Gen Bio Final Exam
Put the steps of the process of signal transduction in the order they occur. 1.A conformational change in the signal-receptor complex activates an enzyme. 2.Protein kinases are activated. 3.A signal molecule binds to a receptor 4.Target proteins are phosphorylated. 5.Second messenger molecules are released. 1, 2, 3, 4, 5 3, 1, 2, 4, 5 3, 1, 5, 2, 4 1, 2, 5, 3, 4
3, 1, 5, 2, 4
what are nucleotides composed of?
5 carbon sugar, phosphate group, nitrogenous base
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE? 4 8 16 64
8
Which of the following statements about a G protein signaling pathway is true? A G protein-coupled receptor bound to TP is in its active state. A G protein bound to GTP is in its active state. A G protein bound to GDP is in its active state Hydrolvsis of bound TP by a G protein activates the G protein
A G protein bound to GTP is in its active state.
start codon for translation
AUG
During which of the following phases of meiosis do centromeres split and sister chromatids migrate to opposite poles of the cell? Anaphase I Telophase I Anaphase II Telophase II
Anaphase II
which molecule shown can increase the concentration of hydrogen ions in a solution and is therefore an organic acid?
C
which of the following molecules is polar? C3H7OH & C2H5COOH
C3H7OH & C2H5COOH are both polar molecules
chemical equation of aerobic cellular respiration
C6H12O6 + 6O2 -> 6 CO2 + 6H2O + energy
central dogma of biology
DNA -> RNA -> AA -> polypeptides -> Protein
In E. coli, which enzyme catalyzes the elongation of a new DNA strand in the 5'--- 3' direction? Primase DNA ligase Helicase DNA polymerase III
DNA polymerase III
Which of the following processes occur during meiosis but not mitosis? Haploid cells fuse to form dioloid cells. Haploid cells multiply into more haploid cells. Diploid cells form haploid cells. A diploid cell combines with a haploid cell.
Diploid cells form haploid cells.
Which of the following characteristics is most likely to be associated with an enzyme that catalyzes two different chemical reactions? The enzyme contains a-helices and 3-pleated sheets The enzyme is subject to competitive inhibition and allosteric regulation. The enzyme is composed of at least two subunits. Either the enzyme has two distinct active sites or the substrates involved in the two reactions have very similar structures.
Either the enzyme has two distinct active sites or the substrates involved in the two reactions have very similar structures.
A chemical reaction that has a negative AG is best described as Exergonic Enthalpic Spontaneous Endergonic
Exergonic
______is a regulatory mechanism in which the end product of a metabolic pathway inhibits an enzyme that catalyzes an early step in the pathway. Allosteric inhibition Cooperative inhibition Feedback inhibition Metabolic inhibition
Feedback inhibition
lons can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through Plasmodesmata Tight junctions Desmosomes Gap junctions
Gap junctions
Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. What is the most probable genotype of each parent? GG × ag Gg × Gg GG × Gg gg × Gg
Gg × Gg
Which of the following metabolic processes normally occurs regardless of whether or not oxygen (02) is present? Citric acid cycle Glycolysis Lactate fermentation Oxidative phosphorylation
Glycolysis
A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (7). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism? Hh HhTt Т HT
HT
Particular receptor tyrosine kinases (RTKs) that promote excessive cell division are found at high levels in various cancer cells. HER2 is an RTK that is present at excessively high levels in some breast cancer cells, Herceptin is a protein that binds to HER2 and inhibits cell division. Herceptin may be an effective treatment for breast cancer treatment under which of the following conditions? If injection of HER2 in the patient's cancer cells stimulates cell division. If the patient's cancer cells have excessive levels of HER2. If the patient's genome codes for the HER2. If the patient has excessive levels of other RTKs in cancer cells.
If the patient's cancer cells have excessive levels of HER2.
Why does testosterone, a lipid-soluble signaling molecule that crosses the membranes of all cells, affect only target cells? Only target cells retain the appropriate genes regulated byTestosterone. Intracellular receptors for testosterone are present only in target cells. Only target cells possess the cytosolic enzymes that transduce the signal from testosterone to adenylyl cyclase. Only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor.
Intracellular receptors for testosterone are present only in target cells.
What is the most likely mechanism by which testosterone functions inside a cell? It acts as a signal receptor that activates tyrosine kinases It binds with a receptor protein that enters the nucleus and activates expression of specific genes. It acts as a steroid signal receptor that activates ion channel proteins in the plasma membrane It coordinates a phosphorylation cascade that reduces spermatogenesis.
It binds with a receptor protein that enters the nucleus and activates expression of specific genes.
Which of the following statements correctly describes a karyotype? It is a display of all of the cell types in an organism. It is a display of a cell's mitotic stages. It reveals the appearance of an organism. It is an organized image of a cell's chromosomes
It is an organized image of a cell's chromosomes
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? It synthesizes RNA nucleotides to make a primer. It joins Okazaki fragments together. It unwinds the parental double helix. It stabilizes the unwound parental DNA
It joins Okazaki fragments together.
Which of the following statements describes what happens to a molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction? It gains electrons and gains potential energy. It loses electrons and loses potential energy. It gains electrons and loses potential energy. It loses electrons and gains potential energy.
It loses electrons and loses potential energy.
Why are males more often affected by sex-linked traits than females? Males are hemizygous for the X chromosome. Female hormones such as estrogen often compensate for the effects of mutations on the X chromosome. X chromosomes in males generally have more mutations than X chromosomes in females. Male hormones such as testosterone often alter the effects of mutations on the X chromosome.
Males are hemizygous for the X chromosome.
Crossing over of chromosomes normally takes place during which of the following processes? Meiosis II Mitosis and meiosis II Mitosis Meiosis I
Meiosis I
Cyanide binds to at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the Mitochondria Ribosomes Peroxisomes Lysosomes
Mitochondria
Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely malfunctioning in this disease? Lysosomes Golgi apparatus Mitochondria Smooth endoplasmic reticulum
Mitochondria
Which of the following statements about NAD* is true? NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and thecitric acid cycle. NAD+ has more chemical energy than NADH. NAD+ can donate electrons for use in oxidative phosphorylation. In the absence of NAD+, glycolysis can still function.
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and thecitric acid cycle.
A man who is a dwarf with achondroplasia and normal vision marries a color-blind woman of normal height. The man's father was six feet tall, and both the woman's parents were of average height. Dwarfism caused by achondroplasia is autosomal dominant, and red-green color blindness is X-linked recessive. How many of their daughters might be expected to be color-blind with achondroplasia? None Half One out of four Three out of four
None
When a molecule of NAD* (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton, but an atom of hydrogen), the molecule becomes Dehydrogenated Oxidized Reduced Redoxed
Reduced
Which of the following is present in a prokaryotic cell? Mitochondria Ribosome Nuclear envelope Chloroplast
Ribosome
The receptors for steroid hormones are located inside the cell instead of the membrane surface like most other signal receptors. How do steroids gain access to their receptors? Steroid hormone receptors undergo conformational changes thatrelocate them on the membrane surface. Both steroid hormones and their receptors are produced by the same cells. Steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell membrane. Steroid hormones first bind to a steroid activator and this complex is transported across the cell membrane b a steroid transport protein.
Steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell membrane.
What is meant by the description "antiparallel" regarding the two strands that make up the DNA double helix? The double helix structure of DNA creates nonparallel strands The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand Base pairings create unequal spacing between the two DNA strands. One strand contains only purines and the other contains only pyrimidines.
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst? The catalyzed reaction will be slower. The catalyzed reaction will have the same ΔG. The catalyzed reaction will have higher activation energy. The catalyzed reaction will consume all of the catalyst.
The catalyzed reaction will have the same ΔG.
Which of the following statements regarding gene linkage is correct? The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%. All of the traits that Mendel studied seed color, pod shape, flower color, and others are due to genes linked on the same chromosome. Linked genes are found on different chromosomes.
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result? The gene involved is located on the Y chromosome. The gene involved is located on the X chromosome. The gene involved is located on an autosome, but only in males. Other male-specific factors influence eye color in flies.
The gene involved is located on the X chromosome.
Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds? The green allele is recessive to the yellow allele. The two alleles exhibit incomplete dominance. The green allele is dominant to the yellow allele. The two alleles are codominant.
The green allele is recessive to the yellow allele.
Gaucher disease is the most common lipid storage disease in humans. It is caused by a deficiency of an enzyme necessary for the breakdown of lipids. This leads to the accumulation of fatty material in organs of the body including the spleen, liver, kidneys, lungs, brain, and bone marrow. Using your knowledge of the structure of eukaryotic cells, identify the statement below that best explains how internal membranes and the organelles of cells mav be involved in Gaucher disease. The mitochondria are most likelv defective and do not produce adequate amounts of ATP needed for cellular energy. The rough endoplasmic reticulum contains too many ribosomes which results in an overproduction of the enzyme involved in lipid breakdown. The lysosomes lack sufficient amounts of enzymes necessary for the metabolism of lipids. The Golgi apparatus produces vesicles with faulty membranes, which fail to be transported to the plasma membrane for secretion.
The lysosomes lack sufficient amounts of enzymes necessary for the metabolism of lipids.
why are hydrocarbons insoluble in water?
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? The pH of the matrix increases ATP synthase pumps protons by active transport. The electrons gain free energy. NAD+ is oxidized.
The pH of the matrix increases
Hormones are chemical substances produced in one organ that are released into the bloodstream and affect the function of a target organ. Which of the following conditions is required for the target organ to respond to a particular hormone? Cells in the target organ must modify their plasma membranes to allow the hormone to enter the cytoplasm The target organ must be the same as the organ that produced the hormone. The target organ must have the opposite mating type of the organ that produced the hormone. The target organ must have receptors that recognize and bind the hormone molecule
The target organ must have receptors that recognize and bind the hormone molecule
The force driving simple diffusion is active transport Is concentration gradient; ADP a concentration gradient; ATP hydrolysis transmembrane pumps; an electrochemical gradient phosphorylated carrier proteins; ATP while the energy source for
a concentration gradient; ATP hydrolysis
for lipids to be fluid at room temperature, they should have
a higher number of cis double bonds
A series of enzymes catalyze the reactions in the metabolic pathway X->Y ->Z-> A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. What is substance X? an allosteric inhibitor a substrate an intermediate the product
a substrate
Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect? abnormally shaped RBCs an insufficient supply of ATP in the RBCs an insufficient supply of oxygen-transporting proteins in the RBCs adherence of RBs to blood vessel walls, causing plaque formation
abnormally shaped RBCs
which of the following molecules is a part of ATP?
adenosine
Which of the following individuals will inherit an X-linked allele from a man who carries it? half of his daughters all of his daughters all of his sons all of his children
all of his daughters
Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will re-seal "inside out." The little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. After the disruption, which components involved in oxidative phosphorylation must be present for electron transfer and ATP synthesis to still occur? only the electron transport system only the ATP synthase system all of the electron transport system and the proteins that add Cod to acetyl groups all of the electron transport system and ATP synthase
all of the electron transport system and ATP synthase
Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division? anaphase I of meiosis anaphase I of meiosis metaphase Il of meiosis prophase I of meiosis
anaphase I of meiosis
programmed cell death
apoptosis
research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that
are mirror images of each other
the figure shows the structures of glucose and fructose. these two molecules differ in the
arrangement of carbon, hydrogen, and oxygen atoms
The figure illustrates the energy states associated with the reactionA + B +> C + D. Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure?
b
How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction? by binding to the active site of the enzyme, thus preventing binding of the normal substrate by binding to the substrate, thus changing its shape so that it no longer binds to the active site of the enzvme by decreasing the free-energy change of the reaction catalyzed by the enzyme by binding to an allosteric site, thus changing the shape of the active site of the enzyme
by binding to an allosteric site, thus changing the shape of the active site of the enzyme
Many organisms spend most of their life cycle in the diploid state. If meiosis produces haploid cells, how is the diploid number restored for these types of organisms? by fertilization through the transcription of DNA to RNA by synapsis of the homologous pairs of chromosomes during prophase of meiosis I by DNA replication
by fertilization
The figure illustrates the energy states associated with the reactionA + B + C + D. Which of the following represents the activation energy required for the non-enzyme-catalyzed reaction in the figure?
c
atomic number of 6
carbon
the element present in all organic molecules is
carbon
which two functional groups are always found in amino acids?
carboxyl and amino groups
An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function? transporting ions against an electrochemical gradient cell-cell recognition attaching the plasma membrane to the cytoskeleton establishing a diffusion barrier to charged molecules
cell-cell recognition
a sharing of electrons
covalent bond
which bond or interaction would be difficult to disrupt when compounds are put into water?
covalent bonds between carbon atoms
The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. In addition to mutations, how might genetic diversity be generated in this species? crossing over only crossing over and random fertilization independent assortment only nothing else
crossing over and random fertilization
The figure illustrates the energy states associated with the reaction A + B < C + D. Which of the following in the figure would be the same in either an enzyme-catalyzed or a noncatalyzed reaction?
d
which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
dehydration reactions assemble polymers: hydrolysis reactions break polymers apart
the chemical reaction that creates a peptide bond
dehydration synthesis
a neutral atom has two, eight, eight electrons in its first, second, and third energy levels. this information
does not tell us about the atomic mass of the element. but it does tell us about atomic number, chemical properties, size
Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH3)?
each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge
Phagocytosis is an example of this process
endocytosis
a component of the phospholipid tails
fatty acid
which of the following is not a polymer? glucose starch RNA DNA
glucose
the energy currency of the cell
glycerol, ATP
Which of the following metabolic processes take place in the cytosol of a eukaryotic cell? glycolysis and fermentation fermentation and chemiosmosis oxidation of pyruvate to acetyl CoA citric acid cycle
glycolysis and fermentation
forms the secondary structure of polypeptides
h bond
the partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. what is this attraction called?
hydrogen bond
describes the heads of phospholipids
hydrophilic
Even though plants cells carry out photosynthesis, they still use their mitochondria for oxidation of pyruvate. Under what conditions will plant cell mitochondria be active in this process? only in photosynthetic cells in the light, while photosynthesis occurs concurrentlv only in cells that store glucose in the form of starch and only in the dark in all cells, with or without light in photosynthesizing cells in the light, and in other cells in the dark
in all cells, with or without light
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following inheritance patterns? a multiple allelic system sex linkage Codominance incomplete dominance
incomplete dominance
The membranes of winter wheat are able to remain fluid when it is extremely cold by increasing the proportion of unsaturated phospholipids in the membrane increasing the percentage of cholesterol molecules in the membrane decreasing the number of hydrophobic proteins in the membrane increasing the proportion of glycolipids in the membrane
increasing the percentage of cholesterol molecules in the membrane
Diffusion of ions across membranes through specific ion channels is driven by active transport pumps X ion concentration gradients only electrical gradients only ion electrochemical gradients
ion electrochemical gradients?
NaCl
ionic bond
if the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, then the concentration of H+ ions
is 10 times higher in the cytoplasm than in the mitochondrial matrix
consider the following reaction at equilibrium: CO2 + H2O-> H2CO3. what would be the effect of adding additional H2O?
it would drive the equilibrium dynamics to the right
chemical equation of photosynthesis
light energy + 6CO2 + 6H2O -> C6H12O6 + 6O2
tubulin subunit polymerization forms these structures
microtubules
the concentration of solute in solution
molarity
Researchers investigating the mechanism of vesicular transport assembled a cell-free system that included microtubule tracks, vesicles, and ATP. However, they observed no movement of transport of vesicles in this system. What were they missing? an axon contractile microfilaments intermediate filaments motor proteins
motor proteins
Suppose a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from a bacterium, but not a eukaryote an animal, but not a plant nearly any eukaryotic organism a plant, but not an animal
nearly any eukaryotic organism
hydrophobic substances such as vegetable oil are
nonpolar substances that repel water molecules
In E. coli, to repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act? nuclease, DNA polymerase, RNA primase helicase, DNA polymerase, DNA ligase DNA ligase, nuclease, helicase nuclease, DNA polymerase, DNA ligase
nuclease, DNA polymerase, DNA ligase
a covalent bond is likely to be polar when
one of the atoms sharing electrons is more electronegative than the other
drives the movement of water across a membrane
osmosis
a covalent chemical bond is one in which
outer shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals
contains 6 valence electrons
oxygen
a glycosidic linkage is analogous to which of the following in proteins?
peptide bond
the speed at which a chemical reaction takes place
rate of reaction
One of the major categories of receptors in the plasma membrane functions by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this? G protein-coupled receptors ligand-gated ion channels steroid receptors receptor tyrosine kinases
receptor tyrosine kinases
What is the function of the enzyme topoisomerase in DNA replication? relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix elongating new DNA at a replication fork by adding nucleotides to the existing chain reattaching the hydrogen bonds between the base pairs in the double helix building RNA primers using the parental DNA strand as a template
relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix
Which of the following is the most common pathway taken by a newly synthesized protein that will be secreted by a cell? rough ER -> Golgi -> transport vesicle ->nucleus Golgi -> rough ER -> lysosome -> transport vesicle -> plasma membrane -> rough ER -> Golgi -> transport vesicle -> plasma membrane rough ER -> lysosome -> transport vesicle -› plasma membrane
rough ER -> Golgi -> transport vesicle -> plasma membrane
A research team is working on the design of a new drug for the treatment of lung cancer. To be most effective, this drug must specifically enter the cytoplasm of lung cells while not entering the cells of other tissues. Which of the following characteristics would likely enhance the specificity of this drug? the relative hydrophobicity of the drug molecule phospholipid composition of lung cell plasma membranes specificity of the drug molecule for binding to the extracellular matrix of lung cells similarity of the drug molecule to other molecules normally transported lung cells
similarity of the drug molecule to other molecules normally transported lung cells?
an atom has four electrons in its valence shell. what types of covalent bonds is it capable of forming?
single, double, or triple
An ion with six protons, seven neutrons, and a charge of 2+ has an atomic number of ________.
six
what is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms?
six
use the following figure to answer the question. the molecule shown in the figure is a
steroid
a salamander relies on hydrogen bonding to stick to various surfaces. therefore, a salamander would have the greatest difficulty clinging to a
surface of hydrocarbons
how do phospholipids interact with water molecules?
the polar heads interact with water; the nonpolar tails do not
In cats. black fur color is determined by an X-linked allele; the other allele at this locus determines orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male? tortoiseshell females; tortoiseshell males black females; orange males tortoiseshell females; black males orange females; black males
tortoiseshell females; black males
Sex determination in mammals is due to the SRY gene found on the Y chromosome. Which of the following situations could allow a person with an XX karyotype to develop a male phenotype? the loss of the SRY gene from an autosome the presence of one normal and one shortened (deleted) X the presence of an extra autosomal chromosome translocation of SRY to an X chromosome
translocation of SRY to an X chromosome
What is a primary function of integrins? connecting intermediate filaments to microtubules involved in vesicular transport linking the primary and secondary cell walls in plants transmitting signals from the extracellular matrix to the cytoskeleton transmitting chemical signals from the Golgi apparatus to the plasma membrane
transmitting signals from the extracellular matrix to the cytoskeleton
In glycolysis, for each molecule of glucose oxidized to pyruvate, two molecules of ATP are used, and two molecules of ATP are produced two molecules of ATP are used, and four molecules of ATP are produced four molecules of ATP are used and two molecules of ATP are produced two molecules of ATP are used, and six molecules of AT are produced
two molecules of ATP are used, and four molecules of ATP are produced
a nitrogenous base
uracil
use the following figure to answer the question. the molecule illustrated in the figure
will be liquid at room temp
Given the following genotypes for two parents, AABBCc × AabbCc, assume that all traits exhibit simple dominance and independent assortment. What proportion of the progeny of this cross will be expected to phenotypically resemble the first parent with the genotype AABBCc? ¼ ¾ ⅜ 1
¾
The mathematical expression for the change in free energy of a system is ΔG = ΔH - TΔS. Which of the following statements is correct? ΔG is the change in free energy. ΔH is the change in entropy, the energy available to do work ΔS is the change in enthalpy, a measure of randomness. T is the temperature in degrees Celsius.
ΔG is the change in free energy.