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