AP Bio review

emergent properties

new properties that emerge with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases

negative feedback

a mechanism of response in which a stimulus initiates reactions that reduce the stimulus

positive feedback

a physiological control mechanism in which a change in a variable triggers mechanisms that amplify the change

inductive reasoning

reasoning based on observed patterns

polymer

large compound formed from combinations of many monomers

hydrolysis

a chemical process in which a compound is broken down and changed into other compounds by taking up the elements of water

enzyme

protein that acts as a biological catalyst

phospholipids

a molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail

cellular respiration

process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

phosphorylation

the transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by phosphorylation

chemiosmosis

a process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

fermentation

the process by which cells break down molecules to release energy without using oxygen

gametes

reproductive cells, have only half the number of chromosomes as body cells

meiosis

a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells

somatic cell

cell that makes up all of the body tissues and organs, except gametes

crossing over

the interchange of sections between pairing homologous chromosomes during the prophase of meiosis

transcription

process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in mRNA

codons

a three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.

RNA splicing

process by which the introns are removed from RNA transcripts and the remaining exons are joined together

mutations

random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity

repetitive DNA

nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome.

transposons

small mobile DNA segments

homeobox

one of various similar homeotic genes that are involved in bodily segmentation during embryonic development

genome project

Research and technology development effort aimed at mapping and sequencing some or all of the genome of human beings and other organisms

adaptations

the behaviors and physical characteristics that allow organisms to live successfully in their environments

natural selection

process by which individuals that are better suited to their environment survive and reproduce most successfully

vestigial structures

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species

convergent evolution

process by which unrelated organisms independently evolve similarities when adapting to similar environments

protists

single-celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom

diatoms

unicellular algae that have a unique glass-like wall made of hydrated silica embedded in an organic matrix

ciliates

a group of protozoans that move by waving tiny, hair-like organelles called cilia

amoeba

A type of protist characterized by great flexibility and the presence of pseudopodia

gastrula

an embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm

cephalization

the concentration of nerve tissue and sensory organs at the anterior end of an organism

symmetry

the way an animal's body parts match up around a point or central line

coelom

fluid-filled body cavity lined with mesoderm

sustainable agriculture

farming method that preserves long-term productivity of land and minimizes pollution

nitrogen fixation

process of converting nitrogen gas into nitrogen compounds that plants can absorb and use (ammonia)

crop rotation

the system of growing a different crop in a field each year to preserve the fertility of the land

epiphyte

plant that is not rooted in soil but instead grows directly on the body of another plant

physiology

processes and functions of an organism

epithelium

membranous tissue covering internal organs and other internal surfaces of the body

thermoregulation

the maintenance of body temperature within a range that enables cells to function efficiently

metabolic rate

the amount of energy an animal uses in a unit of time

acquired immunity

immunity that the body develops after it overcomes a disease, or through inoculation (such as vaccination)

macrophages

engulf bacteria and cellular debris by phagocytosis

inflammatory response

nonspecific defense against infection, characterized by redness, heat, swelling, and pain

antigen

substance that triggers an immune response

sexual reproduction

process in which genetic material from two parents combines and produces offspring that differ genetically from either parent

parthenogenesis

asexual reproduction in which females produce offspring from unfertilized eggs

gametogenesis

the development and maturation of sex cells through meiosis

endometrium

inner lining of the uterus

perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

sliding filament model

The theory explaining how muscle contracts, based on change within a sarcomere, the basic unit of muscle organization, stating that thin (actin) filaments slide across thick (myosin) filaments, shortening the sarcomere; the shortening of all sarcomeres in a myofibril shortens the entire myofibril

smooth muscle

a muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart)

exoskeleton

the exterior protective or supporting structure or shell of many animals (especially invertebrates) including bony or horny parts such as nails or scales or hoofs

compound

a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight

hydrogen bond

weak chemical bond formed by the attraction of positively charged hydrogen atoms to other negatively charged atoms

covalent bond

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

ion

atom that has a positive or negative charge

eukaryotic cells

contain a nucleus and other organelles that are bound by membranes

ribosomes

non membrane bounded organelles responsible for protein synthesis

mitochondria

powerhouse of the cell, produces energy (ATP) from oxygen and sugar

prokaryotic

describes a cell that does not have a nucleus or anyother membrane-covered organelles; also called bacteria

thylakoids

A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy

photosynthesis

process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

autotrophs

organisms that make their own food

CAM plants

store the organic acids made at night in vacuoles and use them for photosynthesis during the day when stomata are closed

hybridization

the act of mixing different species or varieties of animals or plants and thus to produce hybrids

alleles

different forms of a gene

heterozygous

having two different alleles for a trait

pleiotrophy

the ability of a single gene to have multiple effects

operon

a group of genes that operate together

cell differentiation

the process of cell specialization

homeotic genes

any of the genes that control the overall body plan of animals and plants by controlling the developmental fate of groups of cells

oncogenes

cancer-causing genes

community

a group of interdependent organisms inhabiting the same region and interacting with each other

niche

the status of an organism within its environment and community (affecting its survival as a species)

mimicry

the resemblance of an animal species to another species or to natural objects

keystone species

a species that influences the survival of many other species in an ecosystem

geographic variation

differences in the genetic composition of separate populations

Hardy-Weinberg equilibrium

theory of a stable, nonevolving population in which frequency of alleles do not change; only occurs in large, isolated populations with random mating, and no natural selection or mutations

gene flow

movement of alleles into or out of a population due to the migration of individuals to or from the population

disruptive selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

vascular tissue

tissue that conducts water and nutrients through the plant body in higher plants

bryophyte

nonvascular plant; examples are mosses and their relatives

seed

embryo of a living plant that is encased in a protective covering and surrounded by a food supply

roots

underground organs that absorb water and minerals

invertebrates

animals without a backbone

hermaphrodite

individual that has both male and female reproductive organs

complete metamorphosis

the transformation of a larva into an adult that looks very different, and often functions very differently in its environment, than the larva

echinoderms

invertebrates with an internal skeleton and a system of fluid-filled tubes called a water vascular system

complete flowers

a flower that has all four basic floral organs: sepals, petals, stamens, and carpals

pollen grain

male gametophyte in seed plants

dormancy

period of time during which a plant embryo is alive but not growing

fruit

a mature ovary of a flower that protects dormant seeds and aids in their dispersal

hemoglobin

iron-containing protein in red blood cells that transports oxygen from the lungs to the tissues of the body

sinoatrial node

the heart's pacemaker, located in the wall of the right atrium

vasoconstriction

narrowing of blood vessels

platelets

tiny, disk-shaped bodies in the blood, important in blood clot formation