physio ch2

A change in pH value of one unit indicates a 1-fold change in [H+]. change of 10-2 in pH. change of 10-1 in pH. 10 fold change in [H+]. Cannot be determined.

10 fold change in [H+].

If in an acid-base reaction H2SO42- donates two H+, one mole of H2SO42- would equal how many equivalents? 1 2 0.75 4 0.5

2

What is the pH of a 0.005 M HCl solution? Assume complete dissociation. 2.3 3.3 0.30 4.3

2.3

100 mg/dL is a typical blood concentration of glucose. The molecular weight of glucose is approximately 180 daltons. What is the molarity of this solution in millimoles? 10 0.56 5.6 100 18

5.6

How many grams of NaCl, m.w. 58.5 daltons, are necessary to make 1 liter of 5% saline? 6.02 × 1023 58.5 2.9 1 50

50

A 5 M solution of 100 mL of glucose contains how many grams of glucose, m.w. 180 daltons? 6.02 × 1023 180 1.0 90 360

90

Which of the following would be considered an allosteric modulator? A substance that has no effect on the affinity of the ligand. A substance that binds to proteins away from the active site. A substance that can be displaced by competition at the active site. A substance that binds irreversibly. A substance involved in activation via phosphorylation.

A substance that binds to proteins away from the active site.

Which compound is hydrophobic? Potassium ions (K+) Butter Table salt Sugar

Butter

All of these statements about carbohydrates are true except one. Identify the exception. Cellulose is the most abundant carbohydrate on earth. Simple sugars include galactose, glucose, and ribose. Glycogen is a storage polysaccharide made by animal cells. Glycogen is important both for energy storage and to provide structure for cells. Polysaccharides are important both for energy storage and to provide structure to cells.

Glycogen is important both for energy storage and to provide structure for cells.

In the equation H2CO3 ↔ H+ + HCO3- which of these chemical speices is an acid? H2CO3 H+ HCO3-

H2CO3

A component of an important buffer in the human body is H+. NaCl. HCO3-. H2O. HCl.

HCO3-.

During intense exercise our muscles produce lactic acid. This weak acid partially dissociates in water, forming the anion lactate and H+. What do you predict should happen to the pH of the cytoplasm inside of muscle cells during intense exercise? The intracellullar pH of muscles cells should not change. The intracellullar pH of muscles cells should decrease. The intracellullar pH of muscles cells should increase.

The intracellullar pH of muscles cells should decrease

Which of the following would cause a protein response rate to be maximal? There are too few ligand molecules. The protein is denatured. The protein has been down-regulated. The protein binding sites are saturated.

The protein binding sites are saturated.

Which of the following is an important characteristic of lipids? They dissolve in water. They can be linked into long chains. They are nonpolar. They are converted to hormones.

They are nonpolar.

Why do nonpolar molecules, such as cholesterol, repel water? They have an even distribution of electrons. Their electrons tend to cluster around the carbon atoms within the molecule. They contain many hydrogen bonds. The covalent bonds of lipids create a small charge that repels water molecules.

They have an even distribution of electrons.

The most important energy-transferring compound in cells is a nucleotide known as deoxyribonucleic acid. fructose. glucose. adenosine triphosphate. protein.

adenosine triphosphate.

A modulator that increases protein function by binding to a protein distant from the binding site is called __________. allosteric inhibitor allosteric activator a competitive inhibitor a cofactor

allosteric activator

The organic molecules known as phospholipids are key components of cell membranes and composed of which molecules? nucleotides fatty acids glycerol amino acids both glycerol and fatty acids

both glycerol and fatty acids

Essential amino acids that are used to build proteins can be used medically for both diagnosis and treatment of diseases. can only be made by cells within our bodies. are linked together by ionic chemical bonds in proteins. exist in twenty six different configurations. can be derived from the foods we eat and digest.

can be derived from the foods we eat and digest

Which of the following biological molecules does glycogen belong to? lipids nucleotides proteins carbohydrates lipids and proteins

carbohydrates

A positively charged ion is called a(n) neutron. anion. electron. cation. proton.

cation

If a reaction which is stopped by substance X can recover when a lot more of the native activator is supplied, substance X would be considered which of the following? covalent modulator competitive inhibitor a phosphotase irreversible antagonist allosteric modulator

competitive inhibitor

A(n) ________ is any molecule or ion that binds to another molecule. enzyme cofactor phospholipid vitamin ligand

ligand

To which of the following groups of biomolecules do triglycerides and steroids belong? lipids carbohydrates proteins lipids and proteins nucleotides

lipids

Nucleic acids are polymers of units called amino acids. ribose. nucleotides. bases. fatty acids.

nucleotides

Which of the following formulas describes the relationship between pH and hydrogen ions? pH = log [H+] pH= [H+] + [OH-] pH = -log [H+] [H+] = log pH [H+] = -log pH

pH = -log [H+]

Which of the following biological molecules exhibit the characteristics of saturation, specificity and competition? lipids nucleotides receptor proteins carbohydrates lipids and proteins

receptor proteins

Proteins that bind signal molecules and initiate cellular responses are called __________. receptors immunoglobulins binding proteins enzymes

receptors

The concentration of a solution expresses the amount of solute per volume of solvent. solvent per volume of solution. solvent per volume of solute. solute per volume of solution. None of the answers are correct.

solute per volume of solution.

The largest carbohydrate molecules are called polysaccharides because they are composed of ________ molecules bonded together with one another. pyrimidine purine nucleotide sugar amino acid

sugar

When an enzyme reaches its saturation point, the amount of substrate for the enzyme to act upon is very low. the amount of product produced continues to increase. the amount of product produced by the enzyme decreases. the amount of substrate for the enzyme to act upon is very low and the amount of product produced by the enzyme decreases. the amount of substrate for the enzyme to act upon is very high.

the amount of substrate for the enzyme to act upon is very high.

When an enzyme reaches its saturation point, the binding sites are fully occupied, and the reaction rate reaches a maximum value. the binding sites are minimally occupied, and the reaction rate reaches a maximum value. the binding sites are fully occupied, and the reaction rate reaches a minimal value. the binding sites are minimally occupied, and the reaction rate reaches a minimal value.

the binding sites are fully occupied, and the reaction rate reaches a maximum value.

In a 5% NaCl solution, the solute is water. this means there are 5 grams of sodium chloride for every 100 mL of total solution and the solute is water. this means there are 5 grams of sodium chloride for every 100 mL of total solution. this means there are 5 grams of sodium chloride for every 100 mL of water. this means there are 5 grams of sodium chloride for every 100 mL of water and there are 5 grams of sodium chloride for every 100 mL of total solution.

this means there are 5 grams of sodium chloride for every 100 mL of total solution.