Bio 1330 Final Online Questions

Starting with one molecule of glucose, the energy-containing products of glycolysis are _______.

2 NADH, 2 pyruvate, and 2 ATP

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence _________.

5'TGCAAT3'

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?

A + G = C + T

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?

A hydrogen bond

During elongation, which site in the ribosome represents the location where a codon is being read?

A site

How does termination of translation take place?

A stop codon is reached.

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of _______.

ATP, CO2, and ethanol (ethyl alcohol)

What event accompanies energy absorption by chlorophyll (or other pigment molecules of the antenna complex)?

An electron is excited.

The glucose molecule has a large quantity of energy in its _______.

CH bonds

_______ atoms give organic molecules their overall shape; _______ atoms determine the overall chemical behavior of organic molecules.

Carbon; H, N, and O

In eukaryotic cells, chromosomes are composed of ______.

DNA and proteins

Which of the following statements best summarizes the differences between DNA and RNA?

DNA nucleotides contains a different sugar than RNA nucleotides.

Which of the following can occur by the process of meiosis but not mitosis?

Diploid cells form haploid cells.

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?

ER→Golgi→vesicles that fuse with plasma membrane

Which of the following is a statement of the first law of thermodynamics?

Energy cannot be created or destroyed.

Which of the following is true of enzymes?

Enzymes increase the rate of chemical reaction by lowering activation energy barriers.

Which of the following is a major difference between prokaryotic cells and eukaryotic cells?

Eukaryotic cells have more intracellular organelles than prokaryotes.

In solutions, why do hydrolysis reactions occur more readily than condensation reactions?

Hydrolysis increases entropy and is exergonic.

Which of the following is true of osmosis?

In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.

In the figure associated with this question, what is the function of the AGU on the loop of the tRNA?

It base pairs with a codon of mRNA

Why is carbon so important in biology?

It can form a variety of carbon skeletons and host functional groups.

Which of the following is a characteristic feature if a carrier protein in a plasma membrane?

It exhibits a specificity for a particular type of molecule.

As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy?

It is used to establish and maintain a proton gradient.

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

It joins Okazaki fragments together

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.

What is the function of the nuclear pore complex found in eukaryotes?

It regulates the movement of proteins and RNAs into and out of the nucleus.

Why is glycolysis described as having an investment phase and a payoff phase?

It uses stored ATP and then forms a net increase in ATP

Which of the events listed below occurs in the light reactions of photosynthesis?

Light is absorbed and funneled to reaction-center chlorophyll a.

What does it mean when we say the genetic code is redundant?

More than one codon can specify the addition of the same amino acid.

Which electron carrier(s) function in the citric acid cycle?

NADH and FADH2

In addition to ATP, what are the end products of glycolysis?

NADH and pyruvate

Why is the smooth endoplasmic reticulum unable to synthesize proteins?

No ribosomes are attached to its surface.

Which structure

PICTURE

Which of the following statements best describes the relationship between photosynthesis and respiration?

Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules

What is the major difference between eukaryotic DNA replication and prokaryotic DNA replication?

Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic have multiple origins of replication

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called ______.

RNA interference

In the process of transcription, _______.

RNA is synthesized

What is the difference between a ribonucleotide and a deoxyribonucleotide?

Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.

Which one of the following statements about RNA processing is true?

Ribozymes may function in RNA splicing.

How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?

The base sequence of DNA carriers the information needed to code for proteins.

Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?

The catalyzed reaction will have the same ∆G.

Which statement described the functioning of photosystem II?

The electron vacancies in P680+ are filled by electrons derived from water.

Which of the following statements best represents the relationship between the light reactions and the Calvin cycle?

The light reactions provide ATP and NADPH to the Calvin cycle, and the Calvin cycle returns ADP, P, and NADP+ to the light reactions.

What does it mean to say that a signal is transduced?

The physical form of the signal changes from one form to another.

Which of the following always tends to make chemical reactions spontaneous?

The reactants are more ordered that the products.

Which of the following is TRUE for all exergonic reactions?

The reaction proceeds with a net release of free energy.

Why is it that RNA can catalyze reactions but DNA cannot?

The sugar of RNA is much more reactive than the sugar of DNA.

Steroid hormones are large communication molecules that are modified cholesterol molecules. How do you think they enter a cell?

Their lipid nature probably allows them to diffuse through the plasma membrane.

How do the α and β forms of glucose differ?

Their ring structures differ in the location of a hydroxyl group.

Which aspect of phospholipids is most important to the formation of bilayers?

They are amphipathic

Which of the following structural features is common ti cellulose, chitin, and peptidoglycan?

They can all form bonds between polymer chains that create parallel strands.

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is _____.

UUU

Of the following, which is the most current description of a gene?

a DNA sequence that is expressed to form a functional product: either RNA or polypeptide

Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?

a base pair deletion near the start of the gene

Which of the following DNA mutations is most likely to damage the protein is specifies?

a base pair-deletion

Cellulose is _______.

a major structural component of plant cell walls

Which of the following descriptions best fits the class of molecules known as nucleotides?

a nitrogenous base, a phosphate group, and a sugar

A glycosidic linkage is analogous to which of the following in proteins?

a peptide bond

Which one of the following is NOT a component of each monomer used to make proteins?

a phosphorus atom, P Is a component: an amino function group, NH2 a side chain, R a carboxyl group, COOH

Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. The cell is most likely ______.

a plant cell in the process of cytokinesis

What is responsible for termination of transcription in eukaryotic protein-coding genes?

a polyadenlation, or poly(A), signal

Which of the following statements describes a eukaryotic chromosome?

a single linear molecule of double-stranded DNA plus proteins

Which of the following mutations is likely to cause the most dramatic phenotypic change?

a single nucleotide deletion in an exon coding for an active site

Which of the following crosses lipid bilayers the fastest?

a small, nonpolar molecule like oxygen (O2)

Which of the following nucleotide triplets best represents a codon?

a triplet in the same reading frame as an upstream AUG

The oxygen consumed during cellular respiration is involved directly in which process or event?

accepting electrons at the end of the electron transport chain (ETC)

The primary role of oxygen in cellular respiration is to ________.

act as an acceptor for electrons and hydrogen, forming water

A cyclin _______.

activates a Cdk molecule when it is in sufficient concentration

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's _______.

activation energy

Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in _________.

all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors

Which of the following allows more than one type of protein to be produced from one gene?

alternative forms of RNA splicing

Which of the following is NOT synthesized from a DNA template?

amino acids

A ribozyme is _______.

an RNA with catalytic activity

All of the following are part of a prokaryotic cell EXCEPT ________.

an endoplasmic reticulum

In meiosis, homologous chromosomes are separated during ______.

anaphase I

Lipids _______.

are insoluble in water

Steroids are considered to be lipids because they ______.

are not soluble in water

Ribosomes can attach to prokaryotic messenger RNA ______.

before transcription is complete

In eukaryotes, general transcription factors,

bind to other proteins or to the TATA box

Which of the following processes is central to the initiation of transcription in bacteria?

binding of sigma to the promoter region

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the _____.

binding of the anticodon to the codon and the attachment of amino acids to tRNAs

Chlorophylls absorb most light in which colors of the visible range?

blue and red

How might a change of one amino acid at a site, distant from the active site of an enzyme, alter an enzyme's substrate specificity?

by changing the shape of an enzyme

Alternative RNA splicing ________.

can allow the production of proteins of different sizes and functions from a single mRNA

Amino acids are acids because they always possess which functional group?

carboxyl

Which of the functional groups below acts most like an acid in water?

carboxyl

What two functional groups are always found in amino acids?

carboxyl and amino groups

What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

catabolic pathways

Proteins in biological systems _______.

catalyze reactions

Which polysaccharide is an important component in the structure of many animals and fungi?

chitin

The anticodon of a particular tRNA molecule is _______.

complementary to the corresponding mRNA codon

The difference between the sugar in DNA and the sugar in the RNA is that the sugar in DNA _______.

contains one less oxygen atom

Proteins that are invovled in the regulation of the cell cycle and that show fluctuations in concentration during the cell ceyle are called _______.

cyclins

Mitosis separates chromosomes. Cytoplasm is divided between two daughter cells by _______.

cytokinesis

Which of the following includes all of the pyrimidines found in RNA and DNA?

cytosine, uracil, and thymine

There are 20 amino acids. What makes one amino acid different from another?

different side chains (R-groups) attached to an α (alpha) carbon

Which of the following best describes DNA's secondary structure?

double antiparallel helical strands

A frameshift mutation could result from _______.

either an insertion or a deletion of a base

A chemical reaction that has a positive ΔG is best described as _______.

endergonic

Whenever energy is transformed, there is always an increase in the _______.

entropy of the universe

DNA methylation and histone acetylation are examples of ______.

epigenetic phenomena

Chitin is a major component of the _______.

exoskeleton of insects

Muscle cells differ from nerve cells mainly because they ______.

express different genes

The predominant mechanism driving cellular differentiation is the difference in gene _____.

expression

The mechanism in which the product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as _______.

feedback inhibition

If meiosis produced haploid cells, how is the diploid number restored for those organisms that spend most their life cycle in the diploid state?

fertilization

A peptide bond _______.

forms the primary structure of proteins

One of the primary functions of RNA molecules is to _______.

function in the synthesis of proteins

Photorespiration ________.

generates carbon dioxide and consumes ATP and oxygen

Which of these best reflects the following relationship: monosaccharide versus polysaccharide?

glucose versus glycogen

Which metabolic pathway is common to both cellular respiration and fermentation

glycolysis

Which of the following are purine nitrogenous bases?

guanine and adenine

How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I? They have _______.

half the number of chromosomes and one-fourth the amount of DNA.

After telophase I of meiosis, the chromosomal makeup of each daughter cell is _____.

haploid, and the chromosomes are each composed of two chromatids

If you were to observe the activity of methylated DNA, you would expect it to _____.

have turned off and slowed down the process of transcription

In a nucleosome, the DNA is wrapped around ______.

histones

Humans can digest starch but not cellulose because ________.

humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose

Which type of interaction stabilizes the α-helix and the β-pleated sheet structures of proteins?

hydrogen bonds

What type of interaction is directly responsible for the formation of secondary structure?

hydrogen bonds between sections of the polypeptide backbone

C6H12O6 (glucose) + 6 O2 → 6 CO2 + 6 H2O Where is most of the water in this reaction produced?

in the electron transport chain

Enzymes ________.

increase the rate of a reaction by lowering the activation energy barrier

Regulatory transcription factors ______.

influence the assembly of the basal transcription complex

The product of the p53 gene ______.

inhibits the cell cycle

Which of the following is characteristic of a steroid hormone action?

internal receptor binding

A nonsense mutation in a gene ______.

introduces a premature stop codon into the mRNA

A mutation that results in premature termination of translation _______.

is a nonsense muation

Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water ________.

is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

The active site of an enzyme is the region that ______.

is involved in the catalytic reaction of the enzyme

The statement "DNA → RNA → Proteins" ______.

is known as the central dogma

A codon ________.

is the basic unit of the genetic code

All of the following are polysaccharides EXCEPT

lactose

Which one of the following is least likely to cause mutations in DNA?

lights from an incandescent bulb

Which of the following contains hydrolytic enzymes?

lysosome

According to the central dogma, what molecule should go in the blank? DNA → ______ → Proteins

mRNA

Codons are part of the molecular structure of ______.

mRNA

Translation requires ______.

mRNA, tRNA, and rRNA

Translation directly involves _____.

mRNA, tRNA, ribosomes, and GTP

Side chains of amino acids ________.

may be polar or nonpolar

Mutations that result in a single amino acid substitution in an enzyme _______.

may change the enzyme's optimal temperature or optimal pH

A primary function of carbohydrates attached to the glycoproteins and glycolipids of animal cell membranes is to _______.

mediate cell--cell recognition

Crossing over normally takes place during which of the following processes?

meiosis I

Independent assortment of chromosomes occurs during ______.

meiosis I only

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

Homologous pairs of chromosomes align opposite to each other at the equator of the cell during _______.

metaphase I of meiosis

What are prions?

misfolded versions of normal protein that can cause disease

The mutation resulting in sickle cell disease changes one base pair of DNA so that a codon now codes for a different amino acid, making it an example of a _______.

missense mutation

Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?

mitochondrial intermembrane space

During cellular respiration, acetyl CoA accumulates in which location?

mitochondrial matrix

Which organelle is the primary site of ATP synthesis in eukaryotic cells?

mitochondrion

Which plant cell organelle contains its own DNA and ribosomes?

mitochondrion

Sister chromatids separate from each other during ________.

mitosis and meiosis II

What kind of molecules serve as electron acceptors in cellular respiration?

molecules with low potential energy

Which of the following membrane activities requires energy from ATP?

movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Histone acetyl transferases exert their effect on gene activity by ______.

neutralizing positive charges on the lysines of histones

What is the most common source of the extra chromosome 21 in an individual with Down syndrome?

nondisjunction in the mother

Bonds between two atoms that are equally electronegative are _________.

nonpolar covalent bonds

A phospholipid is a _______.

nonpolar lipid molecule that is made amphipathic by the addition of a phosphate

Nucleic acids are polymers made up of which of the following monomers?

nucleotides

Why is each element unique with respect to its chemical properties? Each element has a distinctive _________.

number of protons

Which is the smallest unit containing the entire human genome?

one male somatic cell

A covalent bond is likely to be polar when ________.

one of the atoms sharing electrons is more electronegative than the other atom

A covalent chemical bond is one in which _________.

outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals.

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

oxidation of pyruvate to acetyl CoA and the citric acid cycle

Which of the following produced the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide and water?

oxidative phosphorylation (chemiosmosis)

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes _______.

oxidized

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is ________.

oxygen

If a cell has accumulated DNA damage, it is unlikely to ______.

pass the G2 checkpoint

Which bonds are created during the formation of the primary structure of a protein?

peptide bonds

Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen?

peroxisomes

Which of the following types of molecules are the major structural components of the cell membrane?

phospholipids and proteins

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atoms by ________.

polar covalent bonds

Lipids that form membranes have what kind of structure?

polar heads and nonpolar tails; the polar heads interact with water

The normal function of a tumor suppressor gene is to ______.

prevent progression of the cell cycle unless conditions are right for moving forward

Eukaryotes have three nuclear RNA polymerases. The primary function of RNA polymerase II is transcription of _____.

protein-coding genes

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

proteins

Which of the following are directly associated with photosystem I?

receiving electrons from the thylakoid membrane electron transport chain (ETC)

Why are polymerization reactions endergonic? Polymerization reactions _______.

reduce entropy

Which process is most directly driven by light energy?

removal of electrons from chlorophyll molecules

Which of the following does NOT occur during mitosis?

replication of the DNA Does occur: separation of the spindle poles condensation of the chromosomes spindle formation separation of sister chromatids

Which structure is the site of the synthesis of proteins that may be exported from the cell?

rough ER

Which level of protein structure do the α-helix and the β-pleated sheet represent?

secondary

DNA synthesized through a process is known as______.

semiconservative replication

The mitotic spindle is a microtubular structure that is involved in ______.

separation of sister chromatids

The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different ______.

sets of regulatory proteins

In eukaryotic cells, transcription cannot begin until ______.

several transcription factors have bound to the promoter

Which of the following help(s) to hold the DNA strands apart while they are being replicated?

single-strand DNA binding proteins

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?

smooth endoplasmic reticulum

When oxygen is released as a result of photosynthesis, it is a direct by-product of _______.

splitting water molecules

Proto-oncogenes ______.

stimulate normal cell growth and division

Where do the enzymatic reactions of the Calvin cycle take place?

stroma of the chloroplast

The ATP made during fermentation is generated by ________.

substrate-level phosphprylation

Catabolic pathways ________.

supply energy, primarily in the form of ATP, for the cell's work

Which of the following occurs in meiosis but not in mitosis?

synapsis of chromosomes

What is the primary function of the Calvin cycle?

synthesizing simple sugars from carbon dioxide

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's _______.

target cell

At which level of protein structure are interactions between the side chains (R-groups) most important?

tertiary

Reactions that require CO2 take place in _______.

the Calvin cycle alone

What is the major structural difference between starch and glycogen?

the amount of branching that occurs in the molecule

What ensures that the correct amino acid is added during translation?

the anticodon of a property formed aminoacyl tRNA

The complexity and variety of organic molecules is due to _______.

the chemical versatility of carbon atoms

What component of amino acid structure varies among different amino acids?

the components of the R-group

What provides the energy for the polymerization reactions in DNA synthesis?

the deoxyribonucleotide triphosphate substrates

Which of the following is an exception to the central dogma?

the discovery of RNA viruses that synthesis DNA in reverse transcriptase

What is a telomere?

the ends of linear chromosomes

Which of the following events takes place in the electron transport chain?

the extraction of energy from high-energy electrons remaining from glycolysis and the citric acid cycle

The leading and lagging strand differ in that ______.

the leading strand is synthesized in the same direction of the replication fork, and the lagging strand is synthesized in the opposite direction

In a bacterium, we will find DNA in _______.

the nucleoid

There should be a strong positive correlation between the rate of protein synthesis and _______.

the number of ribosomes

Cell differentiation always involves ______.

the production of tissue-specific proteins, such as muscle actin

Independent assortment of chromosomes is a result of ________.

the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I

There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that _____.

the rules for base pairing between the third base of a codon and tRNA are flexible

Which of the following do starch and cellulose have in common?

the size of their monosaccharide subunits

Which of the following is the first event to take place in translation in eukaryotes?

the small subunit of the ribosome recognizing and attaching to the 5' cap of mRNA

What is/are the variable structure(s) of a nucleotide?

the sugar and the base

Which of the following is directly related to a single amino acid?

the three-base sequence of mRNA

Some bacteria are metabolically active in hot springs because ________.

their enzymes have high optimal temperatures

What is the main purpose of light-dependent reactions of photosynthesis?

to produce NADPH and ATP

Enthalpy (H) is the ______.

total energy in biological systems

Regulatory proteins that prevent a cell from entering the S phase under conditions of DNA damage are also known as ______.

tumor supressors

Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?

two

The tertiary structure of a protein is the _______.

unique three-dimensional shape of the fully folded polypeptide

Which organelle often takes up much of the volume of a plant cell?

vacuole

The electron of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?

water

Under what circumstances does membrane transport require energy?

whenever a solute is moved against its electrochemical gradient

The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct?

ΔG is the change in free energy.