Bio Test December 3
How many sex chromosomes does the normal human male inherit from his father?
1
What is the approximate probability that two individuals share all alleles if three different STR regions are analyzed?
1 in 1,000,000
You run a DNA fingerprint for an individual suspected of a crime at 6 loci. What is the maximum number of bands you would expect on your gel?
12
If a cell containing 18 chromosomes divides by mitosis, how many chromosomes will each daughter cell have?
18
The first cloned vertebrate was a sheep named Dolly in the year:
1997
In humans, the haploid number, n, equals:
23
The human genome comprises:
23 pairs of chromosomes
How many STR alleles are analyzed when the FBI creates DNA fingerprints?
26
About 0.1% of the DNA sequences of two individuals will differ. This difference translates to approximately how many base-pair differences?
3 million
If a scientist starts out with 10 copies of a particular DNA segment to be copied and runs 5 cycles of PCR, how many copies will she have at the end?
320 copies
Based on the information below, which describes the offspring's alleles for the STR region? (The repeat is "ATCG.") Chromosome inherited from mother: TCATCGATCGATCGATCGTCGA. Chromosome inherited from father: AGATCGATCGATCGATCGATCGATCGATCGATCGATCGCATTAC.
4/9
A human skin cell contains 46 chromosomes (23 paternally inherited and 23 maternally inherited). Before mitosis begins, this cell must duplicate its genetic material. What are the products of this duplication?
92 sister chromatids, in 46 pairs that are connected by a centromere
In which situation might a cell not pass the G1/S checkpoint?
A cell cultured in a lab has insufficient nutrients in its growth medium.
In asexual reproduction, daughter cells inherit their DNA from:
A single parent
Hermaphrodites are individuals with functioning male and female reproductive organs who are capable of producing both male and female gametes. Which statement about hermaphrodites is false?
An XYY human is a hermaphrodite.
Which of these describes a genetically modified organism?
An organism that has at least one gene from another species inserted into its DNA
Separation of the chromatids at the end of metaphase leads into the next phase, which is:
Anaphase
When comparing STR alleles of a biological father and son, what would you expect to find?
At each of the STR locations, the child would have at least one allele in common with his father.
Why have scientists inserted the human insulin gene into the genome of E. coli bacteria?
Bacteria express the human insulin gene and produce large quantities of the insulin protein, which is sold pharmaceutically.
Which of these is a symptom of vitamin A deficiency?
Blindness
Radiation therapy for cancer works because a cell's DNA is exposed during mitosis and is most vulnerable to damage from radiation. Because cancer cells are uncontrollably undergoing mitosis, they die when exposed to the treatment. The common side effects of radiation treatment are hair loss and vomiting. What does this imply?
Both stomach and skin cells are constantly being replaced.
You are a researcher who wants to inactivate the gene in mosquitoes that allows them to host the malarial parasite. What biotechnology tool would be best suited for this task?
CRISPR
What would you expect to happen in an individual with shorter-than-normal telomeres?
Cells and tissues would begin to appear aged soon after birth.
Which statement does not represent a way in which meiosis and mitosis differ?
Chromosome replication occurs before mitotic division but not before meiotic division.
Which statement is true about cloning?
Cloning refers to a variety of techniques, ranging from whole organism cloning to tissue and organ cloning.
Variation in rates of cell division is regulated by a cell-cycle control system, which is a group of molecules, mostly proteins, within a cell that coordinates the events of the cell cycle. This control system functions through a system of checkpoints. Which assessment occurs at the G1/S checkpoint?
DNA is checked for damage before cell division.
Within interphase, which stage is defined by the active replication of the cell's genetic material?
DNA synthesis
In female gamete development in humans and other vertebrates, the net result of meiosis is the production of one large egg and three small cells with very little cytoplasm. These three small cells:
Degrade almost immediatly
Put the steps of creating a DNA fingerprint in the correct chronological order.
Determine the genotype of each STR allele, amplify the STR region, and sort the alleles by size.
Which of the following statements cannot be made based on the graphed data?
Equal quantities of genetically modified cotton and soybean plants are produced in the United States.
Using traditional cross-breeding techniques, scientists have been able to create featherless chickens. Which situation has not been a problem with featherless chickens?
Featherless chickens have trouble digesting corn.
A diploid cell undergoes meiosis. What are the products of this division?
Four haploid cells
Within interphase, which stage is defined by the active replication of the cell's genetic material?
Gap 1
A cell becomes arrested within the cell cycle because it is unable to replicate its DNA. In which stage would you predict the cell would become arrested?
Gap 1 phase
How are gene cloning and whole organism cloning different?
Gene cloning allows foreign genes to be inserted into a recombinant bacterial plasmid, whereas whole organism cloning does not involve recombinant technology.
In humans, both sexes have the same number of autosomes but different ratios of sex chromosomes. Males are XY, and females are XX. Which statement comparing the X and Y chromosomes is true?
Genetic instructions on the Y chromosome instruct the fetal gonads to develop as testes instead of ovaries.
What is golden rice?
Golden rice is rice that has had genes from other organisms added to it. These genes produce beta-carotene.
Which statement is not a problem or risk related to genetically modified organisms?
Heavy government regulation is driving up the price of modified food crops for consumers.
Which of these does not occur during prophase I of meiosis?
Homologues separate and are pulled to opposite poles.
Some forms of dwarfism in children can be treated by ____________, which is(are) made by recombinant DNA techniques.
Human growth hormone
You amplify the same gene from two different people using PCR (polymerase chain reaction). When you electrophorese the two samples on a gel, you see that two bands are present in the sample from Individual 1, whereas only one band is present in the sample from Individual 2. What is a likely explanation for this outcome?
Individual 1 is heterozygous, whereas Individual 2 is homozygous.
Which statement about gene therapy is false?
It is performed on cells of the body, which ensures that a defective gene cannot be passed on to offspring.
You read the following headline in the newspaper: "Scientists Find Gene Linked to Schizophrenia." As exciting as this news seems, the reality is that many more years of research will be required before this new knowledge will have any impact on people who have schizophrenia. How will this information likely benefit scientists as they continue to search for treatments?
It will help scientists identify the DNA mutations that cause schizophrenia.
What is the best way to distinguish male from female?
Males produce motile gametes.
Bacteria reproduce asexually, whereas most plants and animals reproduce sexually. Which is the better method?
Neither method is better; each is effective in different environments for different kinds of organisms.
The number of chromosome pairs in a species is
Not correlated with the species complexity
What conclusion can be drawn from this graph? (Incidence of down syndrome per 1000 births)
Older women have a higher probability of having a baby with Down syndrome than younger women.
A 30-year-old woman has a 1 in 3,000 chance of giving birth to a child with trisomy 21; however, a 48-year-old woman has a 1 in 9 chance. Which statement is the most likely explanation for why a woman has a higher probability of giving birth to a child with trisomy 21 as she ages?
Older women have older oocytes, and the older the oocytes, the greater the chance they will experience a nondisjunction event during meiosis.
Why is trisomy 21 seen so often, but other trisomies (such as trisomy 1) are relatively rare?
Other trisomies are most often lethal; the fetuses are spontaneously aborted.
When creating a gene library, how is recombinant DNA introduced into bacterial cells?
Plasmids
Some fertility clinics now promise that a couple can choose the sex of their baby. What technique might allow for this?
Separating the father's sperm according to weight, because the X chromosome weighs more than the Y chromosome.
Which of these does not occur in a cell during the mitotic cell cycle?
Sister chromatids pair up and join at the centromere.
In mammals, the most rapid cell division by mitosis occurs in:
The bone marrow
Which statement about the cell cycle is false?
The increase in cytoplasm occurs during the DNA synthesis phase.
Eukaryotic somatic cells alternate in a cycle between cell division and other cell activities. The cell division portion of the cycle is called:
The mitotic phase
One of the possible concerns about genetically modified foods is that they might kill organisms that we don't want to kill. Which statement is an example of this phenomenon?
The pollen from plants containing insect-killing Bt genes can be blown onto other plants. Insects that we don't want to kill, such as monarch butterflies, may be killed by such pollen.
During metaphase I in meiosis, a cell contains ________ of the DNA that it contained during prophase I.
The same amount
Which of these happens in telophase after the two sets of chromosomes have been separated?
The spindle dissasembles
Which statement describes the function of the histones in eukaryotic cells?
They enable DNA to be tightly and efficiently packed inside the nucleus.
Which of these is not a common concern about genetically modified food crops?
They may increase the number of human infections by transgenic E. coli.
Which statement about prokaryotes is true?
They reproduce using binary fission
Which statement correctly describes the process of crossing over?
Two chromatids (one maternal and one paternal) break off at corresponding points on homologous chromosomes. The pieces of chromatid rejoin to the chromosome in each other's places.
Which of these is a correct statement about the Irish Potato Famine?
When the crops were infected by a rot-causing mold, all of the potato plants were susceptible and most were wiped out.
Which of these human sex chromosome genotypes is not possible?
YYYY
Is it possible to clone a dinosaur?
Yes, but scientists would have to find the DNA in a fossilized mosquito, hope the mosquito had bitten a dinosaur, and then isolate all of the dinosaur's DNA.
Most prokaryotes carry their genetic information in:
a single, circular chromosome.
Mitosis produces two daughter cells that
are genetically identical to each other and to the original parent.
A karyotype
can be used to diagnose down syndrome in humans
A recombinant plasmid created during a recombinant DNA experiment:
carries and allows expression of a foreign gene of interest
Transgenic salmon:
carry a version of the growth hormone gene that functions year-round, instead of primarily in the summer.
Which of these is an example of a medical application for animal cloning?
cloning hamsters to produce human erythropoietin (EPO)
The division of the cytoplasm during cell division is referred to as:
cytokinesis.
Bacteria use restriction enzymes to:
destroy foreign DNA
The polymerase chain reaction (PCR) is a lab technique that ultimately results in which of the following?
duplication of a small strand of DNA into billions of copies
Stem cells have great potential to repair damaged tissues because they:
have the potential to develop into any type of cell in the body.
A gene from a bacterium can be inserted into a corn plant, and the corn plant will make the same protein as the bacterium. This kind of gene transfer works because:
he bacterium and the corn plant use the same process and genetic code for synthesizing proteins.
The first gene therapy experiments were undertaken in an attempt to cure otherwise fatal genetic diseases in children. What type of incurable genetic disease was the first gene therapy trial attempting to cure?
immune deficiency
Scientists have inserted a gene from the bacterium Bacillus thuringiensis into
increase the corn's resistance to insects.
You are cloning a sheep. You have just implanted the nucleus from a mammary cell from one sheep into an egg cell from another. What is the very next step?
inducing cell division
Gene therapy
involves introducing non-defective genes into the cells of an individual with a genetic disorder.
What role does Cas9 play in CRISPR
it cuts the target gene in a specific location
During which phase of the cell cycle do the chromosomes align in one plane at the center of the cell?
metaphase
Crossing over takes place during:
middle prophase I of meiosis only.
Transgenic plants have been modified for all of the following characteristics except
nitrogen fixation.
Transgenic plants have been modified for all of the following characteristics except:
nitrogen fixation.
The number of chromosome pairs in a species is:
not correlated with the species' complexity.
Short tandem repeats (STRs) are highly variable sets of repeating sequences within the genome. Because the probability of any two having an identical number of repeats at different STR regions within the genome is astronomically low, they are useful for identifying samples of DNA. With so much variability in these regions of DNA, one would assume that STRs:
occur outside of protein-coding regions of DNA.
in birds, sex determination is
opposite of that in humans because the mother has one copy of each of two different sex chromosomes
You are working in a biotechnology lab, and you have only a small amount of DNA available for analysis. Which could you use to duplicate that small piece of DNA repeatedly?
polymerase chain reaction
A whole organism clone is a clone of the organism that:
provides the nuclear (diploid) DNA.
The ability for cancer cells to divide indefinitely is made possible because they:
rebuild their telomeres after every cell division
The combination of DNA from two or more sources is called:
recombinant DNA
All of these are somatic cells except:
sperm cells
Animal cells have "counters" that keep track of how many times a cell has divided. These counters are called:
telomeres
In the __________ stage of mitosis, the daughter chromosomes of the cell reach the poles, after which the cell passes into the next interphase, and the nuclear envelope and nucleoli re-form
telophase
When a DNA fingerprint is created, what determines the size of each fragment?
the number of times the repeating sequence is repeated in each STR region
Some animals are primarily asexual in their reproduction, but they have the ability to switch to sexual reproduction under certain conditions. Why might an animal that generally reproduces asexually make this switch to sexual reproduction?
to increase the genetic diversity of its offspring during periods of stress
A tomato plant that has pest-resistance genes inserted into its genome can be called a(n):
transgenic organism.
What is biotechnology?
use of technology to isolate and modify biological molecules to achieve practical benefits
Which of these is not a characteristic of Klinefelter syndrome?
web of skin between the neck and shoulders XXY genotype
Microsatellites are short sequences of DNA that consist of several two- or three- nucleotide motifs repeated in tandem (e.g., AATAATAAT or GAGAGAGAGAGA). Each allele consists of a different number of repeats. Microsatellites are typically not under selection, and they are inherited through Mendelian inheritance. Given this information, which question might you answer with the use of microsatellites?
whether two puppies were sired by the same father
