Bio Exam 4
A purple flower is crossed with a white flower. What does the hypothesis of blending inheritance predict that their offspring should look like?
purplish-white
Which of the following happens commonly in BOTH mitosis and meiosis? a. sister chromatids are separated b. homologous chromosomes are separated c. chromosome number stays the same from start to finish d. paternal vs. maternal chromosomes assort independently into gametes e. non-sister chromatids exchange segments during "crossing over"
sister chromatids are separated
Practice making and interpreting a Punnet square. Suppose there are two alleles of a gene, called A and a, and A is dominant to a. In a cross, Aa x Aa, among the offspring there are _____ possible genotypes and _____ possible phenotypes. A.4, 3 B.3, 2 C.2, 1 D.1, 2 E.2, 4
3,2
Suppose a diploid cell has 4 chromosomes. Due to independent assortment, how many distinct combinations of chromosomes are possible in gametes that might be formed from this cell? (Hint: remember the 2-to-the-nth-power rule.) a. 4 b. 2 c. 16 d. 32 e. 8
4
Great white sharks reproduce sexually and have 82 chromosomes per diploid cell. How many of a great white shark's chromosomes were inherited from one of its parents? a. 41 b. 0 c. 82 d. it could be any number between 0 and 82 because of independent assortment e. it could be any number between 0 and 82 because of random fertilization
41
Human skin cells typically have 46 chromosomes. A human skin cell in G2 phase has ___________ chromosomes, ____________ chromatids, and ______________ DNA molecules. a. 92, 92, 46 b. 46, 92, 92 c. 23, 46, 46 d. 46, 46, 46 e. 23, 23, 23
46, 92, 92
Human skin cells typically have 46 chromosomes. A human skin cell in G2 phase has ___________ chromosomes, ____________ chromatids, and ______________ DNA molecules. a. 92; 92; 46 b. 46; 92; 92 c. 23; 46; 46 d. 46; 46; 46 e. 23; 23; 23
46; 92; 92
Suppose you are examining a cell under a very powerful microscope. The cell has multiple chromosomes. You can see the chromosomes and you notice that the chromosomes are lined up two-by-two in a line across the middle of the cell. Which of the following is most likely FALSE about this cell? a. It is diploid b. It is in the process of mitosis c. It is in the process of meiosis d. DNA has been replicated, but copies have not yet been separated e. This cell is going to divide very soon
It is in the process of mitosis
What name is given to the most common phenotype in a natural population?
wild type
The scientific method does NOT involve which of the following? A.Using inductive logic to come up with general hypotheses that can explain a particular phenomenon of interest. B.Concluding a hypothesis is correct because it provides an answer to the question we're asking. C.Comparing observed data to predictions of hypotheses. D.Fitting complementary hypotheses together in an explanatory framework. E.Using deductive logic to make predictions from hypotheses and to design tests of those predictions.
.Concluding a hypothesis is correct because it provides an answer to the question we're asking.
A cell at the very beginning of meiosis has a total of 4 chromatids. What is "n" for the cell? A.1 B.2 C.4 D.8 E.Can not be determined from information provided
1
Suppose a cell in G2-phase has 12 chromatids. How many double-stranded DNA molecules does it have? a. 12 b. 6 c. 24 d. 96 e. 48
12
Fill in the blanks. Suppose a cell at the end of S-phase has 48 chromatids. At the end of mitosis, each cell produced would have ______ chromosomes and ______ chromatids. a. 24, 48 b. 24, 24 c. 48, 48 d. 48, 96 e. 24, 12
24, 24
Fill in the blanks. Suppose a cell at the beginning of meiosis has 30 chromosomes. This cell has ________ chromatids. At the end of meiosis, each of its "daughter cells" will have _________ chromosomes. a. 60, 15 b. 30, 15 c. 60, 30 d. 15, 15 e. 30, 30
60, 15
Fill in the blanks. Suppose a cell at the beginning of meiosis has 36 chromosomes. This cell has ________ chromatids. At the end of meiosis, each of its "daughter cells" will have _________ chromosomes. a. 72, 18 b. 36, 18 c. 72, 36 d. 18, 18 e. 36, 36
72,18
For this question, assume that the species is diploid (and that the gene in question is NOT on a sex chromosome). In a hypothetical species of fox, suppose there is a gene that can cause a fox to have a stripe of gray fur down its side. This gene has two alleles, denoted "s" and "S" (note lower- and upper-case). Foxes with one or two "S" alleles have the stripe, and the stripe looks the same whether an individual's genotype is "SS" or "Ss"; foxes with only "s" alleles have no stripe. If a male and female fox that both have the genotype "Ss" have offspring, what percentage of the offspring are predicted to have a stripe? a. 0% b. 23% c. 50% d. 75% e. 100%
75%
If an organism has a diploid number of 6 chromosomes, how many different combinations of maternal and paternal chromosomes are possible in its gametes?
8
If an organism has a diploid number of 6 chromosomes, how many different combinations of maternal and paternal chromosomes are possible in its gametes? A.6 B.8 C.12 D.16 E.3
8
Suppose that at the beginning of S phase, a skin cell has 8 chromosomes total. How many chromosomes will each cell produced from this cell have after mitosis and cytokinesis are complete
8
Suppose that at the end of G2 phase, a skin cell (in some species of mammal) has 16 chromatids total. How many chromosomes will each cell produced from this cell have after mitosis and cytokinesis are complete
8
Fill in the blanks. Suppose a cell in G1 of the cell cycle has 48 chromosomes. At the end of G2, this cell would have ______ chromatids and ______ chromosomes a. 48, 96 b. 96, 48 c. 96, 96 d. 48, 24 e. 48, 48
96, 48
Which of the following is TRUE about dominant alleles? a. The dominant allele is always more common than the recessive allele in a population. b. Every gene has two alleles, with one completely dominant to the other. c. Dominant alleles are always more adaptive than recessive alleles. d. Dominant alleles are more likely to be inherited than recessive alleles e. A dominant allele affects the phenotype of the organism, whether or not a recessive allele is present.
A dominant allele affects the phenotype of the organism, whether or not a recessive allele is present.
Who has the highest percentage of cells in S phase
A fetus
Why does each parent in the P generation make only one kind of gamete? A.because only one gamete is produced during the two rounds of meiosis B.because we are only going to look at one offspring C.because each parent is homozygous for both genes D.because mutations happened E.because only dominant alleles are passed on to gametes
C.because each parent is homozygous for both genes
Which of the following is true about checkpoints on the cell cycle? a. Checkpoints are regulated by concentrations of molecules in a cell's cytoplasm b. Cells have only one checkpoint on their cell cycles c. Your brain directly controls each of your cell's checkpoints d. There are no checkpoints in the process of mitosis e. Healthy cells do not need checkpoints
Checkpoints are regulated by concentrations of molecules in a cell's cytoplasm
In the process of mitosis, which of the following events happens first? a. Chromosomes condense b. Chromosomes attach to the spindle c. Chromosomes line up in the middle of the cell d. Sister chromatids are separated from each other e. A new nuclear membrane forms around chromosomes
Chromosomes condense
Chemotherapy drugs stop the cell cycle. Why are stomach upset, hair loss, and immune system depression all common side effects of chemotherapy Cells in these tissues are more sensitive to toxins than others Compared to other tissues cells in these tissues are marked by higher rates of cell division Cells in these tissues are generally not replaced after being damaged All of the above
Compared to other tissues cells in these tissues are marked by higher rates of cell division
Which of the following is consistent with the hypothesis of blending inheritance? a. Crossing a purple-flowered pea plant with a white-flowered pea plant produces only purple-flowered offspring b. Great variability in traits is found within any biological population. c. Crossing two pea plants with yellow seeds produces some offspring with green seeds d. A phenotype from the "P" generation of a heredity experiment disappears in the "F1" generation then reappears in the "F2" generation e. Crossing a red flower with a white flower yields a pink flower
Crossing a red flower with a white flower yields a pink flower
Which of the following lists the processes involved in Meiosis in the correct order? a. Separation of homologous chromosomes → Cell division → DNA replication → Separation of sister chromatids → Cell division b. DNA replication → Separation of sister chromatids → Cell division → Separation of homologous chromosomes → Cell division c. DNA replication → Separation of homologous chromosomes → Separation of sister chromatids → Cell division → Cell division d. DNA replication → Separation of homologous chromosomes → Cell division → Separation of sister chromatids → Cell division e. DNA replication → Separation of sister chromatids → Cell division → Separation of homologous chromosomes → Cell division Submit
DNA replication → Separation of homologous chromosomes → Cell division → Separation of sister chromatids → Cell division
When one allele is dominant to another, what is the most common biological mechanism for this dominance? a. Dominant alleles often encode functional products, whereas recessive alleles often do not encode functional products b. Dominant alleles subdue or repress recessive alleles c. Cellular machinery recognizes which allele is dominant and only reads the instructions from that one d. A dominant allele on one chromosome causes the other, homologous chromosome (containing the recessive allele) to be completely inactivated
Dominant alleles often encode functional products, whereas recessive alleles often do not encode functional products
Most of the cells in your body are diploid. How did they become this way?
Each of us is a product of sexual reproduction, having one set of genes from one parent and one set of genes from the other.
Two brown-haired parents have a child with bright red hair. Which of the following is the best explanation for this observation? a. Each parent has one allele for brown hair and one allele for red hair, and the brown allele is dominant b. Each parent has two alleles for red hair, but brown hair is dominant c. Each parent has two alleles for brown hair, but red hair is dominant d. The mother has one allele for red hair and one allele for brown hair, the father had two alleles for brown hair, and the red allele is dominant e. Each parent has one allele for brown hair and one allele for red hair, and the red allele is dominant
Each parent has one allele for brown hair and one allele for red hair, and the brown allele is dominant
Considering a cell that is currently in G1 phase, which of the following is most likely to be true about this cell? a. The cell just finished replicating its genetic material b. The cell is at the beginning of meiosis c. From this point, the cell could go on to G0 or S d. The mitotic phase will be the very next step for this cell
From this point, the cell could go on to G0 or S
Most of the cells in your body right now are in which phase of the cell cycle?
G0
Suppose that at the very beginning of meiosis, a cell in your ovary/testis has 46 chromosomes. At the end of meiosis I (but before meiosis II), this cell will have given rise to two cells that are each ________ and each have ________ chromosomes and ________ chromatids. A.Diploid, 46, 46 B.Haploid, 46, 92 C.Diploid, 23, 46 D.Haploid, 23, 46 E.Haploid, 92, 92
Haploid, 23, 46
How are sister chromatids and homologous chromosomes different from each other? a. They are not different. Homologous chromosomes and sister chromatids are both identical copies of each other. b. Sister chromatids are only formed during mitosis. Homologous chromosomes are formed during meiosis. c. Homologous chromosomes are identical copies of each other. One sister chromatid comes from the father, and one comes from the mother. d. Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication. e. Homologous chromosomes are closely associated with each other in both mitosis and meiosis. Sister chromatids are only associated with each other during mitosis.
Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication.
In which of the following situations would you expect to find the strongest support for the "law of independent assortment"? a. If I were studying two characters influenced by one gene each, and the two genes involved were located on different (non-homologous) chromosomes b. If I were studying one character influenced by one gene c. If I were studying two characters influenced by one gene each, and the two genes involved were located close together on the same chromosome d.If I were studying two characters that were both influenced by the same gene e. If I were studying three characters influenced by one gene each, and the three genes involved were located on close together on the same chromosome
If I were studying two characters influenced by one gene each, and the two genes involved were located on different (non-homologous) chromosomes
Which of Mendel's four hypotheses can, on its own, directly explain why there are NO white flowers in the F1 generation and why the purple F1's look just as purple as the purple plants in the parental ("P") generation? A.Alternative versions of heritable "factors" (i.e., alleles) account for variations in inherited characters B.For each character an organism inherits two alleles, one from each parent C.If the two alleles at a locus differ, then one (the dominant allele) determines the organism's appearance, and the other (the recessive allele) has no noticeable effect on appearance. D.The "law of segregation"
If the two alleles at a locus differ, then one (the dominant allele) determines the organism's appearance, and the other (the recessive allele) has no noticeable effect on appearance.
A cell is in the process of meiosis, and pairs of homologous chromosomes are present in the cell. Which of the following is most likely TRUE about this cell? a. It could be at the beginning of meiosis I b. It could be at the beginning of meiosis I or beginning of meiosis II c. It is at the end of meiosis II d. It is in the middle of meiosis II e. It could be in the middle of meiosis I or the middle of meiosis II
It could be at the beginning of meiosis I
Which of the following processes most clearly provides the biological mechanism for Mendel's "law of segregation"? a. Meiosis b. Mitosis c. Fertilization d. DNA replication e. Mutation
Meiosis
When, precisely, in the life cycle of a sexually reproducing organism does the transition from diploid to haploid occur? a. Meiosis I b. Fertilization c. Meiosis II d. When crossing over happens e. Mitosis
Meiosis 1
Which of the following processes most clearly provides the biological mechanism for Mendel's "law of independent assortment"? a. Meiosis I b. Mitosis c. Fertilization d. Meiosis II e. Mutation
Meiosis I
Horses have 64 chromosomes per diploid cell. When horse parents have horse babies (foals) via sexual reproduction, those babies also have 64 chromosomes per diploid cell. How is this possible? a. Meiosis makes horse gametes with 32 chromosomes each, and then fertilization makes a horse zygote with 64 chromosomes b. Fertilization makes a horse zygote with 128 chromosomes, and then meiosis makes the first four horse cells having 64 chromosomes each c. Fertilization makes a horse zygote with 128 chromosomes, but then independent assortment makes half those chromosomes disappear d. Horse cells can tell when they have too many or too few chromosomes, and they selectively make or eliminate chromosomes as necessary e. Fertilization makes a horse zygote with 128 chromosomes, and then the 64 dominant chromosomes eliminate the 64 recessive chromosomes
Meiosis makes horse gametes with 32 chromosomes each, and then fertilization makes a horse zygote with 64 chromosomes
"In the P (parental) generation, a female fly with pink eyes and short antennae was crossed with a male fly having red eyes and long antennae. When two F1 individuals were crossed and a large number of F2 individuals were counted, there were NO F2 individuals with pink eyes and long antennae, and NO F2 individuals with red eyes and short antennae." This result contradicts which hypothesis a. Mendel's law of independent assortment b. Mendel's law of segregation c. When an organism inherits two different alleles for a gene, one of them will always be dominant d. Offspring inherit one allele for each gene from each parent Submit
Mendel's law of independent assortment
Which of the following is NOT a universal feature of the life cycles of sexually reproducing organisms? a. Meiosis is the transition from the diploid life stage to the haploid life stage b. Fertilization is the transition from the haploid life stage to the diploid life stage c. The products of meiosis are haploid cells called gametes or spores d. The product of fertilization is a diploid cell called a zygote e. Mitosis can only happen in the diploid life stage
Mitosis can only happen in the diploid life stage
In general, cells go from being healthy cells to being cancer cells when: a. A single mutation has removed the G1 checkpoint on the cell cycle b. Multiple mutations have removed multiple checkpoints on the cell cycle c. The cell cycle is stopped by a mutation d. Cells become more sensitive to density-dependent inhibition e. Cells are exposed to a carcinogen once
Multiple mutations have removed multiple checkpoints on the cell cycle
The number of DNA molecules in a cell changes during which phase(s) of the cell cycle?
S and M
Suppose a scientist tricked a cell to skip from G1 phase of interphase to the mitotic phase. Which of the following processes would be impossible for this cell during mitosis? Breakdown of nuclear envelope Condensation of chromosomes Assembly of mitotic spindle Attachment of spindle to chromosomes Separation of sister chromatids
Separation of sister chromatids
For this question, assume that the species is diploid. In a hypothetical species of antelope, suppose there is a gene that can cause an antelope to have white or brown fur. This gene has two alleles, denoted "f" and "F" (note upper- and lower-case). Antelopes with one or two "F" alleles have brown fur; antelopes with only "f" alleles have white fur. Is the "F" allele dominant or recessive, and why? a. The "F" allele is dominant because genotype "Ff " has brown fur b. The "F" allele is recessive because genotype "Ff " has brown fur c. The "F" allele is dominant because genotype " ff " has white fur d. The "F" allele is recessive because genotype " ff " has white fur e. The "F" allele is dominant because genotype "F" has brown fur
The "F" allele is dominant because genotype "Ff " has brown fur
For this question, assume that the species is diploid (and that the gene in question is NOT on a sex chromosome). In a hypothetical species of flower, suppose there is a gene that can cause a flower to be yellow or red. This gene has two alleles, denoted "Y" and "y" (note lower- and upper-case). Suppose there is an additional gene that can cause the flower to have 4 petals or 5 petals. This gene also has two alleles, denoted "P" and "p". A true breeding yellow four-petaled flower is crossed with a true-breeding red five-petaled flower. The F1 offspring of this cross have the genotype YyPp and are yellow with 4 petals. When two F1 individuals are crossed the following F2 offspring are produced: 153 individuals are yellow with 4 petals 51 individuals are yellow with 5 petals 51 individuals are red with 4 petals 17 individuals are red with 5 petals a. The genes are likely to be on different chromosomes b. The genes are on the same chromosome c. There is not enough information to answer this question d. No allele is dominant for either flower color or petal number e. This species of flower does not undergo sexual reproduction
The genes are likely to be on different chromosomes
"Independent assortment" refers to which of the following? a. The orientation of each homologous pair of chromosomes during meiosis I is independent of other pairs. b. Homologous chromosomes pair up and non-sister chromatids exchange homologous segments early in meiosis I. c. A diploid cell has pairs of homologous chromosomes. d. Sister chromatids are separated during meiosis II e. The orientation of each pair of sister chromatids during meiosis II is independent of other chromsomes. Submit
The orientation of each homologous pair of chromosomes during meiosis I is independent of other pairs.
Below is a picture of a child's skin cell, showing 6 of the cell's chromosomes, all of which have been replicated. 3 chromosomes were inherited from one parent, and 3 from the other. Which of the following best describes a pair of homologous chromosomes?
Two chromosomes, one inherited from each parent, that have the same genes as each other
"A red-flowered snapdragon was crossed with a white-flowered snapdragon, and the offspring were all pink." This result contradicts which hypothesis? a. Mendel's law of independent assortment b. Mendel's law of segregation c. Blending inheritance d. When an organism inherits two different alleles for a gene, one of them will always be dominant e. Offspring inherit one allele for each gene from each parent Submit
When an organism inherits two different alleles for a gene, one of them will always be dominant
Which of the following human cells contains a gene that influences eye color? a. Cells in the eye b. Cells in the heart c. Gametes (sperm and eggs) d. Cells in the eye and gametes e. All of the above
all of the above
Which of the following contribute(s) to the variation in offspring produced by sexual reproduction? a. Crossing over b. Mutation c. Independent assortment d. Random fertilization e. All of these
all of these
The cell cycle must be regulated in a multicellular organism in order to ... maintain the proper cell number in tissues. activate cell division when repair of a tissue is needed. halt cell division when repair of a tissue is complete.prevent cancer. all of these answers are correct.
all of these answers are correct
A human offspring typically has ________ of the same genes and ___________ of the same alleles as his/her mother. a. half; all b. all; all c. half; none d. all; half e. none; none
all; half
Suppose that a certain gene functions to enforce a checkpoint on the cell cycle. A mutation causing the loss of this gene's function would cause a person to ... be more likely to have cancer at some point in his/her life.develop an extra lim have cancer immediatel lose the capability to produce gamete be extra protected from ever getting cancer.
be more likely to have cancer at some point in his/her life
"Two purple-flowered pea plants were crossed and produced some offspring that had purple flowers and some offspring that had white flowers." This result contradicts which hypothesis? a. Mendel's law of independent assortment b. Mendel's law of segregation c. Blending inheritance d. When an organism inherits two different alleles for a gene, one of them will always be dominant e. Offspring inherit one allele for each gene from each parent
blending inheritance
In general terms, normally a cell in your body crosses a checkpoint in the cell cycle when .. a. it receives a "go-ahead" signal directly from your brain b. concentrations of proteins in the cytoplasm reach the appropriate level c. it receives a "go-ahead" signal from your external environment d. concentrations of DNA in the nucleus reach the appropriate level e. a mutation in the DNA occurs.
concentrations of proteins in the cytoplasm reach the appropriate level
Which of the following events happens FIRST during meiosis I? a. crossing over b. chromosomes line up two-by-two across the middle of the cell c. chromosomes line up one-by-one across the middle of the cell d. homologous chromosomes are separated e. sister chromatids are separated
crossing over
Mendel did not know about genes or chromosomes per se. However, in modern terms, Mendel's "law of segregation" can be phrased as stating that the TWO alleles an individual possesses for a given gene SEPARATE during gamete formation. If a cell in G1 phase possesses exactly TWO alleles for a given gene, the cell must be A.diploid B.haploid C.could be either A or B D.not enough information to choose between A and B
diploid
Which statement provides the best description of the interphase portion of the cell cycle? a. Interphase is a resting stage prior to cell division b. During interphase, a cell is metabolically active c. Interphase is a brief period between mitosis and chromosome duplication.
during interphase, a cell is metabolically active
Which of the following is true of a species that has a chromosome number of 2n = 16? a. Each cell has eight homologous pairs b. The species has 16 sets of chromosomes per cell c. During the S phase of the cell cycle there will be 32 separate chromosomes d. A gamete from this species has four chromosomes.
each cell has eight homologous pairs
When, precisely, in the life cycle of a sexually reproducing organism does the transition from haploid to diploid occur? a. Meiosis I b. Fertilization c. Meiosis II d. When crossing over happens e. Mitosis
fertilization
Biologically speaking, what part(s) of a parent is/are physically duplicated and passed on to offspring?
genes
If a diploid organism possesses one dominant allele and one recessive allele for a particular gene, then ________ of its gametes will possess the dominant allele and ________ of its gametes will possess the recessive allele a. all, none b. half, half c. none, all d. 75%, 25% e. Not enough information is given
half, half
Mendel did not know about genes or chromosomes per se. However, in modern terms, Mendel's "law of segregation" can be phrased as stating that the TWO alleles an individual possesses for a given gene SEPARATE during gamete formation. If the two alleles an individual possesses for a given gene "segregate" (i.e., separate) during gamete formation, what is happening at the chromosomal level during the process of this separation? A.diploid cells are arising from haploid ones B.haploid cells are arising from diploid ones C.could be either A or B D.not enough information to choose between A and B
haploid cells are arising from diploid ones
For this question, assume that the species is diploid (and that the gene in question is NOT on a sex chromosome). In a hypothetical species of rabbit, suppose there is a gene that can cause a rabbit to have floppy ears. This gene has two alleles, denoted "E" and "e" (note upper- and lower-case). Rabbits with one or two "E" alleles have ears that stand up straight; rabbits with only "e" alleles have floppy ears. Suppose that a male rabbit with ears that stand up straight and a female rabbit with floppy ears have one offspring, and that offspring has ears that stand up straight. What is the genotype of the male (the father of the offspring)? a. his genotype could only be "EE" b. his genotype could only be "ee" c. his genotype could only be "Ee" d. his genotype could be "Ee" or "EE" e. his genotype could be "Ee" or "ee"
his genotype could be "Ee" or "EE"
In human beings, males typically have one X and one Y chromosome, and females typically have two X chromosomes. "Colorblindness" in humans is caused by a recessive allele of gene on the X chromosome. Which relative's (or relatives') genotype(s) typically determine(s) whether or not a human male is colorblind? a. his father's father's genotype only (paternal grandfather) b. his father's mother's genotype only (paternal grandmother) c. his father's genotype only d. the genotypes of both parents e. his mother's genotype only
his mother's genotype only
In general, the frequency with which crossing over occurs between two linked genes depends on __________ a. how far apart they are on the chromosome b. the phase of meiosis in which the crossing over occurs c. whether the genes are on the X or some other chromosome d. whether the genes are dominant or recessive e. the characters the genes code for
how far apart they are on the chromosome
Even in the absence of any mutations or crossing over, what process would still ensure genetic variability in the gametes produced by a single individual? a. Separation of sister chromatids b. Random fertilization c. Independent assortment e. Mitosis d. None of these
independent assortment
when does DNA replication occur in mitosis and meiosis
interphase
For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable? a. It targets only rapidly dividing cells b. It is safe enough to limit all apoptosis c. It only attacks cells that are density dependent d. It does not affect metabolically active cells.
it targets only rapidly dividing cells
During which of the following does the separation of homologous chromosomes occur? a)Mitosis only b)Meiosis I only c)Meiosis II only d)Mitosis and Meiosis I e)Mitosis and Meiosis II
meiosis 1
Which of the following is TRUE about meiosis and sexual life cycles? a)the haploid stage in a sexual life cycle is always just a unicellular gamete b)meiosis halves the number of chromosomes; fertilization makes a diploid cell from two haploids c)meiosis is unique to sexually reproducing animals d)all diploid organisms reproduce strictly sexually
meiosis halves the number of chromosomes; fertilization makes a diploid cell from two haploids
During which of the following does the separation of sister chromatids occur? a)Mitosis only b)Meiosis I only c)Meiosis II only d)Mitosis and Meiosis I e)Mitosis and Meiosis II
mitosis and meiosis 2
The original (ultimate) source of all genetic variation is a. recombination b. crossing over c. mutation d. independent assortment e. random fertilization
mutation
Which of the following can NOT contribute to genetic variation in offspring arising from sexual reproduction? a)crossing over during meiosis in the parents b)independent assortment during meiosis in the parents c)random fertilization d)errors during DNA replication before meiosis e)mutations in DNA caused by UV rays hitting an a parent's dividing skin cells
mutations in DNA causes by UV rays hitting a parents dividing skin cells
Consider two imaginary genes, a "finger number gene" and a "hand size gene", in an imaginary population of aliens. Since we're imagining things, let's also imagine that the aliens have diploid genomes and life cycles just like human beings. Each gene has two possible alleles. For the finger number gene, "N" is the dominant allele for having 4 fingers on each hand, and "n" is the recessive allele for having 5 fingers on each hand. For the hand size gene, "H" is the dominant allele for having small hands, and "h" is the recessive allele for having large hands. Neither gene is on a sex chromosome. Suppose an alien with the genotype nnHH mates with an alien having the genotype NNhh. Under the hypothesis of strict dependent assortment, what are the genotypes of gametes that their offspring could produce? a. NH, Nh, nH, and nh b. NH and nh only c. nH and Nh only d. nH and NH only e. Nh and NH only
nH and Nh only
Consider cells in a tissue that is growing by mitosis. The number of chromosomes in these cells changes in which of the following parts of the cell cycle?
none, chromosome number does not change
Researchers began a study of a cultured cell line. Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away? a. The cells have altered series of cell cycle phases b. The cells originated in the nervous system c. The cells show characteristics of tumors d. The cells were originally derived from an elderly organism.
the cells show characteristics of tumors
Which of the following descriptions correctly defines a genome? a. representation of a complete set of a cell's polypeptides b. the complete set of an organism's polypeptides c. a karyotype d. the complete set of an organism's genes
the complete set of an organism's genes
What is crossing over? a. a direct consequence of the separation of sister chromatids b. the exchange of homologous portions of non-sister chromatids c.the movement of genetic material from one chromosome to a non-homologous chromosome d. making an RNA copy of a DNA strand e. also referred to as the "independent assortment of chromosomes" Submit
the exchange of homologous portions of nonsister chromatids
The most likely reason that the characters of "seed color" and "seed shape" showed independent assortment in Mendel's experiments is that a. the genes for these two characters were very close together on the same chromosome b. these two characters were the product of the same gene c. the genes for these two characters were on different chromosomes d. the genes for both characters were sex-linked
the genes for these two characters were on different chromosomes
Mitosis and meiosis are different in a. whether or not sister chromatids are separated b. the number of cells produced c. the replication of genetic material before any division has occurred d. the occurrence of cytokinesis e. the involvement of a spindle to help guide the movements of chromosomes Submit
the number of cells produced
Why do neurons and some other specialized cells divide infrequently? a. They no longer produce cyclins b. They have been shunted into G0 c. They no longer carry receptors for signal molecules d. They no longer have active nuclei.
they have been shunted into G0
What is true of all cancers a. They have escaped normal cell cycle controls b. They are inherited c. They are caused by chemical carcinogens.
they have escaped normal cell cycle controls
One replicated chromosome (consisting of two sister chromatids) contains a total of ... two single-stranded DNA molecules one double-stranded DNA molecule four double-stranded DNA molecules two double-stranded DNA molecules
two double stranded DNA molecules
Mitosis yields _________ daughter cells that are genetically ____________ and that have ____ ____ number of chromosomes compared to the parent cell. a. four,identical, the same b. two, identical, the same c. two, identical, half the d. four, different, the same e. four,different, half the
two, identical, the same
Your dog has puppies. A pair of homologous chromosomes inside a puppy's cell a. must be genetically identical b. must have the same alleles in the same locations c. were both inherited from the same parent d. will fight with each other to determine which one will be dominant e. will have the same genes at the same locations
will have the same genes at the same locations
