Life 120 Exams 1, 2, & 3- Angeletti
Terms in this set (148)
Both phospholipids and nucleic acids
If cells are grown in a medium containing radioactive 32P-labeled phosphate, what molecules will be labeled?
A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in
Signals from the ECM to the cytoskeleton may be transmitted by
Eukaryotic cells have a nucleus surrounded by a nuclear membrane; bacterial cells don't
What is a true statement comparing bacteria and eukaryotes?
The patients's red blood cells will swell because the blood fluid has become hypotonic compared to the cells.
A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water-equal to the volume of blood lost-is transferred directly into one of his veins. What will be the most probable result of this transfusion?
Water will leave the cells, causing them to shrivel and collapse.
Mammalian blood contains the equivalent of 0.15M NaCl. Seawater contains the equivalent of 0.45M NaCl. What will happen if red blood cells are transferred to seawater?
Which of the following explains most specifically the attraction of water molecules to one another?
it moves through aquaporins in the membrane.
Water passes quickly through cell membranes because
phagocytic white blood cell
Which cell would be best for studying lysosomes?
pinocytosis is non-selective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity.
The difference between pinocytosis and receptor-mediated endocytosis is that
They can move laterally along the plane of the membrane
According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?
A carbon atom is most likely to form which of the following bonds with other atoms?
Testosterone and estradiol have different functional groups attached to the same carbon skeleton.
Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other?
The element present in all organic molecules is
Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight to
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
phospholipids and proteins
Which of the following types of molecules are the major structural components of the cell membrane?
separate the major organelles so that their particular functions can be determined.
A primary objective of cell fractionation is to
An ER (endoplasmic reticulum)
All of the following are part of the prokaryotic cell except: cell wall, plasma membrane, ribosomes, an ER, DNA
They are both polymers of glucose.
Which of the following is true of both starch and cellulose?
Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.
Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
Which of the following molecules contains the most polar covalent bond?
C and D
Which functional group(s) shown in Figure 3.4 is (are) present in all amino acids?
It requires genetic variation, results in descent with modification, and involves differential reproductive success.
Which of the following is (are) true of natural selection?
Which component is the peripheral protein?
Which component is a microfilament of the cytoskeleton?
Which component is the fiber of the extracellular matrix?
Transmission electronic microscope
When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using a
They have the same number of electrons in their valence shell.
In what way are elements in the same column of the periodic table the same?
Which of the following is not a polymer?
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
The nitrogen atom has a mass number of approximately 14 and an atomic number of 7.
The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?
small and hydrophobic
What kinds of molecules pass through a cell membrane most easily?
Initially, in terms of tonicity, the solution in side A with respect to that in side B is
Which of these are not embedded in the hydrophobic portion of the lipid bilayer?
enables the membrane to stay fluid more easily when cell temperature drops.
The presence of cholesterol in the plasma membranes of some animals
Which functional group is not present in this molecule?
It is a major structural component of plant cell walls.
Which of the following is true of cellulose?
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?
Bacteria and Archaea
Prokaryotes are classified as belonging to two different domains. What are the domains?
Which structure is the site of the synthesis of proteins that may be exported from the cell?
The number of protons plus neutrons in the element.
Knowing just the atomic mass of an element allows inferences about which of the following?
Which plant cell organelle contains its own DNA and ribosomes?
If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence
An atom has 6 electrons in its outer shell. how many unpaired electrons does it have?
Which structure is common to plant and animal cells?
Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells?
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?
They are not soluble in water.
Why are human sex hormones considered to be lipids?
mitochondrial intermembrane space
Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?
Nothing; the reaction will stay at equilibrium
If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
synthesize simple sugars from carbon dioxide
What is the primary function of the Calvin cycle?
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a delta G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the delta G for the new reaction?
Which of the following represents the delta G of the reaction in Figure 6.4?
Which of the following in Figure 6.4 would be the same in either an enzyme-catalyzed or a noncatalyzed reaction?
Which of the following represents the activation energy required for the enzyme-catalyzed reaction in Figure 6.4?
stroma of the chloroplast
Where does the Calvin cycle take place?
entropy of the universe
Whenever energy is transformed, there is always an increase in the
B & E only (Bisphosphoglycerate and Ribulose bisphosphate)
If ATP used by this plant is labeled with radioactive phosphorus, which molecule or molecules of the Calvin cycle will be radioactively labeled first?
the Calvin cycle alone
Reactions that require CO2 take place in
in the plasma membrane
In prokaryotes, the respiratory electron transport chain is located
They protect against oxidative damage from excessive light energy
Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants?
Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid?
For each mole of glucose oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle?
3 ATP, 6 CO2, 9 NADH, 3 FADH2
Starting with citrate, which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle?
is involved in the catalytic reaction of the enzyme.
The active site of an enzyme is the region that
It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
ATP and NADPH
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?
The ATP made during glycolysis is generated by
oxidation of pyruvate to acetyl CoA and the citric acid cycle
Carbon dioxide is released during which of the following stages of cellular respiration?
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?
Photosynthesis stores energy in complex organic molecules, whereas respiration releases it.
Which of the following statements best describes the relationship between photosynthesis and respiration?
splitting water molecules
When oxygen is released as a result of photosynthesis, it is a direct by-product of
on the stromal side of the membrane
In thylakoids, protons travel through ATP synthase form the thylakoid space to the stroma. Therefore, the catalytic "knobs" of ATP synthase would be located
H+ movement down its concentration gradient.
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the
fix CO2 into organic acids during the night
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
NADH and pyruvate
In addition to ATP, what are the end products of glycolysis?
What carbon sources can yeast cells metabolize to make ATP from ADP under anaerobic conditions?
The pH within the thylakoid is less than that of the stroma.
The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find?
It provides energy coupling between exergonic and endergonic reactions.
Why is ATP an important molecule in metabolism?
the light reactions alone
The reactions that produce molecular oxygen take place in
If photosynthesizing green algae are provided with CO2 containing heavy oxygen, later analysis will show that all of the following molecules produced by the algae contain heavy oxygen except
Cells require a constant input of energy to maintain their high level of organization.
Which of the following statements is representative of the second law of thermodynamics?
an allosteric inhibitor
With respect to the enzyme that converts X to Y, substance A functions as
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is
Which process in eukaryotic cells will proceed normally whether oxygen is present or absent?
Bacteria congregated in these areas because these areas had the most oxygen being released.
What did Engelmann conclude about he congregation of bacteria in the red and blue areas?
act as an acceptor for electrons and hydrogen, forming water
The primary role of oxygen in cellular respiration is to
C6H12O6 is oxidized and O2 is reduced
Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2---> 6 CO2 + 6 H2O + Energy
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?
by changing the shape of the enzymes active site
How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
∆G is the change in free energy
The mathematical expression for the change in free energy of a system is ∆G= ∆H - T∆S. Which of the following is correct?
loses electrons and loses potential energy
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction
Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
Which of the following is true of enzymes?
molecular O2 released during photosynthesis
The oxygen atoms in the H2O broken down during photosynthesis end up in:
Where does glycolysis take place in eukaryotic cells?
Which diagram represents anaphase II of meiosis?
Cohesin is cleaved enzymatically
The beginning of anaphase is indicated by which of the following?
Epistasis is involved
These results indicate which of the following?
cohesins are protected from cleavage at the centromere during meiosis I
Experiments with cohesins have found that
Descendants of the living cells are also phosphorescent
After mixing a heat killed, phosphorescent strain of bacteria with a living nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait?
One member of the couple underwent nondisjunction in gamete production.
A couple has a child with down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition?
twice as much DNA as the nuclei of gametes produced by meiosis
Humans produce skin cells by mitosis and gametes by meiosis. The nuclei of skin cells produced by mitosis will have
depends on the action of DNA polymerase
The elongation of the leading strand during DNA synthesis
the probability that either one of two independent events will occur
Which of the following is the best statement of the use of the addition rule of probability
some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic.
In his work with pneumonia-causing bacteria and mice, Griffith found that
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
The leading and lagging strands differ in that
DNA polymerase can join new nucleotides only to the 3' end of a growing strand
What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?
When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?
males are hemizygous for the X chromosome
Males are more often affected by sex-linked traits than females because
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
Replication in prokaryotes differs from replication in eukaryotes for which of the following reasons?
Which of the following investigators was/were responsible for the following discovery? In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine.
One allele was dominant
Why did the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?
Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?
In the late 1950's Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen (15N) and then transferred them to a medium containing 14N. Which of the results in the figure above would be expected after one round of DNA replication int eh presence of 14N?
The gene involved is on the X chromosome
When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkable, all the white-eyed flies were male. What was the explanation for this result?
When we see chiasmata under a microscope, that lets us know which of following had occurred?
5' RNA nucleotides, DNA nucleotides 3'
An Okazaki fragment had which of the following arrangements?
allowing the organism to adjust to changes in environmental conditions
Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways?
DNA polymerase can only add nucleotides to the free 3' end
A new DNA strand elongates only in the 5' to 3' direction because
a single nucleotide insertion downstream of, land close to, the start of the coding sequence
Which of the following mutations would be most likely to have a harmful effect on an organism?
tortoiseshell females; black males
In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?
a reduction in chromosome length in gametes
Which of the following would you expect of a eukaryote lacking telomerase?
by allowing crossing over
Which of these is a way that the sexual life cycle increases genetic variation in a species?
In a nucleosome, the DNA is wrapped around
traits are inherited in discrete units, and are not the results of "blending."
What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
assimilation of external DNA into a cell
How do we describe transformation in bacteria?
relieving strain in the DNA ahead of the replication fork
What is the function of topoisomerase?
to observe whether or not a recessive trait would reappear
Why did Mendel continue some of his experiments to the F2 or F3 generation?
synapsis of chromosomes
Which of the following occurs in meiosis but not in mitosis?
leading strands and Okazaki fragments
You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class is labeled DNA includes very large molecules, and the other includes short stretches of DNA. These two classes of DNA probably represent
Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction.
How is natural selection related to sexual reproduction as opposed to asexual reproduction?
single-strand binding proteins
Which of the following help(s) to hold the DNA strands apart while they are being replicated?
DNA polymerase III
Which enzyme catalyzes the elongation of a DNA strand in the 5' to 3' direction?
the diameter of the helix
Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?
haploid, and the chromosomes are each composed of two chromatids
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
XN Xn and XN Y
Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents?
It consists of a single linear molecule of double-stranded DNA plus proteins
Which of the following statements describes the eukaryotic chromosome?
endonuclease, DNA polymerase I, DNA ligase
To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
What is meant by the description "antiparallel" regarding the strands that make up DNA?
What is the genotype of individual II-5?
more DNA molecules and larger genomes
Compared to most prokaryotic cells, eukaryotic cells typically have
gaps left at the 5' end of the lagging strand
Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?
They give the go-ahead signal to progress to the next checkpoint
All cell cycle checkpoints are similar in which way?
adding numerous short DNA sequences such as TTAGGG, which form a hairpin turn
The enzyme telomerase solves the problem of replication at the ends of linear chromosomes by which method?