Chapter 2: Chemical Level of Organization

What are cations and anions?

A cation is a positively charged ion; an anion is a negatively charged ion.

The energy stored in the bonds of the molecules in the foods that humans eat is

A form of potential energy and referred to as chemical energy.

Which substances in the body can inactivate oxygen -derived free radicals?

Antioxidants such as selenium, zinc, beta-carotene, Vitamin C, and Vitamin E can inactivate free radicals derived from oxygen.

This refers to a weighted average of the atomic weights of all naturally occurring isotopes of an element.

Atomic Mass

The number of protons in an atom is represented by an element's

Atomic Number

Which pH is closer to neutral, 8.41 or 5.59?

Both pH = 8.41 and pH = 5.59 are 1.41 pH units from neutral (pH = 7).

A chemical compound that helps control the pH of a solution by adding or removing hydrogen ions is a(n)

Buffer

The compounds calcium carbonate dissociates into a calcium ion and a carbonate ion. Is it an acid, a base, or a salt? What about sulfuric acid, which dissociates into two protons and one sulfate ion?

Calcium Carbonate is a salt, and Sulfuric Acid is an acid.

What are the four major elements found in the chemicals that comprise the human body?

Carbon, Hydrogen, Nitrogen, and Oxygen.

The four elements that make up about 96% of body matter are ________.

Carbon, oxygen, hydrogen, nitrogen

What are some properties of enzymes?

Catalytic proteins, highly specific, efficient, and subject to a variety of cellular controls.

Which body cells store glycogen?

Cells in the liver and in skeletal muscle store glycogen.

What are some cellular activities that depend on energy supplied by ATP?

Cellular activities that depend on energy supplied by ATP include muscular contractions, movement of chromosomes, transport of substances across cell membranes, and synthesis (anabolic) reactions.

This lipid is used by the body as a precursor for the production of steroid hormones.

Cholesterol

This type of protein is involved with shortening of muscle cells to produce movement.

Contractile

This type of chemical bond involves the sharing of valence electrons between two atoms.

Covalent

This type of chemical reaction breaks larger reactants into smaller products.

Decomposition

Frying an egg causes the clear runny part of the egg to turn to white. This process is called

Denaturation

A chemical that can conduct electrical current when dissolved in water is called an

Electrolyte

Which subatomic particles are shared by two atoms to form covalent bonds?

Electron

This type of chemical reaction will absorb more energy than it releases.

Endergonic

This is defined as the capacity to do work.

Energy

AB + CD → AD + BC is a general example of an _____ reaction.

Exchange

True or False: A key feature of the body's metabolism is the almost exclusive use of exergonic reactions by the body.

False

The chemical bonds formed between the atoms in a water molecule are called

Polar Covalent Bonds

Cellulose is a

Polysaccharide

This type of fatty acid contains more than one double bond in its hydrocarbon chain.

Polyunsaturated

The three types of subatomic particles that are important for understanding chemical reactions in the human body are

Protons, Neutrons, and Electrons.

Why is it that sucrase cannot catalyze the formation of sucrose from glucose to fructose?

Sucrase has specificity for the sucrose molecule and thus would not "recognize" glucose and fructose.

Name some of the lesser elements

Sulfur, Magnesium, Potassium, Calcium

This type of chemical reaction combines reactants to produce larger products.

Synthesis

Why would you expect ammonia to form hydrogen bonds with water molecules?

The N atom in ammonia is electronegative. Because it attracts electrons more strongly than do the H atoms, the nitrogen end of ammonia acquires a slight negative charge, allowing H atoms in water molecules (or in other ammonia molecules) to form hydrogen bonds with it. Likewise, O atoms in water molecules can form hydrogen bonds with H atoms in ammonia molecules.

Which four elements are present most abundantly in living organisms?

The four most plentiful elements in living organisms are oxygen, carbon, hydrogen, and nitrogen.

Does the oxygen in the water molecule removed during dehydration synthesis come from the glycerol or from a fatty acid?

The oxygen in the water molecule comes from a fatty acid.

Which portion of a phospholipid is hydrophilic, and which portion is hydrophobic?

The polar head is hydrophilic, and the nonpolar tail is hydrophobic.

How many carbon atoms are there in fructose? In sucrose?

There are 6 carbons in fructose and 12 in sucrose.

What are some facts about phospholipids?

They contain a glycerol backbone, the head group is polar, the molecule is an important part of cell membranes, and the tail groups are nonpolar.

What is a common function of RNA?

Transfer information for protein synthesis.

What is the major function of ATP in cells?

Transfers energy for cell functions.

This type of lipid is the body's primary long-term energy storage molecule.

Triglyceride

This type of lipid is used by the body for insulation.

Triglycerides

If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon.

UCG

If the nucleotide or base sequence of the DNA strand used as a template for messenger RNA synthesis is ACGTT, then what would be the sequence of bases in the corresponding mRNA?

UGCAA

A chemical reaction involves interactions between the _______ of two different atoms.

Valence Electrons

In the body fluid compartments found in the human body, the solvent is

Water

This is the most abundant and most important inorganic compound in the body.

Water

Name some of the trace elements

Zinc, Selenium, Iodine, Boron.

Which subatomic particle has a neutral charge?

Neutron

Does a catalyst change the potential energies of the products and reactants?

No. A catalyst does not change the potential energies of the produces and reactants; it only lowers the activation energy needed to get the reaction going.

Table sugar (sucrose) easily dissolves in water but is not an electrolyte. Is it likely that all the covalent bonds between atoms in table sugar are nonpolar bonds? Why or why not?

No. Because sugar easily dissolves in a polar solvent (water), you can correctly predict that it has several polar covalent bonds.

Do all proteins have a quaternary structure?

No. Proteins consisting of a single polypeptide chain do not have a quaternary structure.

Which monomer is used to build RNA and DNA?

Nucleotide

What region of an atom contains the protons and neutrons?

Nucleus

List some properties of enzymes

Organic catalysts, may be damaged by high temperature, composed mostly of protein.

In a polar covalent bond, the atom that has the most electronegativity will have a

Partial Negative Charge

What is the principal difference between an ionic bond and a covalent bond?

An ionic bond involves the loss and gain of electrons; a covalent bond involves the sharing of pairs of electrons.

This is the name given to a negatively charged atom.

Anion

What can lower the amount of free radicals in the body?

Antioxidants

Which pH is more acidic, 6.82 or 6.91?

A pH of 6.82 is more acidic than a pH of 6.91.

The primary structure of a protein consists of

A sequence of amino acids linked by peptide bonds.

What is a proton donor?

Acid

A solution with a pH value less than 7 is

Acidic

The initial energy "investment" needed to start a chemical reaction in a cell is called the

Activation Energy

In an amino acid, what is the minimum number of carbon atoms? Of nitrogen atoms?

An amino acid has a minimum of two carbon atoms and one nitrogen atoms.

What is the major significance of the element carbon in the human body?

Forms backbone of all organic molecules.

Specific arrangements of atoms within an organic molecule that confer characteristic chemical properties upon that molecule are called

Functional Groups

What is monosaccharide that is used by cells to produce energy?

Glucose

How many hydroxyl groups does a molecule of glucose have? How many carbon atoms are part of glucose's carbon skeleton?

Glucose has five hydroxyl groups and six carbon atoms.

Name a polysaccharide

Glycogen

What is a polysaccharide that serves as a storage form of energy in muscle and liver cells?

Glycogen

Name a purine base.

Guanine

Which property of water is demonstrated when we sweat?

High Heat of Vaporization

This relatively weak type of bond helps stabilize the three dimensional structure of large molecules like proteins and DNA?

Hydrogen

Surface tension of an aqueous solution is generated by the presence of _______ between water molecules.

Hydrogen Bonds

What type of reaction takes place during catabolism of proteins?

Hydrolysis occurs during catabolism of proteins.

A solute that readily dissolves in water is

Hydrophilic

This type of protein protects against pathogens.

Immunological

Which bases always pair with each other?

In DNA, thymine always pairs with adenine, and cytosine always pairs with guanine.

How are the electrons of carbon distributed between the first and second electron shells?

In carbon, the first shell contains two electrons and the second shell contains four electrons.

Salts are always ________.

Ionic Compounds

What is the major significance of the element chlorine in the human body?

Ionized form is most plentiful anion in extracellular fluid.

What is the major significance of the element iron in the human body?

Ionized forms are part of hemoglobin.

What is the major significance of the element nitrogen in the human body?

Is a component of all proteins and nucleic acids.

Glucose and fructose both have the chemical formula so they are considered

Isomers

The nucleus of unstable _____ of an element will decay leading to emission of radiation.

Isotopes

Name a disaccharide

Lactose

Prostaglandins and leukotrienes are

Lipids and Eicosanoids.

What is the major function of DNA?

Long-term storage of information for protein synthesis.

An enzyme acts to

Lower the activation energy needed to start the reaction.

What is a general term used to refer to the sum of all the chemical reactions occurring in the body?

Metabolism