Chapter 2

A fatty acid that contains two or more double covalent bonds is said to be hydrogenated. carboxylated. monounsaturated. saturated. polyunsaturated.

polyunsaturated.

Isotopes of an element differ in the number of neutrons in the nucleus. electron clouds. electrons in energy shells. electrons in the nucleus. protons in the nucleus.

neutrons in the nucleus

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 cushion. Water acts as a reactant. Water has a high heat of vaporization. Water acts as a lubricant.

Water acts as a reactant.

Nucleotides are the building blocks of DNA and RNA. One nucleotide is also used in the high-energy molecule __________. guanosine diphosphate (GDP) adenosine triphosphate (ATP) cytosine triphosphate adenosine diphosphate

adenosine triphosphate (ATP)

The most abundant high-energy compound in cells is DNA. adenosine triphosphate. adenosine diphosphate. RNA. adenosine monophosphate.

adenosine triphosphate.

Fructose is a carbohydrate. an isomer of glucose. found in male reproductive fluids. a hexose. All of the answers are correct

all of the answers are correct

A side chain on an amino acid is sometimes called a polypeptide chain. an R group. fibrous or globular. an isozyme. nucleic acid.

an R group.

A(n) ________ removes hydrogen ions and a(n) ________ releases hydrogen ions. element; compound acid; base base; acid compound; element molecule; acid

base; acid

A molecule of water (H2O) is formed by what type of bond? polar covalent bonds nonpolar covalent bonds ionic covalent bonds weak bonds

polar covalent bonds

The formation of a complex carbohydrate is what type of reaction? hydrolysis dehydration synthesis phosphorylation decarboxylation

dehydration synthesis

Triglycerides are composed of glycerol and three __________. nucleotides fatty acids amino acids monosaccharides

fatty acids

The most important metabolic fuel molecule in the body is caffeine. protein. glucose. sucrose. vitamins.

glucose

A polysaccharide that is formed in liver and muscle cells to store glucose is fructose. cellulose. glycogen. lactose. sucrose.

glycogen.

The purines found in DNA are ________ and guanine. uracil niacin cytosine adenine thymine

adenine

An atom of oxygen has an atomic number of 8 and a mass number of 18. How many of each type of subatomic particle does it contain? 8 protons, 8 electrons, and 10 neutrons 8 protons, 8 neutrons, and 8 electrons The atomic number and the mass number do not provide enough information to determine how many of each subatomic particle is present. 26 total subatomic particles

8 protons, 8 electrons, and 10 neutrons

Which subatomic particles contribute to an atom's mass number but not its atomic number? electrons protons None of them—atomic number and atomic mass number are essentially the same thing. neutrons

neutrons

Formation of hydrogen bonds requires hydrogen atoms and what else? oxygen ionic bonds water polar covalent bonds

polar covalent bonds

Water molecules are formed by __________. polar covalent bonds Hydrogen bonds ionic bonds nonpolar covalent bonds

polar covalent bonds

Calcium's atomic number is 20. It forms ions with 18 electrons. What is the electrical charge of a calcium ion? -1 +2 -2 +1

+2

Of the following choices, the pH of the least acidic solution is 12.0. 4.5. 1.0. 6.0. 2.3.

12.0.

If an isotope of oxygen has 8 protons, 10 neutrons, and 8 electrons, its mass number is 12. 8. 18. 26. 16.

18

Oxygen (atomic number 8) requires how many additional electrons to fill its outer electron shell? 2 4 8 1 6

2

The innermost electron shell in an atom holds up to ________ electrons. 2 4 8 1 6

2

Baby Sean has cystic fibrosis, which causes thick mucus secretions that can block ducts like the pancreatic duct, leading to insufficient enzymes in the small intestine. Why are these enzymes important? Digestive enzymes catalyze dehydration synthesis reactions that generate important macromolecules like polysaccharides. There are no consequences because there are other enzymes available to catalyze the decomposition reactions. Digestive enzymes catalyze decomposition reactions of complex food molecules into absorbable fragments; without its enzyme, a substrate cannot be degraded. Digestive enzymes are protein molecules that are required to transport food molecules across the intestinal walls for efficient absorption of nutrients.

Digestive enzymes catalyze decomposition reactions of complex food molecules into absorbable fragments; without its enzyme, a substrate cannot be degraded.

Which of the following statements about hydrogen bonds is false? Hydrogen bonds can occur within a single molecule. Hydrogen bonds can form between neighboring molecules. Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms. Hydrogen bonds are important for holding large molecules together. Hydrogen bonds are responsible for many of the properties of water

Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms.

Which of the following statements about water is false? It contains hydrogen bonds. It is composed of polar molecules. It is responsible for much of the mass of the human body. It has a relatively low heat capacity. It can dissolve many substances.

It has a relatively low heat capacity.

An important buffer in body fluids is H2O. NaOH. NaCl. NaHCO3. HCl.

NaHCO3.

__________ molecules store and process genetic information. Ionic Nucleic acid Lipid Protein

Nucleic acid

Which of the following distinguishes hydrogen bonds from covalent bonds? Only hydrogen bonds can form within molecules. Only hydrogen bonds can form between molecules. Only covalent bonds can form between molecules. Only ionic bonds can form within molecules.

Only hydrogen bonds can form between molecules.

In sickle cell anemia, there is a replacement in the amino acid sequence of hemoglobin of glutamic acid by valine. What is the difference between glutamic acid and valine? The protein resulting from this substitution binds more oxygen. Glutamic acid has a lower pH than valine, so the resulting protein is more acidic. Valine does not form a correct peptide bond. The R groups between the amino acids are different.

The R groups between the amino acids are different.

Which of the following is true of polar covalent bonds? The electrons are shared unequally. The same number of electrons are gained by one atom as are lost by another. They are rather weak bonds. Electrons are shared equally.

The electrons are shared unequally.

Which of the following is not a result of hydrogen bonds? Two strands of DNA are linked together taking a shape similar to a ladder. Some hair is straight, some wavy, and some very curly. An enzyme has a unique shape that allows it to bond only with specific molecules. Two hydrogen atoms join together to form a molecule of hydrogen gas

Two hydrogen atoms join together to form a molecule of hydrogen gas

Water acts to dissolve molecules in the body. How does water dissolve the salt (NaCl) in your mouth from a salty pretzel? When water is added to the NaCl, NaCl is broken down by adding OH- to one element and H+ to the other. This is known as hydrolysis. Water acts as a cofactor for enzymes that dissolve the salt. 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.

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.

As part of his diagnostic testing, baby Sean underwent a sweat chloride test that measures the levels of NaCl in the sweat from the skin on the forearm. How does the bond between NaCl form? Cl atoms only need one electron to complete their valence shells, while Na atoms have a single electron in their valence shells. Na and Cl atoms form a covalent bond by sharing a pair of electrons. But since the Cl atom has a greater electronegativity than the Na atom, the electrons are shared unequally; thus, they form a polar covalent bond. Na atoms have a single electron in their valence, while Cl atoms have seven valence electrons. By sharing a pair of atoms and forming a covalent bond, both Cl and Na satisfy their valence shell requirements. The positive Na cation forms a hydrogen bond with the negative Cl anion. When Na donates an electron to Cl, the Na atom becomes a cation and the Cl atom an anion. Since (+) and (-) charges attract each other, the Na+ and the Cl-; ions associate together, forming an ionic bond.

When Na donates an electron to Cl, the Na atom becomes a cation and the Cl atom an anion. Since (+) and (-) charges attract each other, the Na+ and the Cl-; ions associate together, forming an ionic bond.

When two monosaccharides undergo a dehydration synthesis, two new monosaccharides are formed. a polysaccharide is formed. a starch is formed. hydrolysis occurs. a disaccharide is formed.

a disaccharide is formed.

In plasma, a typical body fluid, protein floating around would be considered to be which of the following? a solvent a solute, specifically both a colloid and an electrolyte a solute, specifically both a colloid and a nonelectrolyte

a solute, specifically both a colloid and an electrolyte

What is an ion? an atom that is sharing electrons with another atom an atom that loses all of its protons an atom that has either gained or lost electron(s) an atom that has lost one or more neutrons

an atom that has either gained or lost electrons

Which of the following is not produced through chemical bonding? the heart atoms cells adipose (fat) tissue

atoms

In a covalent bond, An atom loses electrons to another to gain stability. Adjacent atoms share a single electron. An atom gains one or more electrons from another atom to gain stability. Atoms share one or more pairs of electrons.

atoms share one or more pairs of electrons

Ions with a + charge are called positrons. isotopes. cations. radicals. anions.

cations.

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 sodium potassium calcium

chloride

Cholesterol is an important lipid derivative in our bodies. Which of the following is not a function associated with cholesterol? important for cell growth and division coordinate and direct local cellular activities serve as a precursor for testosterone

coordinate and direct local cellular activities

Which of the following correctly ranks the types of chemical bonds, in order, from strongest to weakest? hydrogen, covalent, ionic ionic, hydrogen, covalent hydrogen, ionic, covalent covalent, ionic, hydrogen

covalent, ionic, hydrogen

Chemical reactions that absorb energy are said to be __________. endergonic exergonic thermal exothermic

endergonic

Electrons in an atom occupy an orderly series of electron shells or energy levels. electron lanes. energy circles. energy fields. electron clouds.

energy levels

Helium (He) has an atomic number of 2. It is chemically stable because it will form a covalent bond with another He atom. has a full outer electron shell. readily ionizes to react with other atoms. lacks electrons, thus the He atom is stable. is neutral in electrical charge.

has a full outer electron shell

Covalent bonds: involve the sharing of one to three pairs of electrons. involve the sharing of 8 pairs of electrons. always result in equal distribution of electrons between the atoms. always result in slight electrical charges at different atoms.

involve the sharing of one to three pairs of electrons.

How do ions form ionic bonds? Two atoms come together to share their electrons. Ions of opposite electrical charges are attracted to each other to balance the charges. One atom swaps all of its negative electrons for all of the other atom's positive protons. Ions of the same type are drawn together because they are attracted to their own kind.

ions of opposite electrical charges are attracted to each other to balance the charges

Atoms of the same element whose nuclei contain the same number of protons, but different numbers of neutrons, are called isotopes. isotonics. heterotonics. homotopes. heterotopes.

isotopes

From the description of baby Sean's stool, what macromolecules do you suspect are NOT being digested? nucleic acids only lipids and carbohydrates proteins only carbohydrates and nucleic acids

lipids and carbohydrates

Atoms of oxygen have a total of 8 electrons. Are these atoms stable, and why or why not? No, because the atoms have only 6 valence electrons, but need 8 for stability. Yes, because the Octet Rule says stable atoms have 8 electrons. No, because only atoms with 2 valence electrons are stable. Yes, because oxygen is in the air we breathe and it doesn't hurt us.

no, because the atoms have only 6 valence electrons, but need 8 for stability

Radioactive atoms have unstable __________. protons neutrons nuclei electron clouds

nuclei

Molecules that store and process genetic information are the nucleic acids. steroids. carbohydrates. proteins. lipids.

nucleic acids.

A __________ is to a nucleic acid as an amino acid is to a polypeptide. purine base pyrimidine nucleotide

nucleotide

An amino acid is to a protein as a ________ is to a nucleic acid. nucleotide purine protein proton neutron

nucleotide

The chemical properties of an atom are determined by the __________. number of neutrons in the nucleus number of electrons in the outermost electron shell mass of the nucleus number of protons in the nucleus

numbers of electrons in the outermost electron shell

Carbohydrates, lipids, and proteins are classified as organic molecules. salts. inorganic molecules. acids. bases.

organic molecules.

The chemical behavior of an atom is determined by the number of neutrons. number of protons. outermost electron shell. mass of the nucleus. size of the atom.

outermost electron shell.

By weight, which element is the most plentiful in the human body? potassium oxygen carbon sulfur sodium

oxygen

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

pH of 3

Which of the following molecules is a structural component of the plasma membrane? lipoprotein glycoprotein phospholipid proteoglycan

phospholipid

Molecules with two fatty acid chains and a phosphate group that form biological membranes are called phospholipids. disaccharides. prostaglandins. dipeptides. diglycerides.

phospholipids.

If an atom loses an electron, it becomes a __________. positively charged cation positively charged anion negatively charged cation negatively charged anion

positively charged cation

The "atomic number" of an atom is determined by the number of ________ it has. protons neutrons protons + electrons electrons protons + neutrons

protons

Which type(s) of subatomic particles can be located within the nucleus of an atom? protons and neutrons neutrons only protons and electrons electrons only

protons and neutrons

The mass number represents the number of neutrons in an atom. protons + neutrons. electrons in an ion. neutrons + electrons. protons in an atom.

protons+neutrons

The alpha-helix is an example of the __________ level of protein structure. tertiary quaternary secondary primary

secondary

A shortage of steroids in the body would result in a shortage of glycogen. proteins. sex hormones. plasma membranes. sex hormones and plasma membranes.

sex hormones and plasma membranes.

Which of these lists contains only trace elements? selenium, hydrogen, calcium boron, oxygen, carbon cobalt, calcium, sodium silicon, fluorine, tin sulfur, chlorine, oxygen

silicon, fluorine, tin

If solution A contains a weak acid, and solution B contains a strong acid, in which solution will you observe a one-way reaction? solution B solution A Neither: both solutions will react equally. Both: once in solution, the acid dissociates and cannot reform.

solution B

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

steroid

When placed in water, an inorganic compound dissociates 99 percent, forming hydrogen ions and anions. This compound would be a strong acid. weak base. weak acid. salt. strong base.

strong acid.

Cholesterol, phospholipids, and glycolipids are examples of lipid drugs. dietary fats. prostaglandins. structural lipids. steroids.

structural lipids

Before an enzyme can work, a __________ molecule must bind at the __________ site. product; neutral calcium; regulatory carboxyl; anionic substrate; active

substrate; active

An example of an organic substance is sodium chloride. oxygen. sucrose. carbonic acid. nitric oxide.

sucrose.

A dust particle floating on a water surface illustrates static electricity. chemical tension. heat capacity. surface tension. hydrophilic attraction.

surface tension

The structure of RNA differs from DNA in that DNA contains pyrimidines but not purines. DNA contains purines but not pyrimidines. RNA contains pyrimidines but not purines. RNA contains purines but not pyrimidines. the backbone of RNA contains ribose.

the backbone of RNA contains ribose.

When an ionic bond forms, which part(s) of the atoms are directly involved? the outermost electrons the neutrons both the protons and the electrons the protons

the outermost electrons

The pyrimidine bases found in DNA are ________ and cytosine. cytosine thymine adenine uracil niacin

thymine

Most of the fat found in the human body is in the form of prostaglandins. monoglycerides. triglycerides. phospholipids. cholesterol.

triglycerides.

The average time between synthesis and breakdown is known as the ________ time. metabolism turnover anabolism specificity catabolism

turnover

Which parts of atoms can interact (react) to form chemical bonds? the orbitals the nucleus of each atom protons valence electrons

valence electrons

An example of an inorganic substance is glycerol. water and carbon dioxide. water. carbon dioxide. fructose.

water and carbon dioxide.

Carbon atoms have four valence electrons. Are they likely to react with other atoms, and why or why not? No, because they do not have enough valence electrons. Yes, because they can become more stable by doing so. No, because they have an even number of valence electrons so they are already stable. Yes, but only with other stable atoms.

yes because they can become more stable by doing so