AP biology exam review

cohesion

Water molecules sticking to each other.

adhesion

Water molecules sticking to other surfaces.

cellulose

Carbohydrate component of plant cell walls.

starch

Storage polysaccharide of plants.

glycogen

Extremely branched polymer of glucose.

cholesterol

Steroid common in cell membranes, also in many hormones.

peptide bond

Bonds that connect amino acids.

disulphide bridges

Reinforce tertiary structure by building bridges between two sulfur molecules

primary structure

sequence of amino acids in a polypeptide chain

secondary structure

Either an alpha helix or beta pleated sheet.

tertiary structure

Results from interactions between side chains in a polypeptide.

quaternary structure

Results from two or more polypeptide subunits.

dehydration synthesis

Condensation reaction where molecules are connected by loss of a water molecule.

hydrolysis

Reaction where water split into two hydrogens and one oxygen; this breaks a polymer.

natural selection

A population can change over time if individuals with more fit traits leave more offspring than less fit individuals.

artificial selection

Humans modifying species for desired traits through selective breeding.

fitness

Individuals whose inherited traits confer an advantage have a better chance of surviving in a given environment and will leave more offspring.

homologous structures

Same structure, different function. Comes from common ancestor.

comparative embryology

Embryos of vertebrates share many anatomical homologies.

vestigial structures

Are little or no importance to organism, but remain from an ancestor.

population

Group of individuals of the same species living in the same area.

population genetics

Study of allele frequency distribution and change under the influence of evolutionary processes.

gene pool

All the genes in a given population at a given time.

Hardy-Weinberg Theorem

Helps measure changes in allele frequencies over time. Provides an "ideal" population to use as a basis of comparison.

mutation

Changes in the nucleotide sequence in DNA.

sexual recombination

Crossing over and shuffling of genes during meiosis.

genetic drift

Change in allele frequencies due to chance.

bottleneck effect

When a population has been dramatically reduced, and the gene pool is no longer reflective of the original population's.

founder effect

When a small number of individuals colonize a new area; the new gene pool is not reflective of original population.

gene flow

When a population gains or loses alleles., movement of alleles into or out of a population due to the migration of individuals to or from the population.

genetic variation

Heritable variations in a population.

reproductive isolation

Barriers that impede members of two different species fro producing fertile offspring.

temporal isolation

When two species breed at different times of day, season, or years.

behavioral isolation

Incompatible courtship rituals, pheromones, or bird songs.

gametic isolation

When sperm can't fertilize the eggs.

allopatric speciation

When a population is divided; leads to speciation.

sympatric speciation

Speciation without a divided population.

phylogeny

Evolutionary history of a species or group of species.

analogy

Anatomical similarity due to convergent evolution.

phylogenetic trees

Branching diagrams that depict hypotheses about evolutionary relationships.

outgroups

Species or group of species closely related to the ingroup.

Miller and Urey Experiment

Experiment that found that organic molecules can form in a strongly reducing atmosphere.

endosymbiotic theory

Ancestors of mitochondria and plastids was prokaryotes thatcame to live in a host cell.

photoautotrophs

Photosynthetic bacteria.

chemoautotrophs

Organisms that use hydrogen sulfide or other chemicals as energy source instead of light.

archaea

Domain of unicellular prokaryotes that have cell walls lacking peptidoglycan. Like eukaryotes, DNA contains histone proteins.

antibiotic resistance

Resistance evolving rapidly in many species of prokaryotes due to overuse of antibiotics, especially in agriculture.

abiotic factors

Nonliving components of environment.

biotic factors

All the plant and animal life of a particular region.

population density

The size of the population within a particular unit of space.

reproductive rate

Difference between per capita birth and per capita death rates.

exponential growth

Population increase under ideal conditions, when r > 0. Forms a J-shaped curve.

logistic growth

When limiting factors restrict size of population to the carrying capacity of the environment. Forms an S-shaped curve.

carrying capacity (K)

Maximum population size that a particular environment can support.

density-independent regulation

When birth or death rates do not change with population density.

density-dependent regulation

When birth or death rates do change with population density.

interspecific competition

Species compete for a limiting resource. (-/-)

niche

Sum total of a species' use of the biotic and abiotic resources; an organism's "role".

mutualism

Interspecific interaction that benefits both species. (+/+)

commensalism

Interaction between species that benefits one but neither helps or harms the other. (+/0)

keystone species

Not necessarily abundant, but exert a strong control on community structure due to a pivotal ecological role.

species diversity

Variety of different kinds of organisms that make up a community.

producer

Autotroph.

primary consumer

Herbivore.

secondary consumer

Carnivore that eats herbivores.

tertiary consumer

Carnivore that eats carnivores.

quaternary consumer

Carnivore that eats tertiary consumers.

invasive species

Species generally introduced by humans, that take hold outside of their native range.

ecosystem

Consists of all the organisms living in a community as well as all the abiotic factors with which they interact.

pyramid of energy

90% of all energy is lost between trophic levels.

10% rule

Only 10% of the total energy produced at each trophic level is available to the next level. The amount of energy passed up to the levels of the food pyramid reduces as you go up.

biological magnification

Toxins become more concentrated in successive trophic levels.

Greenhouse Effect

Carbon dioxide and water vapor in atmosphere trap infrared radiation, re-reflecting it back toward earth.

ozone layer

Protective layer in atmosphere that shields earth from UV radiation.

cytoplasm

The region of the cell between the cell membrane and the nucleus.

plasma membrane

The membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell's chemical composition.

nuclear envelope

Double membrane perforated with pores that control the flow of materials in and out of the nucleus.

chromosomes

A threadlike, gene-carrying structure found in the nucleus. Consists of one very long DNA molecule and associated proteins.

chromatin

The readily stainable substance of a cell nucleus consisting of DNA and RNA and various proteins.

nucleolus

Small, dense region within most nuclei in which the assembly of proteins begins.

smooth ER

Synthesis of lipids, phospholipids and steroid sex hormones-help detoxify drugs and poisons (liver cells).

rough ER

A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.

glycoprotein

A protein with one or more carbohydrates covalently attached to it.

transport vesicles

Vesicles in transit from one part of the cell to another.

Golgi apparatus

Stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum.

phagocytosis

Process in which extensions of cytoplasm surround and engulf large particles and take them into the cell.

lysosome

A cell organelle that contains digestive enzymes.

contractile vacuoles

A membranous sac that helps move excess water out of the cell.

mitochondria

The organelles in which nutrients are converted to energy.

chloroplasts

Organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis.

cristae

Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.

thylakoids

Membranous structures within a chloroplast that serve as the site for light harvesting in photosynthesis.

stroma

The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.

cytoskeleton

Network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement.

cell wall

Strong layer around the cell membrane in plants, algae, and some bacteria.

diffusion

When a substance moves from an area of higher concentration to an area of lower concentration. Due to entropy.

osmosis

The diffusion of water through a selectively permeable membrane.

passive transport

Transport of a substance across a cell membrane by diffusion. No cell energy required.

active transport

When a cell gets materials or excretes them by using its own energy, usually through ATP; going against a concentration gradient.

hypertonic

Describes a solution that has a greater concentration of total solute.