Exam 2

Question 1

Catabolism is to anabolism as _____ is to _____

Answer 1

Exergonic; endergonic

Question 2

Which of the following is the strongest evidence that protein structure and function are correlated?

Answer 2

Denatured (unfolded) proteins do not function normally

Question 3

Chemical equilibrium is reached when…

Answer 3

The forward and reverse reactions occur at the same time

Question 4

Which of the following is a chemical reaction?

Answer 4

The formation of a covalent bond between 2 amino acids

Question 5

What is an example of potential energy and kinetic energy?

Answer 5

Water at the top of a dam has potential energy; water falling through a dam has kinetic energy. The moving water performs work by moving the blades of turbines in the dam to generate electricity

Question 6

Energy is observed in 2 basic forms: potential and kinetic. What correctly matches these forms with a source of energy?

Answer 6

The covalent bonds of a sugar molecule: potential energy

Question 7

Has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate

Answer 7

Competitive inhibitor

Question 8

Binds to a site on the enzyme that is not the active site

Answer 8

Noncompetitive inhibitor

Question 9

Forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity.

Answer 9

Irreversible inhibitor

Question 10

The competitive inhibitor competes with the substrate for the _____ ___ on the enzyme

Answer 10

Active site

Question 11

When the noncompetitive inhibitor is bonded to the enzyme, the shape of the ____ is distorted

Answer 11

Enzyme

Question 12

Enzyme inhibitors disrupt normal interactions between an enzyme and its _____.

Answer 12

Substrate

Question 13

What can you do to regain the activity of the enzyme?

Answer 13

The enzyme is inactive at this point. New enzyme must be added to regain enzyme activity.

Question 14

What can you do to speed up the reaction up again?

Answer 14

Add more substrate; it will outcompete the inhibitor and increase the reaction rate.

Question 15

An enzyme is ___ when it loses its native conformation and its biological activity.

Answer 15

Denatured

Question 16

An enzyme is considered a ____ because it speeds up chemical reactions without being used up.

Answer 16

Catalyst

Question 17

An enzyme is considered ____ because of its ability to recognize the shape of a particular molecule.

Answer 17

Specific

Question 18

A ____, such as a vitamin, binds to an enzyme and plays a role in catalysis

Answer 18

Cofactor

Question 19

When properly aligned, the enzyme and substrate from an enzyme-substrate _____.

Answer 19

Complex

Question 20

A substrate binds to an enzyme at the ___ ___, where the reaction occurs.

Answer 20

Active site

Question 21

In a catalyzed reaction a reactant is often called a _____.

Answer 21

Substrate

Question 22

“Conservation of energy” refers to the fact that ____

Answer 22

Energy cannot be created or destroyed but can be converted from one form to another.

Question 23

Chemical energy is a form of _____ energy.

Answer 23

Potential

Question 24

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

Answer 24

Cellular respiration

Question 25

Which of these are by-products of cellular respiration?

Answer 25

Heat, carbon dioxide, and water

Question 26

The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of ___ ___

Answer 26

Catabolic pathway

Question 27

In cells, what is usually the immediate source of energy for endergonic reaction?

Answer 27

ATP

Question 28

The reaction ADP + P - -> ATP is an ___ reaction

Answer 28

Endergonic

Question 29

The energy for an endergonic reaction comes from a(n) _____ reaction.

Answer 29

Exergonic

Question 30

What is the fate of the phosphate group that is removed when ATP is converted to ADP?

Answer 30

It is acquired by a reactant in an endergonic reaction.

Question 31

What is energy coupling?

Answer 31

The use of energy released from an exergonic reaction to drive an endergonic reaction.

Question 32

Enzymes are described as catalysts, which means that they ____

Answer 32

Increase the rate of a reaction without being consumed by the reaction

Question 33

Enzymes work by

Answer 33

Reducing the energy of activation

Question 34

An enzyme is an ____ ____

Answer 34

Organic catalyst

Question 35

What name is given to the reactants in an enzymatically catalyzed reaction?

Answer 35

Substrate

Question 36

As a result of its involvement in a reaction, an enzyme is _____

Answer 36

Unchanged

Question 37

The electrons stripped from glucose in cellular respiration end up in which compound?

Answer 37

Water

Question 38

Which of the following statements about the redox reactions of the electron transport chain is correct?

Answer 38

The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane

Question 39

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the...

Answer 39

H+ movement down it’s concentration gradient

Question 40

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is ___

Answer 40

Oxygen

Question 41

In mitochondrial electron transport, what is the direct role of O2?

Answer 41

To function as the final electron acceptor in the electron transport chain

Question 42

How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation?

Answer 42

Both electron transport and ATP synthesis would stop

Question 43

NADH and FADH2 are both electron carriers that donate their electrons to the electron transport chain. The electrons ultimately reduce O2 to water in the final step of electron transport

Answer 43

Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor that when NADH is the electron donor

Question 44

In cellular respiration, a series of molecules forming an electron chain alternately accepts and then donates electrons. What is the advantage of such an electron transport chain?

Answer 44

The advantage of an electron transport chain is that small amount of energy is released with the transfer of an electron between each of pair of intermediates.

Question 45

In mitochondria, exogenic redox reactions ______

Answer 45

Provide the energy that establishes the proton gradient

Question 46

When electrons flow along the electron transport chain of mitochondria, which of the following changes occur?

Answer 46

The pH of the matrix increases.

Question 47

Hydrophobic substances like salad oil are...

Answer 47

Nonpolar molecules that repel water molecules

Question 48

How do membrane phospholipids interact with water?

Answer 48

The polar heads interact with water; the nonpolar tails do not

Question 49

Which of the following statements is true regarding potential energy?

Answer 49

Potential energy is the energy possessed by matter due to its location or structure.

Question 50

Which property is necessary for protein A to bind to protein B?

Answer 50

Protein A must have regions of shape and charge that are complementary to those on protein B

Question 51

A signal transduction pathway is initiated when a ___ binds to a receptor

Answer 51

Signal molecule

Question 52

A signal molecule is also known as a(n) ____.

Answer 52

Ligand

Question 53

Which is the second of the 3 stages of cell signaling

Answer 53

Transduction

Question 54

The cleavage of glycogen by glycogen phosphorylation releases _____.

Answer 54

Glucose-1-phosphate (glycogen is a polysaccharide composed of glucose monomers).

Question 55

Epinephrine acts as a signal molecule that attaches to ____ proteins.

Answer 55

G-protein-linked receptor

Question 56

Which of these is activated by calcium ions?

Answer 56

Calmodulin

Question 57

Which of these is NOT correct?

Answer 57

Cyclic AMP binds to calmodulin

Question 58

A toxin that inhibits the production of GTP would interfere with the function of a signal transduction pathway that is initiated by the binding of a signal molecule to ____ receptors.

Answer 58

G-protein-linked

Question 59

Which extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor?

Answer 59

Estrogen

Question 60

_____ molecules can diffuse through the plasma membrane and bind to intracellular receptors.

Answer 60

Nonpolar

Question 61

A(n) ____ is an example of a signal molecule that can bind to an intracellular receptor and thereby cause a gene to be turned on or off.

Answer 61

Steroids

Question 62

Thyroid hormones bind to ___ receptors

Answer 62

Intracellular

Question 63

____ hormones are able to pass through the plasma membrane

Answer 63

Thyroid

Question 64

What is responsible for initiating a signal transduction pathway?

Answer 64

Signal molecule

Question 65

What role does a transcription factor play in a signal transduction pathway?

Answer 65

By binding to DNA it triggers the transcription of a specific gene.

Question 66

A signal transduction pathway is initiated when a ___ binds to a receptor.

Answer 66

Signal molecule

Question 67

Which acts as a second messenger?

Answer 67

Cyclic AMP

Question 68

Calcium ions that acts as a second messengers are stored in ____.

Answer 68

Endoplasmic reticula (ER)

Question 69

___ catalyzes the production of ____, which then opens an ion channel that releases ____ into the cell’s cytoplasm

Answer 69

Phospholipase C...IP3...Ca2+

Question 70

A protein kinase activating many other protein kinases is an example of ___

Answer 70

Amplification

Question 71

What statement correctly distinguishes the roles of protein kinases and phosphatases in signal transduction pathways?

Answer 71

Protein kinases activates enzymes by phosphorylating or adding phosphate groups to them. Protein phosphatases dephosphorylate or remove phosphate groups from enzymes, including protein kinases.

Question 72

Steroid hormone receptors in animals tend to be

Answer 72

Soluble proteins in the cytoplasm

Question 73

____ _____ are fluid mosaics of lipids and proteins

Answer 73

Cellular membranes

Question 74

____ ____ results in selective permeability

Answer 74

Membrane structure

Question 75

Is a diffusion of a substance across a membrane with no energy investment

Answer 75

Passive transport

Question 76

Uses energy to move solutes against their gradients

Answer 76

Active transport

Question 77

Bulk transport across the plasma membrane occurs by ____ and _____

Answer 77

Exocytosis; endocytosis

Question 78

The ____ ___ plays a key role in most cell signaling

Answer 78

Plasma membrane