AP Biology Exam Review 2023

Element

A pure substance made of only one kind of atom

Oxygen

A gas produced by plants during photosynthesis that animals use for respiration

Nitrogen

element found in proteins and nucleic acids

trace elements

elements required by an organism in only minute quantities

Atom

Basic unit of matter

Protons

positively charged subatomic particles

Neutrons

the particles of the nucleus that have no charge

Electrons

negatively charged subatomic particles

Nucleus

the center of an atom, which contains the protons and neutrons

isotopes

Atoms of the same element with different numbers of neutrons

radiometric dating

Dating using decay of radioactive isotopes.

Compound

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

chemical reaction

the process by which one or more substances change to produce one or more different substances

chemical bond

The force that holds atoms together

ionic bond

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

covalent bond

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

hydrogen bond

weak attraction between a hydrogen atom and another atom

Ions

charged particles

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

polar covalent bond

A covalent bond in which electrons are not shared equally

polar molecule

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

Cohesion

an attraction between molecules of the same substance, like water and water

Adhesion

An attraction between molecules of different substances, like and water and another substance

surface tension

the force that acts on the surface of a liquid and explains why an insect can "walk" on water

heat capacity

the number of heat units needed to raise the temperature of a body by one degree.

expansion on freezing

water forms a crystalline structure that expands and is less dense than its liquid state

adhesive

able to stick fast to a surface or object; sticky.

capillary action

ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity

acidic

pH less than 7 due to a higher concentration of H+ ions

basic

pH greater than 7 due to a higher concentration of OH- ions

neutral

pH of 7

Alkaline

basic or having a pH of greater than 7

pH scale

measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14

organic compounds

carbon-based molecules

inorganic compounds

Compounds that do not contain carbon

Polymer

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

Monomer

A simple compound whose molecules can join together to form polymers

Carbohydrates

macromolecule made up of monosaccharides

Monosaccharides

monomer of carbohydrates like glucose

disacharidases

carbohydrates made up of TWO monosaccharides like maltose

poysaccharides

polymer of carbohydrates that is made of up of many monosaccharides like starch and glycogen

Glucose

monosaccharide that gets broken down in cellular respiration

Fructose

A monosaccharide found predominantly in fruit and honey

dehydration synthesis (condensation)

reaction that links monomer molecules together, releasing a molecule of water for each bond formed

Hydrolysis

Breaking down complex molecules by the chemical addition of water

Starch

A storage polysaccharide in plants consisting entirely of glucose.

Cellulose

A substance (made of sugars) that is common in the cell walls of many organisms

Glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

amino acids

building blocks of proteins

amino group

NH2

carboxyl group

COOH

R group (side chain)

the part of an amino acid that differentiates it from other amino acids

Dipeptide

Two amino acids bonded together

peptide bond

The chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

Polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

Protein

A three dimensional polymer made of monomers of amino acids.

primary structure

sequence of amino acids

secondary structure

Either an alpha helix or beta pleated sheet due to the interactions of H-bonds

tertiarty structure

R-group interactions cause further folding to contribute to the overall globular protein shape

quarternary structure

The overall protein structure that results from the aggregation of two or more polypeptide subunits.

Lipids

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

Triglycerides

an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid.

Phospholipids

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

Steroids

Made of four rings of carbon.

Glycerol

Combines with fatty acids to make lipids.

Saturated

Fats with the maximum number of hydrogens, all single bonds!

Unsaturated

A solution that contains less than the maximum amount of dissolved solute in a concentration, has at least one double bond

polyunsaturated

two or more double bonds

Hydrophobic

Having an aversion to water; tending to coalesce and form droplets in water.

Hydrophilic

Having an affinity for water.

Cholesterol

A lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids.

nucleic acids

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

nucleotides

monomers of nucleic acids

deoxyribonucleic acid (DNA)

nucleic acid that contains the sugar deoxyribose

ribonucleic acid (RNA)

single-stranded nucleic acid that contains the sugar ribose

Evolution

The gradual change in allele frequencies in a species over time

natural selection

Mechanism for evolution in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

Embryology

the branch of biology and medicine concerned with the study of embryos and their development. Comparison for embryos provides evidence for a common ancestor

comparative anatomy/morphology

the study of similarities and differences among structures of living species

Homologous structures

Structures in different species that are similar because of common ancestry.

molecular biology

the study of heredity at the molecular level (DNA...etc)

common ancestor

An ancestral species from which later species evolved

phylogenetic tree

A family tree that shows the evolutionary relationships thought to exist among groups of organisms

genetic variability

tendency of individual genetic characteristics in a population to differ from one another

environmental pressure

A change in an organism's environment that selects for organisms with slight differences in a trait that give that organism a survival or reproductive advantage

Random mutation

mutations in organisms that, overtime, increases the variation that allows populations to evolve

Adaptation

inherited characteristic that increases an organism's chance of survival

evolutionary fitness

success in passing genes to the next generation

sexual selection

when individuals select mates based on heritable traits

genetic drift

random change in allele frequencies that occurs in small populations

Species

A group of similar organisms that can breed and produce fertile offspring.

reproductively isolated

unable to interbreed under normal circumstances to produce fertile offspring

divergent evolution

when two or more species sharing a common ancestor become more different over time

pre-zygotic barriers

A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted

post zygotic barriers

prevent the hybrid zygote from developing into a viable, fertile adult

Speciation

the formation of new and distinct species in the course of evolution.

Polyploidy

condition in which an organism has extra sets of chromosomes

convergent evolution

Evolution toward similar characteristics in unrelated species

allopatric speciation

The formation of new species in populations that are geographically isolated from one another.