Unit 3 Exam Review

Which of the following statements best defines a karyotype? A) It reveals the appearance of an organism. B)It is an organized image of a cell's chromosomes. C) It is a display of a cell's mitotic stages. D) It is a display of all of the cell types in an organism.

It is an organized image of a cell's chromosomes.

Which of the boxes marked 1-4 correspond to plants that will be true breeding? D) 1 and 4 only A) 1 only B) 1, 2, 3, and 4 C) 2 and 3 only

1 and 4 only

Albinism is a recessive trait where an individual does not produce the pigment melanin. A man and woman both produce melanin, but both have one parent with albinism. What is the probability that their first child will have albinism? A) 1 B) 1/2 C) 0 D) 1/4

1/4

The probability that offspring from a cross between two animals with the genotype AaBbCc are expected to be homozygous recessive for the three traits? A) 1/4 B) 1/16 C) 1/64 D) 1/8

1/64

Phenylketonuria is an inherited disease caused by a recessive allele. If a woman and her husband are both carriers, what is the probability that their first child will be a girl without phenylketonuria? A) 3/4 B) 3/8 C) 1/4 D) 3/16

3/8

Which of the following statements correctly describes the terms monohybrid cross and dihybrid cross? A) A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied. B) A monohybrid cross results in a 9:3:3:1 ratio, whereas a dihybrid cross gives a 3:1 ratio. C) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. D) A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents.

A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied.

Pea plants produce either purple or white flowers with purple showing complete dominance. A gardener was given plants with purple flowers. Which of the following types of crosses would best allow her to determine the genotype of her plant in one generation? A) A testcross B) A monohybrid cross C) A dihybrid cross D) Self-pollination

A testcross

Which of the following results when homologous chromosomes cross over in meiosis? A) Two sister chromatids exchange identical pieces of DNA. B) Two sister chromatids get tangled, resulting in one re-sequencing its DNA. C) DNA repair machinery alters maternal alleles so they match paternal ones D) Corresponding segments of non-sister chromatids are exchanged.

Corresponding segments of non-sister chromatids are exchanged.

Eukaryotic chromatin is composed of: A) DNA and phospholipies B) DNA and RNA C) DNA and proteins D) DNA only

DNA and proteins

Cells that show characteristics of tumors: A) Follow an altered series of cell cycle phases. B) Do not exhibit density-dependent inhibition or anchorage dependence. C) Have nonfunctional MPF. D) Are unable to form spindle microtubiles.

Do not exhibit density-dependent inhibition or anchorage dependence.

In a particular plant, green seed color is dominant to blue. If two plants with green seeds were crossed and resulted in 302 green and 98 blue seed plants, what was the most probable genotype of each parent? A) gg × Gg B) Gg × Gg C) GG × Gg D)G×G

Gg × Gg

Which of the following statements best describes a major difference between mitosis and meiosis I in a diploid organism? A) Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis I. B) DNA replication takes place prior to mitosis, but not before meiosis I. C) Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis II. D) Only meiosis I results in daughter cells that contain identical genetic information.

Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis I.

Why do neurons and some other specialized cells divide infrequently? A) They can no longer degrade cyclins. C) They have entered into Go. B) They no longer produce MPF. D) They no longer have active nuclei.

They have entered into G0

Which of the following statements correctly describes how Mendel explained why traits disappeared in the F1 generation and then reappeared in the F2 generation? A) The processes controlling the appearance of traits in the F1 and F2 plants were different. B) Members of the F1 generation had only one allele for each trait, but members of the F2 had two alleles for each trait. C) New mutations were frequently generated in the cross that generated F2 offspring, causing traits that had been lost in the F1 to reappear in the F2. D) Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1.

Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1.

Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nucler forming on either side of the cell plate. This cell is most likely A) an animal cell in anaphase of mitosis B) a plant cell in metaphase of mitosis_ C) an animal cell in the process of cytokinesis D) a plant cell in the process of cytokinesis

a plant cell in the process of cytokinesis

A human cell containing 22 autosomes and a Y chromosome is spun B) a somatic cell A) a zygote C) an egg D) a sperm

a sperm

For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes based on the independent assortment of chromosomes during meiosis? A) 23 B) about 8 million C)46 D) about 1,000

about 8 million

Which of the following statements describes metaphase? A) separation of the centromeres B) alignment of chromosomes on the equator of the cell C) cytokinesis D) separation of sister chromatids

alignment of chromosomes on the equator of the cell

In which phase of mitosis do the sister chromatids become daughter chromosomes? A) metaphase B) anaphase C) telophase D) prophase

anaphase

The expression of both alleles for a trait in a heterozygous individual illustrates A) codominance. B) polygenic inheritance. C) pleiotropy.

codominance

One difference between cancer cells and normal cells is that cancer cells? A) are unable to synthesize DNA B) continue to divide even when they are tightly packed together C) are arrested at the S phase of the cell cycle D) cannot function properly because they are affected by density-dependent inhibition

continue to divide even when they are tightly packed together

Which of the following pairs of molecules make up an active MPF? A. cyclin and tubulin B. ATP synthetase and a protease C. cyclin and a cyclin-dependent kinase D. a growth factor and mitotic factor

cyclin and a cyclin-dependent kinase

During which phase do sister chromatids separate from each other? A) during meiosis I only B) during meiosis II only C) during both mitosis and meiosis I D) during both mitosis and meiosis II

during both mitosis and meiosis II

Ten plants of the same genotype are planted in a large flower garden. Later that year, some of the ten plants he same genotype are planers have pink flowers. This can be best explained by which of the following statements? A) environmental factors such as soil pH affect the phenotype B) the allele for blue hydrangea is completely dominant over the allele for pink hydrangea C) multiple alleles are involved in color determining flower color D) the alleles are codominant

environmental factors such as soil pH affect the phenotype

Many diploid organisms produce haploid gametes for reproduction. Which of the following best describes how the diploid number of chromosomes is restored in the offspring of these organisms?

fertilization combines chromosomes from each parent into resulting zygote

Which of the following best describes gamete production in plants? A) gametophytes produce gametes by mitosis B) sporophytes produce gametes by mitosis C) gametophytes produce gametes by meiosis D) sporophytes produce gametes by meiosis

gametophytes produce gametes by mitosis

An obstetrician knows that her patient's fetus is at risk for a serious disorder that is detectable in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient? B) sonogram A) karyotyping of the woman's somatic cells D) amniocentesis or CVS C) blood transfusion

karyotyping of the woman's somatic cells

Besides the ability of some cancer cells to grow rapidly, which of the following situations is most likely to result in a tumor? A) lack of appropriate cell death C) inability to form spindles B) changes in the order of cell cycle stages D) failure of cells to enter S phase

lack of appropriate cell death

Genes located close together on the same chromosomes are referred to as ______generally A) homologous; are inherited together B) linked; do not sort independently during meiosis C) linked; sort independently during meiosis D) codependent; do not sort independently during meiosis genes and

linked; sort independently during meiosis

Crossing over of chromosomes normally takes place during: A) mitosis and meiosis II B) mitosis C) meiosis I D) meiosis II

meiosis I

the two homologs of a pair move toward opposite poles of dividing cell during _________? A) meiosis I B) meiosis II C) fertilization D) mitosis

meiosis I

Nondisjunction occurs when A) members of a chromosome pair fail to separate. B) a portion of a chromosome breaks off and is lost. C) an entire pair of chromosomes is lost during meiosis I. D) two chromosomes fuse into one.

members of a chromosome pair fail to separate.

Asexual reproduction occurs during: A) mitosis B) fertilization meiosis C) meiosis D) the exchange of chromosomes between organisms of different species

mitosis

Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects, such as in cystic fibrosis? A) incomplete dominance B) pleiotropy C) multiple alleies D) epistasis

pleiotropy

Which term refers to a situation where a single phenotypic character is determined by the additive effects of two or more genes? Height and skin color are typical of this inheritance pattern. A) polygenic inheritance C) codominance B) incomplete dominance D) pleiotropy

polygenic inheritance

Which phase has just occurred when chiasmata can first be viewed under a microscope? B) meiosis II A) prophase I C) the separation of homologs D) anaphase II

prophase I

Which of the following events occurs during interphase of the cell cycle? A) separation of the spindle poles B) condensation of the chromosomes C) replication of the DNA D) spindle formation

replication of the DNA

Which of the following occurs during S phase? A) replication of the DNA C) condensation of the chromosomes B) separation of sister chromatids D) spindle formation

replication of the DNA

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white? A) red × white D) roan x roan B) white x roan C) red x roan

roan x roan

The role of the mitotic spindle is to: A) trigger condensation of chromosomes B) dissolve the nuclear membrane C) separate sister chromatids D) Split the cell (cytokinesis) following mitosis

separate sister chromatids

After DNA replication, each duplicated chromosome consists of two of which of the following? A) alleles B) daughter chromosomes C) sister chromatids D) daughter nucleosomes

sister chromatids

Meiosis II is similar to mitosis in that A) the daughter cells are diploid B) sister chromatids separate during anaphase C) homologous chromosomes synapse D) DNA replicates before the division

sister chromatids separate during anaphase

Which of the following phenotypes is an example of polygenic inheritance? A) white and purple flower color in peas B) pink flowers in snapdragons C) skin pigmentation in humans D) the ABO blood group in humans

skin pigmentation in humans

Which occurs in meiosis but not in mitosis? A) alignment of chromosomes at the metaphase plate B) chromosome replication C) condensation of chromosomes D) synapsis of chromosomes

synapsis of chromosomes

Mendel's law of independent assortment states that A) independent sorting of genes produces polyploid plants under some circumstances. B) the allele that a gamete receives for one gene does not influence the allele the gamete receives for another gene. C) genes are sorted concurrently during gamete formation. D) chromosomes sort independently of each other during mitosis and meiosis.

the allele that a gamete receives for one gene does not influence the allele the gamete receives for another gene.

What is the name of the region on duplicated chromosomes where the sister chromatids are most closely attached to each other? A) the chromatin B) the centrosome C) the cohesin D) the centromere

the centromere

Genome is best defined as: A) The complete set of a species expressed traits. B) the complete set of an organism's genes and other DNA sequences C) the complete set of a species' polypeptides D) the complete set of an organism's polypeptides

the complete set of an organism's genes and other DNA sequences

Independent assortment of chromosomes is a result of: A) the random combinations of eggs and sperm during fertilization B) the random combition of the sister chromatids to the two daughter cells during anaphase II C) the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I D) the diverse combination of alleles that may be found within any given chromosome

the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I

Cancer is caused by A) uncontrolled cell division. C) formation of eggs and sperm. B) sexual reproduction. D) rapid binary fission.

uncontrolled cell division.