question

Matter is composed of elements, which are composed of

answer

atoms

question

The atomic number of an atom equals the number of ______ and the atomic weight equals the ____.

answer

protons; number of protons plus neutrons

question

In a covalent bond

answer

atoms share a pair or more of electrons.

question

In an ionic bond

answer

oppositely charged atoms attract.

question

Sodium ions and calcium ions are examples of

answer

cations.

question

When cations and anions meet, they

answer

form ionic bonds.

question

Water causes ionically-bonded atoms to

answer

dissociate

question

Carbon can form ___ covalent bonds.

answer

4

question

Which of the following isotopes has the longest half-life?

answer

Cobalt-60

question

The ______ uses iodine in a synthesis reaction.

answer

thyroid gland

question

The isotope most likely to be used to study the thyroid gland is

answer

iodine-131.

question

Atomic radiation is useful for treating cancer because

answer

radiation harms cancer cells more readily than it does most non-cancer cells.

question

Exposure to ionizing radiation may

answer

cloud the lens of the eye. cause cancer. interfere with normal growth.

question

Which of the following is not a source of ionizing radiation?

answer

Cholesterol and triglycerides

question

A CT scan differs from a conventional X-ray image because it is

answer

three-dimensional.

question

PET imaging follows the emission of

answer

positrons.

question

The number of protons in an atom of an element always equals its atomic weight.

answer

False

question

Radioactive isotopes have stable nuclei.

answer

False

question

Sodium and chloride atoms combine readily because they both lose electrons.

answer

False

question

The symbol Na+ represents a sodium atom that has lost an electron.

answer

True

question

Water is an example of a compound.

answer

True

question

An atom with 10 protons and which has lost 2 electrons is electrically neutral.

answer

False

question

Chemistry deals with

answer

the composition and changes of substances that make up living as well as non-living matter.

question

Chemistry is important to the study of physiology because

answer

the foods that we eat are chemicals. body functions depend on cellular functions that reflect chemical changes. chemical reactions enable our bodies to extract energy from nutrients.

question

Which of the following groups of elements accounts for more than 95% of the human body by weight?

answer

Carbon, hydrogen, oxygen, nitrogen

question

The atoms of different elements have

answer

different atomic numbers.

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Isotopes of an element have

answer

the same atomic number but different atomic weights.

question

The atoms of the isotopes of a particular element vary in the number of

answer

neutrons.

question

The first electron shell of an atom can hold a maximum of

answer

2 electrons.

question

The formula H2O refers to

answer

A molecule that contains two hydrogen atoms and one oxygen atom.

question

A decomposition reaction can be symbolized by

answer

AB → A + B.

question

A water solution that contains equal numbers of hydrogen ions and hydroxide ions is

answer

neutral.

question

Electrolytes that release hydrogen ions in water are

answer

acids.

question

The difference in hydrogen ion concentration between solutions with pH 4 and pH 5 is

answer

tenfold.

question

A chemical reaction in which parts of different molecules trade positions is a(n)

answer

exchange reaction.

question

Electrolytes are substances that

answer

ionize in water.

question

The pH scale measures the

answer

concentration of hydrogen ions in solution.

question

A person has alkalosis if the blood pH

answer

rises above 7.5.

question

A complete atom is electrically neutral because

answer

the number of electrons equals the number of protons.

question

Synthesis reactions are particularly important in the body for

answer

growth of body parts.

question

On the pH scale

answer

a tenfold difference in hydrogen ion concentration separates each whole number. the lower the whole number on the scale, the greater the H+ concentration. pH values above 7 are basic (alkaline).

question

An acid reacting with a base is

answer

an exchange reaction.

question

Bases reacting with acids form ________ and water.

answer

salts

question

The secondary structure of a protein molecule is the result of

answer

hydrogen bonds.

question

In the body, oxygen

answer

is used during cellular respiration.

question

Which of the following is characteristic of carbohydrates?

answer

They contain C, H, O, with twice as many hydrogen as oxygen atoms. They provide much of the energy that the cell requires. They include sugars and starches.

question

A simple carbohydrate

answer

has a molecular formula of C6H12O6.

question

Lipids

answer

are insoluble in water. include phospholipids, cholesterol, and fats. contain C, H, and O, but with proportionately less oxygen than in carbohydrates.

question

Proteins denature when

answer

hydrogen bonds break.

question

Saturated fats _______ than unsaturated fats.

answer

have more single carbon-carbon bonds

question

Proteins

answer

are structural materials. can function as enzymes. contain C, H, O, and N, and sometimes S.

question

An enzyme is a ____.

answer

protein that speeds up chemical reactions without being changed or depleted

question

The parts of a protein that change when it denatures are

answer

the secondary and tertiary structures.

question

DNA

answer

stores genetic information, including instructions for enzymes that synthesize fats and carbohydrates.

question

Nucleic acids are

answer

composed of building blocks called nucleotides.

question

The informational content of DNA and RNA is in the nitrogenous bases because

answer

the bases are of several types and therefore can form a code sequence.

question

Nucleic acids include

answer

RNA and DNA.

question

DNA and RNA differ in that

answer

DNA holds genetic information and RNA uses that information to synthesize protein.

question

The type of organic molecule that can replicate is a

answer

nucleic acid.

question

Conformation is

answer

the three-dimensional shape of a molecule, such as a protein.

question

An organic compound always contains

answer

carbon and hydrogen.

question

Which of these is not a monosaccharide?

answer

Sucrose

question

Glycogen is stored in the liver and ______.

answer

skeletal muscles

question

A triglyceride consists of

answer

3 fatty acids and 1 glycerol.

question

A biomarker is

answer

a body chemical associated with a particular disease or exposure to a toxin.

question

An example of a biomarker is

answer

cholesterol.

question

A biomarker test for cancer should ideally be

answer

inexpensive. easy to perform. specific.

question

Chemistry is the study of the composition of matter and how matter changes.

answer

True

question

At atom that has gained or lost electrons is called an ion.

answer

True

question

A substance that releases hydrogen ions in water is a base.

answer

False

question

A strong acid reacting with a strong base produces a salt.

answer

True

question

Chemically inert atoms always have their outermost electron shell full.

answer

True

question

An acid is an electrolyte that releases hydroxide ions (OH-) in water.

answer

False

question

A base is an electrolyte that releases ions that combine with hydrogen ions.

answer

True

question

An electrolyte ionizes in water.

answer

True

question

A person with alkalosis has a blood pH less than 7.3.

answer

False

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