bio 1 chapter 2

What is the maximum number of single covalent bonds a carbon atom can form with other elements?

4

While the maximum number of electrons required to fill the outermost shell of an atom varies depending on the size of the atom, almost all of the smaller atoms (atomic numbers 2-20) are considered stable (nonreactive) when they contain ________ electron(s) in the outermost shell.

8

What is the basic structure of typical dietary fats?

A glycerol head and up to three fatty acid tails

What might happen if a protein has a change in one amino acid?

All of these happen.

What are the monomers of proteins?

Amino acids

What is a trace element?

An element that is required in miniscule amounts for life

Imagine that you have been employed as a technical consultant for a new television program in which the main character is a doctor who works with anabolic steroids. The writers have asked you for a short description to provide them with background about this class of drugs.

Anabolic steroids are synthetic versions of the male sex hormone testosterone. They can increase muscle mass and strength, but they also have dangerous side effects and are illegal without a prescription.

How might rising atmospheric CO2 concentrations lower the pH of the oceans?

As CO2 concentrations rise, excess CO2 is absorbed by the oceans. CO2 in the oceans can react chemically with water to form acid.

How do buffers minimize change in the pH of biological systems?

By absorbing H+ ions when there is an excess By donating H+ ions when there is a shortage

Identify the reactants in the following chemical reaction: C10H8 + 12 O2 → 10 CO2 + 4 H2O

C10H8 and 12 O2

Which is not one of the four atoms that make up the bulk of living organisms?

Calcium

Based on the suffix, a molecule of "maltose" is most likely what type of macromolecule?

Carbohydrate

Which of the following classes of large organic molecules includes table sugar?

Carbohydrates

What are the four classes of large organic molecules important to life on Earth?

Carbohydrates, proteins, lipids, and nucleic acids

Why are all living organisms based on molecules that contain carbon?

Carbon atoms can form strong covalent bonds with many other carbon atoms, and the atoms of hydrogen, oxygen, and nitrogen.

Which of the following is a polysaccharide?

Cellulose

The chemical name for table salt is sodium chloride, or simply NaCl. What type of chemical is NaCl?

Compound

Why is one side of a single water molecule partially negative while the other side is partially positive?

Electron pairs are unevenly shared between the oxygen atom and the two hydrogen atoms.

__________ are substances that CANNOT be broken down into other substances by chemical reactions.

Elements

Proteins are diverse molecules that perform a wide variety of functions. Which of the following is not a typical function of proteins?

Energy storage

Evaluate this statement: Cholesterol is a type of lipid, and thus all cholesterol lipids are bad for human health.

False, because some types cholesterol increase heart disease, but other types are necessary, especially in the plasma membrane.

Which of the following represents a simple sugar (also called monosaccharides)?

Glucose

What is the sum total of all the chemical reactions that take place in your body called?

Metabolism

Which of the following is not made from long chains of glucose?

Monosaccharides

What is the most common element in your body?

Oxygen

What kind of bond joins amino acids together to form a protein?

Peptide bond

__________ bonds hold the oxygen and hydrogen atoms in a molecule of water together.

Polar covalent

Water "beads up" on synthetic fabric like polyester but binds to cotton. What is the most likely explanation for this?

Polyester is nonpolar, whereas cotton is polar.

What is another name for the polymers of carbohydrates?

Polysaccharides

Which would have the highest concentration of C-H bonds?

Saturated fat

What makes one protein capable of a different function than other proteins?

The amino acid sequence of a protein determines its function.

A needle can be made to "float" on the surface tension of water. What causes this surface tension to form?

The cohesion of water molecules to each other

Select the most complete explanation of what the pH scale actually measures.

The concentration of hydrogen ions in a solution

Identify the part of the atom that most determines the chemical properties of the atom.

The number of electrons

What do you think might happen if you put a mixture of proteins and starch in a solution containing trypsin, an enzyme that breaks down proteins?

The protein would be broken down into amino acids.

What will be accomplished by lowering the activation energy of a reaction?

The reaction will proceed more quickly

To a large extent, a protein's function is dependent upon its shape. What determines a protein's shape?

The sequence of amino acids

The majority of the elements essential to life are found in what part of the periodic table?

The top third

When you drink a glass of water, what is the effect on the pH of the acid in your stomach?

The water will dilute the acid, decreasing the concentration of H+ ions and increasing the pH.

What are the ecological consequences of acidification of rain and oceans?

They damage the health of ecosystems.

Oil hydrogenation can produce a product, such as vegetable shortening or margarine, that is spreadable at room temperature because of an unusual bond that does not occur naturally. What is the name of this category of lipid?

Trans fat

Which of the following dietary fats is considered to be the least healthy?

Trans fat

What is responsible for the unusual chemical properties of water?

Water molecules can form an extensive network of hydrogen bonds with one another

Something with a pH of 5 would be ________.

acidic

The four classes of large organic molecules that are essential to life include __________.

carbohydrates, lipids, proteins, and nucleic acids

Organic compounds are distinguished by molecules that contain ________ bonded to other elements.

carbon

The bond in which bonded atoms share electrons is called a(n) ________.

covalent bond

The building of a large organic molecule from small subunits involves multiple ________.

dehydration synthesis reactions

Organic molecules that end in the suffix "-ase" often function as ________ molecules.

enzymatic

Water is the least dense when it ________.

freezes

Starch and glycogen are complex carbohydrates made by joining together long chains of __________ monomers

glucose

The 2+ in Cu2+ tells us that this atom ________.

has two more protons than electrons

Individual water molecules are held to one another by relatively weak ________ bonds.

hydrogen

The breaking of a large organic molecule into smaller individual subunits involves multiple ________.

hydrolysis reactions

All lipids are ________.

hydrophobic

If the number of protons in an atom does not match the number of electrons, the atom is specifically called an ________.

ion

In an atom, the number of neutrons determines most specifically the ________.

isotope

All sodium atoms have 11 protons. The nuclei of some sodium atoms contain 12 neutrons and others contain 11. These different forms of sodium are called __________.

isotopes

Which four elements make up the bulk of living cells?

oxygen, carbon, hydrogen, and nitrogen

Enzymes are a type of ________.

protein

During digestion, __________ are broken down into __________ through __________ reactions.

proteins; amino acids; hydrolysis

During a chemical reaction, atoms are ________.

rearranged

Food processors are phasing out the use of which type of fat because research has shown it to be particularly unhealthy?

saturated fats and trans fats