Sophomore Biology Vocab 2024-2025

Mr. Arnzens 4th period

abiotic factor

A non-living component of an ecosystem.

activation energy

The energy required to begin a chemical reaction.

active transport

The movement of a substance across a cellular membrane from a region of lower concentration to a region of higher concentration using specific transport proteins and energy from ATP.

adaptation

A characteristic that can improve an organism’s ability to survive and reproduce in its environment.

adenosine diphosphate (ADP)

A molecule that is formed during cellular energy release when an ATP molecule loses a phosphate group, and can be converted back to ATP by the addition of a phosphate group and energy.

adenosine triphosphate (ATP)

A molecule that provides energy for many cellular activities. ATP releases energy when one of its high-energy bonds are broken by removing a phosphate group.

aerobic respiration

A form of cellular respiration that requires oxygen to generate energy by converting glucose into CO2 and H2O and then using these molecules to produce ATP.

agriculture

The practice of raising and harvesting plants and/or animals for food, fibers, or other useful products; also can be called farming.

air quality

A measure of the air conditions in an environment relative to the requirements to maintain an internally balanced state of humans or other species.

allele

An alternative variation of a gene. Each gene has two alleles that interact to produce a specific genotype and resulting phenotype.

amino acid

A monomer or “building block” of a protein; there are 20 amino acids.

anaerobic respiration

A form of cellular respiration that occurs in the absence of oxygen and produces ATP by breaking down glucose molecules (e.g., fermentation).

analogous structure

A physical structure present in different species that has a similar function but did not result from sharing a recent common ancestor.

anaphase

The third stage of mitosis or meiosis, during which sister chromatids or chromosome pairs are separated by the spindle and moved toward opposite poles.

anticodon

A sequence of three nucleotides in transfer RNA (tRNA) that is complementary to the codon in messenger RNA (mRNA).

artificial selection

A process in which humans breed organisms to increase or decrease specific genetic traits in offspring.

base-pairing

The principle that adenine should always chemically bond with thymine in DNA (or uracil in RNA) and cytosine should always bond with guanine during nucleic acid formation.

biodiversity

A diverse group of different organisms in a given ecosystem or region at a specific time.

biofuel

A fuel produced from biological materials (e.g., wood, ethanol, dried manure).

biogeochemical cycles

The flow of elements and chemical compounds between the living and nonliving components within ecosystems.

biological fitness

The ability of an organism to survive and reproduce.

biology

The branch of science that studies life.

biomass

A biological material derived from living organisms used as fuel.

biomass pyramid

A model representing the relative amounts of living organic matter at each trophic level in an ecosystem.

biome

A geographic area classified according to the dominant communities of organisms present.

biosphere

The part of Earth in which life exists and living organisms interact with their environment.

biotic factor

A living component of an ecosystem.

Calvin cycle

A series of reactions in the chloroplast during photosynthesis converting carbon dioxide into high-energy compounds.

carbohydrate

A macromolecule composed of carbon, hydrogen, and oxygen that functions to provide energy and structural materials.

carbon cycle

The predictable pattern describing how carbon is used, recycled, and reused in the earth.

carnivore

An organism that eats only animals.

carrying capacity

The maximum population size of a species supported in an environment given the resources available.

catalyst

A substance that accelerates a chemical reaction by decreasing activation energy without being changed.

cell

The basic unit of all living things that is fundamental to the structure and function of the organism.

cell cycle

The sequence of events in a cell's lifespan including growth, duplication, and division.

cell membrane

The outer layer of a cell that separates it from its surroundings and controls substance movement.

cell wall

A rigid structure that provides support and surrounds the cell membrane in plant cells, bacteria, and fungi.

cellular respiration

A complex set of chemical reactions transferring chemical energy from organic molecules to ATP.

Celsius scale

The metric scale for temperature measurement, freezing point at 0°C and boiling point at 100°C.

centriole

A short, cylindrical organelle organizing the formation of a spindle during mitosis or meiosis.

centromere

A region that joins two sister chromatids and is where spindle fibers attach during cell division.

Charles Darwin

An English naturalist who presented the theory of evolution and proposed natural selection as the mechanism for changes.

chemical energy

Energy released by a chemical reaction or absorbed by forming chemical bonds.

chlorophyll

A green pigment in plant chloroplasts that captures solar energy for conversion into chemical energy.

chloroplast

An organelle in plant cells where photosynthesis occurs.

chromatid

One of two identical sister strands of a duplicated chromosome.

chromatin

A group of nucleic acids (DNA or RNA) coiled around proteins that forms a chromosome during cell division.

chromosomal mutation

A genetic alteration changing the number or structure of chromosomes.

chromosome

A structure of genetic material composed of coiled DNA and associated proteins in eukaryotic cells.

cilia

Short, hair-like structures that extend from some eukaryotic cells for movement or moving substances.

circulatory system

An organ system responsible for blood transport throughout the body.

classification/classify

The systematic grouping of organisms based on characteristics or evolutionary relationships.

climate change

Changes in Earth’s average atmospheric temperature and precipitation due to greenhouse gas increases.

cloning

The process of creating an exact genetic copy of a DNA sequence, cell, or organism.

codon

A sequence of three nucleotides in mRNA that is a unit of genetic code for protein construction.

common ancestor

An ancestral species from which two or more species descended.

community (ecological)

Populations of different species interacting in a particular area during the same time.

concentration gradient

The difference in solute concentration between two solutions.

consumer (ecological)

An organism that gets its energy from consuming other organisms.

crossing-over

A process during meiosis where homologous chromosomes exchange genetic material.

cytokinesis

The division of cytoplasm into two daughter cells during cell division.

cytoplasm

The contents of a cell within the plasma membrane.

cytoskeleton

An internal cellular framework that controls cell shape, movement, and transport.

decomposer (ecological)

An organism that recycles nutrients from nonliving organic matter.

deoxyribonucleic acid (DNA)

A double-stranded nucleic acid molecule that encodes genetic information.

dichotomous key

A reference tool using choices between characteristics to identify species.

differentiation

The process where cells become specialized in structure and function.

diffusion

The natural movement of a substance from high to low concentration.

digestive system

An organ system responsible for breaking down ingested nutrients.

diploid

A cell that contains two sets of homologous chromosomes.

DNA polymerase

An enzyme that joins individual nucleotides during DNA replication.

DNA replication

The process in which a cell makes a duplicate copy of its DNA.

dominant

An allele that is expressed in an organism’s phenotype.

ecology

The scientific study of interactions between living organisms and their environment.

ecosystem

A specific region that includes all living organisms and nonliving components.

electromagnetic radiation

A form of energy given off by objects with electrically charged particles.

electron transport chain/system

A stage in cellular respiration where proteins convert ADP into ATP using high-energy electrons.

endocytosis

The process where a cell takes in large substances by forming vesicles.

endoplasmic reticulum (ER)

An organelle that produces and transports proteins and lipids.

energy pyramid

A model showing how energy flows through organisms in an ecosystem.

entropy

The tendency of matter to progress toward increasingly disorganized states.

enzyme

A protein that accelerates a biochemical reaction by reducing activation energy.

equilibrium

A state of a chemical reaction where reactant and product concentrations remain unchanged.

eukaryote

An organism containing cells with a membrane-bound nucleus.

evolution

Changes in the genetic composition of a population over generations.

exocytosis

A process where a cell releases large substances as vesicles through the cell membrane.

facilitated diffusion

The movement of a substance across a membrane through a protein channel without energy use.

flagella

Long, whip-like structures that extend from cells and function in movement.

food chain

A simple model illustrating the transfer of chemical energy between organisms.

food web

A complex model of interrelated food chains showing energy transfer relationships.

fossil

The remains or trace of an organism preserved over geological time.

fossil fuel

A fuel formed from plant or animal remains under geological pressure.

fossil record

A preserved historical record of once-living organisms.

frameshift mutation

A mutation caused by addition or deletion of nucleotides that shifts the codon sequence.

gamete

A specialized reproductive cell containing half the number of chromosomes.

gene

The essential unit of heredity controlling specific traits.

gene expression

The process of transcribing a gene into mRNA and then translating it into a protein.

gene mutation

An alteration that changes a segment of DNA representing a gene.

gene pool

The combined genetic information of every interbreeding organism in a population.

genetic engineering

Techniques for altering the genetic material of organisms.