous wild type female Drosophila and yellow-bodied males all of the F1's were phenotypically wild type. The F2 generation (resulting from matings of the F1s) had 356 wild-type offspring and 123 yellow bodied offspring. However, all 240 females were wild-type and of the 239 males, 116 were wild-type and 123 were yellow bodied. How is the yellow-bodied trait inherited?

X-linked recessive

In cattle, the presence or absence of scurs follows a sex-influenced pattern of inheritance. Therefore a heterozygous male has _______ and a heterozygous female has _______.

Scurs, no scurs

What gene is most responsible for X-inactivation?


Manx cats are heterozygous for a dominant mutation that results in no tails (or very short tails), large hind legs, and a distinctive gait. Homozygous dominant individuals are not viable (they die before birth). A male Manx cat and a female Manx cat produce a live kitten. What is the probability that the kitten has a non manx tail?


Expression of ______ would inhibit X-inactivation.


How many Barr bodies would an individual with a XYY genotype possess?


A modification that occurs to the nuclear gene that alters gene expression without modifying the DNA sequence is called _______ inheritance.


Assume that genes c and d are located on the same chromosome. On one chromosome, alleles c+ and d+ are found, while the homologue contains alleles c and d. Which of the following would be evidence of a recombination event?

Both alleles C+ and d together on one chromosome and alleles c and D+ together on one chromosome

Referring to the previous question, how would you describe the configuration of alleles (c+d+ and cd)?


Crossing over is more likely to occur between genes that are _______ on a chromosome.

Far apart

In a mapping experiment with three linked genes, which phenotype should occur most often in the F2 offspring?

Parental phenotypes

In humans, there are _________ autosomal linkage groups, plus an X and Y chromosome linkage group.


What happens physically during the process of crossing over?

Two homologous chromatids break and rejoin at precisely the same site along the chromosome so that there is no loss or gain of material on either product.

In humans, pattern baldness follows a sex-influenced pattern of inheritance. A heterozygous male has the ________ phenotype and a heterozygous female has a _______ phenotype.

Bald, nonbald

While mapping two genes in Drosophila, you observe 30 recombinants among 200 total offspring. What is the distance between these genes?

15 map units.

In a given mapping experiment, you expect that incidence of double crossovers is 3.5%, but you only observe 2.5%. This can be explained by


The phenomenon in which one crossover decreases the likelihood of crossovers in nearby regions called

positive interference

Klinefelter syndrome in humans, which leads to underdeveloped testes and sterility is caused by which chromosomal condition?

47, XXY

In Drosophila, sex is determined by a balance between the number of haploid sets of autosomes and the number of _________.

X chromosomes

The pairwise map distances for four linked genes are as follows: A-B = 22 m.u., B-C = 7 m.u., C-D = 9 m.u., B-D = 2 m.u., A-D = 20 m.u., A-C = 29 m.u. What is the order of these four genes?


Two human disorders, Prader-Willi syndrome and Angelman syndrome, occur when a small deletion in a specific region of chromosome 15 is contributed by either the father o mother, respectively. Why does this small deltion not behave as a recessive allele for either syndrome, that is, why is its loss not made up for by the good copy of the region on chromosome 15 contributed by the other parent?

The copy of chromosome 15 from the other parent has a gene in the region of the deletion that is imprinted and thus inactive; in the absence of any active copies of these genes, development cannot proceed normally.

The sex of birds, some insects, and other organisms is determined by a ZW chromosomal arrangement in which the males have like sex chromosomes (ZZ) and females are ZW (similar to XY in humans). Assume that a recessive lethal on the Z chromosome causes death of an embryo in birds. What sex ratio would result in the offspring if a cross were made between a male heterozygous for the lethal allele and a normal female?

2:1 male to female

Predict the potential effect of the Lyon hypothesis on the retina of a human female heterozygous for the X-linked red-green color blindness trait.

Females will display mosaic retinas with patches of defective color perception and surrounding areas with normal color perception

Assume hat a dihybrid cross is made in which the genes' loci are autosomal, independently assorting, and incompletely dominant. How many different phenotypes are expected in the offspring?


In chickens, a condition referred to as "creeper" exists whereby the bird has very short legs and wings, and appears to be creeping when it walks. If creepers are bred to normal chickens, one-half of the offspring are normal and one-half are creepers. Creepers never breed true. If bred together, they yield two-thirds creepers and one-third normal. Propose an explanation for the inheritance of this condition.

According to the given data, one would expect the creeper gene to be dominant and homozygous lethal. Normal birds would be homozygous recessive.

In Drosophila, an individual female fly was observed to be XXY and to have white eyes as contrasted with the normal red eye color of wild type. The female's mother wand father had red eyes. The mother, however, was heterozygous for the gene for white eyes. Knowing that white eyes are X-linked and recessive, in which parent and at what stage did nondisjunction occur to produce this XXY, white-eyed female fly?

meiosis II in the mother

The pedigree below is characteristic of an inherited condition known as male precocious puberty, whre affected males show signs of puberty by age 4. Propose a genetic explanation of the phenotype.

This form of male precocious puberty is caused by an autosomal dominant, sex-limited gene.

The cross l+pq/lp+q+ x lpq/lpq is carried out. The "l"gene is determined to be the middle gene. What would be the genotypes of the double crossover games (DCOs) in this cross?

l+p+q+ and lpq

How many different genes are contributing to the wingless phenotype in the mutant fly strains represented in this complementation matrix?


In fruit flies, the recessive pr and cn mutations cause brown and bright-red eyes, respectively (wildtype flies have brick red eyes). The double mutant pr cn combination has orange eyes. An F1 female who is wild-type is crossed to an orange-eyed male.

wildtype: 8

brown: 241

bright red: 239

orange: 12

What classes are the parental types?

Brown and bright red

In fruit flies, the recessive pr and cn mutations cause brown and bright-red eyes, respectively (wildtype flies have brick red eyes). The double mutant pr cn combination has orange eyes. An F1 female who is wild-type is crossed to an orange-eyed male.

wildtype: 8

brown: 241

bright red: 239

orange: 12

What is the genotype of the mother (F1) of these progeny (F2)?


In fruit flies, the recessive pr and cn mutations cause brown and bright-red eyes, respectively (wildtype flies have brick red eyes). The double mutant pr cn combination has orange eyes. An F1 female who is wild-type is crossed to an orange-eyed male.

wildtype: 8

brown: 241

bright red: 239

orange: 12

The F1 mother of these progeny (F2) resulted from a cross between two flies from true breeding lines (P generation). What are the genotypes of these two lines?

prprcn+cn+ and pr+pr+cncn

In fruit flies, the recessive pr and cn mutations cause brown and bright-red eyes, respectively (wildtype flies have brick red eyes). The double mutant pr cn combination has orange eyes. An F1 female who is wild-type is crossed to an orange-eyed male.

wildtype: 8

brown: 241

bright red: 239

orange: 12

What is the map distance between the pr and cn genes?

4 mu

The drosophila genes for white eyes (w), cut wings (ct), and tan body (t) lie at map positions 2, 20, and 28, respectively. Of 1000 progeny, 6 are double crossovers. What is the degree of interference?


Given your calculated p-value and expected values based on a null hypothesis of linkage, what do you conclude about your observed and expected data?

The difference between the observed and expected data was significant. We can reject the null hypothesis and the data are inconsistent with linkage.

Which of the following is primarily responsible for the maternal effect?

Nurse cells

Where is extranuclear DNA located in mammalian cells?


What type of inheritance is observed with extranuclear DNA?

Maternal inheritance

How many Barr bodies would an individual with a XXY genotype possess?


Which of the following is false regarding mtDNA?

It is a linear chromosome

MtDNA contains all of the genes necessary for the complete function of mitochondrial metabolism.


Each new DNA strand is initiated by a

Short RNA primer

If guanine makes up 23% of the nucleotides in a sample of DNA, then thymine would make up what percentage of the bases?


The semisterility of genotypes heterozygous for a reciprocal translocation results from the lethality due to the chromosomal abnormalities produced by

Adjacent 1 segregation and Adjacent 2 segregation

How many Barr bodies would be present in white blood cells of an individual of karyotype 48, XXYY?


Attaches adjacent Okazaki fragments, forming a continuous DNA strand

DNA ligase

The N-terminal tail of histone H3 can be extensively modified, and depending on the number, location, and combination of these modifications, these change may promote the formation of heterochromatin. What is the result of heterochromatin formation?

gene silencing

Because of the number of hydrogen bonds that hold the two strands of a DNA molecule together, unique strands require varying amounts of energy to be separated. Because of this, each unique DNA molecule "melts" at a different temperature. In this context, Tm, melting temperature, is the point at which two strands separate, or become denatured. Which DNA sequence listed below would have the lowest Tm?


The condition that exists when an organism gains or loses one or more chromosomes but not a complete haploid set is known as


Although the most frequent forms of Down syndrome are caused by a random error, nondisjunction of chromosome 21, Down syndrome occasionally runs in families. The cause of this form of familial Down syndrome is

a translocation between chromosome 21 and another small chromosome

A genomic condition that may be responsible for some forms of fragile X syndrome, as well as Huntington disease, involves

various lengths of trinucleotide repeats

The condition known as cri-du-chat syndrome in humans and involves a small deletion of chromosome and has a genetic constitution designated as

46, 5p-

To which of the following does the term heteroplasmy refer?

Cells with a variable mixture of normal and abnormal organelles

If the sperm cell contributes mitochondria to the oocyte, it is called

paternal leakage

Direction of shell coiling (dextral or sinestral) in snails is strongly and most directly influenced by

the genotype of the mother

Direction of shell coiling in snails is conditioned by a form of extrachromosomal inheritance known as

maternal effect

Reverse transcriptase is an enzyme found in association with retroviral activity. It has the property of

synthesis of DNA from an RNA template

Is the accompanying figure DNA or RNA? Is the arrow closest to 5' or 3' end? Spleen diesterase is an enzyme that breaks the covalent bond that connects the phosphate to the 5' carbon. Assume that the dinucleotide is digested with spleen diesterase. To which base and to which barbon on the sugar is the phosphate now attached, A or T?

DNA, 3' end, A, 3'

The basic structure of a nucleotide includes

base, sugar, phosphate

In an analysis of the nucleotide composition of double-stranded DNA to see which bases are equivalent in concentration, which of the following would be true?


DNA polymerase III adds nucleotides

to the 3' end of the RNA primer

DNA polymerase I is thought to add nucleotides

in the place of the primer RNA after it is removed

Which terms accurately reflect the nature of replication of the chromosome in E. coli?

bidirectional and fixed point of initiation

The discontinuous aspect of replication of DNA in vivo is caused by

the 5' to 3' polarity restriction of DNA polymerase

The purine bases are

Adenine and guanine

What is the base sequence of a DNA strand that is complementary to 5'-ATCGGATTC-3'


Which of the following terms should NOT be used to describe a human with three copies of chromosome 12?


Given the following sequence of genes on a chromosome, determine what change in chromosome structure occurred



interstitial deletion

Given the following sequence of genes on a chromosome, determine what change in chromosome structure occurred



Pericentric inversion

Which chromosomal change rarely has a phenotypic effect on resulting offspring?

Balanced translocation

The backbone of the DNA molecule is connected by

phosphodiester bonds

What type of plants are usually seedless?


Trisomy 8 usually leads to early miscarriage of a fetus. However, adult individuals have been found with cells with three copies of chromosome 8 in them. How can this be?

The trisomic cells underwent a mitotic nondisjunction

Who used X-ray crystallography to show a helical DNA structure/double helix?

Rosalind Franklin

Who repeated Griffith's experiments, finally showing that DNA is the transformation factor?

Oswald Theodore Avery

What types of amino acids are most responsible for the binding of DNA to histones

Positively charged amino acids

Viral chromosomes exist in a variety of conformations and can be made up of


Which technique can be used to identify the location of genes on a chromosome?


In Drosophila, the presence of a recessive gene called grandchildless (gs) causes the offspring of homozygous females, but not those of homozygous males, to be sterile. Which statement best explains why females and not males are affected by the mutant gene?

The daughters are li kely sterile because the gs+ allele product has a maternal effect necessary for normal development/functioning of female gonads. Since the mother did not have this allele, all of her daughters do not have functioning gonads, regardless of their own genotype at this locus.

Which of the following is true of negatively supercoiled DNA?

it is underwound