Biology Final Review
You are a genetic counselor that has just been assigned to a case with a couple who have a child recently diagnosed with Tay-Sachs disease. Neither parent has Tay-Sachs, nor does anyone in their families. Which of the following statements should this counselor make to this couple?
"Because you have had one child with Tay-Sachs, you must each carry the allele. Any child you have has a 25% chance of having the disease."
You are getting your PhD in biology by studying the process of photosynthesis in cyanobacteria. A new undergrad, Owen, joins your lab, and you are tasked with training him. When you tell him what you are researching he looks at you and asks, "Where do you find chlorophyll in cyanobacteria?" Your response is,
"In the infolded plasma membrane"
Cancer drugs such as Taxol interfere with microtubule function or formation. What would a drug like this do to cells it was exposed to?
Affect the formation of the mitotic spindle and preventing mitosis.
Which of the following mechanisms is used to coordinate the expression of multiple, related genes in eukaryotic cells?
A specific combination of control elements in each gene's enhancer coordinates the simultaneous activation of the genes.
If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants?
Clone the plant asexually to produce an identical one.
What enzyme is responsible for joining Okazaki fragments together on the lagging strand during DNA replication?
DNA ligase
Two ways that eukaryotic cells use to regulate transcription are
DNA methylation and histone modification.
Five dialysis bags, constructed from a semipermeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed (see the figure above) Referring to the graph above, which line in the graph represents the bag with the lowest initial concentration of sucrose?
E
Gene expression levels can be changed during post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?
Eukaryotic exons may be spliced in alternative patterns.
Which statement best supports the hypothesis that glycolysis is an ancient metabolic pathway that originated before the last universal common ancestor of life on Earth?
Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya.
An organelle with a cis and trans face, which acts as the packaging and secreting center of the cell
Golgi apparatus
In the diagram, identify what the green and grey units are as well as the blue strands.
Green: promoter, Grey: RNA polymerase, Blue: DNA
You're over half-way through with this exam! Take a nice deep breath....Those oxygen molecules you just inhaled are a product of photosynthesis. What reactant of photosynthesis is responsible for all of the oxygen we breathe?
H2O
Which of the following would be regarded as compounds?
H2O and CH4, but not O2
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O → NADPH → Calvin cycle
Which of the following is are presentation of gene density?
Human have ~20,000 genes in 2,900 Mb
Why does ice float in liquid water?
Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
Why is each element unique and different from other elements with respect to its chemical properties?
Each element has a unique number of protons.
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?
Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding
Atherosclerosis is a disease that obstructs blood flow and, therefore, oxygen supply to target organs. A major component of atherosclerosis is the excessive reproduction of smooth muscle cells of the blood vessels (a tumor). In order to treat this disease, scientist need to develop a drug with the potential to reverse or prevent this unregulated reproduction of the nervous tissue. Which processes would this drug need to target in order for it to be effective?
Mitosis
You are a geneticist given the following image. It shows the karyotype of an individual. What condition would you diagnose this person with?
Monosomy, Turner's syndrome
The four cells above represent each of the 4 different stages of mitotic division. Based on the diagrams, which list shows the correct order of mitotic division
N, O, M, L
In an operon, like the lac operon, what happens when the repressor protein is bound to the operator?
RNA polymerase cannot bind and transcription does not take place
During which part of the cell cycle does a chromosome duplicate and look like the chromosome seen in the figure?
S phase
With our dependence on fossil fuels (cars, planes, etc) we have seen a steady increase in atmospheric CO2. What effect on seawater might increased atmospheric CO2 concentrations have?
Seawater will become more acidic, and carbonate concentrations will decrease.
In presenting data that result from an experiment, a group of students show that most of their measurements fall on a straight diagonal line on their graph. However, two of their data points are "outliers" and fall far to one side of the expected relationship. What should they do?
Show all results obtained and then try to explore the reason(s) for these outliers.
Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. Based on this information, which of the following is correct?
Succinate is the substrate, and fumarate is the product.
The Calvin cycle is often referred to as the "light-independent cycle". However, this is not a completely accurate way to view the Calvin cycle. Why is the Calvin cycle actually dependent upon light?
The Calvin cycle depends on the ATP and NADPH produced in the light reactions.
H1N1 flu is a highly contagious viral infection caused by the influenza A (H1N1) virus. The symptoms of H1N1 are listed in the box. An antiviral agent such as Tamiflu® administered within 48 hours of the appearance of symptoms can reduce the severity of the illness. Why is it important to administer an antiviral agent to an infected person within 48 hours of the appearance of symptoms?
The H1N1 virus replicates quickly
Mesothelioma is a cancer that affects the lining of the lungs and/or abdomen. Advanced malignant Mesothelioma cancer cells will often have abnormal chromosomes and an abnormal number of chromosomes. Why would these malignant Mesothelioma cancer cells have chromosomal abnormalities?
The cell cycle checkpoints are not functioning correctly to stop cells with chromosome abnormalities.
Some students used vinegar to dissolve away the shells of three eggs and used these eggs as models of human red blood cells. The students observed the changes in the eggs when they were placed in different solutions. Which statement best describes the role of the cell membrane in this model?
The cell membrane allows water to enter and leave the cell
If a cell were unable to produce histone proteins, which of the following would be a likely effect?
The cell's DNA couldn't be packed into its nucleus.
Light reactions and the Calvin cycle are connected in what way?
The light reactions produce NADPH and ATP to the Calvin cycle, and the Calvin cycle returns ADP and NADP+ to the light reactions.
A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur?
The plants would develop the typical symptoms of TMV infection.
Which of the following statements is true about protein synthesis in prokaryotes?
Translation can begin while transcription is still in progress.
The diagram above shows how a paramecium maintains homeostasis. A paramecium normally lives in a hypotonic environment in which water continually diffuses into the cell. To maintain homeostasis, the paramecium must pump out large amounts of water using its contractile vacuole. If the paramecium is then placed in a hypertonic environment, which of the following will occur?
Water will diffuse out of the paramecium
Xeroderma pigmentosum is a genetic disorder in which those individuals are hypersensitive to sunlight. Being exposed to even small amounts of UV rays from the sun can cause skin cancer. This occurs because their cells are impaired in what way?
They cannot repair thymine dimers - damage to their DNA.
All of the following contain amino acids except
cholesterol.
Which procedure is not required when the shotgun approach to sequencing is modified as sequencing by synthesis, in which many small fragments are sequenced simulteaneously?
cloning each fragement into a plasmid
The cell membranes of Antarctic ice fish might have which of the following adaptations?
a high percentage of polyunsaturated fatty acids
Normally, only female cats have the tortoiseshell phenotype because
a male inherits only one allele of the X-linked gene controlling hair color.
A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Because the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed. What wavelengths of light should be used to maximize plant growth with a minimum of energy expenditure?
a mixture of blue and red light
A recent study compared the H. sapiens genome with that of Neanderthals. The results of the study indicated that there was a mixing of the two genomes at some period in evolutionary history. The data suggested this were
a number of modern H. sapiens with Neanderthal sequences
The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA
contains one less oxygen atom.
What results from an unequal sharing of electrons between atoms?
a polar covalent bond
Which of the following is most likely to have a small protein called ubiquitin attached to it?
a protein needing to be destroyed
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
an electron may move to an electron shell farther away from the nucleus.
The herpes viruses are enveloped DNA viruses that cause disease in all vertebrate species and in some invertebrates such as oysters. Some of the human types are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can then reactivate, replicate again, and be infectious to others. In order to be able to remain latent (dormant) in an infected live cell, herpes simplex virus (HSV) must be able to shut down what process?
apoptosis of a virally infected cell
Referring to the same figure in the previous question, which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure? (hint: not the activation energy required without the enzyme present, or total activation energy)
b
Electron microscopes are very powerful and see smaller images than a light microscope. What is one advantage, however, of light microscopy over electron microscopy?
light microscopy allows one to view dynamic processes in living cells.
Large membrane-bound structures that contain hydrolytic enzymes and that are found predominantly in animal cells
lysosomes
Sex-linked traits affect males more often than females because
males are hemizygous for the X chromosome.
Crassula ovata, otherwise known as a jade plant, is a type of CAM plant which keeps its stomata closed during the day. It does this to prevent evapotranspiration. Crassula ovata can do this because they
fix CO2 into organic acids during the night.
What process was used in 1997 to clone Dolly the sheep?
fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate
Which of the following can be effective in preventing the onset of viral infection in humans?
getting vaccinated
Which of the following is a monomer/polymer pairing? (select all that apply)
glucose/starch; amino acid/protein
Imagine there is a species-specific fishing regulation that mandates only adult fish of this species that are 75 cm or shorter may be kept and larger fish must be released. Based on your knowledge of natural selection, you would predict that the average length of the adult fish population will
gradually increase.
A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was 6 feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. What proportion of their sons would be color-blind and of normal height?
half
A new "wonder food" is being distributed by a rival company. The researchers in your company determine that the "wonder food" contains only carbon, oxygen, hydrogen, and nitrogen. At this point, your researchers can say with certainty that the food
includes proteins.
During meiosis, homologous chromosomes exchange genetic material. This exchange of genetic material -
increases the genetic variation
After living in Africa for many years you notice a lump on your throat/neck area that starts to develop. You also suffer from fatigue and frequent constipation. Which of the following trace elements are you probably lacking in your diet that is required by humans and other vertebrates in minute quantities, but not by other organisms such as bacteria or plants?
iodine
Emerging viruses arise by (Select all that apply)
mutation of existing viruses; the spread of existing viruses to new host species; the spread of existing viruses more widely within their host species
Which of the following characteristics, structures, or processes is common to both bacteria and viruses? (Select all that apply)
nucleic acids; proteins
The difference between pinocytosis and receptor-mediated endocytosis is that
pinocytosis is nonselective in the molecules it brings into the cell, whereas recpetor-mediated endocytosis offers more selectivity
The final product of an expressed gene can be which of the following?
polypeptide
A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3' (mRNA). The charged transfer RNA molecules shown in the figure (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form. What is the dipeptide that will be formed?
proline-threonine.
In bacteria, viral DNA that is integrated into the host cell's genome is called a-
prophage
A primary objective of cell fractionation is to
separate the major organelles so that their particular functions can be determined.
What kinds of molecules pass through a cell membrane most easily?
small and hydrophobic
An organelle that is characterized by extensive, folded membranes and is abundant in cells that detoxify poisons, such as liver cells
smooth endoplasmic reticulum
What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'
met-ser-ser-leu-ser-leu
Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?
soda at pH 2
What is the difference between the leading and the lagging strands?
the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle must be involved in this condition?
the lysosome
The first evidence of differentiation in the cells of an embryo are considered to be what?
the occurrence of mRNAs for the production of tissue-specific proteins
What is proteomics?
the study of the full protein set encoded by a genome
Codons are made up of _____ bases and they specify which _____ will be inserted into the polypeptide chain.
three ... amino acid
As a biologist working on your PhD thesis, your research focuses on the endocrine system; specifically the production of steroids in the body such as testosterone, estrogen, and cholesterol. What organelle is of particular importance to your research as it is primarily involved in the synthesis of these steroids?
smooth endoplasmic reticulum
Black fur color in cats is caused by an X-linked allele (X+); the other allele at this locus causes orange coat color (Xo). The heterozygote is tortoiseshell (X+Xo). What kinds of offspring would you expect from the cross of a black female cat and an orange male cat?
tortoiseshell females; black males
In order to initiate transcription in eukaryotes, RNA polymerase needs the assistance of
transcription factors
Where does transcription and translation occur in a eukaryotic cell?
transcription: nucleus; translation: cytoplasm/ribosomes
If the sequence ATGCCTATCGATTGA were mutated such that a base was inserted after the first G and the third T were deleted, how many amino acids would be changed in the mutant protein?
two
Which of the following is true of a species that has a chromosome number of 2n = 8? [select all that apply]
1. A gamete from this species has 4 chromosomes. 2. The species has 4 pairs of chromosomes per cell.
Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? [select all that apply]
1. Fertilization 2. Meiosis 3. Gametes
Lactose is found in milk products. It is converted by the body into a usable form in a series of chemical reactions. The diagram shows the series of reactions that convert lactose into a usable form. If Enzyme 3 is denatured, the levels of which substance(s) will decrease? (select all that apply)
1. Glucose-6-phosphate 2. Glucose-1-phosphate
Which of the following is true concerning cancer cells? (select all that apply)
1. They do not exhibit density-dependent inhibition when growing in culture. 2. They are not subject to cell cycle controls.
Which of the following is an example of potential rather than kinetic energy? (select all that apply)
1. a condensed metal spring 2. a molecule of glucose
A female athlete wins a silver medal, but then fails a gender test. Someone leaks her tests results to the media, but they reveal that she does in fact have two X chromosomes. This seems puzzling to most, but not you! Which of the following could be reasons as to why she failed the gender test? [select all that apply]
1. a male-determining control gene such as SRY crossed over onto one of her X chromosomes when her father was making the sperm that lead to her conception. 2. She is an XXY individual (has Klinefelter syndrome). Even though she does have two X chromosomes, she has a Y as well making her genetically male.
Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope? (select all that apply)
1. archaea 2. bacteria
Examine the image. What photosynthetic reaction/stage is occurring at the structure labeled "A"? What photosynthetic reaction/stage is occurring at the structure labeled "B"?
1. light independent reaction 2. light dependent reaction
Below you will find examples describing each of the levels of biological organization. Put the examples in order from 1-10, with the lowest level of organization being 1 and the highest level being 10.
1. starch 2.mitochondria 3. skin cell 4. cardiac muscle tissue 5. leaf 6. a guinea pig 7. 10 white-tailed deer 8. deer eating grass and the microbiome in the deer gut breaking down the grass for digestion 9. desert 10. Earth
Two individuals with the genotypes AaBbCcDdEe and AabbCCDdEe are mated. What is the probability of producing an offspring with the genotype AABbCcDDee (assuming independent assortment)?
1/256
A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was 6 feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. They have a daughter who is a dwarf with normal color vision. What is the probability that she is heterozygous for both genes?
100%
If a cell has 12 chromosomes (in chromatin form) in the G1 phase of interphase, how many chromosomes will it have during each of the following stages of meiosis (number of chromosomes is per cell): -Metaphase I? -Telophase I? -Prophase II? -Anaphase II? -End of meiosis II?
12, 12, 6, 12, 6
Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship.
2 --> 4 --> 1 --> 3
A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be
3' AAA-GAA-TAA-CAA 5'.
Thymine makes up 8% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be guanine?
42%
You are studying mitosis in human squamous (skin) cells. How many chromosomes would you expect to find: during S phase; during anaphase; in one new daughter cell?
46; 92; 46
The following is a model of a eukaryotic transcript in the nucleus. (E = exon, I = intron). 5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3' Which components of the model transcript will also be found in mRNA in the cytosol?
5' UTR E1 E2 E3 E4 UTR 3'
During RNA processing in eukaryotes, what is added to the mRNA strands 5' end, 3' end, and what is spliced out?
5' end: A cap consisting of a modified guanine nucleotide; 3' end: a long string of adenine nucleotides otherwise known as a poly-A tail; spliced out: introns
The template strand of a given gene includes the sequence 3'-G C C A C G T A T C A G-5' What is the mRNA sequence made?
5'-C G G U G C A U A G U C-3'
A female that is homozygous recessive for a single trait is crossed with a male that is heterozygote for that same trait, what is the chance of producing an offspring with the same homozygous recessive phenotype as the mother?
50%
If the affected individual from generation IV where to marry a homozygous unaffected male, what is the probability they would have an affected child?
50%
Facial dimples and free earlobes are both considered dominant human traits. What are the expected phenotypes of the offspring of a female with dimples and free earlobes (DDFf) and a male with no dimples and attached earlobes (ddff)?
50% with dimples and free earlobes and 50% with dimples and attached earlobes
Triploidy is when an organism's cells contain three sets of chromosomes (3N). If a cell of a usually diploid species with 48 chromosomes per cell is triploid, this cell would be expected to have which of the following?
72 chromosomes in 24 sets of 3
Each strand of a DNA molecule contains nitrogenous bases that pair with other nitrogenous bases in very specific ways. A diagram of a section of DNA is shown: Which DNA strand is complementary to the one shown above?
A C A T C G A C G C G C A
The figure shows a map of four genes on a chromosome. Between which two genes would you expect the highest frequency of recombination? A 5 W 3 E 12 G
A and G
The terms monohybrid cross and dihybrid cross mean what?
A dihybrid cross involves organisms that are heterozygous for two characters, and a monohybrid cross involves only one.
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
A gene from an organism can theoretically be expressed by any other organism.
Which of the following statements is false?
All organisms require the same elements in the same quantities.
Which of the following pieces of evidence most strongly supports the common origin of all life on Earth?
All organisms use essentially the same genetic code
As an undergraduate student you partake in an undergraduate research project. You decide to repeat the Hershey and Chase experiment, with modifications. You decide to radioactively label the nitrogen of the DNA, rather than the phosphate. Your reasoning is that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. After going through all the work of setting up and performing this experiment, your professor gives you an F! Why did your professor give you a failing grade?
Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.
Being the curious scientist that you are, you decide to inject large amounts of the bicoid gene product into the posterior end of a developing Drosophila. The bicoid gene product is normally localized to the anterior end of the embryo. What do you think would occur due to your experimentation?
Anterior structures would form in both sides of the embryo.
You're on the first human mission to Mars. While there you discover fossil evidence of life! From the fossil evidence you infer that the organism was unicellular and showed clear evidence of having DNA, however, no nuclear membrane appears to have existed. The fossil also appears to be located in an area that strongly suggests it was once a lake or ocean with very high salinity (salt content). Using the current kingdom classification system. Which kingdom would you classify this organism as?
Archaea
Prokaryotes are classified as belonging to two different domains. What are those domains?
Archaea; Bacteria
All of the following are true EXCEPT:
At sexual maturity, ovaries and testes produce diploid gametes by meiosis.
Which of these is tRNA?
B
People who have Alzheimer's disease experience an increasing loss of brain function and cognition over time. Alzheimer's is characterized by a buildup of abnormal protein fragments that damage brain cells. Recently, scientists have discovered an enzyme, BACE2, that decreases these abnormal protein fragments in the brain of a person with Alzheimer's disease. Which statement explains how BACE2 most likely works?
BACE2 speeds up the reaction that breaks down the abnormal protein fragments.
How are gasoline and fat chemically similar?
Both are made up of hydrocarbon chains
Five dialysis bags, constructed from a semipermeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed (see the figure above) Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?
C
The segment of DNA shown in the figure has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?
C A B
Which substances would you find at Y in the diagram above?
CO2 and H2O
A sexually reproducing animal has two unlinked genes, one for eye color (C) and one for tail length (T). Its genotype is CcTt. Which of the following genotypes is possible in a gamete from this organism?
CT
The element present in all organic molecules is
Carbon
Oncogenes are mutated forms of genes. Oncogenes can transform a cell into a tumor cell. Some tumor cells are benign, while others are malignant. How does the presence of an oncogene lead to the formation of a tumor?
Cell division is unregulated
During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?
Characteristics acquired during an organism's life are generally not passed on through genes
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
Males affected with Kartagener's syndrome are sterile because of immotile sperm, and they tend to suffer from lung infections. What is the most likely defect being caused by this genetic disease?
Defects in the microtubule-based movement of cilia and flagella
A scientist discovers a DNA-based test for one allele of a particular gene. This and only this allele, if homozygous, produces an effect that results in death at or about the time of birth. Of the following, which is the best use of this discovery?
Design a test for identifying heterozygous carriers of the allele.
Cyanide is a deadly poison which prevents an organism from being able to utilize oxygen by inhibiting cytochrome c oxidase. What specific stage does cyanide affect? (Hint: it was discussed in the Amoeba Sisters linked for you)
Electron transport chain
Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 2 to 4 picograms per nucleus. How many picograms of DNA would be found at the end of G1 phase and at the end of G2 phase?
G1: 2 picograms; G2: 4 picograms
The HIV virus attacks type of white blood cells, and not other cell types. Why?
HIV receptors are not found on the other cell types
Chromatin is correctly described in which of the following statements?
Heterochromatin is highly condensed, whereas euchromatin is less compact.
A young dog has never had much energy. He is brought to a veterinarian for help and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition?
His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
The diagram shows cellular activity across a cell membrane. Which two processes does this diagram most directly model?
Homeostasis and transport of molecules
Which of the following best describes the logic of scientific inquiry?
If my hypothesis is correct, I can expect certain test results.
If this is an enzyme-catalyzed reaction, how can the rate of this reaction be increased beyond the maximum velocity in this figure?
Increase the amount of enzyme.
The cellular process known as the sodium-potassium pump was discovered in the 1950s by Jens Christian Skou, a Danish scientist. This process is a form of active transport that moves three sodium ions to the outside of a cell for every two potassium ions that it moves into the cell. Which of these best explains why energy is needed for active transport?
Ions are moved against the concentration gradient
How would a prokaryotic organism altering its patterns of gene expression help that organism survive?
It allows the organism to adjust to changes in environmental conditions
A cell is just beginning meiosis II after completing the first meiotic division, which of the following is an appropriate description of its contents?
It has half the amount of DNA as the cell that began meiosis.
What is the effect of a nonsense mutation in a gene?
It introduces a premature stop codon into the mRNA.
Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. What is malonic acid's role with respect to succinate dehydrogenase?
It is a competitive inhibitor.
Which of the following statements is true regarding the molecule illustrated in the figure below? FYI - atherosclerosis is a type of cardiovascular disease
It is a saturated fatty acid, and a diet rich in this molecule may contribute to atherosclerosis.
Marfan syndrome in humans is caused by an abnormality of the connective tissue protein fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine, sometimes weakened arterial walls, and sometimes ocular problems, such as lens dislocation. Which of the following would you conclude about Marfan syndrome from this information?
It is pleiotropic.
Which of the following statements about the DNA in one of your brain cells is true?
It is the same as the DNA in one of your kidney cells.
Why might a point mutation in DNA make a difference in the level of a protein's activity?
It might substitute a different amino acid in the active site.
All of the following are false about glycolysis EXCEPT
It occurs in the cytoplasm.
Fireflies emit light through a process called bioluminescence. To generate visible light, cells in a firefly's tail produce thousands of luciferase enzymes. Luciferase binds to a chemical called luciferin. Firefly luciferase then catalyzes the following reaction: luciferin + ATP --> adenyl-luciferin + pyrophosphate Then, the next reaction occurs spontaneously:adenyl-luciferin + O2 --> oxyluciferin + H2O + CO2 + AMP + light What is the role of luciferase?
Luciferase decreases the amount of energy required for the reaction to start.
Proteins and polysaccharides are polymers. These polymers are formed by dehydration synthesis. Which statement correctly identifies a difference in the structure of proteins and polysaccharides?
Only proteins are formed from amino acids joined by peptide bonds.
Purple sulfur bacteria are photosynthetic, however, they only have photosystem I instead of both photosystem I and photosystem II. Other bacteria, like cyanobacteria, have both of these photosystems. Which of the following might this observation imply?
Photosynthesis with only photosystem I is more ancestral; thus, bacteria like cyanobacteria have evolved to have both photosystems.
Cells pass through a G2 checkpoint before entering mitosis. Ideally, if DNA damage is detected, the cells do not enter mitosis until the damage is repaired. Why is DNA damage repaired before cells enter mitosis?
So that healthy daughter cells are produced, allowing the organism to continue growing
Anitbiotics are used to treat bacterial infections. The overuse of antibiotics, however, has caused bacterial resistance to these antibiotics to increase. Now there are so called "super bugs", which are bacterial species where few, if any, antibiotics treatments will work. As a research scientist, you are trying to solve this problem by engineering a virus to combat a bacterial infection, specifically the beacterium Escherichia coli. What type of virus must you use in your research?
T4 phage virus
John and Jane tried for years to have children. They finally succeeded and had a baby girl. A few days after her birth, however, the doctor told John and Jane that their baby had Down's syndrome. He said there was an error that occurred, and their daughter ended up with an extra chromosome #21. How can a gamete end up with an incorrect number of chromosomes?
The chromosomes do not separate correctly during meiosis I or meiosis II.
All of the following are false about linkage EXCEPT -
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
Humans have 23 pairs of chromosomes. In contrast, chimpanzees have 24 pairs of chromosomes and lack any pair resembling the long human chromosome 2 pair; instead, chimpanzees have two pairs of medium-sized chromosomes. What is the most likely explanation for these differences in the human and chimpanzee genomes?
The common ancestor of humans and chimpanzees had 24 pairs of chromosomes, and at some point in the human lineage, two chromosomes fused end to end, providing some selective advantage.
Thomas Hunt Morgan's F1 generation of flies all had red eyes. When he crossed this F1 generation to each other, the F2 generation had both red and white-eyed flies. However, all the white-eyed flies were male. What is the explanation for this result?
The gene involved is on the X chromosome.
Review the first law of thermodynamics, which of the following is a consequence to humans and other living organisms in reference to this law?
The environment supplies all of the necessary energy an organism needs to sustain life.
As a research physician, you are head of a study in which you are given permission to produce, then inject via the arm, induced pluripotent stem cells (iPS) for replacement of pancreatic insulin-producing cells in people with type 1 diabetes. The iPS cells are produced individually from each patient's adult somatic cells. Which of the following would be problematic for your study? (select all that apply)
The failure of the iPS cells to take up residence in the pancreas. The possibility that, once introduced into the patient, the iPS cells produce nonpancreatic cells.
Texas A&M was the first place to clone a cat. The first cloned cat, CC (for Carbon Copy), was a calico cat. Rainbow, the cat she was cloned from, was obviously also calico; however, the two cats looked very different from one another. What is one explanation as to why CC looked so different from Rainbow?
The gene for orange/black fur is x-linked and x inactivation in the embryo is random and produces different patterns.
Models of the human immunodeficiency virus (HIV) and an animal cell are shown below. What is the difference in the function of the glycoprotein structures of an HIV virion and the cilia of an animal cell?
The glycoprotein structures are used for attachment, and the cilia are used to move fluids surrounding the cell.
In the 1880s, Louis Pasteur developed a method of weakening viruses. The weakened viruses could be injected into healthy individuals. How is the method effective in fighting viral diseases?
The immune system develops antibodies in response to the weakened viruses
The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
The nitrogen atom has a mass number of approximately 14 and an atomic number of 7.
Which of the following is an example of quantitative data?
The plant's height is 25 centimeters (cm).
Which statement best describes the relationship between the products of photosynthesis and the reactants in cellular respiration?
The products of photosynthesis serve as the reactants in cellular respiration to provide chemical energy.
As a geneticist you introduce a transgene into yeast cells and isolate five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all. Which of the following is a likely explanation for the lack of transgene expression in the fifth cell line?
The transgene integrated into a heterochromatic region of the genome.
You are learning about restriction enzymes and their uses in forensics. You and 5 of your classmates are practicing this technique, and so you have taken samples of your own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two restriction sites in a particular gene of interest. Analysis of the data obtained shows that two students in your group each have two fragments, two students each have three fragments, and two students (including yourself) each have one only. What does this demonstrate? (hint: This is NOT a circular plasmid like we used in the lab worksheet. This is a linear piece of DNA (since it's human)).
The two students who have two fragments have one restriction site in this region.
You travel to Australia to conduct research in a remote area. While you are there you discover a brand new organism! You find this organism interesting because it grows with or without oxygen being present. After doing some experimentation, you find that this organism consumes more sugar in anaerobic conditions, however, it doesn't gain any additional mass in this situation. How would you classify this organism?
This organism is a facultative anaerobe.
You would expect the activity of methylated DNA to be what?
To have turned off or slowed down the process of transcription
You are a geneticist studying the gene "infinity" in a newly discovered species called Freshmen lackadaisical. You are trying to solve a problem involving control of the "infinity" gene's expression in the embryo of the Freshmen lackadaisical species. The first question you ask is whether the gene's expression is controlled at the level of transcription or translation. Which of the following might best give you an answer?
You measure the quantity of the appropriate pre-mRNA in various cell types and find they are all the same.
In the 1920s, Muller discovered that X-rays caused mutation in Drosophila. In a related series of experiments in the 1940s, Charlotte Auerbach discovered that chemicals—she used nitrogen mustards—have a similar effect. You're hired on as a food scientist at a cereal company. You help to develop a new chemical food additive that you want to start including in your company's cereal manufacturing. Why should you test this chemical for its ability to induce mutation?
You want to prevent any increase in mutation frequency.
The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely immediate consequence?
a change in the shape of the nucleus
One of the buffers that contributes to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood increases, one would expect
a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-.
One issue with clones that has arisen is premature death. What problem with animal cloning might produce this result?
abnormal gene regulation due to variant methylation
During cellular respiration, the oxygen that is consumed is involved directly in which process/ event?
accepting electrons at the end of the electron transport chain
Changing a single amino acid in a protein consisting of 325 amino acids would
always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity.
Which of these individuals is likely to be most successful in an evolutionary sense?
an organism that dies after five days of life but leaves 10 offspring, all of whom survive to reproduce
Use the following pedigree chart below to answer the following two questions. The pedigree chart is for the "Smith" family. Dark-shaded symbols represent individuals with a particular type of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis (a line through any of these individuals indicates they are no longer living). Roman numerals (I, II, III, and IV) indicate the different generations, and circles represent females while squares are males. From this pedigree, how does this trait seem to be inherited?
as an autosomal dominant
Alternative RNA splicing
can allow the production of proteins of different sizes and functions from a single mRNA.
Which two functional groups are always found in amino acids?
carboxyl and amino
Which one of the following lists contains only polysaccharides?
cellulose, starch, and glycogen
You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, or a virus. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent. Which treatment would allow you to distinguish between these two possibilities?
culturing the substance by itself on nutritive medium, away from any plant cells
Which temperature and pH profile curves on the graphs were most likely generated from analysis of an enzyme from a human stomach, where conditions are strongly acid?
curves 1 and 4
Use the following figures to answer the following two questions: The figures show activity of various enzymes at various temperatures (a) and at various pH (b). Which curve(s) on the graphs may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline (aka basic) hot springs at temperatures of 70°C or higher?
curves 3 and 5
Where in the cell does glycolysis occur?
cytoplasm
During your senior year you get the opportunity to travel to the Amazon rainforest. You spend a lot of time in the area of Lago Grande in Brazil as well as other parts of this vast jungle. You are in awe of all the living organisms that inhabit this particular area as well as the Amazon river that flows through the heart of the rainforest. The tropical climate is humid, but reminds you of home. What type of biological organization was described?
ecosystem
Embryonic stem cells are different from adult stem cells in animals because
embryonic stem cells can differentiate into more cell types than adult stem cells.
The presence of cholesterol in the plasma membranes of some animals (Select all that apply)
enables the membrane to stay fluid more easily when cell temperature drops; enables the membrane to stay less fluid when cell temperature increases
Which of the following polymers contain nitrogen? (select all that apply)
enzymes, ATP, insulin, RNA
Genomic imprinting, DNA methylation, and histone acetylation are all examples of
epigenetic phenomena
The following questions are based on the reaction A + B ↔ C + D shown in the figure below. Which of the following terms best describes the forward reaction in the figure?
exergonic, ∆G < 0
As a cell grows, its plasma membrane expands. Which of the following processes is involved in this growth?
exocytosis
Charles Darwin proposed a mechanism for descent with modification that stated that organisms of a particular species are adapted to their environment when they possess
heritable traits that enhance their survival and reproductive success in the local environment.
Genes in the highly condensed region of the chromosome called ______ are not usually expressed. These regions tend to have a lot of DNA _____ which prevents transcription.
heterochromatin...methylation
The herpes viruses are enveloped DNA viruses that cause disease in all vertebrate species and in some invertebrates such as oysters. Some of the human types are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can then reactivate, replicate again, and be infectious to others. If scientists are trying to use what they know about HSV to devise a means of protecting other people from being infected, which of the following would have the best chance of lowering the number of new cases of infection?
interference with new viral replication in preexisting cases
Cyanide is a really deadly poison. When cyanide enters the body it binds to at least one molecule involved in producing ATP. If you were to examine the cells of a person who had been exposed to cyanide, most of the cyanide would be found within the
mitochondria
These organelles are not found in red blood cells but are present in large numbers in muscle cells
mitochondria
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from
nearly any eukaryotic organism
When the human genome project was completed many were surprised to find out that the number of protein-coding sequences was much smaller than they had expected to find in the human genome as well as other multicellular eukaryotes. Which of the following could account for most of the rest?
non-protein-coding DNA that is transcribed into several kinds of small RNAs with biological function
Use the following information to answer the next three questions: A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was 6 feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. How many of their daughters might be expected to be color-blind dwarfs?
none
In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. This is due to
nonidentical genes that produce different versions of globins during developement
Hydrophobic substances such as vegetable oil are
nonpolar substances that repel water molecules.
The following picture shows what happens when the ras gene is mutated: What type of gene is a mutated ras gene called, and what is the overall outcome of this mutation?
oncogene; increased cell division
What will happen if a cell undergoes mitosis but does not go through cytokinesis?
one cell with two nuclei will form. The nuclei will each be identical to the nucleus of the parent cell
The smallest unit containing the entire human genome is which of the following?
one human somatic cell
A hypothetical organism called Infiniarious collegorous is diploid, and has either purple or silver wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in the figure. If a female of this species has one chromosome 12 with a purple gene and another chromosome 12 with a silver gene, and has both number 19 chromosomes with short genes, she will produce which of the following egg types?
one-half purple short and one-half silver short gene eggs
In an animal cell, DNA may be found
only in the nucleus and mitochondria
You've finally gotten your PhD in genetics and are now a post-doctoral researcher. In your lab you are studying breast cancer and trying to find better treatments for the disease. In one of your experiments, you have made cDNA from dozens of patients' breast tumor biopsies. These cDNAs will be used in a DNA microarray assay (DNA chip), and you will be looking for a -
pattern shared among some or all of the breast-cancer samples that indicates gene expression differing from control samples.
Zellweger syndrome, also called cerebrohepatorenal syndrome, is a rare congenital disorder characterized by the inability to break down very long chain fatty acids (VLCFA) and branched chain fatty acids (BCFA). The organelle that is defective in these individuals is also responsible for the removal of hydrogen atoms in alcohol (thus metabolizing it). Which organelle is defective in individuals with Zellweger syndrome?
peroxisome
If a mutation is embryonic lethal, what will this result in?
phenotypes that are never born/hatched.
Which of the following types of molecules are the major structural components of the cell membrane?
phospholipids and proteins
Sickle-cell anemia results from a point mutation in the HBB gene. The mutation results in the replacement of an amino acid that has a hydrophilic R-group with an amino acid that has a hydrophobic R-group on the exterior of the hemoglobin protein. Such a mutation would most likely result in altered
protein secondary structure as a result of abnormal hydrophobic interactions between R-groups in the backbone of the protein
Which of the following do prokaryotic and eukaryotic cells both contain (Select all that apply)
ribosomes; DNA; cell walls; plasma membrane
Insulin is a protein synthesized in the cells of the pancreas and then transported to the plasma membrane where it enters the blood stream. Which of the following summarizes the pathway for insulin through a pancreatic cell?
rough ER --> Golgi body --> vesicle --> plasma membrane
Pancreatic cells, like the one shown below, produce a lot of protein digesting enzymes. If you were able to examine a pancreatic cell under an electron microscope, what type of organelle would you expect to see a lot of?
rough endoplasmic reticulum
Which of the following would be regarded as an organic molecule (select all that apply)?
sugar; oil
Recent knowledge gained about noncoding RNAs are giving hope for advancement for their use in medicine. Of the following scenarios for future research, which would you expect to gain most from RNAs?
targeting siRNAs to disable the expression of an allele associated with autosomal dominant disease
The complexity and variety of organic molecules is due to
the chemical versatility of carbon atoms.
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that
the fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks
A controlled experiment is one in which
there are at least two groups, one of which does not receive the experimental treatment.
What bonding or interaction is most likely to occur among a broad array of molecules of various types (polar, nonpolar, hydrophilic, hydrophobic)?
van der Waals interactions
