BIO UNIT 2

The sex hormones estrogen, progesterone, and testosterone belong to which class of molecules?

The subunits (monomers) in cellulose are linked together by __________.

One characteristic shared by sucrose, lactose, and maltose is that __________.

Which is the term for compounds that do not mix with water?

The lipids that form the main structural component of cell membranes are __________.

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture __________.

In living organisms, DNA exists as a __________ with the strand(s) __________.

Which of the following is a polymer?

A) Triacylglycerol, or fat
B) Cellulose, a plant cell wall component
C) Testosterone, a steroid hormone
D) Glucose, an energy-rich molecule

The peptide bond is __________ JOINING ____   _____ TOGETHER TO FORM A ______.

Which type of protein shields a newly forming protein from cytoplasmic influences while it is folding into its functional form?

When comparing saturated and naturally occurring unsaturated fats, the unsaturated fats have __________ and are __________ at room temperature.

The type of bond that forms to join monomers (such as sugars and amino acids) into polymers (such as starch and proteins) is a(n) __________ bond.

The components of nucleic acids are __________.

Sickle-cell anemia is a disease that is caused by __________ in the __________ of the protein.

Sugars have a(n) __________ group that interacts with a _________ group that forms ring structures when the dry molecule is placed in water.

Protein molecules are polymers (chains) of __________.

The molecule with four fused rings that is found in animal membranes and is the precursor of vertebrate sex hormones is __________.

At a conference, the speaker's grand finale was sautéing mealworms (insect larvae) in butter and serving them to the audience. They were crunchy (like popcorn hulls) because their exoskeletons contain the polysaccharide __________.

Nitrogenous bases are classified as either purines or pyrimidines. Examples of purines are __________.

A polysaccharide that is used for storing energy in human muscle and liver cells is __________.

Macromolecules, the molecules of life, include all of the following except __________.

A) NUCLEIC ACIDS
B) TRACE ELEMENTS
C) PROTEINS
D) CARBOHYDRATES

__________ is always involved in hydrolysis reactions.

The proper three-dimensional shape and folding of a protein is assisted by _________.

Carbohydrates are used in our bodies mainly for __________.

The secondary structure of a peptide backbone is stabilized by __________ forming either a(n) __________ or a(n) __________.

Sugars are molecules that have __________ C:H:O and are called __________.

In a dehydration synthesis reaction, __________ is always formed as a by-product of the reaction.

The tertiary structure of a protein includes all of the following interactions except _________ bonds.

A) HYDROPHOBIC
B) IONIC
C) HYDROPHILIC
D) PEPTIDE

Generally, animals cannot digest (hydrolyze) the glycosidic linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?

The sequence of amino acids in a protein is called the __________ structure of the protein.

What is entropy?

ATP aka

What is the most abundant for of energy in a cell?

What are the 3 environment or actions that would affect the rate of an enzyme reaction?

What can denature a protein?

Which of the following has the most free energy per molecule?

A) SUGAR MOLECULE
B) CHOLESTEROL MOLECULE
C) starch molecule
D) FATTY ACID MOLECULE

Cellulose is a ______ made of many ____.

Which of the following statements about enzymes is true?

A) Enzymes speed up the rate of the reaction without changing the ΔG for the reaction.
B) Enzymes react with their substrate (form chemical bonds), forming an enzyme-substrate complex, which irreversibly alters the enzyme.
C) Enzymes increase the rate of a reaction by raising the activation energy for reactions.
D) The more heat that is added to a reaction, the faster the enzymes will function.

Which of the following is changed by the presence of an enzyme in a reaction?

A) activation energy
B) G value for the reactants
C) sign of ΔG
D) magnitude of ΔG

How does ATP drive transport work inside a cell?

A) By phosphorylating a transport protein
B) By removing a phosphate from a transport protein
C) By binding to motor proteins
D) By providing free energy to facilitate the formation of polymers from monomers

Which of the following reactions would be endergonic?

A) ATP → ADP + Pi
B) HCl → H+ + Cl
C) C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
D) Glucose + fructose → sucrose

Which of the following correctly states the relationship between anabolic and catabolic pathways?

A) Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.
B) Catabolic pathways produce usable cellular energy by synthesizing more complex organic molecules.
C) Degradation of organic molecules by anabolic pathways provides the energy to drive catabolic pathways.
D) Energy derived from catabolic pathways is used to drive the breakdown of organic molecules in anabolic pathways.

Which of the following statements about enzyme function is correct?

A) Enzymes can greatly speed up reactions, but they cannot change the net energy output because they cannot change the activation energy.
B) Enzymes can change the equilibrium point of reactions, but they cannot speed up reactions because they cannot change the net energy output.
C) Enzymes can greatly speed up reactions, but they cannot change the activation energy because they cannot change the net energy output.
D) Enzymes can lower the activation energy of reactions, but they cannot change the equilibrium point because they cannot change the net energy output.

Which of these statements about enzyme inhibitors is true?

A) The action of inhibitors may be reversible or irreversible.
B) A competitive inhibitor binds to the enzyme at a place that is separate from the active site.
C) When the product of an enzyme or an enzyme sequence acts as its inhibitor, this is known as positive feedback.
D) A noncompetitive inhibitor does not change the shape of the active site.

How does ATP drive mechanical work inside a cell?

A) By binding to motor proteins
B) By phosphorylating a transport protein
C) By removing a phosphate from a transport protein
D) By binding to motor proteins

If the entropy of a living organism is decreasing, which of the following is most likely to be occurring simultaneously?

A) Energy input into the organism must be occurring to drive the decrease in entropy.
B) The first law of thermodynamics is being violated.
C) Heat is being used by the organism as a source of energy.
D) The entropy of the organism's environment must also be decreasing.

Which of the following statements is correct regarding ATP?

A) The energy in an ATP molecule is released through hydrolysis of one of the phosphate groups.
B) The energy in an ATP molecule is released from the ribose group.
C) The energy in an ATP molecule is released from the adenine group.
D) ATP molecules do not release free energy when hydrolyzed.

As ATP begins to build up in a cell, metabolism slows down. How does this happen?

A) ATP binds to the active sites of many of the enzymes involved in metabolism, causing them to stop functioning.
B) Excess ATP causes many of the enzymes involved in metabolism to denature.
C) ATP acts as an allosteric inhibitor to many of the enzymes involved in metabolism, thus slowing their function.
D) ATP acts as an activator, increasing the rate of its production.

An exergonic reaction __________ free energy, and an endergonic reaction __________ free energy.

In general, the hydrolysis of ATP drives cellular work by __________.

A) releasing free energy that can be coupled to other reactions
B) changing to ADP and phosphate
C) releasing free energy that can be coupled to other reactions
D) acting as a catalyst

Which of the following is an example of the second law of thermodynamics as it applies to biological reactions?

A) Cellular respiration releases some energy as heat.
B) All types of cellular respiration produce ATP.
C) None of the listed responses is correct.
D) The aerobic respiration of one molecule of glucose produces six molecules each of carbon dioxide and water.

What best characterizes the role of ATP in cellular metabolism?

A) The ΔG associated with its hydrolysis is positive.
B) The release of free energy during the hydrolysis of ATP heats the surrounding environment.
C) It is catabolized to carbon dioxide and water.
D) The free energy released by ATP hydrolysis that may be coupled to an endergonic process via the formation of a phosphorylated intermediate.

The process of stabilizing the structure of an enzyme in its active form by the binding of a molecule is an example of __________.

A) noncompetitive inhibition
B) competitive inhibition
C) allosteric regulation
D) feedback inhibition

Cells use ATP constantly, but ATP is considered a renewable resource. What process makes this possible?

A) The hydrolysis of ATP is an irreversible reaction.
B) ATP can be regenerated by the addition of a phosphate group to ADP.
C) ADP and ATP are stored in large amounts in a cell.
D) ADP is generated by the addition of a phosphate group to ATP.

Which of the following statements is correct regarding kinetic and potential energy?

A) Potential energy is related to the relative motion of objects, and kinetic energy is the energy that matter possesses because of its location or structure.
B) Potential energy cannot be converted to kinetic energy.
C) Kinetic energy is associated with the relative motion of objects, and potential energy is the energy that matter possesses because of its location or structure.
D) Chemical energy is a type of kinetic energy, and thermal energy is a type of potential energy.

Which of the following states the relevance of the first law of thermodynamics to biology?

A) Photosynthetic organisms produce energy in sugars from sunlight.
B) The total energy taken in by an organism must be greater than the total energy stored or released by the organism.
C) Energy is destroyed as glucose is broken down during cellular respiration.
D) Energy can be freely transformed among different forms as long as the total energy is conserved.

Which of the following is true regarding metabolic pathways?

A) Metabolic pathways consist of a single chemical reaction.
B) Metabolic pathways are not important to a cell’s ability to function.
C) Each reaction in the pathway is catalyzed by the same enzyme.
D) Metabolic pathways consist of a series of reactions, each catalyzed by a different enzyme.

Which of the following statements is correct regarding competitive and noncompetitive enzyme inhibitors?

A) Only competitive inhibitors affect enzyme function.
B) Neither type of inhibitor affects enzyme function.
C) Competitive inhibitors do not bind directly to the active site of an enzyme while noncompetitive inhibitors do.
D) Competitive inhibitors bind to the active site of an enzyme while noncompetitive inhibitors bind to an enzyme away from the active site.

ATP allosterically inhibits enzymes in ATP-producing pathways. The result of this is called __________.

A) feedback inhibition
B) positive feedback
C) competitive inhibition
D) cooperativity

Which of the following statements correctly describes cofactors and coenzymes?

A) Both cofactors and coenzymes act as allosteric inhibitors to various enzymes.
B) Both are nonprotein enzyme helpers; but most coenzymes are metal ions, and most cofactors are organic molecules.
C) Neither cofactors nor coenzymes assist enzyme function.
D) Both are nonprotein enzyme helpers; but most cofactors are metal ions, and coenzymes are organic molecules that are a specific type of cofactor.

Which of the following statements about the active site of an enzyme is correct?

A) The structure of the active site is not affected by changes in temperature.
B) The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.
C) Coenzymes are rarely found in the active site of an enzyme.
D) The active site has a fixed structure (shape).

An exergonic (spontaneous) reaction is a chemical reaction that __________.

A) releases energy when proceeding in the forward direction
B) cannot occur outside of a living cell
C) is common in anabolic pathways
D) occurs only when an enzyme or other catalyst is present

The primary manner in which cells manage their energy resources in order to do work is called energy coupling. Which of the following statements accurately defines energy coupling?

A) Endergonic reactions drive exergonic reactions.
B) Exergonic reactions drive endergonic reactions.
C) Anabolic reactions drive catabolic reactions.
D) Chemical reactions in cells are always at equilibrium.

At low pH, a particular enzyme catalyzes a reaction at a high rate. At neutral pH, the enzyme is completely inactive. What statement best explains the difference in how pH affects the function of this enzyme?

A) Low pH causes the enzyme to denature, and neutral pH causes the enzyme to function normally.
B) The enzyme functions best at both low and neutral pH.
C) The enzyme is adapted for low pH but is denatured at neutral pH, leaving it nonfunctional.
D) Neutral pH provides the optimal environment in which this enzyme functions.

At low temperatures, a particular enzyme catalyzes a reaction, but at a slow rate. At high temperatures, the enzyme is completely inactive. What statement best explains the difference in how temperature affects the function of this enzyme?

A) Low temperatures cause the enzyme to denature, and high temperatures cause the enzyme to move too fast to bind to its substrate.
B) The enzyme functions best at both low and neutral pH.
C) Temperature has no effect on enzyme function.
D) At low temperatures, there is not enough free energy for the enzyme to function at a high rate, and at high temperatures, the enzyme is denatured, leaving it nonfunctional.

Enzyme activity is affected by pH because __________.

A) high or low pH may disrupt hydrogen bonding or ionic interactions and thus change the shape of the active site
B) Low pH causes the enzyme to denature, and neutral pH causes the enzyme to function normally.
C) most substrates don't function well at high or low pH
D) changes in pH can cause loss of cofactors from the enzyme