Question 1

Which one of the following occurs when a phosphate is removed from an ATP molecule?

Accepted Answer

When a phosphate is removed from an ATP molecule, energy is released for cell work. This is because ATP is a high energy molecule and the removal of the phosphate group results in the release of energy that can be utilized by the cell.

Question 2

DNA differs from RNA in that DNA

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 3

A student has isolated a large compound (macromolecule) from cells. Chemical analysis of the compound shows that it is made up of the following elements: carbon, hydrogen, oxygen, nitrogen, and sulfur. To which group of macromolecules does this compound most likely belong?

Accepted Answer

Proteins are macromolecules made up of carbon, hydrogen, oxygen, nitrogen, and sulfur. Carbohydrates and nucleic acids contain only carbon, hydrogen, and oxygen. Lipids are mainly composed of carbon and hydrogen, with some oxygen. Aqueous is not a macromolecule group. Therefore, option B is the best choice.

Question 4

A research student is analyzing the nucleic acid of a virus. He finds that the nucleic acid contains thymine. From this it can be concluded that the nucleic acid

Accepted Answer

Thymine is one of the four nitrogenous bases that are found in DNA (along with adenine, guanine, and cytosine). Therefore, the presence of thymine indicates that the nucleic acid being analyzed is a strand of DNA, rather than RNA (which contains uracil instead of thymine). Ribose, glucose, and proteins are not typically found in nucleic acids.

Question 5

During intense exercise, you produce a lot of heat energy, yet your body temperature rises only in small increments. This temperature stability is because water in body fluids releases the heat very quickly.

Accepted Answer

The answer of During intense exercise, you produce a lot...

Question 6

Electrons are smaller than protons, are negatively charged, and orbit the nucleus.

Accepted Answer

Electrons are smaller than protons and are negatively charged. They do orbit the nucleus.

Question 7

The difference between water molecules in liquid water and water molecules in ice is in the number of covalent bonds that form.

Accepted Answer

The answer of The difference between water molecules in liquid...

Question 8

Which one of the following is TRUE regarding nucleotides?

Accepted Answer

The answer of Which one of the following is TRUE...

Question 9

When water is released from a dam, potential energy is converted to chemical energy.

Accepted Answer

When water is released from a dam, potential energy is converted to kinetic energy, not chemical energy.

Question 10

Potential energy is energy that has not been used yet, but has the potential to do work.

Accepted Answer

This is correct. Potential energy is stored energy that has the potential to do work in the future. Examples of potential energy include a stretched rubber band, water behind a dam, and a compressed spring.

Question 11

Because carbon requires four additional electrons to fill its outermost shell, it has a natural tendency to form four covalent bonds with other atoms, making it an ideal element for forming structures in living cells.

Accepted Answer

This statement is true. Carbon has four valence electrons and needs four additional electrons to complete its outermost shell. This allows it to form four covalent bonds with other atoms, making it a versatile element for building complex structures in living cells.

Question 12

-The figure above shows a triglyceride that contains unsaturated fatty acids.

Accepted Answer

Without the figure, it is impossible to determine if the triglyceride contains unsaturated fatty acids, as this requires visual inspection of the chemical structure.

Question 13

The more buffers present in a body fluid, the more likely that the blood pH will change after absorbing nutrients during digestion.

Accepted Answer

The more buffers present in a body fluid, the more resistant it is to changes in pH. Therefore, the blood pH is less likely to change after absorbing nutrients during digestion if there are more buffers present.

Question 14

All matter is made up of atoms.

Accepted Answer

This is the basic understanding of atomic theory and is widely accepted.

Question 15

One of the most important buffer pairs in blood is carbonic acid and bicarbonate because they regulate the pH of blood by absorbing and releasing hydrogen ions as needed.

Accepted Answer

Carbonic acid and bicarbonate act as a buffer pair in blood, helping to maintain pH by either absorbing or releasing hydrogen ions.

Question 16

Atoms with either more or fewer neutrons than the usual number for an element are referred to as isotopes.

Accepted Answer

This statement is true. Isotopes are atoms that have the same number of protons but different numbers of neutrons in their nuclei. This causes them to have different atomic masses and slightly different physical and chemical properties.

Question 17

A student has isolated a large compound (macromolecule) from cells. Chemical analysis of the compound shows that it is made up of the following elements: carbon, hydrogen, oxygen, nitrogen, and phosphorus. To which group of macromolecules does this compound most likely belong?

Accepted Answer

The presence of nitrogen and phosphorus indicates that the compound is a nucleic acid, which includes DNA and RNA. Carbohydrates and lipids do not contain nitrogen or phosphorus, and proteins contain nitrogen but not phosphorus. Aqueous is not a category of macromolecules.

Question 18

If the number of protons in an atom equals the number of electrons in the atom, the atom is an ion.

Accepted Answer

If the number of protons in an atom equals the number of electrons in the atom, then the atom is electrically neutral and not an ion. An ion is an atom or molecule that has gained or lost one or more electrons, thus acquiring a positive or negative charge.

Question 19

Proteins that function as a catalyst

Accepted Answer

Proteins that function as a catalyst are referred to as enzymes. Enzymes facilitate chemical reactions by lowering the activation energy required for the reaction to occur, but do not alter the final products formed.

Question 20

-The type of bond indicated by the dotted lines in the figure above is a hydrogen bond.

Accepted Answer

Dotted lines are often used to represent hydrogen bonds in diagrams, indicating a weak attraction between a hydrogen atom and an electronegative atom like oxygen or nitrogen.

Quiz 2: The Chemistry of Living Things