Chapter 2. The Chemistry of Life

Which of the following statements about the molecular weight of a molecule are true?

-It is equal for the sum of the atomic weights -It is measured in atomic mass units -It is useful for calculating concentrations

Indicate which statements are true of proteins.

-They act as receptors on cells' surfaces -They catalyze chemical reactions -They make up molecules that can transport oxygen

Hydrophobic organic molecules, such as fatty acids, fats, steroids, and prostaglandins, are classified as what type of molecule?

Lipid

Name the type of bond that holds amino acids together in a protein molecule.

Peptide bond

A(n) ___ is a lipid that consists of two hydrophobic fatty acid tails and a hydrophilic phosphate head.

Phospholipid

What term refers to a covalent bond in which the electrons are not equally shared?

Polar

Proteins are macromolecules composed of numerous amino acids. Based on this, which term describes proteins?

Polymers

Which term is used to mean a chain of more than 15 amino acids?

Polypeptide

What term is used to describe reactions that can proceed in either direction?

Reversible

Which of the following best describes very weak, brief attractions between neutral atoms?

Van der Waals forces

Which type of bond listed below is the weakest?

Van der Waals forces

Hydrophilic means "soluble in ___."

Water

Hydrophobic means that a substance is insoluble in ___.

Water

A molecule with the chemical formula C57H110O6 is an of which type of organic molecule?

Lipid

The abbreviation ___ is a measurement of acidity derived from the concentration of H+. Note; There is only one correct way to write this abbreviation. Capitalization and punctuation matter!

pH

Indicate how pH and temperature affect the activity of an enzyme.

-Altering the shape of the substance binding site -Causing a conformational change in the enzyme

Which of the terms below can be applied to glucose (C6H12O6)?

-Compound -Molecule

Which of the following best describes a glycolipid?

A phospholipid molecule covalently bonded together a carbohydrate.

A base is a compound that acts as a proton ___.

Acceptor

Solutions with a pH below 7 are considered to be which of the following?

Acidic

The energy required to initiate or begin in a chemical reaction is called its ___ energy.

Activation

Which molecule, composed of adenine, ribose, and three phosphate groups, functions as an energy-transfer molecule?

Adenosine triphosphate

Peptide bonds are used to join two of these together.

Amino acids

Metabolic reactions that use energy and build more complex molecules from less complex molecules are considered which type of reaction?

Anabolic

Which of the following best described what occurs in an exchange reaction?

Atoms are traded between molecules

Nucleotides contain a phosphate, a sugar and a nitrogenous ___.

Base

A pH of 7.5 is considered to be which of the following?

Basic

Solutions with a pH above 7 are considered what?

Basic/alkaline

Which term refers to a solution that resists changes in pH?

Buffer

Substances that resist changes in pH are known as ___.

Buffers

The term anabolism specifically applies to metabolic reactions that do which of the following?

Build large molecules from small molecules

The ___ family of macromolecules are composed of carbon, hydrogen and oxygen in a 1:2:1 ration and includes sugars, starches, glycogen, and cellulose.

Carbohydrate

Name the structural polysaccharide found in plant cells.

Cellulose

Which term refers to an attractive force caused by the sharing of transfer of electrons?

Chemical bond

Which term can apply to a molecule composed of two or more different elements?

Compound

A carbohydrate composed of two covalently-bonded simple sugars (monosaccharides) is a(n) ___.

Disaccharide

A(n) ___ is a protein that functions as a biological catalyst.

Enzyme

Choose the monosaccharides form the list below.

Fructose, Galactose, Glucose

Which monosaccharide is the monomer that forms glycogen and starch?

Glucose

A starch molecule may consist of thousands of smaller glucose subunits. Which of the following statements is true?

Glucose is a monomer if starch

Identify the components of a triglyceride below.

Glycerol, three fatty acids

Name a glucose polymer synthesized by liver, muscle, uterine, and vaginal cells that serves as an energy-storage polysaccharide.

Glycogen

A ___ is a protein molecule with a smaller carbohydrate covalently bonded to it.

Glycoprotein

A chemical bond that involves the attraction of a cation and anion is called a(n) ___ bond.

Ionic

Glucose and fructose both have the chemical formula C6H12O6. Which term below describes the relationship between glucose and fructose?

Isomers

Any molecule of large size and high molecular weight, such as a protein or starch, is known as a ___.

Macromolecule

Any molecule of larger size and high molecular weight, such as a protein or starch, is known as a ___.

Macromolecule

Molecules like carbohydrates, proteins, and nucleic acids are examples of ____ because they are made up of many repeating subunits.

Macromolecules

The term ___ refers to the sum of all the chemical reactions in the body.

Metabolism

Fatty acids contain both a(n) ___ group and a(n) ___ group.

Methyl, Carboxyl

Inorganic elements that are extracted from the soil by plants and passed up the food chain are known as ___.

Minerals

Adding together the atomic weights of all atoms in a molecule gives a value known as its ____ weight.

Molecular

A(n) ___ bond is composed of two or more atoms that are held together by chemical bonds.

Molecule

Disaccharides can be broken down into ___.

Monosaccharides

Which term applies to a solution with a pH of 7.0?

Neutral

Nucleotides are the subunits of the macromolecule type called ___ ___.

Nucleic acids

A single covalent bond involves how many pair(s) of shared electrons?

One

Polymers formed of many simple sugars are classified as ___ or ___.

Polysaccharides, complex carbohydrates

A hydrogen bond is a weak attraction between a slightly ___ hydrogen atom of one molecule and a slight ___ oxygen of nitrogen atom of another.

Positive, negative

The ___ structure of a protein is its amino acid sequence.

Primary

Amino acids are the subunits of larger molecules called ___.

Protein

Polypeptides over 100 amino acids long are generally classified as which of the following?

Proteins

Which of the following best defines an acid?

Proton donor

Which best describes the functional role of cyclic adenosine monophosphate (cAMP)?

Serves as a chemical messenger in cells

Which of the following best describes a covalent bond?

Sharing of electrons between two atoms

Which term applies to a chemical bond that involves one pair of shared electrons?

Single covalent bond

Saltwater is a solution made out of NaCl (salt) dissolved in water. In this case, water is the solvent and NaCl is the ___.

Solute

A(n) ___ is defined as a substance consisting of a solute mixed with a more abundant substance called the solvent.

Solution

In a solution, the more abundant substance that dissolved another substance is known as what?

Solvent

Saltwater is a solution of NaCl dissolved in water. In this scenario, NaCl is the solute and water is the ___.

Solvent

Which of the following is the only plant polysaccharide that humans can digest?

Starch

A chemical reaction in which two or more smaller molecules combine to form a larger molecule is what type of reaction?

Synthesis

True or false: Formation of adenosine triphosphate from adenosine diphosphate and an inorganic phosphate molecule requires the input of energy.

True