Chapter 2- Chemical basis of life

Matter

Anything that occupies space and has mass

Mass

The amount of matter in an object

Kilogram

What is the international unit for mass?

Weight

The gravitational force acting on an object of a given mass

Element

The simplest type of matter with unique chemical properties; composed of atoms of only one kind

Atom

Smallest particle of an element that has chemical characteristics of that element

Carbon, hydrogen, oxygen, nitrogen

What are the 4 most common elements in the body?

Neutrons

No electrical charge

Protons

One positive charge

Electrons

One negative charge

electron cloud

Where most of the volume of an atom is occupied by electrons

Atomic number

Equal to number of protons in each atom which is equal to the number of electrons

Mass number

Number of protons plus number of neutrons, approximates mass because represents structures of nucleus

Isotopes

Two or more forms of same element with same number of protons and electrons but different neutron number. They have the same atomic number but different mass numbers

Chemical bonds

Are formed when electrons in the valence shell, are either shared with or transferred to another atom

Ionic bonding

Electrons are transferred from one atom to another

Covalent bonding

Two or more atoms share electron pairs

Octet rule

If the valence shell is incomplete the atom is chemically reactive and forms chemical bonds to achieve and octet

Electronegativity

Type of chemical bond between two atoms is determined by their difference in _____?

Electronegativity

Ability of an atoms nucleus (positive) to attract electrons

Ions

Atoms that have gained or lost 1 or more electrons

Cations

are positively charged because they lost electrons

Anions

Are negatively charged because they gained electrons

Ionic bond

Where electrons are transferred between atoms, creating oppositely charged ions that are attracted to eachother

Covalent bonds

Atoms share one or more pairs of electrons because the atoms have similar electronegativities

Nonpolar covalent

Electrons shared equally because nuclei attract the electrons equally

Polar

Electrons not shared equally because one nucleus attracts the electrons more than the other does.

Molecules

Two or more atoms chemically combined to form and independent unit

Compounds

A substance composed of two or more different types of atoms chemically combined

Intermolecular forces

Forces between molecules

Intermolecular forces

Result from weak electrostatic attractions between oppositely charged parts of molecules, or between ions and molecules

Hydrogen bonds

Type of intermolecular force

Intermolecular forces

Determine the properties of solubility and dissociation

Hydrogen bonds

Occurs when the positively charged H of one molecule is attracted the the negatively charged oxygen, nitrogen, or another molecule.

Solubility

Ability of ones substance to dissolve in another

Charged and polar substances

Solubility is evident in…

Electrolytes

Solutions made by the dissociation of cations and anions in water

Electrolytes

What has the capacity to conduct an electric current

Nonelectrolytes

Solutions made by molecules that dissolve in water, but do not dissociate, do not conduct electricity.

Metabolism

Collective term used for the sum of all anabolic and catabolic reactions in the body

Catabolism

Large molecules are broken down into smaller ones, releasing energy

Anabolism

Small molecules are assembled into larger ones, using energy

Synthesis Reactions

Two or more reactants chemically combine to form a new and larger product, chemical bonds made, energy is stored in the bonds

Dehydration reaction

Synthetic reactions where water is a product

Dehydration reaction

Produce chemical characteristics of life, Carbohydrates, proteins, lipids, and nucleic acids

Decomposition reactions

A large reactant is broken down to form smaller products, collective term for decomposition reaction in the body is catabolism

Hydrolysis reactions

Water is split into two parts that contribute to the formation of the products

Reversible Reactions

Chemical reactions in which the reaction can proceed either from reactants to products or from products to reactants

Equilibrium

Rate of product formations is equal to the rate of reactant formation

Oxidations

Loss of an electron by an atom

Reduction

Gain of an electron by an atom

Oxidation-reduction reaction

The complete or partial loss of an electron by one atom is accompanied by the gain of that electron by another atom

Activation energy

Minimum energy reactants must have to start a chemical reaction

Catalyst

Substances that increase the rate of chemical reactions without being permanently changed or depleted

Enzymes

Protein catalyst that increase the rate of chemical reactions by lowering the activation energy necessary for reaction to begin

Temperature, concentration of reactants

What are other influences of reaction rates

inorganic chemistry

Substances that do not contain carbon hydrogen bonds

Organic chemistry

Study of carbon-containing substances

Cohesion

Attraction of one water molecule to another; creates a surface tension

Adhesion

Is the attraction of water molecules to other molecules; causes the upward movement of water in the xylem of plants

Acid

a proton donor or any substance that releases hydrogen ions

Base

A proton acceptor or any substance that bind to or accepts hydrogen ions

Strong

Acids or bases that almost completely dissociate in water, producing a high number of H or OH

Weak

Acids or bases only partially dissociate in water, producing few H or OH

Strong acids

not easily reversible

Weak acids

Easily reversible and establish an equilibrium

The Ph scale

Refers to the hydrogen ion concentration in a solution

Neutral pH

pH of 7 or equal amounts of hydrogen and hydroxide ions

Acidic

pH of less than 7 with a greater concentration of hydrogen ions

Alkaline

pH of greater than 7 and a greater concentration of hydroxide ions

Neutral ph

The normal pH range for human blood is 7.35 to 7.45

Acidosis

What is it called when a pH drops below 7.35

Alkalosis

What is it called when a pH rises about 7.45

Buffers

Combination resists changed in pH when either acids or bases are added to the solution

Bicarbonate, phosphate, proteins

What are the important biological buffers

H2CO3→ H+HCO3-

What is the formula for bicarbonate

Oxygen

Required in the final step in the series of reactions used to extract energy from food

Carbon dioxide

Produced during the catabolism of organic compounds

Oxygen and carbon dioxide

What combines with water in plasma and forms H+ thus affecting acid-base balance

Organic chemistry

Carbon atoms bounds together by covalent bonds constitute the backbone of many large biomolecules by varying the length of the carbon chains and the combination of atoms involved

Carbohydrates

Divided into monosaccharides, disaccharides, polysaccharides, energy sources, structure, and bulk for elimination, water soluble

Carbohydrates, lipids

Composed of carbon, hydrogen, oxygen

Lipids

Relatively insoluble in water, protection, insulation, physiological regulation, component of cell membranes, energy storage.

Proteins

Sometimes composed of sulfur

Proteins

regulate processes, aid transport, protection, muscle contraction, structure, energy

Nucleic acids

Sometimes composed of nitrogen

Nucleic Acids

ATP, DNA, RNA

triglycerides

Composed of glycerol and fatty acids, protect insulate, energy source

Saturated

contains all single bonds in the carbon chain, which produces a more rigid structure; generally solid

Unsaturated

contains one (mono) or more (poly) double bonds in the carbon chain, which produces a more relaxed structure; generally liquid, better because they do not stick inside the blood vessels

Trans fat

unsaturated fats that are artificially altered to be more saturated. Are the highest cardiovascular risk fat. Double covalent bonds that do not become saturated change to trans = H on different sides

Eicosanoids

Derived from fatty acids, important regulatory molecules

Eicosanoids

Include thromboxane, leukotrienes, and prostaglandins

Steroids

Lipids with four ring like structures

Cholesterol

Component of cell membranes; precursor for steroid hormones

Amino acids

Building protein

Peptide bond

Covalent bonds formed between amino acids during protein synthesis by dehydration

R side chain

What chain makes the 20 amino acids different

Denaturing

Change in shape cause by braking of H-bonds by heat or pH changes

Tertiary structure

Large scale folding due to interacting within protein and surrounding environment which is generally water. Determines shape of a domain and the function of the protein