Bio 041 Final Exam Practice 40 Questions with Verified Answers
Chemical reactions carried out by living systems depend on the ability of some organisms
... [Show More] to capture and use atoms from nonliving sources in the environment. The specific subset of these reactions that use nutrients in food to build macromolecules can be described as _____________.
a) metabolic.
b) catabolic.
c) anabolic.
d) biosynthetic
(question from practice exam 1) - CORRECT ANSWER catabolic
In photosystem I, electrons lost from the special pair are replenished by:
a) plastocyanin
b) plastoquinone
c) photosystem I
d) splitting H2O to form O2 - CORRECT ANSWER plastocyanin
Stage 2 of photosynthesis, sometimes referred to as the dark reactions, involves the reduction of CO2 to produce organic compounds such as sucrose. What cofactor is the electron donor for carbon fixation?
a) H2O
b) NADH
c) NADPH
d) FADH2 - CORRECT ANSWER NADPH
Photosynthesis is a process that takes place in chloroplasts and uses light energy to generate high-energy electrons, which are passed along an electron-transport chain. Where are the proteins of the electron-transport chain located in chloroplasts?
(a) thylakoid space
(b) stroma
(c) inner membrane
(d) thylakoid membrane - CORRECT ANSWER thylakoid membrane
Which type of cell signaling can the signaling molecule travel the greatest distance?
a) paracrine signaling
b) contact-dependent signaling
c) neuronal signaling
d) endocrine signaling - CORRECT ANSWER endocrine signaling
Living systems are incredibly diverse in size, shape, environment, and behavior. It is estimated that there are between 10 million and 100 million different species. Despite this wide variety of organisms, it remains difficult to define what it means to say something is alive. Which of the following can be described as the smallest living unit?
a) DNA
b) cell
c) organelle
d) protein - CORRECT ANSWER cell
Chloroplasts contain their own genome, are able to duplicate, and actually divide on a different time line from the rest of the cell. Nevertheless, mitochondria cannot function for long when isolated from the cell because they are __________________.
a) viruses.
b) parasites.
c) endosymbionts.
d) anaerobes. - CORRECT ANSWER endosymbionts
Which of the following statements about giant viruses, such as pandoravirus, is false?
a) They have much larger genomes than normal viruses.
b) They are large in size, about the size of prokaryotes.
c) They do not need a host cell to replicate.
d) Their genome contains sequences for some gene expression proteins. - CORRECT ANSWER They do not need a host cell to replicate
Which of the following is found in plant cells but not in animal cells?
a) Cell wall
b) Mitochondria
c) Golgi apparatus
d) Nucleus - CORRECT ANSWER cell wall
Atoms that are covalently bonded are in a constant tug of war for the shared electrons. An atom's attraction for the electrons refers to its
a) electronegativity
b) protons
c) nucleus
d) valence electrons - CORRECT ANSWER electronegativity
Which four elements make up 96.3% of the human body?
a) oxygen, iron, hydrogen, nitrogen.
b) carbon, hydrogen, nitrogen, oxygen.
c) calcium, carbon, hydrogen, oxygen.
d) carbon, potassium, hydrogen, nitrogen. - CORRECT ANSWER carbon, hydrogen, nitrogen, oxygen
Which of the following is true for a reaction at equilibrium?
a) ΔG = ΔG°
b) ΔG° + RT ln [X]/[Y] = 0
c) RT ln [X]/[Y] = 0
d) ΔG + ΔG° = RT ln [X]/[Y]
(DEF ON EXAM) - CORRECT ANSWER ΔG° + RT ln [X]/[Y] = 0
Oxidation is the process by which oxygen atoms are added to a target molecule. Generally, the atom that is oxidized will experience which of the following with respect to the electrons in its outer shell?
a) a net gain
b) a net loss
c) no change
d) an equal sharing
(DEF ON EXAM) - CORRECT ANSWER a net loss
Which of the following amino acids would you expect to find inside the core of a folded protein?
(Images of amino acid chains) - CORRECT ANSWER valine
When two sugars are joined together via a condensation reaction, what is the name of the covalent bond formed?
a) Glycosidic
b) Peptide
c) Electrostatic
d) Phosphodiester - CORRECT ANSWER glycosidic
Which of the following is a feature commonly observed in β sheets?
(exam was reverse on our test, list 3 features)
Not a feature- coiled-coil patterns - CORRECT ANSWER antiparallel regions
extended polypeptide backbone
parallel regions
In the 1940s, proteins were thought to be the more likely molecules to house genetic information. What was the primary reason that DNA was not originally believed to be the genetic material?
(a) DNA has a high density of negative charges.
(b) Nucleotides were known to be a source of chemical energy for the cell.
(c) Both protein and nucleic acids were found to be components of chromosomes.
(d) DNA was found to contain only four different chemical building blocks. - CORRECT ANSWER DNA was found to contain only four different chemical building blocks
Fred Griffith studied two strains of Streptococcus pneumonia, one that causes a lethal infection when injected into mice, and a second that is harmless. He observed that pathogenic bacteria that have been killed by heating can no longer cause an infection. But when these heat-killed bacteria are mixed with live, harmless bacteria, this mixture is capable of infecting and killing a mouse. What did Griffith conclude from this experiment?
(a) The infectious strain cannot be killed by heating.
(b) The heat-killed pathogenic bacteria "transformed" the harmless strain into a lethal one.
(c) The harmless strain somehow revived the heat-killed pathogenic bacteria.
(d) The mice had lost their immunity to infection with S. pneumoniae. - CORRECT ANSWER The heat-killed pathogenic bacteria "transformed" the harmless strain into a lethal one
The N-terminal tail of histone H3 can be extensively modified, and depending on the number, location, and combination of these modifications, these changes may promote the formation of heterochromatin. What is the result of heterochromatin formation?
(a) increase in gene expression
(b) gene silencing
(c) recruitment of remodeling complexes
(d) displacement of histone H1
(Something like this on exam) - CORRECT ANSWER gene silencing
DNA polymerases are processive, which means that they remain tightly associated with the template strand while moving rapidly and adding nucleotides to the growing daughter strand. Which piece of the replication machinery accounts for this characteristic?
(a) helicase
(b) sliding clamp
(c) single-strand binding protein
(d) primase
(KNOW THE WHOLE PROCESS, MANY QUESTIONS ON THIS) - CORRECT ANSWER sliding clamp
Which of the following mechanisms best describes the manner in which lysozyme lowers the energy required for its substrate to reach its transition-state conformation?
a) by binding two molecules and orienting them in a way that favors a reaction between them.
b) by altering the shape of the substrate to mimic the conformation of the transition state.
c) by speeding up the rate at which water molecules collide with the substrate
d) by binding irreversibly to the substrate so that it cannot dissociate - CORRECT ANSWER by altering the shape of the substrate to mimic the conformation of the transition state
Because hydrogen bonds hold the two strands of a DNA molecule together, the strands can be separated without breaking any covalent bonds. Every unique DNA molecule "melts" at a different temperature. In this context, Tm (melting temperature) is the point at which two strands separate, or become denatured. Which of the DNA sequences listed below has the highest melting temperature (Tm). Assume that they all begin as stable double-stranded DNA molecules.
a) CCCCGGGG
b) TAAAGTCT
c) TTTTTTTT
d) CAAACCCG - CORRECT ANSWER CCCCGGGG
The most common covalent cross-links in proteins are sulfur-sulfur bonds that form between two amino acids with -SH (thiol) groups as side chains. Which amino acid has this side chain?
a) Phenylalanine
b) Lysine
c) Cysteine
d) Valine
(MOST LIKELY NOT ON EXAM) - CORRECT ANSWER cysteine
Although all protein structures are unique, there are common structural building blocks that are referred to as regular secondary structures. Some proteins have α helices, some have β sheets, and still others have a combination of both. What makes it possible for proteins to have these common structural elements?
a) specific amino acid sequences
b) side-chain interactions
c) the hydrophobic-core interactions
d) hydrogen bonds along the protein backbone - CORRECT ANSWER hydrogen bonds along the protein backbone
Nonhomologous end joining can result in all but which of the following?
(a) the recovery of lost nucleotides on a damaged DNA strand
(b) the interruption of gene expression
(c) loss of nucleotides at the site of repair
(d) joining of nearby DNA fragments from entirely different chromosomes - CORRECT ANSWER the recovery of lost nucleotides on a damaged DNA strand
How many replication forks are formed when an origin of replication is opened?
(a) 1
(b) 2
(c) 3
(d) 4 - CORRECT ANSWER 2
The kidney, like the gut, reabsorbs glucose through a sodium/glucose transporter. The movement of glucose into the cell is be powered by the co-transport of Na+ into the cell. Which of the following is true?
a) Glucose is transported up against its concentration gradient and Na+ is transported down its concentration gradient.
b) Na+ is transported up against its concentration gradient and glucose is transported down its concentration gradient.
c) Glucose and Na+ are both transported down their concentration gradients.
d)Glucose and Na+ are both transported up against their concentration gradients.
(ON EXAM) - CORRECT ANSWER Glucose is transported up against its concentration gradient and Na+ is transported down its concentration gradient
The DNA duplex consists of two long covalent polymers wrapped around each other many times over their entire length. The separation of the DNA strands for replication causes the strands to be "overwound" in front of the replication fork. How does the cell relieve the torsional stress created along the DNA duplex during replication?
(a) Nothing needs to be done because the two strands will be separated after replication is complete.
(b) Topoisomerases break the covalent bonds of the backbone allowing the local unwinding of DNA ahead of the replication fork.
(c) Helicase unwinds the DNA and rewinds it after replication is complete.
(d) DNA repair enzymes remove torsional stress as they replace incorrectly paired bases. - CORRECT ANSWER Topoisomerases break the covalent bonds of the backbone allowing the local unwinding of DNA ahead of the replication fork
Which of the following statements about sequence proofreading during DNA replication is false?
(a) The exonuclease activity is in a different domain of the DNA polymerase.
(b) The exonuclease activity cleaves DNA in the 5′-to-3′ direction.
(c) The DNA proofreading activity occurs at the same time as strand elongation.
(d) If an incorrect base is added, it is "unpaired" before removal. - CORRECT ANSWER The exonuclease activity cleaves DNA in the 5′-to-3′ direction
In eukaryotes, but not in prokaryotes, ribosomes find the start site of translation by ____________________________.
(a) binding directly to a ribosome-binding site preceding the initiation codon.
(b) recognizing the cap and scanning along the mRNA from the 5′ end.
(c) recognizing an AUG codon as the start of translation.
(d) binding an initiator tRNA. - CORRECT ANSWER recognizing the cap and scanning along the mRNA from the 5′ end
What secondary structure is depicted at right?
a) α-helix
b) parallel β-sheet
c) antiparallel β-sheet
d) loop
(ON TEST, KNOW IMAGES) - CORRECT ANSWER parallel β-sheet
Optogenetics is a method in which genetic engineering techniques are used to introduce ________ channels into a selected set of target neurons, and the correct stimulation will allow Na+ to enter the neurons, triggering an action potential.
a) acetylcholine-gated
b) Voltage-gated
c) Light-gated
d) GABA-gated
(ON EXAM) - CORRECT ANSWER light-gated
In glycolysis, ___________ is the 6-carbon molecule that is split into two 3-carbon molecules of aglyceraldehde 3-phosphate.
a) fructose 1,6 bisphosphate
b) pyruvate
c) 3-phosphoglycerate
d) glyceraldehyde 3-phosphate - CORRECT ANSWER fructose 1,6 bisphosphate
Human immune system cells use damaging proteases and reactive oxygen species to destroy foreign invaders such as pathogenic bacteria. The immune system cells are not harmed because the microbes are first sequestered into vesicles. How does the cell get the bacteria into the vesicles?
a) Active transport
b) Phagocytosis
c) Pinocytosis
d) Exocytosis - CORRECT ANSWER phagocytosis
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 rearrangement of bonds within a single molecule.
b) An enzyme that catalyzes a change in the position of a specific chemical group within a single molecule.
c) An enzyme that catalyzes the oxidation of a molecule by removing a hydride ion.
d) An enzyme that catalyzes the addition of phosphate groups to other molecules - CORRECT ANSWER An enzyme that catalyzes the addition of phosphate groups to other molecules
Which of the following might decrease transcription of only one specific gene in a bacterial cell?
a) a decrease in the amount of sigma factor
b) a decrease in the amount of RNA polymerase
c) a mutation that introduced a stop codon into the DNA that precedes the gene's coding sequence
d) a mutation that introduced extensive sequence changes into the DNA that precedes the gene's transcription start site - CORRECT ANSWER a mutation that introduced extensive sequence changes into the DNA that precedes the gene's transcription start site
For eukaryotic transcription to begin, the initiation complex must assemble. What are the enzymatic functions of TFIIH?
a) TFIIH unwinds DNA strand and polyadenylates the tail of RNA polymerase.
b) TFIIH unwinds DNA strand and phosphorylates the tail of RNA polymerase.
c) TFIIH recognizes the TATA promoter site and unwinds the DNA strand.
d) TFIIH recognizes the TATA promoter site and phosphorylates the tail of RNA polymerase
(KNOW TFIIO AS WELL) - CORRECT ANSWER TFIIH unwinds DNA strand and phosphorylates the tail of RNA polymerase
Transcription is similar to DNA replication in that ___________________.
(a) an RNA transcript is synthesized discontinuously and the pieces are then joined together.
(b) it uses the same enzyme as that used to synthesize RNA primers during DNA replication.
(c) the newly synthesized RNA remains paired to the template DNA.
(d) nucleotide polymerization occurs only in the 5′-to-3′ direction. - CORRECT ANSWER nucleotide polymerization occurs only in the 5′-to-3′ direction
Which of the following does not occur before a eukaryotic mRNA is exported from the nucleus?
(a) The ribosome binds to the mRNA.
(b) The mRNA is polyadenylated at its 3′ end.
(c) 7-methylguanosine is added in a 5′-to-5′ linkage to the mRNA.
(d) RNA polymerase dissociates. - CORRECT ANSWER The ribosome binds to the mRNA
You have a piece of DNA that includes the following sequence:
5′-ATAGGCATTCGATCCGGATAGCAT-3′
3′-TATCCGTAAGCTAGGCCTATCGTA-5′
Which of the following RNA molecules could be transcribed from this piece of DNA?
(a) 5′-UAUCCGUAAGCUAGGCCUAUGCUA-3′
(b) 5′-AUAGGCAUUCGAUCCGGAUAGCAU-3′
(c) 5′-UACGAUAGGCCUAGCUUACGGAUA-3′
(d) none of the above - CORRECT ANSWER b [Show Less]