BIS 2A final set
In eukaryotic cells the pre-mRNA undergoes processing. Check the following options that are a type of mRNA processing.
*5'G Cap *3' Poly A tail *removal of introns
RuBisCo is considered to be an inefficient enzyme because:
*It is unusually slow for an enzyme. *It uses the wrong substrate ¼ of the time. *It produces the wrong product ¼ of the time.
Cells contain multiple motor proteins that travel along the cytoskeleton filaments to transport vesicles to and from different compartments in the cell. Which of the following are the problem/sub-problems that are solved by the motor protein-cytoskeleton partnership?
*Large cell size *Energy requirements for large cells.
A common electron carrier we will use a lot in this class is ________________ when it is in the oxidized state and ________________ when it is in the reduced state.
*NAD *NADH
What are the three components of a nucleotide?
*Nitrogenous base *Phosphate group *5 carbon sugar (Ribose)
What does OIL RIG mean?
*Oxidation is loss of electrons *Reduction is gain of electrons
When would a cell use Passive Transport?
*When the cell needs to move a compound that cannot move freely through the membrane. *When the cell needs to move a compound down its concentration gradient.
The two strands of the DNA are ______________to each other such that at the end of the DNA one strand will be 3' paired with a 5' end. The two strands of the DNA are held together with ________________bonds. In DNA, A binds with_________ and G binds with_____________ . _________________unwinds the DNA for replication to begin. An RNA primer is created by enzyme ______________which then supplies the___________ (3 or 5)' hydroxyl group used by________________- to start adding DNA nucleotides. The DNA strand is made from_________ (3 or 5)' to_____________ (3 or 5)'. The_____________ (leading or lagging) strand is made in short segments called okazaki fragments. The______________ (leading or lagging) strand is made in one continuous piece. After replication, the RNA primers are removed by enzyme _______________-and replaced with DNA nucleotides. The enzyme ____________ seals the nicks in the sugar-phosphate backbone after the RNA primers are removed. On linear chromosomes the enzyme _____________ extends the ends by creating a repeating sequence of nucleotides which helps prevent loss of genetic material with each replication.
*antiparallel *hydrogen *t *c *dna helicase *rna primase *3 *dna polymerase 3 *5 *3 *lagging *leading *dna polymerase 1 *dna ligase *telomerase
The reaction C6H12O6 + 6O2 --> 6CO2 +6H2O + energy is a reaction you have probably seen before. 1. The reactant C6H12O6 enters your body through_____________ 2. The reactant 6O2 enters your body through __________________ 3. The product 6CO2 leaves your body through __________________
*food *breathing *breathing
In prophase I, _________________(sister chromatids or homologous chromosomes) are held together by ____________, which, once resolved, create a cross over event. In anaphase I, the homologous chromosomes separate. In anaphase II, the_______________ separate. The end result of Meiosis is 4 __________________(identical or unique) cells.
*homologous chromosomes *chiasmata *sister chromatids *unique
Photosynthesis Energy in ____________ is absorbed by an electron in a photocenter. This energy is converted from light energy into chemical energy into kinetic energy as the energized electron is used in back to back REDOX reactions in the electron transport chain, ETC. The ETC creates _________________which is used by the cell to power the formation of ATP. In ______________(cyclic or non-cylic) photosynthesis the electron returns to the photocenter. In _________________(cyclic or non-cyclic) photosynthesis the electron reduces NADP+ to form________________ .
*light *PMF *cyclic *non-cyclic *NADPH
Oxidation of glucose means:
*loss of electrons from glucose *oxidation of glucose
The ____________terminus denotes the beginning of a protein chain (first amino acid in the chain) and the ___________terminus denotes the end of a protein chain (the last amino acid in the chain).
*n *c
Oxidative Phosphorylation A metabolic pathway that ____________________ (oxidizes or reduces) an energy-rich source to produce ATP from ADP. Electrons are transferred from electron _________________(donors or acceptors) to compounds with a _________________ (weaker or stronger) reduction potential. As electrons move through an electron transport chain, ETC, the energy in the electron is used to pump_________________ across a membrane. The pumping of these molecules against their concentration gradient is a form of ________________ transport. The movement of these molecules back into the cell (down their concentration gradient) releases energy which the cell couples to the formation of_________________ .
*oxidizes *donors *stronger *protons *active *ATP
The first phase of Mitosis is____________ . In this phase the DNA condenses down into compact____________- , and the duplicated_______________ separate. The second phase of Mitosis is ______________. In this phase the sister chromatids line up on the_____________ plate through a push and pull motion as they connect to the microtubule spindle fibers emanating from the___________ . The third phase of Mitosis is _________________-. In this phase the ________________(sister chromatids or homologous chromosomes) are pulled apart. The fourth phase of Mitosis is _________________. In this phase the nuclear ______________starts to reform and the DNA de-condenses.
*prophase *chromatin *centrosome *metaphase *metaphase *centrosomes *anaphase *sister chromatids *telophase *membrane
The cell membrane is considered __________________because it only allows certain compounds to travel through freely. The random movement of molecules down their concentration gradient is called:___________ Moving down a concentration gradient means moving from a ___________(lower or higher) to a ___________(lower or higher) concentration. Some compounds need to travel into the cell through a membrane protein, this is an example of _________________. When compounds are pumped against their concentration gradient they are being moved from __________(lower or higher) to_____________ (lower or higher) by this type of transport:_______________ The majority of the cell membrane is composed of what type of lipids?___________
*selective permeability *diffusion *higher *lower *facilitated diffusion *lower *higher *active *phospholipids
The process of ____________-makes an RNA copy from a DNA template. The RNA is made by the enzyme___________ which makes the RNA from__________ (3 or 5)' to_______________ (3 or 5)'. The process of ____________makes a protein from an mRNA. The protein is made by the ___________- which catalyzes the peptide bond between each amino acid. In bacterial cells these two processes occur in the cytoplasm. However, in eukaryotes the process _________ occurs in the nucleus and the process __________ occurs in the cytoplasm
*transcription *rna polymerase *5 *3 *translation *ribosome *transcription *translation
A chemical reaction occurs in a test tube in lab. During the reaction, "reactants" gradually become "products" until equilibrium is reached. At equilibrium:
*∆G = 0 *Some molecules of reactant become product, and some molecules of product become reactant.
Which atoms would you consider more electronegative than carbon?
- Fluorine -Oxygen -Nitrogen
In thermodynamics, a living organism is an example of a...
...open system
Which of the statements below best describes covalent bonds?
...the sharing of an electron pair between two atoms; a relatively strong bond.
List the following molecules by their diffusion rate through a membrane (list the molecules that can diffuse most easily first). 1: O₂, 2: glucose, 3: water.
1, 3, 2.
Fill in the blanks below by pairing each of these macromolecules with its building block (lipid, carbohydrate, nucleotide or amino acid). ________________ -> Starch ________________ -> protein ________________ -> nucleic acid ________________ -> triglyceride
1. Carbohydrate 2. Amino Acid 3. Nucleotide 4. Lipid
This is a reaction that you can find the two half reactions for on a REDOX tower in your discussion manual: NAD+ +H2 --> NADH + 2H+ 1. Which compound is the electron donor?_______________ 2. Which compound is the electron acceptor?_______________ 3. When the electron donor loses the electron it becomes:____________ 4. When the electron acceptor accepts the electron it becomes:____________ 5. Overall the electron travels from:________________
1. H2 2. NAD+ 3. 2H+ 4. NADH 5.H2 and NAD+
Match the correct stage of protein folding to the description. 1. Primary: 2 Secondary: 3. Tertiary: 4. Quaternary:
1. Sequence of amino acids 2. Hydrogen bonds are formed through the backbone atoms 3. Hydrogen bonds, ionic bonds, covalent bonds are formed through the R group 4. Multiple proteins in the tertiary state come together to form a larger functioning enzyme
When a mutation occurs in the DNA sequence the protein sequence may or may not change. Match up the mutation with the resulting phenotype. Nonsense - > Missense -> silent mutation -> frameshift mutation ->
1. codons for a stop 2.codons for a diff. amino acid 3.codons for the same amino acid 4.codons and subsequent codons for the wrong amino acid
Understanding the REDOX tower. 1. More negative E values mean:__________ 2. More positive E values mean:___________ 3. Compounds on the right side of the slash are: _______________ 4. Compounds on the left side of the slash are:_____________________
1. more likely to donate electrons 2.more likely to accept electrons 3. the reduced form of the compound 4. the oxidized form of the compound
What is the complementary base sequence to this strand of DNA? 5' -ATGGTCGTAGTGA-3
3'- TACCAGCATCACT-5'
An mRNA has the sequence 5'-AUGAAAUCCUAG-3'. What is the template DNA strand for this sequence?
3'-TACTTTAGGATC-5'.
Sort the following items in the order in which they occurred: 1. Eukaryotes evolve 2. Oceans present on Earth 3. Collision of the Earth with the planetoid Theia 4. Photosynthesis evolves 5. Cyanobacteria evolve a pathway to oxidize water
3, 2, 4, 5, 1
Approximately how many possible gamete genotypes are possible when a human organism has 23 chromosome pairs (one from the biological mother and one from the biological father)? A) 2²³ = 8x10⁶. B) 46. C) 23. D) 2.
A
Which is NOT a function of chiasmata? A) Keep the sister chromatids together in prophase of mitosis. B) Promote genetic exchange between sister chromatids in meiosis. C) Allow homologous chromosomes to be pulled together to opposite poles of the cell in meiosis. D) None (i.e. all of the above are functions of chiasmata).
A
Which of the following statement is correct regrading poly(A) tails in eukaryotic mRNAs? B) Reduced mRNA poly(A) tail length is associated with greater mRNA stability and lifespan in the cytoplasm. A) Increased mRNA poly(A) tail length is associated with greater protein translation per mRNA transcript. D. The poly(A) tail is non-functional and added randomly to transcripts. C. The poly(A) tail is a molecular motor that helps the mRNAs swim in the cytoplasm.
A
How are the three domains of life related?
A bacterium and an archean became symbionts; some of their descendants later evolved into eukaryotes.
Which of the following is most likely to cause the most long-lasting damage in an organism? Assume the gene is essential for the organism's survival.
A nonsense mutation in DNA
What's the difference between a photosystem (ie, PSI) and a photoreaction center (ie, P700)?
A photosystem contains many pigments and proteins, but only a subset of these pigments (the photoreaction center) can actually perform photochemistry- donating electrons to an ETC.
A small inhibitory molecule binds to the regulatory site on an enzyme, resulting in a change of the protein's shape, which makes the active site inaccessible to the substrate. This change in shape is probably due to:
A rearrangement of the tertiary or quaternary structure that extends from the regulatory site to the active site.
A protein that forms an ion channel through a membrane is most likely to be...
A transmembrane protein.
The sub-problem of__________, is solved by __________. A) Lining up the sister chromatids in metaphase, The equal push and pull of the spindle fibers on each sister chromatid. B) Condensing down the DNA, Motor proteins moving the DNA into tight spheres. C) Separating the sister chromatids, The protein cohesin. D) Generating two copies of each chromosome, Fertilization.
A) Lining up the sister chromatids in metaphase, The equal push and pull of the spindle fibers on each sister chromatid.
Oxidative phosphorylation of ATP is directly powered by: A) The negative ∆G of protons moving down a gradient. B) The positive ∆G of protons moving down a gradient. C) Redox reactions during the breakdown of glucose via glycolysis and fermentation. D) Redox reactions during pyruvate oxidation and the citric acid cycle.
A) The negative ∆G of protons moving down a gradient.
Assume that the two thick black lines represent a double-stranded DNA molecule and the box represents a gene which is transcribed in the direction of the arrow. The letters below correspond to sites that can be found in the DNA that regulate transcription and translation. What is the correct order of the sites on the DNA?Assume everything is written from 5' to 3'. A. 5' end B. 3' end C. Translational Stop D. Transcriptional stop E. Promoter F. Ribosome binding site G. Translational start H. Transcriptional start
A, E, H, F, G, C, D, B
What happens to ATP when you "use" it?
ATP is converted into ADP which can be recycled back into ATP.
NADH does NOT play a direct role in:
ATP synthesis by ATP synthase.
Your muscle cells, nerve cells, and skin cells have different functions because each kind of cell:
Activates different genes.
We have only one genome, but, many, many transcriptomes and proteomes. Why is this? Because: *Each cell type has a unique transcriptional and proteomic profile according to its function. *Organisms may only express certain genes at certain times in their life cycle. *Different organs have different metabolic needs, which require the presence of different proteins.
All of the above
What parts of metabolism occur in and require the membrane? *Electron transport *PMF formation. *ATP synthesis. *Light reaction of photosynthesis.
All of the above
You are given a diagram of an mRNA. What features could you use to tell whether it is a eukaryotic or prokaryotic mRNA? *Poly(A) tail. *5'-methyl-G cap *Presence of one or multiple genes (i.e. protein coding regions, cistrons, or open reading frames).
All of the above
The "Hydrogen hypothesis" suggests that...
An archean "teamed up" with a bacterium that provided it with hydrogen (H2); this symbiont evolved into present-day eukaryotes.
In photosynthesis, the source of electrons for NADPH formation is
An external electron donor
A glucose molecule is processed through glycolysis, pyruvate oxidation, and the TCA cycle only. The molecule is completely oxidized to CO2, a process that involves a substantial loss of free energy (a negative ∆G). At this point, in what form is some of that energy retained by the cell?
As ATP and NADH.
Which below are "pros" (advantages) of meiosis, that is producing the next generation with a mate? A) Finding a mate takes time B) Meiosis generates genetic variation C) Meiosis is energetically expensive D) Has a slower generation time
B
Which of the following statements is true about the mitotic spindle apparatus? A) Spindle fibers are made up of centrioles. B) Spindle fibers are made up of microtubules. C) Spindle fibers are made up of microfilaments. D) Spindle fibers bring together sister chromatids. E)More than one of the above statements is true.
B
A eukaryotic cell wants to ensure an mRNA is transcribed pretty much all the time (i.e. constitutive expression or "always on"). Which of the following mechanisms would NOT help the cell to reach that goal? A) A long poly-A tail on the 3' end of the mRNA B) Extensive methylation of histones around the DNA encoding the mRNA, resulting in tightly packed nucleosomes C) Acetylation of histones around the DNA encoding the mRNA, resulting in loose packing of nucleosomes
B) Extensive methylation of histones around the DNA encoding the mRNA, resulting in tightly packed nucleosomes
Why are mutations in the third codon positions often called synonymous mutations? (Note: "synonymous" means "the same").
Because third codon changes often lead to the same amino acid.
The first few steps of glycolysis are referred to as the "investment" phase. Why is that? A) Because they have a negative ∆G. B) Because NAD+ is made. C) Because they generate ATP from ADP + Pi. D) Because you lose some ATP, turning them into ADP, in these steps. E) Because they have a positive ∆G.
Because you lose some ATP, turning them into ADP, in these steps.
Cell division in bacteria takes place mainly by:
Binary fission.
Respiration and the light reactions of photosynthesis have several features in common. Which of the following is NOT a common feature?
Both reduce NAD+ to NADH, thereby generating reducing power for anabolic reactions.
A scientist discovers a new eukaryotic species that is diploid and has 12 pairs of chromosomes. They conduct additional experiments to determine the species undergoes meiosis to generate gametes. Approximately how many possible gamete genotypes can this organism generate through independent assortment (that is, ignoring crossing over events)? Assume the math is correct within each answer. A) 2²³ = 8 x 10⁶ B) 12 C)2¹² = 4,096 D)2
C
Which is NOT a key difference between meiosis and mitosis? A) In metaphase of meiosis I, both kinetochores are attached to same pole. B) In meiosis I, homologous chromosomes pair with each other during prophase I & homologs segregate from each other, NOT chromatids. C) DNA condenses. D) Attachments between homologs are done by chiasma (chiasmata) crossing over in meiosis and not mitosis.
C
Order the four steps in eukaryotic gene expression below from beginning to end. (1) Pre-mRNA is processed to make mRNA. (2) Ribosomes translate the mRNA message to make proteins. (3) mRNA is transported to the cytoplasm. (4) DNA is used as a template make pre-mRNA.
C) 4; 1; 3; 2
In eukaryotes, DNA wraps around histone proteins to make nucleosomes. Histone acetylation causes nucleosomes _______________, thus we would expect to see more acetylation in areas if the genome that ________________. A) to pack loosely, do not experience high levels of transcription B) to pack tightly, are transcribed regularly C) to pack loosely, are transcribed regularly D) none of the above
C) to pack loosely, are transcribed regularly
Which of these bonds would you consider a polar covalent bond? C-O C-H C-C H-N H-O
C-O H-N H-O
Glucose is processed via glycolysis, pyruvate oxidation, and the citric acid cycle. What is left of the original glucose molecule when this processing is complete? A) Acetyl coA, CO2, and 2 ATP's. B) Water and CO2, plus energy stored in many (30+) ATP's. C) 2 Pyruvates and some energy stored as ATP. D) CO2, some energy (stored as ATP), and some high-energy electrons (stored as NADH and FADH2). E) 2 Oxaloacetates, a few ATP's built by substrate-level phosphorylation, and 6 CO2.
CO2, some energy (stored as ATP), and some high-energy electrons (stored as NADH and FADH2).
Ecosystems exist deep under the ocean, where no light penetrates. The chemical disequilibrium at deep sea vents provides energy and electrons that are captured by __________, which then act as fuel sources for __________.
Chemoautotrophs, organotrophs.
In living things, the two major components of G, "Potential energy", are
Concentration and Molecular Structure
In diagram #1, which arrow represents the activation energy for the forward (left to right) reaction?
D
The total DNA content of each daughter cell is reduced during meiosis because: C) half of the chromosomes from each gamete are lost during fertilization B) chromosomes do not replicate between meiosis I and II E) chromosome arms are lost during crossing over D) sister chromatids separate during anaphase of meiosis I A) chiasmata completely fuse homologous chromosomes
D
Which of the following mechanisms for drugs could be (or are) used in drugs to treat cancer? A) Preventing DNA replication using base analogs D) All of the above B) Blocking the mitotic spindle C) Targeting growth factors that are important at cell cycle check points E) None of the above
D
There are many reasons eukaryotes tend to have larger genomes than prokaryotes. Which of the following is NOT one of those reasons? A) Eukaryotes have introns and alternative splicing B) Eukaryotes have mobile genetic elements, aka jumping genes (examples: transposons, LINE, SINE) C) Eukaryotes have more energy available to replicate large genomes D) All of the above are reasons eukaryotes tend to have larger genomes than prokaryotes
D) All of the above are reasons eukaryotes tend to have larger genomes than prokaryotes
Why do histone proteins normally have a large amount of positive charges? A) So they can bind DNA tightly, preventing transcription B) So they can bind RNA tightly, preventing translation C) So they can bind DNA loosely, allowing transcription by RNA polymerase D) None of the above
D) None of the above
Which of the following is NOT one of the three major components of the cytoskeleton?
DNA
Transcription factors bind to ______ and act to alter ____________ .
DNA, transcription
Addition of a catalyst to the reaction will:
Decrease the activation energy.
A gene encodes an enzyme that digests xylose. This enzyme is expensive to make. The cell can regulate the transcription of this gene in multiple ways. Which of the following is a possible mechanism for regulation of this gene? A) The regulation of this gene will be constitutive, always ON. B) Positive regulation: where a small compound such as xylose could bind to the positive regulator, inducing a conformational change, to allow binding of the positive regulator-xylose complex to the DNA. C) Negative regulation: where a small compound such as xylose could bind to the negative regulator, inducing a conformational change, to remove the negative regulator-xylose complex from the DNA. D) A and B are both likely E) B and C are both possible
E
Autotrophs can: A) Fix carbon from CO₂. B) Capture high energy electrons from organic sources (food). C) Capture high energy electrons from inorganic sources. D) A and B only. E) A, B, and C.
E
How does metaphase in mitosis differ from metaphase I of meiosis? A)The nuclear envelope disappears only in metaphase I of meiosis. B)The sister chromatids separate in mitotic metaphase, not in metaphase I of meiosis. C)Chiasmata are present in metaphase I of meiosis but not in mitotic metaphase. D)A and B are correct . E)B and C are correct.
E
In diagram #1, which arrow represents the energy of the transition state?
E
Monozygotic twins share 100% of their genome (i.e. they are clones) yet, even in between these twins there are differences in phenotype. What is/are the most likely explanation(s) for these differences? A) epigenetic B) mRNA processing and other transcription-level gene regulation C)telomeres D)starts codons E) a and b
E
Which of the following would be the most likely to diffuse most quickly through a lipid bilayer?
Ethane
TRUE or FALSE: Diploid organisms do not have mitosis, because meiosis can produce haploid or diploid cells.
FALSE
True or False: The DNA-dependent DNA polymerase is the only enzyme required to replicate DNA
False
True or False: The transcriptome of an organism cannot be determined because it is a violation of central dogma to go from RNA to DNA.
False
What is the external source of electrons used to reduce NAD+ during respiration of glucose?
Glucose.
In which compartment does glycolysis occur in the mitochondria?
Glycolysis does not occur in the mitochondrion
When illuminated with white light, leaves look green because:
Green photons are more weakly absorbed by chlorophyll than other visible photons.
In the reaction 2H2 + O2 -> 2H20, what is being oxidized?
H2
The genome is the entire collection of an organism's*:(*referring to cellular organisms only in this case)
Heritable information stored in DNA.
What types of molecular interactions are occurring between the base pairs?
Hydrogen Bonds
What functional group is at the 3' end of the DNA?
Hydroxyl Group
Very early in the Earth's history, there was no O2 in the atmosphere. For this reason...
In early forms of respiration, electrons must have been delivered to a different external terminal electron acceptor (not O2).
In what compartment of the plant cell does ATP synthase generate ATP?
In the matrix of the mitochondrion.
Where is CO2 fixed into sugars in green plants?
In the stroma.
ATP is synthesized by ATP synthase in the light reactions of photosynthesis. In green plants, where is ATP synthase located, and when it is generating ATP, which way will it allow protons to flow?
In the thylakoid membrane, directing protons into the stroma.
A mutation occurs that leads to higher rates of mutation in actively dividing cells but has no obvious effect in non-dividing cells. You would be justified in concluding that the mutation:
Inactivated the proof-reading activity associated with DNA polymerase.
An organism is tetraploid ("tetra"="4"). This means:
It has four copies of each chromosome
How does the activation energy affect the ∆G of the reaction?
It has no effect on the ∆G
The laws of thermodynamics state that the amount of energy in the universe is a constant, but, the quality of energy in the universe is decreased every time energy changes from one form to another, with disorder (entropy) constantly increasing. If this is so, how can a living thing grow and display increasing levels of order, taking random molecules and reorganizing them into something very specific, organized, and complex?
Living things capture energy from their environment and use that energy to create local order.
The drop in H2 concentration in the Earth's atmosphere and oceans made life much more difficult for bacteria that specialize in:
Methanogenesis.
Two fish species live side-by-side in the same environment. One has a genome that is several million base pairs larger than the other. What type of sequence is most likely responsible for the majority of this difference?
Mobile genetic elements, also known as jumping genes (examples: transposons, LINE, SINE).
The ribosome synthesizes polyproteins (a polymer) from an mRNA template. In which direction are the monomers added?
N-C.
See the table. Which of the following redox reactions, proceeding in the direction written, would have the greatest negative ∆G per electron transferred?
NADH + O2 → H2O + NAD+
NADH and FADH₂ are produced during the citric acid cycle. Which electron donor, when it donates its electrons to the ETC, results in more protons? A) FADH₂, because it is a 2 electron carrier. B) NADH, because it is a two electron carrier. C) That would depend on which terminal electron acceptor is used. D) Both electron carriers produce the same # of protons pumped. E) NADH, because it donates electrons earlier in the ETC.
NADH, because it donates electrons earlier in the ETC.
The overall charge of DNA is _____, so proteins that bind DNA have a _____ charge in the area that binds with DNA.
Negative, positive.
A geneticist isolates a gene for a specific trait under study. She also isolates the corresponding mRNA. Upon comparison, the mRNA is found to contain 1,000 fewer bases than the DNA sequence. Did the geneticist isolate the wrong DNA and why?
No. The final mRNA contains only exons, as the introns were removed.
The proton pump cytochrome bf of green plants has a reduction potential identical to that of complex III of the respiratory chain of mitochondria. Could this proton pump, under standard conditions, be part of an electron transport chain that reduces NADP+ to NADPH?
No. This complex has too high of a reduction potential to reduce NADP+.
The reaction "2H2 + O2 ↔ 2H2O" has a ∆G°' of -237 kcal/mol. Mixing H2 and O2 at room temperature will have this effect: __________ because of this reason: __________.
Nothing. High energy of the transition state.
In fermentation of glucose in human cells, the terminal electron acceptor is pyruvate, forming lactate. In respiration of glucose in human cells, the terminal electron acceptor is _____, forming ___
O2, water
DNA is composed of two strands, only one of which is typically used as a template for RNA synthesis. By what mechanism is the correct strand chosen?
Only one strand is in the 5' to 3' direction.
Which of the following phosphate-containing molecules is the strongest phosphate donor? Assume that all are at the same concentration. A) PEP (phosphoenolpyruvate), the last molecule in glycolysis before pyruvate B) ADP C) Glucose-6-P D) ATP E) AMP
PEP (phosphoenolpyruvate), the last molecule in glycolysis before pyruvate
The cell uses regulation of transcription to turn genes on or off in certain circumstances. In _____ regulation, binding of a transcription factor _____ transcription, whereas in _____ regulation, binding of a transcription factor _____ transcription.
Positive, stimulates, negative, inhibits.
What is the most important reason that Bacteria and Archaea mainly regulate gene expression at the level of transcription and not at the level of translation?
Protein synthesis is very energetically expensive, and prokaryotes have less energy available than eukaryotes.
It is said that the RNA polymerase "doesn't care about translation signals (sequences)." What is meant, in more scientific language, by this statement?
RNA polymerase does not recognize ribosome binding sites, start and stop codons, and will transcribe DNA if given a promotor, transcription start and termination signals (regardless of whether the transcript encodes a messenger RNA).
n order for DNA polymerase to begin polymerizing, the enzyme primase must first create a short polymer made out of _____. This primer supplies the _____ for DNA polymerase to use.
RNA; 3' -OH group.
The light reactions of photosynthesis produce NADPH in order to:
Reduce CO₂.
What is the external source of electrons used to build NADPH from NADP in green sulfur bacteria?
Reduced sulfur compounds, like H₂S.
The central dogma states that information flows from DNA to RNA to protein. Which of the following below is an exception to this rule?
Reverse transcriptase uses RNA to make a DNA copy.
Ribosomal RNA in E. coli bacteria is around 50% of total bulk RNA. Using this information, what conclusion could you reasonably reach?
Ribosomal RNA promoters are strong
A cell cycle "checkpoint" would be best described as:
Specific places where further progress in the cell cycle can be halted.
DNA is composed of two strands. RNA polymerase binds to one of them to create messenger RNA. The strand that the RNA polymerase binds to is called the _____ strand and its polarity is _____.
Template, 3'-5'.
What is one way in which the citric acid cycle (CCC) and the reverse citric acid cycle (RCCC) different from one another?
The CCC produces ATP (from GTP); the RCCC consumes ATP.
What is the most likely outcome of multiple mutations in the promoter sequence of a gene in a prokaryote?
The RNA polymerase will bind less and create fewer transcripts of the gene.
What is the biological (adaptive) value of a hydrogenosome?
The ability to ferment pyruvate in a way that generates ATP from ADP.
Why would you predict that positive regulation by a transcription factor would not happen at a promoter that exactly matches the consensus promoter sequence in a bacterium?
The binding of RNA polymerase is strong, so the gene is already highly transcribed.
For the reaction A→B, "steady state" means:
The concentrations of A and B are not changing.
The concentration of methane in the Earth's atmosphere has changed radically during Earth's history-going up at first, and then down later. These changes were induced by the sequential evolution of two major innovations created by living, evolving prokaryotes. What were these? A) The evolution of aerobic respiration, and then methanotrophy (using methane as fuel). B) The evolution of methanogenic respiration, and then methanotrophy. C) The evolution of methanogenic respiration, and then aerobic respiration. D) The evolution of methanogenic respiration, then anaerobic photosynthesis. E) The evolution of methanogenic respiration, then oxygenic photosynthesis.
The evolution of methanogenic respiration, then oxygenic photosynthesis.
The generation of glucose 6-phosphate from glucose, catalyzed by hexokinase, is the first step in glycolysis. This step is energetically favorable because:
The formation of glucose-6-phosphate is coupled to the separation of Pi from ATP.
Which of the following compartments would be expected to be most acidic when O₂ is available in the mitochondria?
The intermembrane space.
In which compartment does water-splitting occur in the chloroplast?
The lumen of the thylakoids.
Which compartment is most acidic when light is available in the chloroplast?
The lumen of the thylakoids.
Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription?
The phosphate bonds in the nucleotide triphosphates that serve as substrates.
The leaves of green plants are green because:
The pigments in the leaves of green plants do not absorb green light as strongly as they absorb other visible light photons.
Why do photosynthetic organisms need to use up ATP molecules to form glucose from CO₂?
The reaction (CO₂ + NADPH → Glucose + NADP) is energetically unfavorable.
The hydrolysis of maltose to glucose is exergonic under standard conditions. Which of the following statements about the hydrolysis of maltose to glucose is true?
The reaction release free energy
A heme group carrying an Fe atom is part of a cytochrome protein involved in electron transfer. Two closely related species have different versions of this protein. One version (A) carries the cytochrome in an active site that has a neutral charge; the other (B) has the cytochrome in an active site that has a net charge of -2. What would you predict would be the effect, if any, on the ability of this cytochrome to accept electrons from other molecules?
The reduction potential of B would be lower (more negative); it would be a weaker electron acceptor.
Which of the following statements about cytoskeleton motor proteins, dyenins and kinesins, is FALSE? *Their energy source is ATP and they require one ATP to take one step along the microtubule. *They each move in a specific direction in the cell according to the polarity of the microtubule (i.e. they are plus- or minus-directed). *Their energy source is the breaking of hydrogen bonds that bind the tubulin monomers. *They convert chemical energy to kinetic energy
Their energy source is the breaking of hydrogen bonds that bind the tubulin monomers.
The strawberries we commonly find in the market are octoploids, unlike their diploid ancestor, wild strawberries. Which of the following statements is false? *These strawberries contain four times the genetic material of their ancestors. *These octoploid strawberries have eight chromosomes *The octoploids have bigger nuclei and bigger cells. *The octoploid strawberries carry eight copies of each chromosome.
These octoploid strawberries have eight chromosomes
Which of the following generalizations concerning motor proteins is correct?
They convert chemical energy into kinetic energy.
How do enzymes (catalysts) affect the ∆G of a reaction?
They have no effect on the ∆G.
Which of the following is true of both positive and negative gene regulation?
They involve regulatory proteins binding to DNA
Mutations in DNA occur in the genomes of most organisms, including humans. What is the most important result of these mutations?
They provide a fundamental source of genetic variation for future generations.
Which of the following is not a known function of the cytoskeleton?
To maintain a critical limit on cell size.
In a gene on the coding strand of DNA, which special sequence would come last?
Transcription termination site.
TRUE or FALSE: If a bacterium needed a gene to always be on (i.e. continuously transcribed), it could have a strong promoter and no transcription factors.
True
True or False: Spontaneous mutations are those that occur in the normal process of DNA replication.
True
Alleles are __________
Variant sequences (i.e. alternative forms) of the same gene.
When would a cell have to use Active Transport?
When the cell needs to move a compound against its concentration gradient.
The energy released during the transport of electrons from NADH to O₂ via the electron transport chain is directly harvested in the form of...
a proton gradient
A cell pumps Na⁺ out of the cell, resulting in a high concentration of Na⁺ outside of the cell versus a low concentration inside of the cell. This is an example of:
active transport
∆G˚' refers to the change in Gibbs free energy under (biological) standard conditions. These standard conditions include:
all chemical components (reactants and produces) are constantly at 1 Molar
Which of the following is true for both transporter proteins and enzymes? *The direction of transport or catalysis is determined by ∆G. *The rate of transport or catalysis is determined by the number of active proteins available. *Both transporters and enzymes can be regulated by small metabolites. *Reactions and transport can be pushed uphill (+∆G) if another reaction/transportation event with sufficient -∆G is coupled to it.
all of the above are true for both transporters and enzymes.
A functional group on an amino acid that is polar and can become positively charged:
amine
A functional group that is basic and part of the amino acid backbone:
amine
A macromolecule that can exist as linear or cyclized, where it has a 1:2:1 ratio of carbon, hydrogen and oxygen
carbohydrate
A functional group on an amino acid that is polar and can become negatively charged:
carboxylic acid
A functional group that is acidic and part of the amino acid backbone:
carboxylic acid
A protein's primary structure is maintained by:
covalent bonds
Transcription factors are made in the __________ but then migrate into the _______.
cytoplasm, nucleus
A reaction that results in the formation of water as an end product:
dehydration
The hormone estrogen moves directly across the cell membrane without the assistance of a transporter protein. The process by which estrogen crosses the membrane is called:
diffusion
The tendency of an atom to attract electrons towards itself
electronegativity
The ingredients listed below will give you 2 ml of ½ molar sodium chloride after mixing. Which will release the greatest amount of energy (= has the largest negative ∆G) when doing so? A) 1ml of 1 molar NaCl plus 1ml water B) one ml tubes of 1/2 molar NaCl C) dry NaCl (enough to make 1ml, 1 molar NaCl solution), plus 2ml water D ) enough sodium metal and CL2 gas to produce the amount of sodium chloride salt described above, plus 2ml water
enough sodium metal and CL2 gas to produce the amount of sodium chloride salt described above, plus 2ml water
What's the difference between "steady state" and "equilibrium"?
equilibrium is an example of steady state, but not all steady states are at equilirium
TRUE OR FALSE: The end goal of mitosis is to create cells that can have sex and generate genetic diversity.
false
True or False: All transcribed RNA's are messenger RNA's
false
Constitutive transcription is
genes that are expressed all of the time
Regulated transcription is
genes that are expressed only at certain time or in certain cells.
Which molecule, if employed as an external electron source to build NADH, could donate the most electrons per mole of reductant?
glucose
Which compounds can act as an electron donor for acetate?
glucose H2 HADH
See the table. Which half-reaction in the table has the greatest reduction potential? Which has the lowest?
greatest = row 4 lowest = row 1
Which type of chromosomes allow recombination to occur:
homologous chromosomes
Chiasmata, which reflect crossover events, link a pair of:
homologous chromosomes at meiotic prophase I.
In order for a polar compound to enter into the hydrophobic space of the phospholipid tails, it would need to break the many ____________ bonds it has formed with the water and enter into a space where these bonds cannot form. Therefore, it is not a repelling action but a "lack of attraction."
hydrogen
Polar compounds are forming bonds with the water on the outside of the membrane. These bonds are called
hydrogen
A bond that forms between an electronegative atom and a hydrogen atom with a positive dipole
hydrogen bond
What types of interactions can the polar compound have with the interior of this passage way (channel protein)?
hydrogen bonds
A reaction that requires water as a reactant:
hydrolysis
A bond that exists between two full, opposite charges
ionic bond
A macromolecule that can exist as linear or cyclized, where it has a polar "head" group and a majority nonpolar "tail" group
lipid
vThe cell uses regulation of transcription to turn genes on or off in certain circumstances. In _________ regulation, binding of a transcription factor ____________ transcription, whereas in ___________ regulation, binding of a transcription factor _______________ transcription.
negative, inhibits, positive stimulates
Can polar compounds interact in this same way with the hydrophobic tails of the phospholipids? (yes or no)
no
Do interactions form between polar compounds and the hydrophobic tails? (yes or no)
no
A type of covalent bond where electrons are shared equally
nonpolar bond
A macromolecule that contains a sugar, a phosphate group and a nitrogenous base
nucleic acid
The compound that became reduced acts as the _________________ agent.
oxidation
____________- is the loss of electrons.
oxidation
What functional group is at the 5' end of the DNA?
phosphate group
What types of amino acid R groups do you think will line the channel protein interior?
polar
A type of covalent bond where electrons are shared unequally
polar bond
A glucose molecule has a bond between O and C. This is a...
polar covalent bond
A macromolecule that exists with a backbone where the functional groups are the amine and the carboxylic acid
protein
Transcription factors are
proteins
Fermentation allows a cell to...
recycle NADH
The compound that became oxidized acts as the ______________ agent.
reducing
___________________- is the gain of electrons.
reduction
The measure of a compounds likeliness to gain or lose an electron is its _________________
reduction potential
Protein cofactors are...
required for the function of their protein.
Which type of chromosomes are identical:
sister chromatids
Fermentation occurs when: A) the cell has an external electron acceptor it can use. B) the cell needs more NAD+ to perform glycolysis, and no useable external electron acceptor is available. C) glucose is not available. D) the cell needs to get as much energy as possible from E) glucose, burning it to completion (CO2). the cell has too much NAD+.
the cell needs more NAD+ to perform glycolysis, and no useable external electron acceptor is available.
ATP is called a "high-energy compound" because...
the ΔG for the hydrolysis of ATP is very negative.
TRUE OR FALSE: The end goal of meiosis is to create cells that can have sex and generate genetic diversity.
true
An external electron source must be utilized to reduce environmental CO₂ and build sugars. In the Calvin cycle, the electrons used to fix CO₂ come from:
water
H2O is a liquid at room temperature while CO2 is a gas. Why is this?
water molecules are attracted to each other, CO2 molecules are not
Are these the same interactions that this polar compound can have on the outside of the membrane with water?
yes
