Final Cell Bio

"The flow of genetic information is controlled by a series of biochemical reactions that result in the production of proteins, each with its own specific order of amino acids. Choose the correct series of biochemical reactions from the options presented here." -"replication, transcription, translation" -"replication, translation, transcription" -"translation, transcription, replication" -"translation, replication, transcription"

"replication, transcription, translation"

Which of the following steps or processes in aerobic respiration include the production of carbon dioxide? (a) breakdown of glycogen (b) glycolysis (c) conversion of pyruvate to acetyl CoA (d) oxidative phosphorylation

(c) conversion of pyruvate to acetyl CoA

Operons ___________________________. -are commonly found in eukaryotic cells. -are transcribed by RNA polymerase II. - contain a cluster of genes transcribed as a single mRNA. -can only be regulated by gene activator proteins.

- contain a cluster of genes transcribed as a single mRNA.

"Select the option that correctly finishes the following statement: ""A cell's genome _________________."" -is defined as all the genes being used to make protein. - contains all of a cell's DNA. -"constantly changes, depending upon the cell's environment." -is altered during embryonic development.

- contains all of a cell's DNA.

Membrane curvature is influenced by the differential lipid composition of the two membrane monolayers. Which factor do you think has the largest impact on the curvature of biological membranes? -amount of cholesterol -charge of the lipid head group -length of the hydrocarbon tails -size of the lipid head group

-size of the lipid head group

There are two properties of phospholipids that affect how tightly they pack together: the length of the hydrocarbon chain and the number of double bonds. The degree of packing, in turn, influences the relative mobility of these molecules in the membrane. Which of the following would yield the most highly mobile phospholipid (listed as number of carbons and number of double bonds, respectively)? 24 carbons with 1 double bond 15 carbons with 2 double bonds 20 carbons with 2 double bonds 16 carbons with no double bonds

15 carbons with 2 double bonds

Which statement is NOT true about mutations? -A mutation is a change in the DNA that can generate offspring less fit for survival than their parents. -A mutation can be a result of imperfect DNA duplication. -Correct A mutation is a result of sexual reproduction. -A mutation is a change in the DNA that can generate offspring that are as fit for survival as their parents are.

A mutation is a result of sexual reproduction.

Modern eukaryotes depend on mitochondria to generate most of the cell's ATP. How many molecules of ATP can a single molecule of glucose generate? A. 30 B. 20 C. 2 D. 36

A. 30e

In the final stage of the oxidation of food molecules, a gradient of protons is formed across the inner mitochondrial membrane, which is normally impermeable to protons. If cells were exposed to an agent that causes the membrane to become freely permeable to protons, which of the following effects would you expect to observe? A. The ratio of ATP to ADP in the cytoplasm would fall. B. The consumption of oxygen would fall. C. Carbon dioxide production would cease. D. NADH would build up.

A. The ratio of ATP to ADP in the cytoplasm would fall.

Glycolysis generates more stored energy than it expends. What is the net number of activated carrier molecules produced in this process (number and type of molecules produced minus the number of those molecules used as input)? A. 6 ATP, 2 NADH B. 2 ATP, 2 NADH C. 4 ATP, 4 NADH D. 4 ATP, 2 NADH

B. 2 ATP, 2 NADH

Which of the following is not part of the process known as oxidative phosphorylation? A. Molecular oxygen serves as a final electron acceptor. B. ATP molecules are produced in the cytosol as glucose is converted into pyruvate. C. FADH2 and NADH become oxidized as they transfer a pair of electrons to the electron-transport chain. D. The electron carriers in the electron-transport chain toggle between reduced and oxidized states as electrons are passed along.

B. ATP molecules are produced in the cytosol as glucose is converted into pyruvate.

Several different classes of enzymes are needed for the catabolism of carbohydrates. Which of the following descriptions best matches the function of a kinase? A. An enzyme that catalyzes the oxidation of a molecule by removing a hydride ion. B. An enzyme that catalyzes the addition of phosphate groups to other molecules. C. An enzyme that catalyzes a change in the position of a specific chemical group within a single molecule. D. An enzyme that catalyzes the rearrangement of bonds within a single molecule.

B. An enzyme that catalyzes the addition of phosphate groups to other molecules.

Which of the following statements describes the mitochondrial outer membrane? A. It contains transporters for ATP molecules. B. It is permeable to molecules with molecular mass as high as 5000 daltons. C. It contains enzymes required for the oxidation of fatty acids. D. It contains proteins that are released during apoptosis.

B. It is permeable to molecules with molecular mass as high as 5000 daltons.

Which of the following statements about a protein in the lumen of the ER is false? A. Some of the proteins in the lumen of the ER can end up in the lumen of an organelle in the endomembrane system. B. Some of the proteins in the lumen of the ER can end up in the plasma membrane. C. A protein in the lumen of the ER is synthesized by ribosomes on the ER membrane. D. Some of the proteins in the lumen of the ER can end up in the extracellular space.

B. Some of the proteins in the lumen of the ER can end up in the plasma membrane.

Pyruvate can be converted into many other molecules by various biosynthetic and metabolic pathways, which makes it a central hub in the regulation of cellular metabolism. Which of the following molecules is not made from pyruvate? A. ethanol B. lactate C. NADH D. oxaloacetate

C. NADH

Stage 1 of oxidative phosphorylation requires the movement of electrons along the electron-transport chain coupled to the pumping of protons into the intermembrane space. What is the final result of these electron transfers? A. pyruvate is oxidized to CO2 B. OH- is oxidized to O2 C. O2 is reduced to H2O D. H- is converted to H2

C. O2 is reduced to H2O

Which of the following statements is true? A. Because bacteria do not have mitochondria, they cannot produce ATP in a membrane-dependent fashion. B. Chloroplasts and mitochondria share their DNA. C. The nuclear membrane is thought to have arisen from the plasma membrane invaginating around the DNA. D. Lysosomes are believed to have originated from the engulfment of bacteria specialized for digestion.

C. The nuclear membrane is thought to have arisen from the plasma membrane invaginating around the DNA.

Select the best option to fill in the blanks of the following statement: Fermentation is a/an _____________________ process that converts _____________ into carbon dioxide and _____________________. A. prokaryotic, lactate, propanol B. eukaryotic, glyceraldehyde 3-phosphate, ethanol C. anaerobic, pyruvate, ethanol D. anaerobic, lactate, ethanol

C. anaerobic, pyruvate, ethanol

In anaerobic conditions, skeletal muscle produces _____________. A. ethanol and CO2. B. lactate and CO2. C. lactate only. D. ethanol only.

C. lactate only.

In stage 1 of photosynthesis, a proton gradient is generated and ATP is synthesized. Where do protons become concentrated in the chloroplast? A. inner membrane B. stroma C. thylakoid space D. thylakoid membrane

C. thylakoid space

During respiration, energy is retrieved from the high-energy bonds found in certain organic molecules. Which of the following, in addition to energy, are the ultimate products of respiration? CO2, H2O CH3, H2O CH2OH, O2 CO2, O2

CO2, H2O

NADH contains a high-energy bond that, when cleaved, donates a pair of electrons to the electron-transport chain. What are the immediate products of this bond cleavage? A. NAD- + H+ B. NAD+ + OH- C. NAD + H D. NAD+ + H-

D. NAD+ + H-

Which of the following statements about G-protein-coupled receptors (GPCRs) is false? A. GPCRs are used in endocrine, paracrine, and neuronal signaling. B. GPCRs are the largest family of cell-surface receptors in humans. C. GPCRs are found in yeast, mice, and humans. D. The different classes of GPCR ligands (proteins, amino acid derivatives, or fatty acids) bind to receptors with different numbers of transmembrane domains.

D. The different classes of GPCR ligands (proteins, amino acid derivatives, or fatty acids) bind to receptors with different numbers of transmembrane domains.

Glycolysis is an anaerobic process used to catabolize glucose. What does it mean for this process to be anaerobic? A. glucose is broken down by the addition of electrons B. it takes place in the lysosome C. no oxidation occurs D. no oxygen is required

D. no oxygen is required

TRUE OR FALSE. Enzymes alter the equilibrium point of a reaction.

False

TRUE OR FALSE. The ultimate source of energy for living systems is chlorophyll.

False

DNA and RNA are different types of nucleic acid polymer. Which of the following is TRUE of DNA but not TRUE of RNA? It contains uracil. It contains thymine. It is single-stranded. It has 5′-to-3′ directionality.

It contains thymine.

Which of the following molecules is thought to have arisen first during evolution? protein DNA RNA all came to be at the same time

RNA

Unlike DNA, which typically forms a helical structure, different molecules of RNA can fold into a variety of three-dimensional shapes. This is largely because ___________________. RNA contains uracil and uses ribose as the sugar. RNA bases cannot form hydrogen bonds with each other. RNA nucleotides use a different chemical linkage between nucleotides compared to DNA. RNA is single-stranded.

RNA is single-stranded.

Transcription in bacteria differs from transcription in a eukaryotic cell because __________________________. RNA polymerase (along with its sigma subunit) can initiate transcription on its own. RNA polymerase (along with its sigma subunit) requires the general transcription factors to assemble at the promoter before polymerase can begin transcription. the sigma subunit must associate with the appropriate type of RNA polymerase to produce mRNAs. RNA polymerase must be phosphorylated at its C-terminal tail for transcription to proceed.

RNA polymerase (along with its sigma subunit) can initiate transcription on its own.

Which of the following statements about prokaryotic mRNA molecules is false? -A single prokaryotic mRNA molecule can be translated into several proteins. -Ribosomes must bind to the 5â ² cap before initiating translation. -mRNAs are not polyadenylated. -Ribosomes can start translating an mRNA molecule before transcription is complete.

Ribosomes must bind to the 5â ² cap before initiating translation.

The ribosome is important for catalyzing the formation of peptide bonds. Which of the following statements is true? - The number of rRNA molecules that make up a ribosome greatly exceeds the number of protein molecules found in the ribosome. - The large subunit of the ribosome is important for binding to the mRNA. - The catalytic site for peptide bond formation is formed primarily from an rRNA. - Once the large and small subunits of the ribosome assemble, they will not separate from each other until degraded by the proteasome.

The catalytic site for peptide bond formation is formed primarily from an rRNA.

Which of the following statements about resting membrane potential is not true? -The resting membrane potential for most animal cells is 0 mV, because the positive and negative ions are in balance. -The resting membrane potential for most animal cells is positive, because Na+ ions are so plentiful inside cells. - The resting membrane potential for most animal cells is negative, because the inside of the cell is more negatively charged than the outside of the cell. - At the resting membrane potential, no ions enter or exit the cell.

The resting membrane potential for most animal cells is negative, because the inside of the cell is more negatively charged than the outside of the cell.

Carbon-based compounds make up the vast majority of molecules found in cells

True

Electron shells fill discrete regions around the nucleus of the atom and limit the number of electrons that can occupy a specific orbit. True False

True

Several different classes of enzymes are needed for the catabolism of carbohydrates. Which of the following descriptions best matches the function of an isomerase? A. An enzyme that catalyzes the rearrangement of bonds within a single molecule. B. An enzyme that catalyzes the oxidation of a molecule by removing a hydride ion. C. An enzyme that catalyzes a change in the position of a specific chemical group within a single molecule. D. An enzyme that catalyzes the addition of phosphate groups to other molecules.

a) an enzyme that catalyzes the rearrangement of bonds within a single molecule

Several different classes of enzymes are needed for the catabolism of carbohydrates. Which of the following descriptions best matches the function of a dehydrogenase? A. An enzyme that catalyzes the rearrangement of bonds within a single molecule. B. An enzyme that catalyzes the oxidation of a molecule by removing a hydride ion. C. An enzyme that catalyzes a change in the position of a specific chemical group within a single molecule. D. An enzyme that catalyzes the addition of phosphate groups to other molecules.

a. An enzyme that catalyzes the rearrangement of bonds within a single molecule.

Pumps are transporters that are able to harness energy provided by other components in the cells to drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called _____________. active transport. free diffusion. facilitated diffusion. passive transport.

active transport.

"Proteins are important architectural and catalytic components within the cell, helping to determine its chemistry, its shape, and its ability to respond to changes in the environment. Remarkably, all of the different proteins in a cell are made from the same 20 __________. By linking them in different sequences, the cell can make protein molecules with different conformations and surface chemistries, and therefore different functions." nucleotides. sugars. amino acids. fatty acids.

amino acids.

There are two properties of phospholipids that affect how tightly they pack together: the length of the hydrocarbon chain and the number of double bonds. The degree of packing, in turn, influences the relative mobility of these molecules in the membrane. Which of the following would yield the most highly mobile phospholipid (listed as number of carbons and number of double bonds, respectively)? Select one: a. 24 carbons with 1 double bond b. 15 carbons with 2 double bonds c. 20 carbons with 2 double bonds d. 16 carbons with no double bonds

b. 15 carbons with 2 double bonds

The tryptophan operator ___________________________. - is an allosteric protein. - binds to the tryptophan repressor when the repressor is bound to tryptophan. - is required for production of the mRNA encoded by the tryptophan operon. - is important for the production of the tryptophan repressor.

binds to the tryptophan repressor when the repressor is bound to tryptophan.

Changes in DNA sequence from one generation to the next may result in offspring that are altered in fitness compared with their parents. The process of change and selection over the course of many generations is the basis of __________. mutation. evolution. heredity. reproduction.

evolution.

Where does most new membrane synthesis take place in a eucaryotic cell? Select one: a. in the Golgi apparatus b. in the endoplasmic reticulum c. in the plasma membrane d. in the mitochondria e. on ribosomes

in the endoplasmic reticulum

Foreign substances like nicotine, morphine, and menthol exert their initial effects by _____. A. killing cells immediately, exerting their physiological effects by causing cell death. B. removing cell-surface receptors from the plasma membrane. C. diffusing through cell plasma membranes and binding to transcription factors to change gene expression. D. interacting with cell-surface receptors, causing the receptors to transduce signal inappropriately in the absence of the normal stimulus.

interacting with cell-surface receptors, causing the receptors to transduce signal inappropriately in the absence of the normal stimulus.

Double covalent bonds are both shorter and stronger than single covalent bonds, but they also limit the geometry of the molecule because they ____________________. - create a new arrangement of electron shells. - change the reactivity of the bonded atoms. - limit the rotation of the bonded atoms. - prevent additional bonds from being formed with the bonded atoms.

limit the rotation of the bonded atoms.

Cholesterol serves several essential functions in mammalian cells. Which of the following is not influenced by cholesterol? membrane permeability membrane fluidity membrane rigidity membrane thickness

membrane thickness

Carbon 14 is an unstable isotope of carbon that decays very slowly. Compared to the common, stable carbon 12 isotope, carbon 14 has two additional ______________. electrons. neutrons. protons. ions.

neutrons

Your body extracts energy from the food you ingest by catalyzing reactions that essentially "burn" the food molecules in a stepwise fashion. What is another way to describe this process? reduction oxidation dehydration solvation

oxidation

Osmosis describes the movement of water across a biological membrane and down its concentration gradient. In chemiosmosis, useful energy is harnessed by the cell from the movement of _______________ across the inner mitochondrial membrane into the matrix _________________ a concentration gradient. A. electrons, down B. ADP, against C. protons, down D. ATP, against

protons down

The sigma subunit of bacterial RNA polymerase ___________________. contains the catalytic activity of the polymerase. remains part of the polymerase throughout transcription. recognizes promoter sites in the DNA. recognizes transcription termination sites in the DNA.

recognizes promoter sites in the DNA.

A covalent bond between two atoms is formed as a result of the ______________. sharing of electrons. loss of electrons from both atoms. loss of a proton from one atom. transfer of electrons from one atom to the other.

sharing of electrons

A neuron and a white blood cell have very different functions. For example, a neuron can receive and respond to electrical signals while a white blood cell defends the body against infection. This is because ______. - the proteins found in a neuron are completely different from the proteins found in a white blood cell. - the neuron and the white blood cell within an individual have the same genome. - the neuron expresses some mRNAs that the white blood cell does not. - neurons and white blood cells are differentiated cells and thus no longer need to transcribe and translate genes.

the neuron expresses some mRNAs that the white blood cell does not.

Using genetic engineering techniques, you remove the sequences that code for the ribosome-binding sequences of the bacterial LacZ gene. The removal of these sequences will lead to ___________. -more LacZ protein produced due to faster ribosome movement across the LacZ mRNA. -transcriptional repression, resulting in fewer mRNA molecules produced from this gene. - a longer half-life for the LacZ mRNA. -translational inhibition of the LacZ mRNA.

translational inhibition of the LacZ mRNA.

Which of the following is true for a reaction at equilibrium? ΔG = ΔG° ΔG° + RT ln [X]/[Y] = 0 RT ln [X]/[Y] = 0 ΔG + ΔG° = RT ln [X]/[Y]

ΔG° + RT ln [X]/[Y] = 0