HB Unit 1 Chem of Life & Scientific method

inquiry

The search for information and explanation, often focusing on specific questions.

Quantitative data collection

data expressed in numerical measurements

Qualitative Data Collection

data that includes observation such as color, behavior, etc. (not numbers)

inductive reasoning

A type of logic in which generalizations are based on a large number of specific observations.

Hypothesis

An educated guess, a testable statement

Theory

well-tested explanation that unifies a broad range of observations

deductive reasoning

reasoning in which a conclusion is reached by stating a general principle and then applying that principle to a specific case (The sun rises every morning; therefore, the sun will rise on Tuesday morning.)

controlled experiment

An experiment in which only one variable is manipulated at a time.

dependent variable

The measurable effect (Data), outcome, or response in which the research is interested.

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

Element

A pure substance made of only one kind of atom

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

essential elements

A chemical element required for an organism to survive, grow, and reproduce.

C, H, O, N

trace elements

required by an organism in only minute quantities

Atom

Basic unit of matter

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

atomic number

the number of protons in the nucleus of an atom

mass number

the sum of the number of neutrons and protons in an atomic nucleus

atomic mass

The average mass of all the isotopes of an element

radioactive isotope

An isotope whose nucleus decays spontaneously, giving off particles and energy.

isotope

Atoms of the same element that have different numbers of neutrons

valence electrons

Electrons on the outermost energy level of an atom

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

ionic bond

Formed when one or more electrons are transferred from one atom to another

hydrogen bond

Attraction between a slightly positive hydrogen atom and a slightly negative atom.

van der Waals forces

a slight attraction that develops between the oppositely charged regions of nearby molecules

Cation

A positively charged ion

Anion

A negatively charged ion

Reactant

A chemical substance that is present at the start of a chemical reaction

product

A substance produced in a chemical reaction

Chemical equilibrium is reached when _____.

the forward and reverse reactions occur at the same rate so that the concentrations of reactants and products remain the same

polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end. Example water!

Cohesion

Attraction between molecules of the same substance

Adhesion

An attraction between molecules of different substances

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid

specific heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree C

Ice is ____ dense than water

less

aqueous solution

a solution in which water is the solvent

hydration shell

the sphere of water molecules around each dissolved ion

Hydrophobic

Water fearing

Hydrophilic

water loving

Acid

A substance that increases the hydrogen ion concentration of a solution. (pH 1 - 6)

Base

A substance that decreases the hydrogen ion concentration in a solution. (pH 8 - 14)

pH scale

scale with values from 0 to 14, used to measure the concentration of H+ ions in a solution; a pH of 0 to 6 is acidic, a pH of 7 is neutral, and a pH of 8 to 14 is basic

Buffer

compound that prevents sharp, sudden changes in pH

organic compounds

Compounds that contain carbon

Macromolecules

carbohydrates, lipids, proteins, nucleic acids

Hydrocarbons

Compounds composed of only carbon and hydrogen

Isomers

Two different molecules that have the same chemical formula

structural isomers

differ in the covalent arrangements of their atoms

cis-trans isomers

have the same covalent bonds but differ in spatial arrangements

Enantiomers

isomers that are mirror images of each other

hydroxyl group

A functional group consisting of a hydrogen atom joined to an oxygen atom by a polar covalent bond. Molecules possessing this group are soluble in water and are called alcohols.

carbonyl group

A chemical group present in aldehydes and ketones and consisting of a carbon atom double-bonded to an oxygen atom.

carboxyl group

A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group.

amino group

A functional group that consists of a nitrogen atom bonded to two hydrogen atoms

sulfhydryl group

A chemical group consisting of a sulfur atom bonded to a hydrogen atom.

phosphate group

A functional group consisting of a phosphorus atom covalently bonded to four oxygen atoms

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Monomer

small chemical unit that makes up a polymer

dehydration synthesis reaction

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

Hydrolysis

Breaking down complex molecules by the chemical addition of water

Carbohydrates

sugars (end in -ose)

monosaccharides, disaccharides, polysaccharides

3 types of carbohydrates

mono = 1

di = 2

poly = many

Glycogen

storage form of glucose in animals

Starch

storage form of glucose in plants

Cellulose

polysaccharide consisting of glucose monomers that reinforces plant-cell walls

Chitin

A structural polysaccharide, consisting of sugar monomers, found in the exoskeletons of all arthropods.

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

triglyceride structure

glycerol + 3 fatty acids

Phospholipids

a lipid consisting of a glycerol bound to two fatty acids and a phosphate group.

Makes up cell membranes.

Proteins

Chains of amino acids

amino acid structure

Central carbon atom

Amino group

Carboxyl group

Single hydrogen

Variable R group (20 different)

peptide bond

Bonds that connect amino acids.

nucleic acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus.

DNA & RNA (polymer)

Made up of nucleotides (monomer)

Nucleotide

a monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

DNA = Sugar is deoxyribose, bases are A, T, C, G

RNA = Sugar is Ribose, bases are A, U, C, G

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Deoxyribonucleic acid

RNA

A single-stranded nucleic acid that passes along genetic messages to create proteins

Ribonucleic acid