Bio CH2/3 Study Guide

___ is a region where a polypeptide chain forms a uniform helical coil beta globin alpha globin beta turns &helix beta-pleated sheet

&helix

What is the atomic mass of the most common isotope of carbon? 12.01 amu 20.18 amu 16.01 amu 1.01 amu 14.01 amu

12.01 amu

It takes one calorie of heat to raise the temperature of one gram of water by one degree Celsius at sea level. This is referred to as the ____ of water. A. specific heat B. heat of fusion C. homeostasis D. vaporization E. heat of transformation

A. specific heat

What is the difference between an electrically neutral atom and an ion? An ion has an unequal number of protons and electrons, while a neutral atom has an equal number An ion has an equal number of protons and electrons, while an atom has an unequal number An atom has an unequal number of neutrons and protons, while an ion has an equal number An atom has its electrons in orbitals, while an ion has its electrons in its nucleus An atom must have an equal number of neutrons and electrons, while an ion does not.

An ion has an unequal number of protons and electrons, while a neutral atom has an equal number

what is the purpose of molecular chaperones? To transfer an amino acids To attach a carboxyl group To straighten other molecular proteins To straighten the tertiary structure of a protein To assist the folding of other molecular proteins

To assist the folding of other molecular proteins

What is the OH− concentration of a solution having a pH of 2? a. 1 × 10-12 b. 1 × 10-10 c. 1 × 10-7 d. 1 × 10-2

a. 1 x 10-12

Which organic compound is not only responsible for energy storage, but can also provide thermal insulation? a. Lipids b. Proteins c. Nucleic acids d. Carbohydrates e. Monosaccharides

a. Lipids

The primary difference between the amino acids commonly found in proteins is in their: a. R or variable groups b. number of potassium groups c. number of phosphate groups d. number of carbonyl groups e. number of asymmetric carbons

a. R or variable groups

Which statement about van der Waal interactions is false? a. They are very strong. b. They are attractive forces. c. They operate over very short distances. d. They form between nonpolar molecules. e. They involve transient regions of positive and negative charges.

a. They are very strong.

Which is the main structural component of the walls that surround plant cells? a. cellulose b. sugars c. starches d. fatty acid e. glucose

a. cellulose

Sticking together of like molecules a. cohesion b. surface tension c. capillary action d. adhesion

a. cohesion

What type of protein accelerates the thousands of different chemical reactions that take place in an organism? a. enzyme b. amino acid c. transport protein d. regulatory protein e. protective protein

a. enzyme

Strong attractive force resulting from the transfer of electrons between atoms a. ionic bond b. covalent bond c. van der Waals in d. hydrogen bond

a. ionic bond

Most are nonpolar a. lipid b. carbohydrate c. protein d. nucleic acid

a. lipid

cholesterol a. lipid b. carbohydrate c. protein d. nucleic acid

a. lipid

When two amino acids combine in a condensation reaction, a ____________ is formed. a. peptide bond b. dipeptide bond c. polypeptide bond d. trans bond e. cis bond

a. peptide bond

A steroid consists of carbon atoms arranged in four attached rings. How many carbon atoms do three of the rings contain? a. six carbon atoms b. five carbon atoms c. three carbon atoms d. seven carbon atoms e. two carbon atoms

a. six carbon atoms

A calorie is the amount of heat energy required to raise the temperature of 1 g of water 1 degree Celsius (C). a. true b. false

a. true

An essential amino acid is one that the body cannot synthesize in sufficient amounts. a. true b. false

a. true

Hemoglobin consists of 574 amino acids arranged in four polypeptide chains. a. true b. false

a. true

What substance is removed during a condensation reaction? a. water b. a dimer c. a polymer d. a hydrocarbon e. a carboxyl group

a. water

What is the difference between a stable isotope and a radioisotope? a. A stable isotope emits light. b. A radioisotope emits radiation. A stable isotope emits radiation. A stable isotope absorbs radiation. A radioisotope has an unequal number of protons and electrons.

b. A radioisotope emits radiation.

A beta-pleated sheet is an example of a protein's tertiary structure. a. True b. False

b. False

Why is ATP important in living organisms? a. It is easily converted to starch for long-term storage. b. It can transfer some of its energy to other chemicals. c. It is an important structural component of cell membranes. d. Like all other nucleic acids, it stores hereditary information. e. Like RNA, it acts as a source code for the formation of proteins.

b. It can transfer some of its energy to other chemicals.

Which is a property of unsaturated fats? a. They are more common in animals. b. They are generally liquid at room temperature. c. They have no double bonds in the carbon chains of their fatty acids. d. They have fewer fatty acids per fat molecule than do saturated fats. e. They contain more hydrogen than saturated fats that have the same number of carbon atoms.

b. They are generally liquid at room temperature.

What differentiates an organic compound from an inorganic compound? a. an organic compound lacks isotopes b. an organic compound contains carbon c. an organic compound lacks valence electrons d. an organic compound is basic rather than acidic e. an organic compound contains two or more atoms

b. an organic compound contains carbon

cellulose a. lipid b. carbohydrate c. protein d. nucleic acid

b. carbohydrate

monomers are joined by a glycosidic linkage a. lipid b. carbohydrate c. protein d. nucleic acid

b. carbohydrate

Strong attractive force resulting from the sharing of electrons between atoms a. ionic bond b. covalent bond c. van der Waals in d. hydrogen bond

b. covalent bond

A combination of adhesive and cohesive forces accounts for surface tension. a. true b. false

b. false

A pyrimidine is a double-ring molecule. a. true b. false

b. false

Condensation and hydrolysis reactions are catalyzed by the same enzymes. a. true b. false

b. false

Oxidation occurs when an atom gains one or more elections a. true b. false

b. false

Which component becomes oxidized in the following chemical reaction? 4 Fe + 3 O2 → 2 Fe2O3 a. rust b. iron c. water d. oxygen e. hydrogen

b. iron

Unlike lipids, hydrophilic functional groups typically contain ____ atoms, which make them more soluble in water. a. carbon b. oxygen c. hydrogen d. nitrogen e. phosphate

b. oxygen

Enables certain insects to walk on water a. cohesion b. surface tension c. capillary action d. adhesion

b. surface tension

Which of the following solutions has a pH value of 9? beer blood bleach seawater rainwater

bleach

Which lipid can be identified by its isoprene units? a. Fats b. Steroids c. Carotenoids d. Amino acids e. Phospholipid

c. Carotenoids

A salt is a compound in which the hydrogen ion of ____ is replaced by some other cation. a. water b. a base c. an acid d. an anion e. a hydroxide ion

c. an acid

Tendency of water to move in narrow tubes a. cohesion b. surface tension c. capillary action d. adhesion

c. capillary action

Water molecules have a strong tendency to stick to one another, a property known as ___________. a. adhesion b. capillary action c. cohesion d. surface tension e. osmosis

c. cohesion

Which characteristic of water molecules directly contributes to their remarkable "water walking" success? a. ionic bonds b. capillary action c. hydrogen bonds d. adhesive forces e. nonpolar covalent bonds

c. hydrogen bonds

Sugar dissolves readily in water because it is a(n) ____ substance. a. adhesive b. cohesive c. hydrophilic d. hydrophobic e. evaporative

c. hydrophilic

Isotopes differ from each other with respect to the number of: a. protons only b. electrons only c. neutrons only d. both protons and electrons e. both neutrons and protons

c. neutrons only

When a nucleic acid undergoes hydrolysis, the resulting subunits are: a. fatty acids b. amino acids c. nucleotides d. carotenoids e. monosaccharides

c. nucleotides

a beta-pleated sheet is one typical structure a. lipid b. carbohydrate c. protein d. nucleic acid

c. protein

has 20 different types of monomers a. lipid b. carbohydrate c. protein d. nucleic acid

c. protein

Which atom would most likely be involved in an ionic bond? a. hydrogen b. oxygen c. sodium d. nitrogen e. helium

c. sodium

A molecule of a saturated triacylglycerol contains: a. the maximum number of double bonds between carbons in the fatty acid chains b. the maximum number of triple bonds between carbons in the fatty acid chains c. the maximum number of hydrogen atoms in the fatty acid chains d. fatty acid chains with both amino and carboxyl groups e. alternating single and double bonds between carbons in the fatty acid chains

c. the maximum number of hydrogen atoms in the fatty acid chains

Which of the following fatty acids include one or more adjacent pairs of carbon atoms joined by a double bond? a. saturated fatty acids b. monounsaturated fatty acids c. unsaturated fatty acids d. polyunsaturated fatty acids e. trans fatty acids

c. unsaturated fatty acids

Very weak attractive force joining nonpolar molecules a. ionic bond b. covalent bond c. van der Waals in d. hydrogen bond

c. van der Waals in

What is the specific heat of water? a. 0.5 cal/g of water per degree Celsius b. 0.75 cal/g of water per degree Celsius c. 3 cal/g of water per degree Celsius d. 1 cal/g of water per degree Celsius e. 2 cal/g of water per degree Celsius

d. 1 cal/g of water per degree Celsius

Sulfur has six valence electrons. How many covalent bonds does a sulfur atom typically form? a. 3 b. 1 c. 5 d. 2 e. 4

d. 2

Sulfur has six valence electrons. How many covalent bonds does a sulfur atom typically form? a. 3 b. 1 c. 5 d. 2 e. 4

d. 2

A chlorine atom has 17 protons and 18 neutrons. What is its atomic mass? a. 1 amu b. 17 amu c. 18 amu d. 35 amu e. 306 amu

d. 35 amu

___ are isomers that are mirror images of each other. a. Geometric isomers b. Structural isomers c. Disaccharides d. Enantiomers e. Amino groups

d. Enantiomers

Sticking together of unlike molecules a. cohesion b. surface tension c. capillary action d. adhesion

d. adhesion

Which of the following would most likely form electrolytes in water? a. glucose b. ethanol c. an organic compound d. an inorganic compound e. a nonionic compound

d. an inorganic compound

How many covalent bonds are formed by carbon atoms, producing a wide variety of molecular shapes and sizes? a. six b. two c. three d. four e. seven

d. four

Holds adjacent water molecules together a. ionic bond b. covalent bond c. van der Waals in d. hydrogen bond

d. hydrogen bond

contains purines and pyrimidines a. lipid b. carbohydrate c. protein d. nucleic acid

d. nucleic acid

The chemical behavior of an atom is determined most directly by the: atomic number a. atomic weight b. number of neutrons c. number protons d. number of valence electrons

d. number of valence electrons

Which of the following describes an amphipathic molecule? a. A phospholipid with two polar ends b. A phospholipid with two hydrophobic ends c. A steroid with a hydrophilic functional group d. A steroid with a hydrophobic functional group e. A phospholipid with both a hydrophobic end and a hydrophilic end

e. A phospholipid with both a hydrophobic end and a hydrophilic end

Which element forms the backbone of organic molecules? a. magnesium b. iron c. chlorine d. sodium e. carbon

e. carbon

You isolate a compound that is insoluble in water, has alternating single and double bonds and has a bright orange color. You correctly conclude that this compound is a: a. protein b. nucleic acid c. polysaccharide d. steroid e. carotenoid

e. carotenoid

When we know what kinds of ____ are present in an organic compound, we can predict its chemical behavior. a. proteins b. enzymes c. triacylglycerols d. macromolecules e. functional groups

e. functional groups

What are compounds that have the same molecular formulas but different structures and different molecules? a. thiols b. monomers c. hexoses d. amyloplasts e. isomers

e. isomers

Which substance is an example of a very strong acid? a. milk b. coffee c. bleach d. seawater e. lemon juice

e. lemon juice

Which pair matches the correct macromolecule with the bond that joins its subunits? a. protein−ester linkage b. steroid−peptide bond c. polysaccharide−peptide bond d. triacylglycerol−glycosidic linkage e. nucleic acid−phosphodiester linkage

e. nucleic acid−phosphodiester linkage

The helical coil shape of an &-helix fibrous protein provides what type of property to that protein? rigidity strength elasticity heat tolerance water retention

elasticity

A chemical formula shows the types and numbers of atoms in a molecule and their arrangement true false

false

A solution having a pH8 is slightly acidic true false

false

An example of an anion is K+ true false

false

Specific heat refers to the amount of energy required to change 1 gram of a substance from the liquid phase to the vapor phase true false

false

The hydroxyl group is weakly acidic because of the presence of a strongly electronegative oxygen. a. True b. False

false

When glucose and fructose undergo condensation, maltose is produced as a product true false

false

Which of the following is sometime referred to as animal starch cellulose sugars starch fatty acid glycogen

glycogen

the cohesiveness between water molecules is due largely to ____ ionic bonds hydrogen bonds polar covalent bonds nonpolar covalent bonds hydrophobic interactions

hydrogen bonds

Which element activates many enzymes and is needed in blood and other tissues of animals? magnesium iron sulfur chlorine sodium

magnesium

Which of the following is a covalent compound? potassium chloride methane lithium bromide magnesium oxide sodium floride

methane

A liquid with a pH of 7 is considered to be a(n) ____ solution basic acidic neutral hydrophilic hydrochloric

neutral

When a nucleic acid undergoes hydrolysis, the resulting subunits are: fatty acids amino acids nucleotides carotenoids monosaccharides

nucleotides

Which component is the oxidizing agent in the following chemical reaction? 4 Fe + 3 02 --> 2 Fe.2O3 rust iron water oxygen hydrogen

oxygen

Which functional group in cysteine residues can form bridges that helps stabilize a protein's tertiary structure? amino carbonyl. hydroxyl phosphate sulfhydryl

sulfhydryl

What is the purpose of regulatory proteins? to store nutrients to defend against foreign invaders to catalyze a specific chemical reaction to control the expression of specific genes to strengthen and protect cells and tissues

to control the expression of specific genes

A disaccharide is composed of two monosaccharides joined by a glycosidic bond true false

true

A phosphate group is weakly acidic. a. True b. False

true

By definition, geometric isomers are mirror images of each other true false

true

The carboxyk group can exist in either an ionized or nonionized form true false

true

The tetrahedron shape of a methane molecule is the result of orbital hybridization? true false

true

The valence shell of hydrogen or helium is unstable when it contains two electrons true false

true

Most animals convert carotenoids to which vitamin? vitamin K vitamin A vitamin D vitamin B vitamin E

vitamin A

____ are isomers that are mirror images of each other Geometric isomers Structural isomers Disaccharides Enatiomers Amino Groups

Enatiomers

Which of the following is responsible for the alpha-helical structure of proteins? Hydrogen bonds Ionic interactions Polar covalent bonds Hydrophobic interactions Nonpolar covalent bonds

Hydrogen bonds

Which of the following atoms can form five covalent bonds? oxygen phosphorus hydrogen carbon nitrogen

phosphorus

At which level of protein structure are peptide bonds most important? primary secondary tertiary quaternary globular

primary