CH. 2: CHEMICALS OF LIFE

Matter definition

Anything that occupies space

What is chemistry?

the scientific study of **matter** and the interactions of matter

What is composed of matter?

the physical universe (living and nonliving)

What are elements?

substances that cannot be broken down into simpler substances by ordinary chemical means

How many out of 118 known elements are “naturally occurring”?

92

How many elements are involved in maintaining life?

24

What’s group 1’s name?

alkali metals except hydrogen

What’s group 2’s name?

alkali earth metals

What’s group blue’s name?

transitional metals

What’s group 7’s name?

halogens

What’s group 0’s name?

noble gases

What group does carbon, nitrogen, oxygen, phosphorus, sulfur, and selenium belong to?

nonmetals

What group does boron, silicon, geranium, arsenic, antimony, tellurium, and polonium belong to?

metalloid

What does aluminum, gallium, indium, tin, thallium, lead, bismuth, ununtrium, flerovium, ununpentium, livermorium belong to?

basic metals

What group does the top green period belong to?

lanthanide

What group does the bottom green period belong to?

Actinide

What are the elements important to physiology?

C, N, O, F, S, O, H, Ca, P

Approximately, 96% is composed of the human body?

oxygen, carbon, hydrogen, and nitrogen

Atom definition

the smallest unit of an element.

What is a proton?

a positively charged particle in an atomic nucleus

What is a neutron?

a noncharged particle in an atomic nucleus.

What is an electron?

a negatively charged particle that revolves around an atomic nucleus

What is a nucleus comprised of ?

protons and neutrons

What are electron shells?

where electrons orbit, or revolve around, the nucleus at high speeds that are located at various distances from the nucleus

What are valence shells?

an atom’s outermost shell of electrons

The overall electrical charge of an atom is _______.

neutral

The number of protons = the number of ________.

electrons

Most neutral atoms are ________

unstable

How do atoms gain stability?

lose, gain, or share electrons

Atomic number definition.

the number of protons (the number of electrons)

Chemical symbol definition.

a shorthand for referring to an element or atom of an element

Atomic mass definition.

the sum of the number of protons and neutrons

What are isotopes?

Atoms of the same element with different numbers of neutrons

What are radioisotopes?

certain isotopes of some elements have an unstable nucleus that emits high-energy radiation as it breaks down to form a more stable nucleus

Molecule definition.

a substance formed by two or more atoms bonded together by covalent bonds only

A molecule can have what atoms?

identical or different

Compound definition

a substance formed by the atoms from two or more elements

What bonds are in a compound?

ionic and covalent

What is a chemical formula?

expresses the chemical composition of a substance

Molecular formula definition.

expresses the composition of the molecule or compound using chemical symbols and numbers but it does not describe how the atoms are arranged

Structural formula definition

is a diagram that indicates the composition and number of atoms but also shows how the atoms are linked to each other

Chemical bond definition

a force of attraction between two atoms

Ionic bond formation.

is the formation of 2 ions with opposing charges; cation (+) and an anion (-) that creates a force bond and an ionic compound

What are covalent bonds?

atoms that form molecules by sharing electrons

What are nonpolar covalent bonds?

they are shared electrons that spend equal time revolving between the two atoms

A characteristic of a nonpolar covalent bond?

are **hydrophobic**

What are polar covalent bonds?

they are an unequal sharing of electrons between the two atoms

What are characteristics of a polar covalent bond?

* One atom has greater electronegativity
* are **hydrophilic**

What is a hydrogen bond?

weak attractive force between slightly positive and a slightly negative areas

How does a hydrogen bond occur?

occur within the same molecule, between different molecules, and between polar molecules and ions

What is a chemical reaction?

bonds between atoms are formed or broken

Synthesis (anabolic) reaction definition

the combining of smaller molecules to form more complex molecules

Decomposition (catabolic) reaction definition

the breakdown of complex molecules into simpler molecules.

Exchange (rearrangement) reaction

a reaction in which two reactants exchange components to form two different products.

Reversible reaction definition

the reactants and products may convert in both directions

Inorganic substances definition

contain carbon or hydrogen but not both

Organic substances definition

always contain **both** carbon and hydrogen, usually oxygen as well

What is a major inorganic substance?

water

What are some facts about water?

* composes approximately 2/3 of body weight
* occurs in the body as part of an aqueous solution
* the solvent for electrically charged solutes
* serves as a site for chemical reactions
* used for transport of solutes
* serves as a lubricant
* aids in maintaining a constant body temperature
* serves as a reactant in the breakdown (hydrolysis) of organic molecules

What are water compartments?

specific locations where water is found in the body

Intracellular fluid (ICF) definition

fluid within cells; about 65% of the total body water

Extracellular fluid (ECF) definition

all fluid not in cells; about 35% of the total body water

Interstitial fluid (tissue fluid) definition

fluid in spaces between cells

Plasma definition

fluid portion of blood

Lymph definition

fluid in lymphatic vessels

Transcellular fluids definition

fluid in more limited locations/ more specific locations

What are electrolytes?

Ionic compounds ionize (dissociate) in water, releasing ions

Nonelectrolytes definition

do not ionize when they dissolve in water and are usually organic compounds

Acid definition

increases H+ concentration in solution and releases H+ ions (protons)

Base definition

decreases the H+ concentration in a solution

What is pH?

a measure of the H+ concentration in a solution

What is a pH scale?

indicates the measure of acidity or alkalinity of a solution

What is a buffer?

* Maintain normal pH of body fluids because slight pH changes can be harmful to body cells
* Chemical or chemicals that either picks up or releases H+ to keep a solution’s pH constant

What are salts?

are ionic compounds that ionize in water but do not produce H+ and OH-

What is the dehydration synthesis?

removes water to join molecules

What is hydrolysis?

adds water to break apart molecules

What are carbohydrates?

an organic molecule composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio.

Carbohydrates are what to the body?

the primary source of nutrient energy for cells of the body

What are monosaccharides?

a simple sugar; a structural unit of carbohydrates.

What is glucose?

the monosaccharide that is the primary energy source for cells

Disaccharide definition

a molecule composed of two monosaccharides chemically combined

Polysaccharide definition

an organic macromolecule formed of many monosaccharide units

What are fructose and galactose?

isomers of glucose

What is an isomer?

molecules with the same molecular formula but different structures

Where are pentose sugars found in?

DNA nad RNA

What is maltose?

aka malt sugar; glucose + glucose

What is sucrose?

aka table sugar, glucose + fructose

What is lactose?

aka dairy sugar; glucose + galactose

What is glycogen?

the polysaccharide that is the storage form for carbohydrates in the body for animals

Starch definition

* plant carbohydrate storage
* a common polysaccharide in foods derived from plants

What are lipids?

* a class of organic macromolecules that includes steroids, triglycerides, and phospholipids
* diverse group composed of carbon, hydrogen, and oxygen atoms

What are triglycerides?

a lipid molecule composed of three fatty acids attached to glycerol; a fat molecule.

What are phospholipids?

a molecule containing two fatty acids and a phosphate group attached to glycerol

What are steroids?

a group of lipids that includes sex hormones and cholesterol.

What forms triglycerides?

Formed of one **glycerol** molecule and three **fatty acid** molecules

What is glycerol?

an organic molecule that is the backbone of triglyceride and phospholipid molecules.

What is a fatty acid?

an organic molecule that forms part of a triglyceride

Triglycerides are nonpolar molecules, meaning that they are ______

hydrophobic

What are triglycerides classified as?

saturated or unsaturated fats

Where are triglycerides found in?

adipose tissue around internal organs and beneath the skin