Final Review over Exam 3
Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration?
30-32
Which of the following statements best describes the central role that ATP plays in cellular metabolism?
ATP provides energy coupling between exergonic and endergonic reactions
What is the name of the barrier that must be overcome before products are formed in a spontaneous reaction?
Activation energy
The general category of metabolic pathways that use energy to build molecules is known as an ________ pathway
Anabolic
Radioactive Thymine is added to media containing one actively dividing E. coli bacterium, which of the following outcomes would be seen after a single cell division?
DNA in both daughter cells would be radioactive
After DNA replication, the resulting daughter DNA double Helix contains one strand of the roginal parental DNA and one new strand. What is the explanation for the phenomenon?
DNA replication is semiconservative
In E. Coli, which enzyme catalyizes the elongation of a new DNA strand in the 5' -> 3' direction?
Dna polymerase III
Which of the following terms best describes a chemical reaction for which G is positive?
Endergonic
_________ is a measure of molecular disorder referred to in The Second Law of Thermodynamics
Entropy
Which of the following molecules is the lowest energy donor of electrons to the electron transport chain?
FADH2
Which of the following statements best summarizes a consequence of the second law of thermodynamics?
If entropy of a system decreases, there must be a corresponding increase in the entropy of the universe
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
It is lost to the environment
Which of the following statements describes a primary function of both alcohol fermentation and lactic acid fermentation?
oxidation of NADH to NAD+
When a glucose molecule loses a hydrogen atom in an oxidation-reduction reation, the glucose molecule is ________
oxidized
AN ________ agent has electrons donated to it and is reduced
oxidizing
Which of the following products result from the oxidation of pyruvate to acetyl-COA?
NADH and CO2
Which of the following molecules is the final electron acceptor for electrons from photosystem I?
NADP+
In E. Coli, a mutation in a gene called dnaB prevents the helicase from binding at the origin of replication. Which of the following events would you expect to occur as a result of this mutation?
No replication fork will be formed
the first enzyme in the Calvin cycle is _______
Rubisco
High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an example of
allosteric regulation
Which of the following types of metabolic poison would most directly interfere with glycolysis?
an agent that closely mimics the structure of glucose but is not metabolized
Which of the following events is most immediately associated with the absorption of energy by chlorophyll molecules of the reaction-center complex?
an electron is excited
Zinc is an essential trace element for most organisms. Zing is required in the active site of the enzyme carboxypeptidase where is most likely function sin which of the following ways?
as a cofactor necessary for enzyme activity
which of the following terms most precisely identifies the cellular process of breaking down large molecules into smaller ones?
catabolism (catabolic pathways)
A _______ is any compound that speeds up a chemical reaction. AN enzyme is an example of one
catalyst
A decrease in entropy is associated with which type of reaction?
dehydration
In the following reaction which molecule functions as the oxidizing agent? Pyruvate + NADH + H+ -> Lactate + NAD+
pyruvate
When electrons are passed from one atom to a more electronegative atom, the more electronegative atom is ______
reduced, and energy is released
Which of the following processes occurs in the Calvin Cycle?
reduction of co2
What is the function of the enzyme topoisomerase in DNA replication?
relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix
A reaction that is nonspontaneous and requires an input of energy is known as a _________ reaction
endergonic
Which of the terms below best describes a regulatory mechanism in which the end product of a metabolic pathway inhibits an enzyme that catalyzes an early step in the pathway?
feedback inhibition
In chemiosmosis, the most direct source of energy used to convert ATP+ to pi to ATP is energy released _______-
from movement of protons through ATP synthase, down their electrochemical gradient
Which of the following metabolic processes normally occurs in most cells regardless of oxygen availability?
glycolysis
__________ is the enzyme that unzips or unwinds the DNA strands from each other to form the replication bubble
helicase
Which of the following statements best describes the electron transport chain?
it consists of a series of redox reactions
Which of the following types of molecules help hold the DNA strands apart while they are being replicated?
singe-strand DNA binding proteins
Which of the following types of molecules help to hold the DNA strands apart while they are being replicated?
single-strand DNA binding proteins
The atp synthase that generates ATP at the end of cellular respiration consists of four parts. The _______ is the name of the channel in which protons are loaded into the rotor
stator
The calvin cycle takes place in the _______ of the chloroplast
stroma
Which of the following processes would be most directly affected if a thylakoid membrane is punctured so that the interior of the thylakoid is no longer separated from the stroma?
synthesis of ATP
Each end of a chromosome is known as a _________ which is a repetitive sequence that prevents the loss of genes during replication.
telomere
In DNA polymerization, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer?
the 3' OH
A change of a single amino acid at a position distant from the active site of an enzyme can alter the substrate specificity by changing ________
the 3D shape of the enzyme
When a cell is deprived of oxygen, which of the following processes will be inhibited first?
the electron transport chain
What are telomeres
the ends of linear chromosomes
Which of the following statements best describes a system at chemical equilibrium
the system can do no work
The first mobile carrier in the aerobic cellular respiration electron transport chain is _______ while the second mobile carrier is cytochrome c.
ubiquinone
An enzyme-catalyzed reaction has a G of -20 kcal/mol under standard conditions. What will be the G for the reaction if the amount of enzyme is doubled?
-20 kcal/mol
How many kilocalories of energy per mole of ATP are released in the exergonic reaction of breaking the terminal (Gamma) phosphate bond? (Consider this NOT in a cell)
7.3
Disruption of the active site of an enzyme would most likely result in which of the following?
A decreased ability of the enzyme to bind substrates
What are the products of linear electron flow in the light reactions of photosynthesis?
ATP and NADPH
The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis and is inhibited by high levels of which of the following molecules?
ATP and citrate
A typical eukaryotic cell has enough available ATP to met its needs for about 30 seconds. What is likely to happen to an individual when they exhaust their ATP supply?
Catabolic process will be activated to generate additional ATP
In the citric acid cycle, succinate dehydrogenase catalyzes the conversion of succinate to fumarate. This reaction is inhibited by malonate, which resembles succinate by cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate molecules to those of malonate in the reaction reduces the inhibitory effect of malonate. What role does malonate play with respect to succinate dehydrogenase?
Malonate is a competitive inhibitor
Which of the following statements correctly describes the difference between the leading and lagging strand in DNA replication>
The leading strand is synthesized continuous yin the 5'->3' directions, while the lagging strand is synthesized discontinuously in the 5' -> 3' direction
IN A plant, which of the following reactions produces molecular oxygen (O2)?
The light reactions alone
Which of the following statements best describes an exergonic reaction?
The reaction proceeds with a net release of free energy
Yeast utizile ________ fermentation which produces carbon dioxide
alcohol
