Biology Final Exam Study Guide
What is the complementary base-pairing rule?
5) Adenine will always pair with thymine, and cytosine will always pair with guanine
Mexican hairless dogs are hairless because of a dominant allele of a particular gene. Homozygous dogs die in utero (before being born). What is the probability of one hairless dog having a hairy puppy?
0
Two parents are each homozygous dominant at the cystic fibrous gene. What is the probability that their first child will have cystic fibrosis?
0
Genetic diversity is measured in terms of allele frequencies (the relative proportions of a specific allele in a gene pool). A population of 3,200 mice has 4,200 dominant G alleles and 2,200 recessive g alleles. What is the frequency of recessive g alleles in the population?
0.34
What is the significance of gene mutations in terms of protein function and clinical outcome?
1) Changes in gene sequence can alter the shape or function of a protein. 2) Analyzing specific mutations allows researchers to study overall gene function. 3) Gene mutations allow researchers to identify deficient proteins and aid in therapeutic intervention, such as in cystic fibrosis. (all the above)
A mutation in a DNA coding region of a protein can cause
1) a change in primary structure of the protein. 2) a change in secondary structure of the protein. 3) a change in tertiary structure of the protein. 4) a change in quaternary structure of the protein. 5) (All of the above)
Ovaries produce ________.
1) estrogen 2) hormones 3) eggs 4) progesterone 5) (All of answers are correct.)
Evolution and natural selection can be witnessed in the human population by examining
1) skin-tone variation and sunlight exposure. 2) the sickle-cell trait and malaria. 3) lactase persistence and cattle farming. 4) the CF allele and cholera resistance. 5) (All of the answers are correct.)
Y chromosome analysis has been used in
1) studying human evolution. 2) tracing genealogy. 3) evaluating stories about the descendants of Thomas Jefferson. 4) tracing the descendants of Genghis Khan. 5) All of the above.
One of every _______ children born is neither strictly male nor female, but intersex.
1,600
Mexican hairless dogs are hairless because of a dominant allele of a particular gene. Homozygous dominant dogs die in utero (before being born). What is the probability of two hairless dogs having a hairy puppy?
1/4
What is the overall infertility rate in the United States?
15%
Looking at the left image in infographic 30.2, and counting the connections of the PNS to the spinal cord DOWN from the brain to the base of the spinal cord (so the top one is "1", the next one up is "2", etc.), at what number would you expect a spinal cord injury to cause leg paralysis, but not arm paralysis?
18
At the end of the S phase, cells have ____ set(s) of genetic material, compared to a cell at the beginning of S phase.
2
How many alleles for a single trait are present in each human cell?
2
Humans first walked on planet Earth approximately _____ years ago.
200,000
all chromosomes, except the X and Y.
22
How many chromosomes are in a human sperm?
23
How many chromosomes do human sperm and egg cells have?
23
Humans have
23 pairs of chromosomes, which include the sex chromosomes
A population of aliens with similar genetics as humans is affected by a homozygous recessive condition known as "xbziq." This condition causes aliens to die at young ages because their digestive tracts are not able to effectively process food and obtain the necessary nutrients and energy from their diets. Approximately 2% of the newborn aliens have the xbziq condition. What is the carrier (heterozygote) frequency in the population?
24% The frequency of homozygous recessives (q2) is 2% (0.02). Therefore, the frequency of q is the square root of 0.02 = .1414. P = 1 - q = 0.86. The carrier frequency is 2pq = 24.1%
In a given population of mice, if there are 15 mice each with 2 alleles for each gene, there are _____ alleles for each gene.
30
Quitting smoking reduces a woman's risk of developing cancer by _____.
30%
How many mass extinctions have occurred between the Precambrian Era and the Jurassic Period?
4
A woman produces an egg with 24 chromosomes, including 2 copies of chromosome 21. If the egg is fertilized by a normal sperm, the zygote will have _____ chromosomes.
47
An individual inheriting the genotype aaBbCc falls in the _____ foot phenotype.
5
If the genotype HH represents curly hair, Hh represents wavy hair, and hh represents straight hair, in a population where 20% of the population has curly hair, what is the genotype frequency of the people who have wavy hair?
50%
A mother is heterozygous for an X-linked trait. Her husband has the trait. What is the probability that they will have a child with the trait?
50% for their daughters; 50% for their sons
Mass extinction involves between _____ % and _____% of all species and occurs relatively rapidly.
50; 90
An alien species has 102 chromosomes in its diploid somatic cells. Its haploid gametes will have _____ chromosomes
51
A fossil is found at the top layer of rock with relative dates of 585 mya and 550 mya. What is the fossil's approximate age?
550 mya
In a mating of two people of medium height (where three genes control height): AaBbCc x AaBbCc produce _____ distinct phenotypes determined by the number of genes inherited.
7
If the first child of two parents with polydactyly does not exhibit this trait, what is the probability that their next child will have polydactyly?
75%
If two individuals were heterozygous for freckles, which is a dominant trait, what percentage of their progeny would have freckles?
75%
Baking soda is a base and has a pH of ____.
9
Which statement is false?
A human zygote has 23 chromosomes
Which of these statements about natural selection is false?
A mutation that is advantageous to an individual will be advantageous to all individuals in all environments.
A mismatch that occurs during A DNA molecule containing a gene has the sequence AACT on one strand. During replication, DNA polymerase synthesizes the sequence TTGT on the new strand. Which of these is the most likely new allele of the original strand after replication?
AACA
What conclusions are drawn from Darwin's proposal of descent with modification, now known as the theory of evolution?
All living things are related.
If a person with AB− blood is in need of a transfusion, people with what blood types will be able to donate blood for them?
A−
You have type B blood. Therefore, you can accept blood donations from people with a(n) _____ genotype
BB and BO
Timber wolves in Wisconsin have gene pools with very few different alleles. Therefore, more defective, recessive traits are increasing in this wolf population. What are some steps that conservationists might consider to introduce new alleles into this population?
Bring in an unrelated population of female wolves and release them to breed with the Wisconsin wolves.
What causes cancer to kill people?
Cancer cells crowd out normal cells and disrupt organ functions.
Cancer cells have distinctive properties that set them apart and contribute to malignancy. Which characteristic is NOT one of those exhibited by cancer cells?
Cancer cells exhibit anchorage dependence.
Ultraviolet light is essential for the formation of this vitamin.
D
The information that ultimately encodes the shape and sequence of a protein comes from _____.
DNA
Which of the steps of bacterial reproduction occurs first?
DNA is replicated.
Variations of human skin tone is driven by
DNA variation in the population. natural selection. inheritance and survival. adaptations over time. (All of the answers are correct.)
How are eggs obtained for in vitro fertilization?
Eggs are obtained by using fertility drugs, and then collecting eggs directly from the ovaries.
What would be the best way to distinguish between two alleles and two genes?
Examine their DNA; the DNA sequences of two different alleles would be more similar than the sequences of two different genes.
What observation made Fleming investigate the mold on the plate?
Far fewer bacterial colonies were growing near the mold on the plate.
Which of the following statements does NOT accurately describe human DNA?
Females receive two X chromosomes from their mother.
Which statement does NOT accurately describe human DNA?
Females receive two X chromosomes from their mother.
Folate (vitamin B9) is important for reproductive health. Why?
Folate prevents spina bifida in babies and maintains high sperm count in men.
Choose the list that gives the most correct and complete order of events during the cell cycle.
G1, S, G2, mitosis, and cytokinesis
Organelles duplicate during
G2 phase.
Many kinds of molds produce antibiotics that can slow down the growth of bacteria. If you were looking for a new antibiotic produced by a particular mold, how might you do this properly?
Grow the mold in a large vat, purify chemicals from the vat, and see if any of the chemicals can interfere with the growth of bacteria on the petri plate.
Which of the following best describes Hardy-Weinberg equilibrium?
Hardy-Weinberg equilibrium represents a population that is not evolving.
The principle that in a nonevolving population, both allele and genotype frequencies remain constant from one generation to the next is the basis for _____.
Hardy−Weinberg equilibrium
A single 40-year-old woman wants to have children, but she is not in a stable relationship. She recognizes that she may have to be a single mother. If she chooses IVF using her own eggs, what will be the relationship between her and her potential future children?
Her children will all have the same mother, and her children will all be carried in her uterus.
A woman lacks one of the amino acids used to build insulin, a protein that helps control blood sugar levels. What is the expected outcome of this deficiency?
Her insulin will no longer function normally
Which of these was the first hominid to use and control fire?
Homo erectus
Which of these is the only surviving lineage in the evolutionary history of humans?
Homo sapiens
Homologous chromosomes behave differently in mitosis and meiosis. What process do they go through in meiosis that does not occur in mitosis?
Homologous chromosomes pair up with each other.
A women can become pregnant if she has intercourse up to 5 days before ovulating or on the day she ovulates. What does this suggest about sperm and egg?
Human eggs cannot survive for very long after ovulation.
If you ran a pharmaceutical company, what would be the most effective series of steps for your company to discover new drugs from plants and bring them to market?
Identify likely drug sources, test chemicals on cultured cells, select the most effective chemical, convert chemical into a form for delivery into humans, do clinical trials, get FDA approval for drug sales, scale up drug supply
Why is the Hardy−Weinberg principle useful when studying population genetics?
It explains how alleles and genotypes behave in a nonevolving population, because the Hardy-Weinberg principle gives biologists a baseline to evaluate whether or not evolution is occurring in a population
Why would someone with a mutation in the BRCA1 gene have a higher risk of developing cancer earlier in life than someone without a mutation in the BRCA1 gene?
It increases the chance that damaged DNA will not be fixed.
An island has a population of 10,000 birds and has 80% gray individuals and 20% black individuals. Generation after generation, this ratio and population size remains basically the same. Which statement must be true about this population?
It is in Hardy−Weinberg equilibrium.
Humans have DNA in the nuclei and in the mitochondria of our cells. How is nuclear DNA inherited?
It is inherited by all children from both their mothers and their fathers.
If you have a genetic predisposition to a disease such as cancer, you will eventually get cancer. Is this a true statement?
It is not necessarily true; it may be dependent on the environment.
A cell has an inactivating mutation in one of its two p53 alleles. If this cell sustains DNA damage (e.g., to the HER2 gene), what is likely to happen?
It will undergo apoptosis.
What is the possible outcome of a mutation in terms of protein function?
It's beneficial, It's detrimental, It has no effect, (All of the above)
Which ions are involved in the firing of an action potential?
K+ and Na+
Cells in your kidneys produce different proteins and carry out different tasks than cells in your brain. How is that possible?
Kidney and brain cells have the same DNA but use different genes.
If a section of mRNA contains the nucleotide sequence UUGCCUCAC, the sequence of amino acids translated will be _____.
Leu-Pro-His
Why can you say that males determine the sex of their children?
Males will either contribute an X or a Y chromosome, whereas females will always contribute an X chromosome.
If a section of DNA contains the nucleotide sequence TACCAACGA, the sequence of amino acids translated will be _____.
Met-Val-Ala
Which statement is NOT true with respect to facilitated diffusion?
Movement of solute is from lower to higher concentration
A patient has a rhinovirus infection, causing her to suffer with a cold. She goes to her doctor to ask for a prescription for penicillin. What should the doctor say?
No, I will not write you a prescription for penicillin because it will not be effective against a viral infection.
Do stem cells have a larger genome than specialized cells?
No, because all cells in a person have the identical set of genes in their genome.
A human zygote has 23 chromosomes
One is from her mother and one is from her father.
What is the major difference between facilitated diffusion and simple diffusion?
One requires membrane transport proteins and the other does not.
Which statement about the polymerase chain reaction (PCR) is false?
Only a single strand of DNA can be amplified at a time.
Why would you need to isolate more than one type of stem cell when growing a replacement organ?
Organs are composed of more than one type of tissue.
What was the name of the large land mass comprising the plates approximately 245 million years ago?
Pangaea
Of the three populations described below, each of which has 1,000 members, which population has the highest genetic diversity? Note that only one gene is present and that this gene has three possible alleles: A1, A2, and a. Population A: 70% have an A1/A1 genotype, 25% have an A1/A2 genotype, and 5% have an A1/a genotype. Population B: 50% have an A1/A1 genotype, 30% have an A2/A2 genotype, 20% have an a/a genotype. Population C: 80% have an A1/A1 genotype, and 20% have an A1/a genotype.
Population B
Human proteins can be produced by cells in the milk-producing mammary glands of transgenic mammals if the regulatory sequence of a milk gene is used to produce the recombinant gene. What is the benefit of inducing human protein production within the mammary glands of a transgenic mammal?
Proteins produced in milk are easy to harvest.
How does RNA differ from DNA?
RNA contains uracil (U) instead of thymine (T)
Which statement accurately describes events that occur during prophase of mitosis?
Replicated chromosomes condense and the nuclear envelope disappears.
Which of these is a harmful bacterium?
Salmonella
Which of the following statements is TRUE?
Semen contains sperm.
Why is growing a bladder more difficult than growing skin?
Skin cells are easier to grow because they grow in a sheet.
Species X has a gene A that has this as part of its sequence: ATGCTGCCTAGC Which species is most closely related to species X, based on their gene A sequence?
Species X has a gene A that has this as part of its sequence: ATGCTGCCTAGC Which species is most closely related to species X, based on their gene A sequence?
You have a segment of DNA with a nucleotide sequence reading AATAGC on one strand. Which of the following nucleotide sequences would match it on the opposite strand?
TTATCG
A protein is synthesized, but doesn't function because it does not have its final modifications. What is the most likely reason for this?
The Golgi apparatus is not working properly.
________ required to masculinize a developing fetus.
The Y chromosome is
How is the sequence of amino acids in a protein determined?
The amino acids are determined by codons in the DNA, which are read in 3-base increments.
As a rock that is rich in uranium-238 gets older, what happens to the relative amounts of uranium-238 and lead-206?
The amount of uranium-238 decreases and the amount of lead-206 increases.
What is the function of washing cells off cadaver organs that are used as a scaffold for stem cells?
The cells that are washed off remove cells that could potentially cause organ rejection
A population of ants on a median strip has 12 different alleles, A through L, of a particular gene. A drunk driver plows across the median strip, destroying most of the median strip and 90% of the ants. The surviving ants are homozygous for allele H. What is the impact of this event on the frequency of alleles A through L?
The frequency of alleles A through L has changed drastically. All frequencies except H are reduced to zero. H frequency is now 1.0. This event is an example of a bottleneck effect. (all of these)
If a gene from organism A is NOT homologous to a gene in organism B, what does this mean?
The genes are not derived from a common ancestor.
Our closest primate relatives, chimpanzees, have light-colored skin yet live in tropical (high-UVB) environments. How would the Jablonski−Chaplin hypothesis explain this observation?
The hair of chimpanzees protects their light skin from UVB light.
If a person is addicted to a drug of pleasure, what happens to the level of dopamine receptors on receiving cells?
The level decreases.
A somatic mutation occurs in a 24-year-old woman. Which of these is most likely?
The mutation will not be passed to her children.
Why might a meth-addicted person appear to be intoxicated with alcohol?
The person has trouble walking a straight line.
A gene encodes a protein of 350 amino acids. A mutation creates an allele that only has the first 120 amino acids. What could happen to this mutant allele?
The protein encoded by the mutant allele is shorter than the one encoded by the normal allele, The protein encoded by the mutant allele could be nonfunctional, The mutant allele could be associated with disease, (all of these)
A person has a cystic fibrosis phenotype. What does this mean about the protein encoded by the cystic fibrosis gene in his or her cells?
The protein is not functional.
A scientist studying a species of duck (species A) finds that this species only occurs in one small lake. Despite similar lakes that occur several hundred miles to the north, the other lakes are inhabited by a similar, but different duck species (species B). Which statement could be true?
These two species mate at different times in the spring. Species A may not have the ability to move to other lakes due to distance. The habitat of the northern lakes is not suitable for species A. In the other lake, species A may be outcompeted for food and shelter by the other species B. (all of these)
During meiosis, what happens to homologous chromosomes?
They move apart from one another.
Some humans have a mutation in the gene that encodes for an enzyme required to make melanin. What do you predict about these humans?
They will be fair-skinned and vulnerable to skin cancer.
In prokaryotic cells, gene expression is inherently different than gene expression in eukaryotic cells. Why?
Transcription cannot occur in a nucleus in a prokaryotic cell
If life is found on other planets, it may or may not use the chemical framework used by life on Earth .
True
What happens to plant cells placed in a high salt (10%) solution?
Water diffuses out of the cells and they shrink.
A pedigree chart reveals the presence of a disease trait in both a boy and his mother's father. This pattern would suggest
X-linked inheritance.
The sex chromosomes found in a typical male are
XY.
In humans, the 23rd pair of chromosomes in a male is _____, in contrast to a female's, which is _____.
XY; XX
Genghis Khan ruled the largest empire in the world, pillaging his way across Mongolia and Asia in the 13th century. Today, 16 million men living in the same region are his descendants. What chromosome(s) do you think scientists examined in order to determine that these men are related to Genghis Khan?
Y
Which of the following human chromosomes is passed on intact from father to son?
Y chromosome
Do cells divide in healthy tissues?
Yes, cell death and replacement is an ongoing process.
What is an example of a mutation in an allele?
a base change in the gene coding sequence, a base change in the gene's regulatory regions, a deletion of a base within the gene, an insertion of a base within the gene (all the above)
A scientist has isolated an organic molecule from a new alien life form she is studying. Which statement is true about this organic molecule?
a carbon atom in this molecule will share electrons with one or more carbon atoms also contained within this molecule.
A nucleotide insertion occurs in the middle of the coding sequence of a gene involved in accurately separating chromosomes during mitosis. Which outcome is possible?
a change in the amino acid sequence of the protein, a change in the protein's shape, a change in the protein's function, inaccurate division of the cell, resulting in cancer (all of these)
Relative to one of your liver cells, one of your skin cells has _____.
a different pattern of gene expression
Which two people would have the most different Y chromosomes?
a father and his daughter's biological son
The correlation between vitamin D, folate, sunlight exposure, and the resulting variations of skin tones is an example of
a genetic strategy to increase fitness. natural selection. human evolution. descent with modification. (All the answers are correct.)
Which of these was an adaptation observed in Tiktaalik?
a jointed elbow, wrist, and fingerlike bones
What is a chromosome?
a large, tightly bound piece of DNA and protein found in the nucleus of cells
Founder effect causes
a loss of genetic diversity.
What is DNA?
a molecule common to all life forms
What is an "inherited" or "hereditary" cancer?
a mutation that predisposes an individual to cancer passed from parent to child
Which of the following is an example of cells undergoing mitosis and cytokinesis?
a new embryo growing, a tree producing new branches, dead skin cells being replaced, a wound healing over with a scar (all of the above)
Which of the following is/are used to examine inheritance over generations?
a pedigree chart
A phenotype is
a physical trait.
If cells from a malignant breast tumor in a 27-year-old woman were examined, what would be expected?
a single mutation in a tumor suppressor gene, such as BRCA1, oncogenes, a mutation that permits new blood vessel growth, a mutation in the p53 gene (all of these)
If you were digging in the dirt in a region rich with horse fossils, where would you find fossils with three toes?
about midway between the deepest and shallowest fossils
The response of a population to environmental pressure so that advantageous traits become more common in the population over time is called _____.
adaptation
The term autosome refers to
all chromosomes, except the X and Y.
Chemotherapeutics act on
all dividing cells.
If a nondisjunction occurs during meiosis I _____.
all four resulting cells will be aneuploidy
Two copies of a gene have identical regulatory sequences, but different coding sequences. These copies can be referred to as _____.
alleles
Microscopic organisms are expected to be found in ____.
almost every location on Earth
People with fewer _____ receptors are more easily addicted to nicotine.
alpha-5
XXX, XO, XYY, and XXY conditions are the result of
an error during meiosis.
Which of these does NOT cause addiction?
an increase in dopamine receptors
A group of tissues working together perform the complex functions of
an organ.
An abnormal number of one or more chromosomes (either extra or missing copies) is called
aneuploidy
If a cell is irreparably damaged, it undergoes programmed cell death, called
apoptosis.
Gametes differ from other cells in the body because gametes
are haploid.
B cell−specific genes _____.
are only expressed by B cells
Let's pretend that UVB exposure occurs at the highest levels at the poles, and at the lowest levels at the equator. In this alternate planet Earth, where would you expect to find fair-skinned humans?
around the equator
Put the following steps in order to indicate how a malignant tumor may develop. a - An environmental mutagen such as UV light mutates the p53 gene. b - A single mutation of BRCA1 is inherited. c - Mutation that allows invasion of other tissues develops. d - An oncogene forms when DNA mistakes are not corrected.
b, d, a, c
Why do some people with CF have more severe symptoms than others?
because other genes on other chromosome contribute to the severity of CF
The deletion of a codon in the gene for CF causes the CFTR protein to
become nonfunctional.
Since the prairie chicken is not attracted to the ring-necked pheasant, this is an example of _____.
behavioral isolation
In vitro fertilization (IVF) could be a positive solution for a couple with _____ who wants to have a child who is related to both parents.
blocked oviducts and immotile sperm
One general cause of infertility in men is the inability of sperm to move from the testes into the urethra. Which of the following can cause this problem?
both erectile dysfunction and testicular varicose veins
If blocked at day 20, a decrease in which hormone(s) would lead to early menstruation?
both estrogen and progesterone
With respect to country mice and city mice,
both have similar allele diversity for most genes.
Tissue scarring, cancer, and infection can cause tissue blockages and infertility in ________.
both men and women
Stem cells divide to form _____.
both stem cells and cells that can specialize to form tissue cells
What are the two main components of the human central nervous system?
brain and spinal cord
In researching a paper for your non-majors biology class, you come across a website that is trying to raise money for conservation biologists who are studying a population of wolves in a national park. The money raised would be used to bring new wolves into the park for breeding purposes because the population in the park is currently experiencing inbreeding depression. How can this inbreeding depression be assessed?
by a large number of homozygous recessives
What are the two major mechanisms by which bacterial populations generate genetic diversity?
by gene exchange and mutation
Follicle-stimulating hormone ________.
causes maturation of an egg at the beginning of a menstrual cycle
Which of the following help(s) to prevent cancer?
cell cycle checkpoints, apoptosis, DNA repair enzymes, regulation of the cell cycle (all the above)
The process of _____ is used to replace damaged or worn-out cells.
cell division
The organization of cells from least to most complex is
cell, tissue, organ, organ system.
A tissue is composed of
cells.
Evolution may best be explained as a
change in the frequency of alleles in a population over time.
Side-effects of chemotherapy, such as vomiting, hair loss, and bruising occur because
chemotherapeutic drugs kill both normal and cancerous cells.
Which group is at high risk group for MRSA?
children in day care centers, individuals confined mainly to hospitals, individuals on military bases (all of these)
All of the following statements are true, EXCEPT
children whose parents are different races tend to have more health problems than children whose parents are of the same race.
Nicotine is transported from the lungs to the brain via the _____.
circulation
In a recombinant gene, the _____ sequence controls the amino acid sequence of the protein produced.
coding
A black dog is bred with a brown dog, and all the puppies have patches of black and brown. The color coat alleles for black and brown are an example of _____.
codominance
Which of these is the correct sequence in creating a DNA profile?
collect DNA→extract DNA→PCR to amplify STRs→gel electrophoresis→analyze gel
If you carry staph of any strain but aren't sick, you are _____.
colonized
You isolate cells from a tumor and study them. You observe that the cells continue dividing, even when DNA is damaged, when the cells become crowded, or even when nutrients run low. These observations lead you to suspect that the cells _____.
contain a mutated tumor suppressor gene
Tiny channels may be incorporated into bioprinted organs to _____.
create a capillary network to supply cells with blood
Radiation therapy for cancer works by
damaging the cell's DNA, resulting in cell death.
Which part of the brain includes the thalamus and hypothalamus?
diencephalon
A zygote is _____ because it has _____ chromosomes.
diploid; 46
S. aureus can be transferred from person to person by _____.
direct contact with contaminated skin; the use of soap and towels; contaminated surfaces (all of these)
The type of natural selection in which organisms with phenotypes at one end of the spectrum are favored by the environment is _____.
directional selection
A change in allele frequencies in a population over time in response to environmental pressure is characteristic of _____.
directional selection, diversifying selection, natural selection, stabilizing selection (all of these)
Which category contains the greatest number of organisms?
domain
When would a drug that interferes with heart development be most dangerous if taken by a pregnant woman?
during the first trimester
A woman is heterozygous for the CF-associated gene (the alleles are represented here by the letters A and a). Assuming that meiosis occurs normally, which of the following represents eggs that she can produce?
either A or a
One way in which a fossil may form is if an organism is _____.
embedded in amber
What is the initial source of the hormone hCG?
embryo
Embryos implant into the ________, a specialized tissue that lines the
endometrium; uterus
Melanocytes are located in the
epidermis.
Sperm are stored in the ________ prior to ejaculation.
epididymis
In men, which potential cause of infertility could be treated with hormones?
erectile dysfunction
The change in allele frequencies in a population over time is called _____.
evolution
A pregnant woman has amniocentesis in order to _____.
examine the embryonic/fetal karyotype
Recombination results from _____.
exchange of genes between non-sister chromatids on homologous chromosomes
Variations in skin tone correlate with
exposure to sunlight. folate stores in the body. vitamin D production. melanin expression. (All of the answers are correct.)
A person inherits a functional cystic fibrosis allele from both parents. This person will have cystic fibrosis.
false
DNA replication always results in a mutation.
false
If an egg were in the cervix, fertilization would be possible.
false
Methicillin is currently used to treat staph infections.
false
Scientists have discovered the chemical cues used to direct the division and differentiation of all stem cells.
false
The ancestor of Tiktaalik had limbs that resembled _____.
fins
Which of these would help a fair-skinned person who is living in a high UVB environment?
folate supplementation and a sunscreen lotion
An island has a population of 100,000 moths that has 98% gray individuals and 2% black individuals. Generation after generation, this ratio and population size remains basically the same. After a hurricane, 10,000 black moths are blown onto the island. The resulting change in gene frequency in the population is an example of _____.
gene flow
The total collection of alleles in a population is the
gene pool.
A non-staph bacterium that is resistant to penicillin and a staph bacterium are found in the same host. After the bacteria grow and replicate, it is found that the staph bacteria is now penicillin resistant. This is likely due to _____ between the two bacteria.
gene transfer
All of the following are true of genetic drift, EXCEPT
genetic drift has the greatest influence on large populations.
Random changes in the allele frequency of a population between generations is the definition of
genetic drift.
An organism's _________ determines its __________.
genotype; phenotype
Which trait of Tiktaalik helped it to live in water?
gills
Which hormone helps maintain the corpus luteum until the placenta develops?
hCG
DNA can generally be extracted from
hair, blood, saliva, kin cells (all of the above)
All of the following are good sources of folate, EXCEPT
hamburgers.
In the absence of melanin production, a person would
have albinism.
What biological data could you collect that would provide evidence that a person is addicted to a drug of pleasure?
high levels of dopamine
Investigators at a crime scene have isolated DNA from a Y chromosome and have analyzed it for STRs. They have a prime suspect, but he is not cooperating. However, several of his relatives are willing to help by donating DNA samples. Which relative will have the most similar Y
his father's father
if a woman has ovarian cancer and has her ovaries removed, what follow-up treatment might she require if she chooses to become pregnant with donor eggs?
hormone replacement therapy with estrogen and progesterone
A group of amino acids within a protein are oriented to face water. These amino acids are described as being _____.
hydrophilic
A doctor has placed a human tissue sample in a test tube containing a solution. After a few minutes, the doctor returns to find that the tissue has shrunk and now appears "shriveled." The solution into which the tissue sample was placed is _____.
hypertonic
Which of the following describes sister chromatids?
identical copies of a chromosome held together by a centromere
An individual's DNA is
identical in all cells.
Which body system has been discovered to have the most genes that influence the severity of CF?
immune system
Where is MRSA most likely to be a problem?
in the bloodstream
A deep lake has a variety of conditions. Near the shore, the lake is shallow and there is an abundance of oxygen. At the bottom of the lake at its deepest point, there is virtually no oxygen present. Where in the lake is a dead fish most likely to become fossilized?
in the deepest part of the lake
Mating between closely related individuals is known as
inbreeding.
Drugs that stimulate the feelings of pleasure _____ the amount of dopamine released.
increase
Which features of sperm do NOT affect fertility?
increased motility
A healthy cell spends most of its lifetime in
interphase.
Chromosomes are most stretched out and relaxed during
interphase.
A transitional fossil is important because it provides information about _____.
it provides information about how a group of organisms evolved from one form to another.
Which group do we share with the greatest number of species?
kingdom
If a person injured his or her cerebellum, which of these would be symptoms of that injury?
lack of balance
Who would be in the greatest need of folate supplementation?
light-skinned women living in Africa
Allele A has 235 codons. Allele a (an alternative allele of the same gene) has 233 codons. When comparing the protein encoded by allele A to that encoded by allele a, protein A must be:
longer by two amino acids.
Which of the following is likely to result in the GREATEST loss of allelic diversity?
losing 50% of a population of 100 individuals
DNA profiling with STRs is most accurate when _____.
many STRs are examined
Grandchildren share their mitochondrial DNA with their _____.
maternal grandmother
Recent evidence indicates that for most people, kicking the smoking habit will require _____.
medications and behavioral strategies
In meiosis, sister chromatids separate during _____.
meiosis II
Skin color is determined by the amount of _______ a person has in their skin
melanin
This molecule protects folate from destruction by damaging ultraviolet light.
melanin
When neurons "fire," the first thing that happens is that sodium ions enter the cell. This does not require an input of energy. One can infer from this that _____.
membrane transport proteins are required in order for neurons to fire
Based on _____ DNA, all humans today can trace their ancestry to _____.
mitochondrial; a single female in Africa
Which of these would most likely lead to nonhereditary cancer?
mitosis in a skin cell damaged by UV exposure
Atoms linked by covalent bonds are called______?
molecules
An amino acid is to a protein as a ____ is to a complex carbohydrate.
monosaccharide
The fact that a human arm and a bird wing look different is that during the process of inheritance, _____ are continuously introduced into the DNA of genes.
mutations
All of the following are true of mutations, EXCEPT
mutations always lead to the organism's death.
There are five characteristics that a population must have to NEVER experience a change in allele frequencies. Which of these is NOT one of them?
natural selection
Allele frequencies of a population can change by
natural selection, genetic drift, mutations in the gene pool, founder effect. All of the above.
The most severe disease that can result from MRSA is _____.
necrotizing fasciitis
Founder effect describes a
new population arising from a few individuals.
A healthy mother has no family history of cystic fibrosis. Her husband's brother has cystic fibrosis. Is the mother predicted to pass the cystic fibrosis allele to her children?
no
Zygotes with _______ usually cannot survive until birth.
no X chromosome
How many cell types make up the myelin sheath?
one (the glial cell)
In humans, a homologous chromosome pair consists of
one chromosome from mom and one from dad.
Which hypothetical antibiotic would treat bacterial infections by interfering with bacterial reproduction?
one that decreases cell membrane synthesis
Which structure in the female reproductive system produces eggs (ova)?
ovaries
Once an egg is released from the _____, it enters the _____.
ovary; oviduct
Fertilization normally occurs in the _________.
oviduct
The molecule found in bacterial cell walls that confers rigidity is _____.
peptidoglycan
Scientists at a pharmaceutical company are exposing bacteria to new "prototype" antibiotics. During antibiotic treatment, many of these bacteria swell and eventually lyse. These new antibiotics likely target which of the following in bacteria?
peptidoglycan synthesis and cell walls
Which of the following is a stressor for city mice?
pollution, living in crowded quarters competition for sex, competition for food (All of the above.)
Gene flow can be described as changes in allele frequency due to
populations mating with other populations.
You are starting your own forensics lab and need to purchase the proper elements for polymerase chain reaction (PCR) analysis. In addition to the DNA samples from the crime scenes, what other molecular items would you need?
primers, DNA polymerase, and nucleotides
If we change a nucleotide base in the coding sequence of a gene, it may alter the _____.
protein's amino acid sequence, protein's 3-D shape, protein's folding, protein's function (all these)
An unstable form of an element that decays into another element by radiation is a(n) _____.
radioactive isotope
An allele that reveals itself in the phenotype only if the organism has two copies of that allele is a _____ allele.
recessive
If a trait is not displayed in the phenotype, it is called
recessive
One of mom's chromosome 7's has a nonfunctional CTFR allele (cf−) next to a functional allele of another gene (A+). Her other homologue has a functional allele of the CTFR (CF+) gene next to a nonfunctional allele of the other gene (a−). Dad has functional alleles of both genes on both homologues (CF+, A+). A child of theirs has a maternal homologue that is CF+, A+; and a paternal homologue that is also CF+, A+. The best explanation for this is _____.
recombination in mom
A series of strong storms opened a stream channel between two lakes. The western lake contains a large, diverse population of a species of minnow. The eastern lake has never been populated by fish. When the channel opened, a small group of fish migrated to the eastern lake. Soon after, the stream channel dried up and was never opened again. The fish in the eastern lake thrived and continued to reproduce, building a large population over time. Compared with the fish in the western lake, what characteristics would you expect the population in the eastern lake to exhibit?
reduced genetic diversity and a change in allele frequency
Untreated pelvic inflammatory disease (PID) may lead to infertility because it _____.
scars and blocks the oviducts
Sperm are produced by the ________.
seminiferous tubules
The correct order of the path that sperm take out of a man's body is
seminiferous tubules, epididymis, vas deferens, urethra
You are suffering from depression. Which neurotransmitter is involved in these symptoms?
serotonin
Cell division is usually kept under control by
several checkpoints in the cell cycle and by apoptosis.
A woman has cystic fibrosis. Therefore, _____.
she must have inherited a cystic fibrosis allele from both her mother and father
Which of the following cell types goes through the cell cycle most frequently?
skin cell
If human ancestors had been able to obtain more food (calories and nutrients) with an arboreal lifestyle in highly shaded environments, what trait(s) would have been retained?
small brains, opposable big toe, and light skin
Peripheral nerves in your limbs communicate first with the central nervous system by communicating with the _____.
spinal cord
Which type of molecule is NOT made up of a chain of repeating monomers?
steroids
The role of hCG is to _____.
stimulate the corpus luteum to produce progesterone
According to the text, which antibiotic(s) can pass easily through the Gram-negative bacterial cell wall and interfere with protein synthesis?
streptomycin
Population genetics is the _____.
study of the genetic makeup of populations and how it changes over time
What are nucleotides?
subunits that combine to make DNA
Physical side-effects from chemotherapy and radiotherapy could be maximally reduced by
targeting specific tumor cells.
The leopard frog mates in early spring and the bullfrog mates in early summer. This is an example of _____.
temporal isolation
The SRY gene on the Y chromosome is responsible for
testes development.
Chromosomes are duplicated during
the S phase.
It is simpler to use DNA to identify the father for a son than for a daughter because
the X chromosome may recombine during meiosis whereas the Y is passed intact.
The Hardy−Weinberg principle states that in a nonevolving population _____.
the allele frequencies and the genotypes are constant from one generation to the next
Mitochondrial Eve is:
the ancient African woman to whom all modern humans can trace their ancestry.
What triggers the release of neurotransmitters at the axon terminal?
the arrival of an action potential at the axon terminal
A scientist is studying a population of frogs in a pond. One day, copious amounts of pesticides are mistakenly released into the pond, killing off the majority of frogs (leaving only a few survivors). When the researcher revisits this pond five years later, he notices that the genetic diversity of this frog population has been dramatically reduced (compared to pre-pesticide levels). This is an example of _____.
the bottleneck effect
The ice age 10,000 years ago killed off most cheetahs. This is an example of
the bottleneck effect.
A person sustains a blow to the head. After the injury, their heart rate is very low, and they are very fatigued. What part of the brain may have been injured?
the brain stem
Cytokinesis occurs in animal cells when
the cell membrane pinches to form two separate cells.
Which part of a gene is actually copied into mRNA?
the coding sequence
When amniotic fluid is tested for chromosome analysis, whose karyotype is being examined?
the embryo's
What event initiates an action potential?
the entry of Na+ into the cell
What is a genotype?
the genetic makeup of an individual
In the course of human evolution, which environmental factor likely influenced whether populations have mostly light-skinned individuals or mostly dark-skinned individuals?
the levels of UVB light
During the era of Eve, many other women had descendants but a dead-end linage occurred. This was due to:
the lines of these descendants dying off. a large catastrophic event. mutations (all of these)
What structure must a sperm arrive at in order to fertilize an egg?
the oviduct
Autosomes are:
the paired chromosomes present in both males and females.
What is the environmental pressure in the case of antibiotic resistance?
the presence or absence of antibiotics in the environment
A male has a son and a daughter. Both the son and daughter have one son and one daughter. Which grandchild has a Y chromosome that is identical to the grandfather in this question?
the son's son
Metastasis is
the spread of cancer from one location in the body to another.
Which pair does NOT represent intermediate fossils that have been discovered by scientists?
the transition between fish and amphibians
A person's genotype refers to _____.
their genetic makeup
Why do population biologists use the Hardy−Weinberg equation?
to compare population studies and determine if a population is evolving
What is the function of the myelin sheath?
to increase the efficiency of axon potential transmission along the length of the axon
What could limit the potential for multiples resulting from intrauterine insemination?
treatment with drugs that reduce the activity of hCG
The differences in strains of Staphylococcus are contained in its DNA.
true
Which ability is NOT important in Tiktaalik performing "pushups"?
turn its head independently of its body
The end result of mitosis and cytokinesis is
two cells identical in size and genetic material.
Which combination of mutations is the most likely to convert a normal cell to a cancerous cell?
two mutated p53 alleles, two mutated BRCA1 alleles, one activated allele of HER2
Which situation puts a healthy person at greater risk for a MRSA infection?
undergoing a medical procedure that weakens the immune system; undergoing a procedure that causes a break in the skin; being a child whose immune system is still maturing being elderly (all of these)
Cancer is
unregulated cell division.
A patient has a neurodegenerative brain disease (one in which the nervous tissue of the brain is progressively lost over time). What kind of therapy might benefit this patient?
use of drugs to stimulate division of neural stem cells in the brain
A fetus develops in the ________.
uterus
Sperm enters the female reproductive system at the ________.
vagina
Which of the following correctly lists the structures through which sperm must pass from entry into the female reproductive tract to the site of fertilization?
vagina, cervix, uterus, oviduct
In a person of very dark skin tone, it is expected that their melanocytes produce
very large quantities of melanin pigment.
It would be expected that a population geographically located where UVB exposure is minimal to have a skin tone that is
very light.
Whether or not viruses are alive is frequently debated. Name one characteristic of viruses that make them similar to other living organisms.
viruses seem alive because they produce themselves in host cells
Osmosis is the movement of _____ into solutions with _____ concentrations of solutes.
water; higher
When is the polymerase chain reaction (PCR) a useful technique?
when there is a limited sample of DNA
If a person is addicted to meth, this person will _____.
will have more difficulty memorizing lists of words
A woman is secreting very thick cervical mucus, which is essentially blocking the cervix. Is this woman likely to experience difficulties in getting pregnant?
yes
A fertilized egg is called a(n) ________.
zygote
Your physician had prescribed a β-lactam antibiotic for your sister. Your sister took biology in high school and is refusing to take the antibiotic because she says that it will affect osmosis in her cells. Which reason can you use to help your sister understand how the antibiotic will work?
β-lactam affects bacterial cell walls, and it can't affect human cells because they do not have cell walls.
A cell membrane has ____layers of phospholipids.
2
Humans inherit _____ chromosomes from each parent; a male inherits the _____ chromosome from his father.
23; Y
The atomic number of carbon is 6. How many electrons does it contain in its outer valence shell?
4
Which statement is true of amino acids?
All amino acids have unique chemical side chains
Which statement is NOT true of the shape of proteins?
All humans are genetically identical and, therefore, produce identical proteins.
How are cadaver organs used in regenerative medicine?
Cadaver organs provide a scaffold for growing stem cells.
Which statement about DNA replication is false?
It does not require the enzyme DNA polymerase when it occurs in the cell.
Why is DNA called a "double helix"?
It has two strands of nucleotides twisted around each other.
Which of these is NOT required to produce transgenic animals?
The genes used to form recombinant DNA must be from closely related species.
Why do you think bacteria cannot be used to produce complex proteins, such as spider silk?
The proteins bacteria produce are not as complex as human proteins.
Viruses reproduce by infecting a host cell and hijacking its cellular machinery to make copies of itself
True
The presence or absence of _____ differentiates prokaryotic cells from eukaryotic cells.
a nucleus
A chromosome is _____.
a single, large DNA molecule found in the nucleus of human cells
The order of _____ in a protein determines a protein's three-dimensional shape. The protein's three-dimensional shape determines its _____.
amino acids; function
Mitochondria are found in _____.
animal and plant cells
A chemical that can slow or stop the growth of bacteria is a(n) _____.
antibiotic
The cell theory states that living organisms _____.
are made up of cells
The number of protons an element has is its ___, whereas the number of electrons will determine ____.
atomic number; the type of bond it can form
Which of these are prokaryotic cells?
bacteria
Which tissue type(s) is/are never replaced?
cerebral cortex neurons
Two strands of nucleotides pair up and twist around each other to form the shape of DNA, called a _____.
double helix
A news item from December 2014 announced that NASA had identified a novel form of bacterial life from Mono Lake in California. Unlike other living organisms, which require carbon, hydrogen, nitrogen, sulfur, oxygen, and phosphorus to survive, this bacterium is able to live and grow without a supple of carbon, hydrogen, nitrogen, sulfur, oxygen, and arsenic. The essential items required by this bacterium (such as nitrogen) are ____?
elements
On a NASA mission that was looking for life on Mars, soil samples were taken and measures for the breakdown of nutrients and the production of carbon dioxide gas. Which characteristic of life would this test measure?
energy use
The process of DNA replication requires _____.
enzymes to add new nucleotides in a complementary fashion
Maintaining a stable internal environment that is separate and distinct from the external environment is called ___.
homeostasis
Certain types of radiation can damage DNA. When DNA is damaged, which function is compromised?
information storage
Some antibiotics interfere with bacterial ribosomes by _____ protein synthesis.
interfering with bacteria
The nuclear envelope differs from the cell membrane and the membranous endoplasmic reticulum because it _____.
is a double membrane
Where are chromosomes located in eukaryotic cells?
nucleus
An individual's STR may vary from the same STR of another individual by the _____.
number of times a specific sequence is repeated
Under a microscope, Gram-positive bacteria (when dyed with the Gram stain) appear _____.
purple
Directing stem cells to form differentiated cells that can replace or repair damaged tissue is called _____.
regenerative medicine
When one DNA molecule is replicated, the resulting DNA molecule contains _____.
one new strand and one old strand in each molecule
You create an artificial membrane that contains phospholipids but not proteins. Which substance will be able to cross that membrane and in which direction?
oxygen from the side with the higher concentration to the side with the lower concentration
A scientist is looking at a cell's membrane. She notices that the membrane is composed (primarily) of a certain type of macromolecule. These macromolecules are unique in that they are not composed of monomers, but instead resemble "hairpins" with fatty acid tails. The scientist id looking at ____.
phospholipids
Under a microscope, Gram-negative bacteria (when dyed with the Gram stain) appear _____.
pink
A scientist as discovered a new macromolecule in mice. He determines that this macromolecule contains a unique combination of 20 distinct monomers, folds into an intricate three-dimensional shape, and is involved in a distinct chemical reaction. This scientist has likely discovered a ____.
protein
Which functional trait of a living organism is a mule NOT capable of?
reproduction
In a solution, the solute dissolves in the _____?
solvent
What is a genome?
the complete set of genetic material encoded within the DNA of an organism
Which factor is NOT important in determining the shape of a protein?
the speed of translation
Human antithrombin, a protein that causes blood clotting, extracted from transgenic goat milk is as effective in preventing blood clotting as antithrombin extracted from human blood.
true
Many of the soybeans grown in the United States for animal feed are transgenic.
true
Stem cells are not specialized in the way that cells such as cardiac muscle cells are.
true
Stem cells help keep tissues in which they reside healthy.
true
To what does gene expression refer?
turning the expression of a gene either on or off
DNA replication results in __________ copies of a cell's genome.
two identical
Molecules that can cross the cell membrane by simple diffusion are _____.
uncharged
A scientist is interested in making a rice plant that produces a vaccine protein in the rice. This would mean that vaccinations could be accomplished by eating rice, which does not require refrigeration. The best approach would be to fuse the _____ with the _____.
vaccine protein coding sequence; regulatory sequence of a rice gene