Biology STAAR Flashcards
activation energy
energy needed to start a chemical reaction; lowered by enzymes
active transport
movement of molecules across a membrane requiring energy to be expended by the cell
adaptation
inherited characteristic that increases an organism’s chance of survival
allele
the different forms of a gene; could be dominant or recessive
amino acid
basic building blocks of proteins
analogous structures
structures that do not have a common evolutionary origin but are similar in form or function
anaphase
the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles
antibiotic
compound that blocks the growth and reproduction of bacteria
archaea
domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan
ATP
a nucleotide that stores and transfers energy within cells
autotroph
organism that can capture energy from sunlight or chemicals and use it to produce its own food; also called a producer
bacteria
domain of unicellular prokaryotes that have cell walls containing peptidoglycans
bacteriophage
virus that infects bacteria
base deletion
mutation which results in the loss of nucleotide pairs in a gene; have a major effect on the resulting protein
base insertion
mutation which results in the addition of nucleotide pairs in a gene; have a major effect on the resulting protein
base-pair substitution
a type of point mutation where one nucleotide and its partner are replaced by another pair of nucleotides
behavioral adaptation
an inherited behavior that helps an organism survive; like escaping from predators or find a mate
binary fission
asexual reproduction in prokaryotes by which one cell divides into two identical cells
binomial nomenclature
Classification system in which each species is assigned a two-part scientific name including the genus and species
biodiversity
the variety of different species in a given area
biogeochemical cycle
process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another; like the carbon and nitrogen cycle
biomass
the total amount of living matter within a given trophic level
capsid
the outer covering of protein surrounding the nucleic acid of a virus
carbohydrate
organic compound used by cells to store and release energy; composed of carbon, hydrogen, and oxygen
carbon cycle
the organic circulation of carbon from the atmosphere into organisms and back again
carnivore
a consumer that only eats other consumers
catalyst
substance that speeds up the rate of a chemical reaction; like an enzyme
cell
basic unit of life
cell cycle
the cycle of growth and reproduction of a cell, consisting of interphase (g1, s, g2) and mitosis (division of the nucleus-prophase, metaphase, anaphase, and telophase) and cytokinesis (division of cytoplasm)
cell division
the process by which a cell divides into two new daughter cells
cell membrane
The lipid bilayer that forms the outer boundary of the cell
cell wall
a rigid structure that surrounds the cell membrane and provides support to the cell; made of carbohydrates
cellular respiration
process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
centriole
organize the spindle fibers to separate chromosomes during animal cell mitosis
centromere
area where the chromatids of a chromosome are attached
chlorophyll
green pigment in plants that absorbs light energy used to carry out photosynthesis
chloroplast
organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy
chromatid
one of two identical “sister” parts of a duplicated chromosome
chromosome
condensed threads of genetic material formed from chromatin as a cell prepares to divide
cladogram
diagram showing evolutionary relationships of organisms with a common ancestor; resembles a tree
climax community
a relatively stable long-lasting community reached in a successional series
codon
in RNA, a three-base “word” that codes for one amino acid
commensalism
symbiotic relationship in which one member of the association benefits and the other is neither helped nor harmed
comparative embryology
study of multicellular organisms as they develop from fertilized eggs to fully formed organisms. shows how organisms are related by evolution.
competition
the struggle between organisms to survive in a habitat with limited resources
concentration gradient
difference in concentration of a substance on two sides of a membrane
consumer
an organism that obtains energy by feeding on other organisms
crossing over
exchange of genetic material between homologous chromosomes during prophase I of meiosis
cytokinesis
division of the cytoplasm
cytoplasm
a jellylike fluid inside the cell in which the organelles are suspended
decomposer
organism that breaks down and obtains energy from dead organic matter
differentiation
process in which cells become specialized in structure and function
diffusion
the process by which molecules move from an area of higher concentration to an area of lower concentration; passive
dihybrid cross
genetic cross using two traits with two alleles each
diploid number
cell condition in which two of each type of chromosome are present
disturbance
A discrete event that disrupts an ecosystem or community. Examples of natural disturbances include fires, hurricanes, tornadoes, droughts, and floods. Examples of human-caused disturbances include deforestation, overgrazing, and plowing.
DNA
deoxyribonucleic acid, the material that contains the information that determines inherited characteristics
domain
Most inclusive taxonomic category; larger than a kingdom
dominant
trait that will show up in an organism’s phenotype if gene is present
double helix
two strands of nucleotides wound about each other; structure of DNA
ecological succession
gradual change in living communities that follows a disturbance
ecosystem
living and nonliving things in an environment, together with their interactions
egg
Female sex cell
embryo
organism in its early stage of development
endoplasmic reticulum
a system of membranes that is found in a cell’s cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids
energy pyramid
a diagram that shows the amount of energy that moves from one feeding level to another in a food web
enzyme
protein that speeds up a chemical reaction
equilibrium
When the concentration of a solute is the same throughout a solution
eukaryote
A cell that contains a nucleus and membrane bound organelles
evolution
the gradual change in a species over time
experiment
the act of conducting a controlled test or investigation