TASC Biology Level 3 key terms

A thin, flexible layer of lipids and proteins that surrounds every cell and controls which substances move into and out of it.

An organelle with folded inner membranes where aerobic respiration releases usable energy from glucose and other food molecules.

A green plant organelle containing chlorophyll, where light energy is captured and used to build sugars from carbon dioxide and water.

A protein that speeds up a specific chemical reaction by lowering the activation energy needed, without being consumed in the process.

The particular molecule an enzyme binds to and chemically changes, fitting into the enzyme's active site like a key in a lock.

Loss of a protein's normal three-dimensional shape caused by heat, extreme pH, or chemicals, which destroys the protein's ability to function.

The net movement of particles from an area of higher concentration to an area of lower concentration, driven by random molecular motion.

The diffusion of water across a selectively permeable membrane from a region of higher water concentration to one of lower water concentration.

The process in which green organisms use light energy to convert carbon dioxide and water into glucose and oxygen inside chloroplasts.

The set of reactions in cells that break down food molecules, releasing energy stored as ATP and producing carbon dioxide and water.

A double-stranded molecule made of nucleotides that carries the inherited instructions for building proteins and controlling cell activities.

A segment of DNA that codes for a particular protein or trait and is passed from parents to offspring.

One of the alternative versions of a gene that can occupy the same position on a chromosome, such as the tall or short form.

A long threadlike structure of DNA and protein that carries many genes and is copied and separated during cell division.

The particular combination of alleles an organism carries for a trait, whether or not those alleles are visibly expressed.

The observable characteristics of an organism, produced by the interaction of its genotype with the surrounding environment.

An allele whose trait appears in the phenotype even when only one copy is present, masking the effect of a recessive partner.

An allele whose trait appears only when two copies are present, because a dominant allele hides its effect in heterozygotes.

A grid used to predict the possible genotypes of offspring by combining the alleles each parent can contribute to a cross.

A two-stage form of cell division that halves the chromosome number and produces genetically varied gametes for sexual reproduction.

A change in the sequence of DNA bases that may alter a protein and can be inherited if it occurs in reproductive cells.

The process by which individuals with inherited traits better suited to their environment tend to survive and leave more offspring.

An inherited feature or behavior that improves an organism's chance of surviving and reproducing in its particular environment.

Change over generations in the inherited characteristics of a population, often driven by natural selection acting on variation.

A group of organisms that can interbreed under natural conditions and produce fertile offspring, sharing a common gene pool.

Preserved remains or traces of an organism, usually found in sedimentary rock, that provides evidence about past life.

The tendency of an organism to keep internal conditions such as temperature and water balance within stable, workable limits.

A control mechanism in which the output of a process affects that same process, either counteracting a change or amplifying it.

All the individuals of one species living together in the same area at the same time and able to interbreed.

The largest population size an environment can support over the long term with the resources available there.

Any resource or condition, such as food, water, or space, that restricts the growth or size of a population.

An organism, usually a plant or alga, that makes its own food from sunlight or chemical energy and forms the base of a food web.

An organism that cannot make its own food and instead obtains energy by eating other organisms, either plants or animals.

A network of overlapping food chains showing how energy and matter pass among producers, consumers, and decomposers in an ecosystem.

An organism such as a fungus or bacterium that breaks down dead matter and recycles nutrients back into the environment.

A close, long-term relationship between organisms of two different species, which may benefit both, one, or neither partner.

A testable, specific prediction or explanation that can be supported or rejected by evidence gathered in an investigation.

A factor that is deliberately kept the same across all trials of an experiment so it cannot affect the outcome.

A systematic approach to investigation that involves asking questions, forming hypotheses, gathering data, and drawing evidence-based conclusions.