5 Steps to a 5 AP Biology

abiotic components

the nonliving players in an ecosystem, such as climate and nutrients

abscisic acid

plant hormone that inhibits cell growth, prevents premature germination, and stimulates closing of the stomata

achondroplasia

autosomal dominant form of dwarfism seen in one out of 10,000 people

ACTH

adrenocorticotropic hormone

active site

part of the enzyme that interacts with the substrate in an enzyme-substrate complex

active transport

the movement of a particle across a selectively permeable membrane against its concentration graident. This requires the input of energy

adaptation

a trait that, if altered, affects the fitness of the organism. These are the result of natural selection and can include not only physical traits, but also the intangible traits of an organism

adaptive radiation

a rapid series of speciation events that occur when one or more ancestral species invades a new environment

ADH

anidiuretic hormone

adrenocorticotropic hormone

a hormone that stimulates the secretion of adrenal cortical hormones, which work to maintain electrolytic homeostasis in the body.

aerobic respiration

energy-producing reactions in animals that involve three stages: glycolysis, the Krebs cycle, and oxidative phosphorylation. Requires oxygen

age structure

statistic that compares the relative number of individuals in the population from each age group

agonistic behavior

behavior that results from a conflict of interest between individuals; often involves intimidation and submission

alcohol

organic compound that contains a hydroxyl (-OH) functional group

alcohol fermentation

occurs in fungi, yeast, and bacteria. Pyruvate is converted in two steps to ethanl, regenerating two molecules of NAD⁺

aldehyde

carbonyl group in which one R is a hydrogen and the other is a carbon chain. Hydrophilic and polar

aldosterone

released from the adrenal gland, this hormone acts on the distal tubules to cause the reabsorption of more Na⁺ and water. This increases blood volume and pressure

allantois

transports waste products in mammals to the placenta. Later it is incorporated into the umbilical cord

allele

a variant of a gene for a particular character

allopatric speciation

interbreeding ceases because some sort of barrier separates a single population into two (an area w/ no food or a mountain for example). The two populations evolve independently, and if they change enough, then, even if the barrier is removed, they cannot interbreed

alternation of generations

plant life cycle, so named because during the cylde, plants sometimes exist as a diploid organism and at other times exist as a haploid organism

altruistic behavior

behavior pattern that reduces the overall fitness of one organism while increasing the fitness of another

alveoli

functional unit of the lung where gas exchange occurs

amines

compounds containing amino groups

amino acid

a compound with a carbon center surrounded by an amino group, a carboxyl group, a hydrogen, and an R group that provides its unique chemical characteristics

aminoacyl tRNA synthase

enzyme that makes sure that each tRNA molecule picks up the appropriate amino acid for its anticodon

amino group

a functional group that contains -NH₂and that acts as a base (ex. amino acid)

amnion

structure formed from epiblast that encloses the fluid-filled cavity that helps cushion the developing embryo

amygdala

the portion of the human brain that controls impulsive emotions and anger

amylase

enzyme that breaks down the starches in the human diet to simpler sugars such as maltose, which are fully digested farther down in the intestines

anaerobic respiration

energy-producing reactions, known as fermentation, that do not involve oxygen. It begins with glycolysis and concludes with the formation of NAD⁺

anemia

illness in which a lack of iron causes red blood cells to have a diminished capacity for delivering oxygen

aneuploidy

the condition of having an abnormal number of chromosomes

angiosperm

flowering plant divided into monocots and dicots (monocotyledons and dicotyledons)

anion

ion with a negative charge that contains more electrons than protons

anterior pituitary gland

structure that produces six hormones: TSH, STH (or HGH), ACTH, LH, FSH, and prolactin

anther

pollen-producing portion of a plant

antheridia

male gametangia in bryophytes and ferns designed to produce flagellated sperm that swim to meet up with the eggs produced by the female gametangia

anticodon

region present at a tRNA attachment site; a three-nucleotide sequence that is perfectly complementary to a particular codon

antidiuretic hormone

a hormone produced in the brain and stored in the pituitary gland; it increases the permeability of the collecting duct to water, leading to more concentrated urine content

antigen

a molecule that is foreign to our bodies and causes our immune systems to respond

apical meristem

region at the tips of roots and shoots where plant growth is concentrated and many actively dividing cells can be found

apoplast pathway

movement of water and nutrients through the nonliving portion of cells

aposematic coloration

warning coloration adopted by animals that possess a chemical defense mechanism

archaebacteria

one of two major prokaryotic evolutionary branches. THese organisms tend to live in extreme environments and include halophiles, methanogens, and thermoacidophiles

archegonium

female gametangia in bryophytes, ferns, and gymnosperms

archezoa

eukaryotic organism that allegedly most closely resembles prokaryotes

arteries

structures that carry blood away from the heart

artificial selection

when humans become the agents of natural selection (breeding of dogs)

ascospores

haploid meiotic products produced by certain fungi

A site

region on protein synthesis machinery that holds the tRNA carrying the next amino acid

associative learning

process by which animals take one stimulus and associate it with another

atom

the smallest form of an element that still displays its unique properties

ATP synthase

enzyme that uses the flow of hydrogens to drive the phosphorylation of an adenosine diphosphate molecule to produce adenosine triphosphate

auditory communication

communication that involves the use of sound in the conveying of a message

autonomic nervous system (ANS)

a subdivision of the peripheral nervous system that controls the involuntary activities of the body: smooth muscle, cardiac muscle, and glands. It is divided into the sympathetic and parasympathetic divisions

autosomal chromosome

one that is not directly involved in determining gender

autotroph

an organism that is self-nourishing. It obtains carbon and energy without ingesting other organisms

auxin

plant hormone that leads to elongation of stems and plays a role in phototropism and gravitropism

axon

a longer extension that leaves a neuron and carries the impulse away from the cell body toward target cells

balanced polymorphism

when there are two or more phenotypic variants maintained in a population

bare-rock succession

the attachment of lichen to rocks, followed by the step-by-step arrival of replacement species

barr bodies

inactivated genes on X chromosomes

batesian mimicry

an animal that is harmless copies the appearance of an animal that is dangerous as a defense mechanism to make predators think twice about attacking

behavioral ecology

science that studies the interaction between animals and their environments from an evolutionary perspective

bile

substance that contains bile salts, phospholipids, cholesterol, and bile pigments such as bilirubin, is stored in the gallbladder, and is dumped into the small intestine on the arrival of the food

bile salts

help to mechanically digest fat by emulsifying it into small droplets contained in water

binary fission

mechanism by which prokaryotic cells divide. The cell elongates and pinches into two new daughter cells

binomial system of classification

system created by Linnaeus in which each species is given a two-word name: Genus + species

biogeochemical cycles

cycles that represent the movement of elements, such as nitrogen and carbon, from organisms to the environment and back in a continuous cylce

biomass pyramid

biomass represents the cumulative weight of all the members at a given tropic level

biome

the various geographic regionhs of the earth that serve as hosts for ecosystems

biosphere

the entire life-containing area of a planet - all ecosystems and communities

biotic components

living organisms of an ecosystem

biotic potential

the maximum growth rate for a population given unlimited resources, unlimited space, and lack of competition or predators

birth rate

offspring produced per a specific time period

bivalves

mollusks with hinged shells such as oysters and clams

blastula

as a morula undergoes its next round of cell divisions, fluid fills its center to create this hollow-looking structure

"blending" hypothesis

theory that the genes contributed by two parents mix as if they are paint colors and the exact genetic makeup of each parent can never be recovered; the genes are as inseparable as blended paint

bottleneck

a dramatic reduction in population size that increases the likelihood of genetic drift

bronchi

tunnels that branch off the trachea that lead into the individiual lungs and divide into smaller branches called bronchioles

bronchioles

tiny lung tunnels that branch repeatedly until they conclude as tiny air pockets containing alveoli

brush border

large numbers of microvilli that increase the surface area of the small intestine to improve absorption efficiency

bryophytes

the first land plants to evolve from the chlorophytes. Members of this group include mosses, liverworts, and hornworts.

bundle sheath cells

cells that are tightly wrapped around the veins of a leaf. They are the site for the Calvin cycle in C₄plants

C₄ photosynthesis

photosynthesis process that alters the way in which carbon is fixed to better deal with the lack of CO₂that comes from the closing of the stomata in hot, dry regions

C₄ plant

plant that has adapted its photosynthetic process to more efficiently handle hot and dry conditions

Calvin cycle

a name for the light-independent (dark) reactions of photosynthesis

CAM photosynthesis

(crassulacean acid metabolism) Plants close their stomata during the day, collect CO₂ at night and store the CO₂ in the for of acids until it is needed during the day for photosynthesis

capsid

a protein shell that surrounds genetic material

carbohydrate

organic compound used by the cells of the human body in energy-producing reactions and as a structural material. The three main types are monosaccharides, disaccharides, and polysaccharides

carbon cycle

the movement of carbon from the atmosphere to living organisms and back to the environment in a continuous cycle

carbon fixation

the attachment of the carbon from CO₂ to a molecule that is able to enter the Calvin cycle, assisted by rubisco

carbonyl group

a functional group that is hydrophilic and polar. It has a central carbon connected to R groups on either side. If both Rs are carbon chains it is a ketone. If one R is a hydrogen and the other a carbon chain, it is an aldehyde.

carboxyl group

an acidic functional group (COOH) that shows up along with amino groups in amino acids

cardiac muscle n

involuntary muscle of the heart that is striated in appearance and contains multiple nuclei

carnivore

a consumer that obtains energy and nutrients through consumption of other animals

carotenoid

a photosynthetic pigment

carrying capacity

the maximum number of individuals a population can sustain in a given environment

casparian strip

obstacle that blocks the passage of water through the endodermis of plants