Bio 101 Diggs Loyola
How do mitogen-activated protein (MAP) kinases get deactivated?
Phosphatases remove phosphate groups
_________ are organisms that derive energy from sunlight
Phototrophs
Batteries in your flashlight are examples of _______ energy
Potential
Which statement is true regarding pyruvate oxidation?
Pyruvate oxidation forms the same number of NADH (per glucose molecule) as glycolysis
Why are some mutations of Ras associated with cancer?
Ras activates the MAP kinase signal transduction pathway that regulates cell division
A researcher is evaluating the role of a growth factor during embryonic development. She notices that this factor functions in both neural development and limb development. How is that possible?
Receptors for the growth factor must be present in both neurons and cells in the developing limb
What does reduced mean in chemistry?
Reduction is a chemical reaction that involves the GAINING of electrons
Energy released by transferring electrons along the electron transport chain is stored as potential energy in the form of:
a proton gradient
Metal ions bound to enzymes are called:
cofactors
Which of the following is an example of anabolism?
combining glucose molecules to form glycogen
The first phase of glycolysis require the input of two ATP molecules. It is therefore:
endergonic
Cell signaling over a long distance is known as
endocrine signaling
The degree of disorder, or number of microstates, is called:
entropy
The lid of a container containing a gas is removed. As a consequence, the molecules of the gas can leave the container and have more space available to them to spread out. For the gas released from the container, which of the following increases?
entropy
A cell can only respond to signals from other cells, not from the physical environment
false
The outer surface of the F0 subunit of ATP synthase must be ________ to be embedded in the membrane
hydrophobic
Which has the most entropy, individual nucleotides or a nucleic acid?
individual nucleotides
The citric acid cycle is a cycle because the starting molecule, _________ is regenerated at the end
oxaloacetate
In eukaryotes, pyruvate oxidation takes place in the:
mitochondrial matrix
In what organelle is pyruvate oxidation carried out in a cell?
mitochondrion
Spontaneous reactions have a _______ delta G
negative
Growth factors such as platelet-derived growth factor (PDGF) function in:
paracrine signaling
During which phase(s) of glycolysis do we observe pyruvate production, ATP synthesis, and reduction of NAD+?
payoff phase
Which process produces the highest number of reduced electron carriers and thus the greatest potential for generating ATP?
the citric acid cycle
In eukaryotic cells, glycolysis occurs in:
the cytoplasm
At then end of glycolysis, the carbon originally found in the starting glucose molecule is now present in:
two pyruvate molecules
In a simplified equation for respiration we can say that _________ is reduced and ________ is oxidized
oxygen; glucose
Oak trees are categories as:
photoautotrophs
The energy of activation of a reaction is:
the energy input needed to reach the transition state
Which is the only reaction in the citric acid cycle that produces ATP by substrate-level phosphorylation?
the formation of succinate
We can tell from their structure that fatty acids are a good source of energy because of:
the large number of carbon-carbon and carbon-hydrogen bonds they contain
Signaling molecules involved in paracrine and autocrine signaling
travel by diffusion
Tracing the metabolism of one glucose molecule, how many carbon atoms are available for further oxidation at the completion of the pyruvate oxidation stage?
4
During the citric acid cycle:
ATP is synthesized by substrate level phosphorylation.
One of the enzymatic results of the pyruvate oxidation stage of cellular respiration is the reduction of _________ to ___________
NAD+ ; NADH
When oxygen is depleted, the citric acid cycle stops. What would you need to add to the system to restore activity?
NAD+, FAD
What product of the pyruvate oxidation stage of cellular respiration will have the two electrons that are lost form pyruvate?
NADH
What product of the pyruvate oxidation stage of cellular respiration will have the two electrons that are lost from pyruvate?
NADH
Which of the following is an electron carrier in its reduced form?
NADH
The immediate source of electrons for the electron transport chain is:
NADH and FADH2
What is true regarding neurotransmitters?
Neurotransmitters are typically dispersed over small distances
A researcher is comparing the amount of protein contained in inner and outer mitochondrial membranes
The amount of proteins would be greater in the inner membrane
What purpose does the signal transduction process serve?
The cascade serves to amplify the signal so one activated receptor can have a significant response
Cell signaling between two nerve cells can be thought of as an example of paracrine signaling because
The cells are in close proximity
Imagine that several atoms bond to form a carbohydrate, creating a more orderly system. Which statement is true regarding the universe after this carbohydrate forms?
The entropy of the universe increases
You walk out of your warm house on a cold winter's day. What is different between the air inside and outside of your house in this scenario?
The molecules in the warm air of your house are moving faster than those outside
A large polar signaling molecule produced by bacteria is introduced to eukaryotic cells. The signaling of the bacteria results in an increase in eukaryotic gene expression. How is this possible?
The signal is likely similar in structure to ligands utilized by eukaryotic cells
if pneumococcal cells did not express receptor protein, how would the rate of DNA uptake be affected when the cells reach high density?
There would be no increase in the rate of DNA uptake
Many scientists use chemical inhibitors to interfere with normal signaling pathways within eukaryotic cells. If such inhibitors are large, nonpolar molecules, what is the likely method action of these chemical inhibitors?
These chemical inhibitors likely bind to receptors on the cell surface and interfere with receptor activation or signal-receptor binding
Imagine that a researcher is studying the embryonic development of mice that do not express the signal molecule Delta. What will likely be true of these mice?
These mice will have fewer glial cells compared to their normal counterparts
Cancer is a disease of cell division
True
Although glycolysis produces four molecules of ATP by substrate phosphorylation, the net gain of ATP for the cell is two molecules. This is because:
Two molecules are used in the initial stage
What is the cell's likely response to ligand binding to a steroid receptor located in the nucleus?
a change in gene expression
What is the end-result of activating the MAP kinase pathway?
a change in gene expression
What is the very first effect of ligand binding to a G protein-coupled receptor?
a conformational change in the cytoplasmic domain of the receptor
In the cleavage phase of glycolysis:
a phosphorylated sugar molecule is broken apart and the products rearranged
Platelet-derived growth factor (PDGF) binds to
a receptor kinase
Which type of cell-surface receptor undergoes changes in phosphorylation in response to binding of its ligand?
a receptor kinase
In cellular respiration, oxygen:
gains electrons and is reduced
What is an input, but not an output of glycolysis?
glucose
Which molecule has the greatest chemical potential energy?
glucose
What happens when glucose is phosphorylated during phase 1 of glycolysis?
glucose is destabilized so that it can be broken apart in phase 2
Excess glucose is stored in large branched molecules of:
glycogen in animals
The storage carbohydrate in animals is _________ and in plants is___________
glycogen; starch
Based on what you know of ATP's chemistry, which of these substances is most likely to have similar functions in energy-management processes?
guanosine nucleotide triphosphate
Enzymes are typically:
highly specific
ATP is a good energy currency for cells because it has a(n) _________ amount of Gibbs free energy
intermediate
How did the earliest organisms on Earth most likely product ATP?
by glycolysis
Carbon dioxide dissolves in water to form
carbonic acid
Cellular respiration is a series of __________reactions
catabolic
During ________, large molecules are broken down and energy is released
catabolism
Enzymes in your gastrointestinal tract digest your lunch. These chemical reactions are categorized as
catabolism
Endergonic
chemical reactions that require energy
You discover a microbial deep-sea organism that can derive energy from (inorganic) hydrogen gas (H2). In addition, this microbe can synthesize organic compounds from carbon-containing inorganic molecules in the ocean. This microbe is a:
chemoautotroph
You discover a carnivorous deep-sea fish that cannot utilize the carbon in carbonic acid, or any other inorganic molecule, present in seawater to form glucose, or other organic molecules. Living so far beneath the water's surface, this fish is also incapable of harnessing energy from the sun. This fish would be considered a:
chemoheterotroph
Escherichia coli bacteria in your colon are categorized as:
chemoheterotrophs
allosteric inhibitor
binds to allosteric site and reduces enzyme activity
Animals such as cats, worms, and butterflies are classified as
chemoheterotrophs
E coli bacteria in your colon are categorized as
chemoheterotrophs
The first law of thermodynamics is also known as the law of:
conservation of energy
During what phase of glycolysis is NADH formed?
during phase 3, when glyceraldehyde 3-phosphate is phosphorylated
Where would you expect to find the receptor for a nonpolar ligand?
either in the nucleus of the cell or in the cytosol
During glycolysis, pyruvate oxidation, and the citric acid cycle, the chemical energy in glucose is transferred to:
electron carriers and ATP
What is true about exergonic reactions?
Exergonic reactions are catabolic
In a reaction, enzymes change the
activation energy
Suppose that, in a given reaction, the enthalpy (H) increases by 10 units, and the disorder (TS) increases by 12 units. By how many units did the Gibbs free energy change?
-2
What is the order of stages of cellular respiration?
1. Glycolysis 2. pyruvate oxidation 3. citric acid cycle 4. oxidative phosphorylation
During the pyruvate oxidation stage of cellular respiration, what occurs?
1. oxidation of pyruvate 2. formation of NADH 3. formation of acetyl-CoA 4. formation of CO2
What is a net product of glycolysis?
2 pyruvate
Starting from glucose, lactic acid fermentation results in _______ molecules of lactic acid, each with ______ carbons, whereas ethanol fermentation results in _______ molecules of ethanol, each with _______ carbons
2;3;2;2
Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of aerobic respiration?
6
catabolic
A process in which large molecules are broken down
anabolic
A process in which large molecules are built from small molecules
Consider the refrigerator in your kitchen. Based on what you know about the first and second laws of thermodynamics, how does a refrigerator most likely work?
A refrigerator removes heat from its interior and transports this energy outside, into the kitchen
In the context of cell signaling, to what does the term ligand refer?
A signaling molecule that bind to the receptor
In the context of cell signaling, to what does the term ligand refer?
A signaling molecule that binds to the receptor
Which best describes energy captured in ATP during aerobic cellular respiration?
A small amount of energy is captured in ATP by substrate-level phosphorylation; most is captured in ATP by oxidative phosphorylation
The hydrolysis of _________ is an exergonic reaction that drives many endergonic reactions in a cell
ATP
What is required for the preparatory phase of glycolysis and then produced during the payoff phase?
ATP
During a long bout of sustained exercise, in which order will your body's energy stores/sources be used?
ATP stored in muscle, glycogen in muscle, glycogen stored in the liver, fatty acids
What is true about receptors that are localized to the nucleus?
All
G proteins of G protein-coupled receptors are often made up of what subunits?
Alpha, beta, and gamma
Chemoheterotrophs
An organism that must consume organic molecules for both energy and carbon.
Ligand binding to a receptor kinase results in:
Binding of cytoplasmic signaling molecules, receptor dimerization, phosphorylation of the cytoplasmic domain of the receptor
ligand binding to a receptor kinase results in
Binding of cytoplasmic signaling molecules, receptor dimerization, phosphorylation of the cytoplasmic domain of the receptor.
Each molecule of acetyl-CoA that enters the citric acid cycle carriers two of the carbon atoms from the original starting glucose molecule. These carbon atoms will ultimately leave the citric acid cycle as carbon atoms in what form?
CO2
The chemical bonds of carbohydrates and lipids have high potential energy because:
Many of these bonds are C-C and C-H bonds, in which electrons are shared equally between atoms
Each molecule of acetyl-CoA that enters the citric acid cycle carries two of the carbon atoms from the original starting glucose molecule. These carbon atoms will ultimately leave the citric acid cycle as carbon atoms in which of the following?
CO2
The ethanol resulting from fermentation of glucose only accounts for four of the six starting carbon atoms. In which of the following are the other two carbon atoms found?
CO2
Some bacteria run the citric acid cycle in reverse. Without any other modifications to the cycle, what inputs would be required to do this?
CO2, FADH2, NADH and ATP
Which types of cellular activities can be a response to cell signaling
Cell signals are released to communicate with other cells, cell division is triggered, enzyme activities are changed, gene expression patterns are changed
Exergonic
Chemical reactions that release energy
How do you calculate Delta G?
Delta H - TdeltaS
We consume a variety of carbohydrates that are digested into a variety of different monosaccharides. How do these different sugars enter glycosis?
Different sugars can be modified to form different intermediates of glycolysis
The majority of the energy captured in the citric acid cycle is in the form of:
Electrons donated to NAD + and FAD
Synthesis of a protein is an example of a chemical reaction that is:
Endergonic and anabolic
Which type of cell signaling generally occurs between cells that are distant from each other?
Endocrine
Photoheterotrophs
Energy from sunlight, carbon from organic compounds
Why doesn't evolution contradict the second law of thermodynamics?
Even though evolution may decrease the entropy of living organisms, it increases the entropy of the Earth ( or universe), as the chemical reactions that are required to make organisms release heat
Which organisms are considered heterotrophs?
Most bacteria and dogs
Fermentation produces nearly twice as much ATP as aerobic respiration, which explain why it is a preferred pathway for bacteria
FALSE
In which organisms would you expect ethanol fermentation to occur?
Fungi and plants
What happens when glucose is phosphorylated during phase 1 of glycolysis?
Glucose is destabilized so that it can be broken apart in phase 2
in order for a G protein signaling to be active
the alpha subunit must bind GTP
Some present-day bacteria use a system of anaerobic respiration characterized by an electron transport chain analogous to that found in aerobic organisms. Which of the following correctly characterizes the anaerobic electron transport chain?
It established a proton gradient between the cytoplasm and the extracellular fluid
In cell communication, what is a requirement of the responding cell?
It must express receptor proteins
Which type of protein adds a phosphate group to another molecule?
Kinase
Which best describes how ATP synthase converts the potential energy of the proton gradient to the chemical energy of ATP?
Kinetic energy from the flow of protons is converted to the kinetic energy of rotation of the F0 subunit; the rotation of the F0 subunit leads to rotation of the F1 subunit, which can then catalyze ATP synthesis
Notch and Delta are both transmembrane proteins involved in cell communication in the developing nervous system of vertebrate animals. What makes Notch different from Delta?
Notch is a receptor, and Delta is a signaling molecule
Following a heart attack, what would occur in the heart tissue d/t a block in the coronary arteries?
Production of ATP would decrease, lactic acid would accumulate in the tissue d/t glycolysis and fermentation, phosphofructokinase, an intermediary enzyme of glycolysis, would be activated
What is the key difference between blood serum and blood plasma that affects their ability to help fibroblasts grow in culture?
Serum contains factors released by platelets during blood clotting. Plasma is from unclotted blood and does not contain these factors
What is the role of signal transduction in cell signaling?
Signal transduction connects the activation of the receptor to the cellular response
Why are receptors for steroid hormone signals found inside the cell rather than on the cell surface?
Steroid hormones are nonpolar and can pass through the cell membrane
Both NAD+ and molecular oxygen serve as electron acceptors in cellular respiration
TRUE
Conditions that reduce the strength of the proton gradient across the inner mitochondrial membrane slow the production of ATP by ATP synthase
TRUE
In a plan cell, the oxidative phosphorylation stage of cellular respiration is not carried out in the cytoplasm
TRUE
The ATP produced during glycolysis is the result of substrate-level phosphorylation
TRUE
Which signaling molecules would you expect to travel the longest distance in the human body?
Testosterone
What causes the inactivation of a G protein?
The a (alpha) subunit catalyzes the hydrolysis of GTP to GDP and inorganic phosphate
A researcher is comparing the amount of protein contained in inner and out mitochondrial membranes. What do you predict they will find?
The amount of proteins will be greater in the inner membrane
A chemical that binds to a cell and causes its activity to change is an example of which element of cellular communication?
a signaling molecule
Glycolysis is a series of chemical reactions by which the cell can obtain ATP. NAD+ plays a crucial role in reactions of glycolysis by:
accepting electrons during glycolysis, with the overall result that glucose is partially oxidized to pyruvate
Beta-oxidation does not produce any ATP directly, but it does produce:
acetyl-CoA, NADH, and FADH2
In a reaction, enzymes change the:
activation energy
Give an example of something that could be a product of a catabolic reaction
an amino acid like tryptophan
Which of the following types of inhibitor permanently alters the enzymes it inhibits?
an irreversible inhibitor
The assembly of glucose molecules into polysaccharides is a(n). _______ process
anabolic
Building a protein by adding amino acids to the polypeptide chain is an example of:
anabolism
Glycolysis is:
anaerobic
Lactic acid fermentation occurs in:
animals and bacteria
Second messengers:
are small intracellular molecules that participate in signal transduction, play a role in activation of intracellular signal transduction, amplify the effects of the signal, are removed in order to terminate a cellular signaling response
List the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell
autocrine, paracrine, endocrine
Lactic acid fermentation occurs in
bacteria and animals
The breakdown of fatty acids takes place by a process called:
beta-oxidation
Most of the proteins of the electron transport chain are:
embedded in the inner mitochondrial membrane
Most cells usually only have only one signaling pathway
false
Where does the F1 subunit of ATP synthase get its energy to catalyzed the synthesis of ATP?
from rotational energy provided by the flow of protons through the channel in the F0 subunit
What does a ligand-gated channel do?
it allows ions to move across the plasma membrane, it opens a channel through the plasma membrane when signal molecules bind, it can be closed and restrict ion flow when signal molecules are absent
Termination is an important step in adrenaline signaling because
it allows organisms to respond to new stresses, allows an appropriate level of response, prevents an excessive response to adrenaline
How is a G protein classified?
it is a peripheral membrane protein
During the citric acid cycle, what happens to the coenzyme A that is part of acetyl-CoA?
it is recycled for use in other reactions
Pyruvate oxidation is an important stage in cellular respiration because:
it links glycolysis to the citric acid cycle
pyruvate oxidation is an important stage in cellular respiration because:
it links glycolysis with the citric acid cycle
An avalanche is an example of ________ energy
kinetic
A cougar chases its prey. Running is a form of:
kinetic energy
On completion of either ethanol or lactic acid fermentation, the yield is only two ATP molecules per glucose molecule. The remaining chemical energy from the glucose is found primarily in:
lactic acid and ethanol
Red blood cells in the human bloodstream do not have mitochondria. What metabolic process would you predict these cells use to provide cellular energy/ATP?
lactic acid fermentation
During pyruvate oxidation, pyruvate is broken down into CO2 and an acetyl group. The CO2 is:
less energetic than the acetyl group
Acetate is the starting point for synthesis of a cell's
lipids
When a substance in a reaction is oxidized, it:
loses electrons
The citric acid cycle takes place in the:
mitochondrial matrix
ATP is a type of ________ and is composed of adenine, _____, and three phosphate groups
nucleotide; ribose
The mitochondrial electron transport chain is part of:
oxidative phosphorylation
When an electron is transferred from NADH to CoQ, NADH is _______ and CoQ is ____________
oxidized; reduced
The final (terminal) electron acceptor of the electron transport chain is:
oxygen
Gibbs free energy
the amount of energy available to do work
Phosphofructokinase is an allosteric enzyme in the pathway that breaks down glucose to product ATP. Regulation of glycolysis is directly releated to the level of ATP and citrate. If ATP or citrate levels are high, phosphofructokinase is inhibited. What will happen to this enzyme when ATP levels drop?
phosphofructokinase is activated
Oak trees are categorized as:
photoautotrophs
Organisms that derive their energy from the sun and carbon from carbon dioxide are:
photoautotrophs
Organic molecules store _________ energy in their ________ bonds
potential: covalent
Organic molecules store _________ energy in their ________ bonds
potential; covalent
During the action of ATP synthase, the __________ energy of the proton gradient is transformed into _______ energy of the F1 subunit, and this is converted into _________ energy of chemical bonds in ATP.
potential; kinetic; potential
Chemoautotrophs
prokaryotes that derive energy from the oxidation of inorganic chemicals
Enzymes are most often:
proteins
Acetyl-CoA synthesis occurs during:
pyruvate oxidation
Which stage of cellular respiration occurs following production of pyruvate?
pyruvate oxidation
When you exhale, there is more CO2 than was present in the air that you inhaled. This CO2 comes from reactions in:
pyruvate oxidation and the citric acid cycle
Which stages of cellular respiration produce CO2 as a waste product?
pyruvate oxidation and the citric acid cycle
In pyruvate oxidation, the electron donor is ______ and the electron acceptor is _______
pyruvate; NAD +
In many signaling pathways, once a signaling molecule binds to a receptor, the receptor becomes phosphorylated. This initial phosphorylation step best demonstrates:
receptor activation
Which is the correct order for the steps in cell signaling?
receptor activation, signal transduction, response
During lactic acid fermentation, pyruvate is:
reduced
The __________ forms of the electron carrier NAD+/NADH and FAD/FAH2 have high potential energy
reduced
Which of the following is a part of ATP?
ribose
which of the following is a part of ATP?
ribose
Cyclic AMP (cAMP) is an example of
second messenger
Cyclic AMP (cAMP) is an example of a:
second messenger
You have entered a 5K race, as you finish the last 50 m, you are breathing harder than at the start of the race and sweating profusely. This is an example of ________ law of thermodynamics because __________ is increasing
second; entropy
Which components of cell signaling is involved in only some types of cell communication?
signal transduction molecules
A cell that responds to an environmental condition by release of a chemical is an example of element of cellular communication
signaling cell
Reactions in which there is a negative change in free energy (-Delta G) are
spontaneous and exergonic
In glycolysis, ATP is synthesized by:
substrate-level phosphorylation
Which signaling molecules would would you expect to travel the longest distance in the human body?
testosterone
Ras is most similar to:
the (alpha) subunit of three-subunit G proteins
A mutant eukaryotic cell has a defect in its adrenaline signaling G protein-coupled receptor, even though adrenaline can bind to its G protein-coupled receptor, nothing happens. What could the mutation in these cells disrupt?
the mutation might prevent; G protein alpha subunit from binding to GTP, the activation of adenylyl cyclase, protein kinase A (PKA) from binding to cAMP
In the G protein-coupled signal transduction pathway, phosphatases are responsible for the inactivation of:
the proteins activated by protein kinase A
inactivation of a cell-surface receptor depends on:
the release of the ligand from the receptor ligand binding site
in a given reaction, which of the following has the highest amount of free energy?
the transition state when the reaction is not catalyzed by an enzyme
Nearly all cells use ATP as their primary energy source. This is evidence that:
the use of ATP of cells evolved early in the history of life and has been conserved over time
If two signaling pathways are activated simultaneously:
they may inhibit each other, one may inhibit the other, they may strengthen each other
How does an "activated" receptor transfer information into the cell?
through a conformational change of the receptor
An energy input is necessary for both endergonic and exergonic reactions
true
The energy of a system is defined as the system's capacity to do work
true
Which of the following summarizes the net final products of glycolysis?
two molecules of pyruvate, two molecules of ATP, and two molecules of NADH
Which is a product (as opposed to a substrate) of at least one of the processes of cellular respiration?
water
Carbon-carbon covalent bonds, such as the ones in carbohydrates and lipids, are ________ and have_________
weak; a lot of potential energy
