BIO 201 CH.2

Which pH is more acidic, a pH of 3, a pH of 7, or a pH of 9?

pH of 3

Which of the following does NOT describe uses for the ATP molecule?

pigment structure

What is the ratio of fatty acids to glycerol in triglycerides (neutral fats)?

3:1

Starch is a ________.

polysaccharide

What structural level is represented by the sequence of amino acids in a polypeptide chain?

primary structure

What is a chain of more than 50 amino acids called?

protein

Which organic molecules form the major structural materials of the body?

proteins

Carbohydrates and proteins are built up from their basic building blocks by the ________.

removal of a water molecule between each two units

A patient voices concern that her normal cholesterol level is dangerous. "I eat no cholesterol at all. That stuff is toxic!" she declares. What is your best response?

"A normal cholesterol level is a good thing. Your cells depend on cholesterol to stay healthy, and you can't make vital hormones without it."

The husband of a patient who is critically ill asks, "Why do they keep checking my wife's pH? Isn't knowing her oxygen level enough?" What is the best response?

"Many of her body's systems only work properly when her pH is within a narrow range, so we monitor it carefully."

What is the primary energy-transferring molecule in cells?

ATP

In a solution, the solute is the substance present in the greatest amount.

False

Which of the following is a neutralization reaction?

HCl + NaOH → NaCl + H2O

Rank the chemical bonds from relatively weakest to strongest. I. Ionic II. Covalent III. Hydrogen

III < I < II

What is the difference between kinetic and potential energy?

Kinetic energy is energy in action, while potential energy is stored energy.

Which of the following elements is necessary for proper conduction of nerve impulses?

Na

Which of the following is true of protein structure?

Secondary protein structures involve hydrogen bonding between amine and carboxyl groups.

Salivary amylase is an enzyme produced by the salivary glands that breaks down carbohydrates. What will happen to this enzyme as it follows the food into the stomach where the pH drops to 2.5?

The enzyme will denature and become inactive.

Which of the following statements regarding atoms is true?

The reactivity of an atom is based on the number of electrons in its outer valance shell.

All salts are ionic compounds, but not all ionic compounds are salts.

True

________ is fat soluble, produced in the skin on exposure to UV radiation, and necessary for normal bone growth and function.

Vitamin D

Foods are broken down into their building blocks by adding water. This would be an example of which characteristic of water?

Water acts as a reactant.

Water acts to dissolve molecules in the body. How does water dissolve the salt (NaCl) in your mouth from a salty pretzel?

Water acts as a solvent because the partial negative charge on the oxygen in water attracts sodium, while the partial positive charge on hydrogen attracts chloride. This results in the separation of sodium from chloride, thus breaking the ionic bond.

Which of the following is not considered a form of matter?

X rays

Choose the answer that best describes HCO3-.

a bicarbonate ion

In plasma, a typical body fluid, protein floating around would be considered to be which of the following?

a solute, specifically both a colloid and an electrolyte

What is the classification of a solution of NaOH with a pH of 8.3?

alkaline solution

Which of the following is a chemical that has an amine group and an organic acid group, but does not contain a peptide bond?

amino acid

What is a cation?

an atom that loses one or more electrons and acquires a net positive charge

Which of the following is an example of a suspension?

blood

What happens in redox reactions?

both decomposition and electron exchange occur

You notice that you cannot read your book through a test tube of patient fluid held against the print, making it so blurred as to be unreadable. There is no precipitant in the bottom of the beaker, though it has been sitting for several days in a rack. What type of liquid is this?

colloid

Water is an important molecule because it __________.

can form hydrogen bonds

Which four elements comprise approximately 96% of our body weight?

carbon, oxygen, hydrogen, and nitrogen.

Electrolytes are charged particles called ions that are dissolved in body fluids. Which of the following ions would be considered a major anion in the body?

chloride

The single most abundant protein in the body is ________.

collagen

Which type of proteins can function as chemical messengers or as receptors in the plasma membrane?

communication

ATP → ADP + Pi is an example of a(n) ________ reaction.

decomposition

Biological macromolecules are synthesized by ___________ reactions and are broken down by ___________ reactions.

dehydration synthesis; hydrolysis

A dipeptide can be broken into two amino acids by dehydration synthesis.

false

Carbohydrates are stored in the liver and skeletal muscles in the form of ________.

glycogen

When DNA is replicated, it is necessary for the two strands to "unzip" temporarily. Choose which bonding type is most appropriate for holding the strands together in this way.

hydrogen bonding

A high fever causes an enzyme to lose its three-dimensional structure and function. Which bonds are broken when a protein denatures?

hydrogen bonds

Which of the following is NOT one of the three major types of chemical reactions?

hyperbolic

Kidneys play a major role in helping to maintain proper levels of Na+ and K+ ions in the blood. If the kidneys fail to function properly, one of the direct consequences would be_________.

impaired nerve impulse transmission

Salts are always ________.

ionic compounds

The pH scale __________.

is based on the concentration of hydrogen ions in a solution

Which of the following is not a fundamental subatomic particle that forms elements?

nucleus

Which of the following is not a compound?

oxygen gas

The genetic information is coded in DNA by the ________.

sequence of the nucleotides

Cortisol is a type of lipid hormone. Which type of lipid would cortisol be classified as?

steroid

Amino acids joining together to make a peptide is a good example of a(n) ________ reaction.

synthesis

The chemical symbol O=O means ________.

the atoms are double bonded

A chemical reaction in which bonds are created is usually associated with ________.

the consumption of energy

What is the most significant factor in the formation of a covalent bond? Bond formation between carbon and hydrogen to form methane.

the sharing of electron pairs between two atoms

In a DNA molecule, the phosphate serves ________.

to hold the molecular backbone together

ATP is an unstable, high-energy molecule that provides body cells with a form of energy that is immediately usable.

true

All organic compounds contain carbon except CO2 and CO.

true

Buffers resist abrupt and large changes in the pH of body fluids by releasing or binding ions.

true

The pH of body fluids must remain fairly constant for the body to maintain homeostasis.

true

How many phosphates would ADP have attached to it?

two

Phospholipids make up most of the lipid part of the cell membrane. Since water exists on both the outside and inside of a cell, which of the following phospholipid arrangements makes the most sense?

two back-to-back phospholipid layers with the polar heads facing out on both sides

In general, the lipids that we refer to as oils at room temperature have ________.

unsaturated fatty acids