Deck 2: Chemical Basis of Life

Question 1

Sodium ions and calcium ions are examples of

A) cations.
B) uncharged particles.
C) anions.
D) salts.

Answer 1

A

Question 2

Matter is composed of elements, which are composed of _____.

A) atoms
B) inorganic molecules
C) organic molecules
D) chemicals

Answer 2

A

Question 3

When cations and anions meet, they

A) repel.
B) form ionic bonds.
C) form covalent bonds.
D) form individual molecules.

Answer 3

B

Question 4

Radioactive isotopes have stable nuclei.

Question 5

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

A) neutrons; number of protons
B) protons; weight of all the electrons
C) neutrons; number of protons plus electrons
D) protons; number of protons plus neutrons

Question 6

Exposure to ionizing radiation may

A) cloud the lens of the eye.
B) cause cancer.
C) interfere with normal growth.
D) all of the above.

Question 7

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

A) iodine-131.
B) iron-59.
C) thallium-201.
D) cobalt-60.

Question 8

Carbon can form ___ covalent bonds.

A) 1
B) 2
C) 4
D) 8

Question 9

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

Question 10

Water causes ionically-bonded atoms to

A) bond more strongly.
B) dissociate.
C) bond covalently.
D) decompose.

Question 11

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

Question 12

PET imaging follows the emission of

A) positrons.
B) electrons.
C) neutrons.
D) protons.

Question 13

In a covalent bond

A) one atom loses and another atom gains electrons.
B) atoms share a pair or more of electrons.
C) oppositely charged atoms attract.
D) like-charged atoms repel.

Question 14

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

A) two-dimensional.
B) three-dimensional.
C) four-dimensional.
D) safer.

Question 15

Atomic radiation is useful for treating cancer because

A) radiation affects cancer cells but not normal cells.
B) radiation protects normal cells against the effects of cancer.
C) radiation harms cancer cells more readily than it does most non-cancer cells.
D) normal cells are not affected by radiation.

Question 16

In an ionic bond

A) each atom gains electrons.
B) atoms share a pair or more of electrons.
C) oppositely charged atoms attract.
D) like-charged atoms repel.

Question 17

The ______ uses iodine in a synthesis reaction.

A) spleen
B) liver
C) thymus
D) thyroid gland

Question 18

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

Question 19

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

A) Iodine-131
B) Iron-59
C) Phosphorus-32
D) Cobalt-60

Question 20

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

A) Cosmic rays from outer space
B) Cholesterol and triglycerides
C) Atomic and nuclear weapons
D) Smoke detectors

Question 21

Which of the following substances is an element?

A) Iron
B) Water
C) Sodium chloride
D) Glucose

Question 22

Isotopes of an element have

A) the same atomic number and same atomic weight.
B) the same atomic number but different atomic weights.
C) different atomic numbers but the same atomic weight.
D) different atomic numbers and different atomic weights.

Question 23

Deep Check
A decomposition reaction can be symbolized by

Question 24

Which of the following is(are) ionizing radiation?

A) Cosmic radiation only
B) Gamma radiation only
C) Both cosmic radiation and gamma radiation
D) Neither cosmic nor gamma radiation

Question 25

The type of chemical bond formed when ions with opposite electrical charges attract is a(n) ________ bond.

Question 26

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

A) Carbon, hydrogen, oxygen, nitrogen
B) Calcium, hydrogen, oxygen, nitrogen
C) Carbon, phosphorus, oxygen, hydrogen
D) Calcium, phosphorus, hydrogen, nitrogen

Question 27

The type of subatomic particle that does not have an electrical charge is a(n) ________.

Question 28

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

A) electrons.
B) protons.
C) neutrons.
D) nuclei.

Question 29

The atomic weight of an element whose atoms contain 8 protons, 8 electrons, and 8 neutrons is

A) 8.
B) 16.
C) 24.
D) 32.

Question 30

Chemistry deals with

A) the composition and changes of substances that make up living as well as non-living matter.
B) the composition and changes of substances found in organisms only.
C) the composition of and changes of substances that make up non-living matter only.
D) the location of organs in body cavities.

Question 31

The parts of an atom that carry single negative electrical charges are called ________.

Question 32

The atoms of different elements have

A) the same atomic number and same atomic weight.
B) the same atomic number but different atomic weights.
C) different atomic numbers.
D) different atomic numbers but the same number of electrons.

Question 33

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

A) acidic.
B) basic.
C) alkaline.
D) neutral.

Question 34

Water is an example of a compound.

Question 35

The formula H₂O refers to

A) Two hydrogen molecules and one oxygen molecule.
B) One hydrogen molecule and two oxygen molecules.
C) A molecule that contains two hydrogen atoms and one oxygen atom.
D) A molecule that contains one hydrogen atom and two oxygen atoms.

Question 36

When forming a bond, an atom that has 3 electrons in its second shell and a filled first shell will

A) lose 3 electrons from its second shell.
B) lose all of the electrons from its first shell.
C) lose all of the electrons from both its first and second shells.
D) gain 5 electrons in its second shell.

Question 37

Chemistry is important to the study of physiology because

A) the foods that we eat are chemicals.
B) body functions depend on cellular functions that reflect chemical changes.
C) chemical reactions enable our bodies to extract energy from nutrients.
D) all of the above.

Question 38

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

Question 39

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

A) 1 electron.
B) 2 electrons.
C) 4 electrons.
D) 8 electrons.

Question 40

Two or more atoms bonding form a ________.

Question 41

Proteins denature when

A) bonds between carbon and oxygen break.
B) hydrogen bonds break.
C) peptide bonds break.
D) peptide bonds form.

Question 42

Which of the following is the most abundant inorganic substance in the body?

A) Carbohydrate
B) Water
C) Lipid
D) Protein

Question 43

Consider the following list of commonly found items and their pH values: Which of the following choices includes all acids?

A) Egg whites, baking soda, milk of magnesia, and bleach
B) Tomatoes, egg whites, and baking soda
C) Vinegar, grapes, tomatoes, and coffee
D) Beer, butter, and baking soda

Question 44

Electrolytes that release hydrogen ions in water are

A) bases.
B) nucleotides.
C) acids.
D) electrons.

Question 45

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

A) twofold.
B) fivefold.
C) tenfold.
D) twentyfold.

Question 46

In the body, oxygen

A) reacts with water to form carbonic acid.
B) is used during cellular respiration.
C) is a major electrolyte.
D) is produced by cells.

Question 47

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

A) decomposition reaction.
B) exchange reaction.
C) reversible reaction.
D) synthesis reaction.

Question 48

Which of the following is characteristic of carbohydrates?

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

Question 49

An acid reacting with a base is

A) a synthesis reaction.
B) hydrolysis.
C) a decomposition reaction.
D) an exchange reaction.

Question 50

A simple carbohydrate

A) has a molecular formula of C₆H₁₂O₆.
B) is a building block of protein.
C) consists of several joined chains.
D) has only one nucleotide.

Question 51

A person has alkalosis if the blood pH

A) is above 7.0.
B) is below 7.0.
C) rises above 7.5.
D) drops below 7.3.

Question 52

Which of the following is not organic?

A) Sodium chloride
B) Lipids
C) Nucleic acids
D) Enzymes

Question 53

Lipids

A) are insoluble in water.
B) include phospholipids, cholesterol, and fats.
C) contain C, H, and O, but with proportionately less oxygen than in carbohydrates.
D) all of the above.

Question 54

Electrolytes are substances that

A) form covalent bonds with water.
B) ionize in water.
C) cannot conduct electricity in solution.
D) form bonds that are stable in water.

Question 55

The secondary structure of a protein molecule is the result of

A) oxygen double bonds.
B) covalent bonds.
C) ionic bonds.
D) hydrogen bonds.

Question 56

The pH scale measures the

A) concentration of hydrogen ions in solution.
B) number of molecules of salts dissolved in water.
C) number of hydroxide ions in water.
D) strength of an electrical current that a solution carries.

Question 57

Synthesis reactions are particularly important in the body for

A) release of energy.
B) digestion of food products.
C) growth of body parts.
D) neutralization of acids by buffers.

Question 58

A complete atom is electrically neutral because

A) the number of protons equals the number of neutrons.
B) the number of electrons equals the number of neutrons.
C) the number of electrons equals the number of protons.
D) electrons is greater than the number of protons.

Question 59

On the pH scale

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

Question 60

Bases reacting with acids form ________ and water.

A) buffers
B) salts
C) new elements
D) proteins

Question 61

Glycogen is stored in the liver and ______.

A) spleen
B) skeletal muscles
C) pancreas
D) heart

Question 62

A biomarker is

A) a gene that encodes a particular protein.
B) always a protein.
C) a body chemical associated with a particular disease or exposure to a toxin.
D) any chemical in the body.

Question 63

An organic compound always contains

A) carbon and hydrogen.
B) oxygen and nitrogen.
C) carbon and oxygen.
D) nitrogen and hydrogen.

Question 64

The parts of a protein that change when it denatures are

A) the primary and secondary structures.
B) the secondary and tertiary structures.
C) the amino acid sequence and the secondary structure.
D) the tertiary and quaternary structures.

Question 65

A triglyceride consists of

A) 3 glycerols and 1 fatty acid.
B) 3 glucose molecules.
C) 3 fatty acids and 3 phosphate groups.
D) 3 fatty acids and 1 glycerol.

Question 66

Which of the following groups of compounds is hydrophobic?

A) Carbohydrates
B) Lipids
C) Proteins
D) Nucleic Acids

Question 67

DNA

A) is a protein.
B) plays no role in the synthesis of fats.
C) stores genetic information, including instructions for enzymes that synthesize fats and carbohydrates.
D) is routinely broken down to provide cellular energy.

Question 68

In phenylketonuria, an individual cannot break down the amino acid phenylalanine. Molecules that include phenylalanine build up in the blood, which causes intellectual disability and other symptoms. This inherited disease can be controlled by following a diet that is very low in

A) carbohydrates.
B) cholesterol.
C) protein.
D) nucleic acids.

Question 69

Nucleic acids are

A) very small, simple molecules.
B) structural molecules that have no function other than support.
C) composed of building blocks called nucleotides.
D) primary sources of cellular energy.

Question 70

Which of the following molecules does not have a polar region?

A) Water
B) Triglyceride
C) Water-soluble amino acid
D) Glucose

Question 71

DNA and RNA differ in that

A) RNA has deoxyribose and DNA has ribose.
B) RNA is double-stranded and DNA is single-stranded.
C) DNA holds genetic information and RNA uses that information to synthesize protein.
D) RNA is found only in the nucleus and DNA is found only in the cytoplasm.

Question 72

Saturated fats _______ than unsaturated fats.

A) contain more water
B) have more glycerol
C) have more single carbon-carbon bonds
D) have fewer hydrogen atoms bonded to carbon atoms

Question 73

Conformation is

A) the three-dimensional shape of a molecule, such as a protein.
B) the energy held in the bonds of an organic molecule, such as a protein.
C) the ability of DNA to copy itself.
D) the amino acid sequence (primary structure) of a protein.

Question 74

Nucleic acids include

A) proteins and DNA.
B) RNA and DNA.
C) enzymes and RNA.
D) steroids and triglycerides.

Question 75

Table sugar breaking down into glucose and fructose is a(n) _______ reaction.

A) synthesis
B) hydrolysis
C) acid-base
D) exchange reaction

Question 76

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

A) the bases are of several types and therefore can form a code sequence.
B) they all contain nitrogen.
C) the sugars and phosphates vary.
D) the bases are also parts of amino acids.

Question 77

The type of organic molecule that can replicate is a

A) protein.
B) lipid.
C) carbohydrate.
D) nucleic acid.

Question 78

Which of these is not a monosaccharide?

A) Glucose
B) Ribose
C) 6-carbon sugar
D) Sucrose

Question 79

Proteins

A) are structural materials.
B) can function as enzymes.
C) contain C, H, O, and N, and sometimes S.
D) all of the above.

Question 80

An enzyme is a ____.

A) protein that speeds up chemical reactions without being changed or depleted
B) protein that functions as a hormone
C) protein that inhibits chemical reactions by being changed or depleted
D) fibrous protein that is part of certain tissues in the body