Biology 8th Guide: 300 Simplified Terms and Energy Processes

Observation

Using senses to gather information.

Hypothesis

An educated guess that can be tested.

Experiment

A test to check if the hypothesis is correct.

Independent Variable

The factor you change in an experiment.

Dependent Variable

What you measure in the experiment.

Control Group

The group that doesn’t get the experimental treatment.

Constants

Things kept the same for all groups.

Theory

A well-tested explanation.

Biology

The study of life.

Organism

Any living thing.

Cell

Basic unit of life.

Homeostasis

Keeping internal conditions stable.

Metabolism

All chemical reactions in an organism.

Reproduction

Making more of the same organism.

Growth

Getting bigger or more cells.

Development

Changes that happen as an organism matures.

Response to Stimuli

Reacting to the environment.

Adaptation

Inherited trait that helps survival.

Evolution

Change in species over time.

Atom

Basic unit of matter.

Element

Substance made of one type of atom.

Molecule

Group of atoms bonded together.

Compound

A substance made from different elements.

Covalent Bond

Atoms share electrons.

Ionic Bond

Electrons are transferred between atoms.

Water (H2O)

Most important molecule for life.

Polarity

Molecule has a positive and negative end.

Hydrogen Bond

Weak bond between water molecules.

Cohesion

Water sticks to water.

Adhesion

Water sticks to other things.

Solvent

A substance that dissolves other substances.

pH Scale

Measures acidity (0-14).

Acid

Below 7 on pH scale.

Base

Above 7 on pH scale.

Buffer

Keeps pH stable.

Organic Molecule

Has carbon and hydrogen.

Macromolecule

Big molecules like carbs, proteins, lipids, nucleic acids.

Carbohydrate

Main energy source (sugars, starch).

Monosaccharide

Simple sugar (glucose).

Polysaccharide

Complex sugar (starch, cellulose).

Lipid

Fats and oils; store energy.

Fatty Acid

Building block of lipids.

Protein

Made of amino acids; build structures and enzymes.

Amino Acid

Building block of proteins.

Enzyme

Speeds up chemical reactions.

Substrate

What an enzyme acts on.

Nucleic Acid

DNA and RNA.

Nucleotide

Building block of DNA/RNA.

Cell Theory

All living things are made of cells.

Prokaryote

Simple cells without nucleus (bacteria).

Eukaryote

Cells with nucleus (plants, animals).

Nucleus

Holds DNA in eukaryotic cells.

Cytoplasm

Gel inside the cell.

Cell Membrane

Controls what goes in/out of the cell.

Cell Wall

Rigid outer layer in plants/bacteria.

Ribosome

Makes proteins.

Endoplasmic Reticulum (ER)

Moves materials in cell.

Golgi Apparatus

Packages and ships proteins.

Mitochondria

Makes energy (ATP).

Chloroplast

Where photosynthesis happens (plants).

Vacuole

Stores stuff (big in plant cells).

Lysosome

Breaks down waste.

Cilia/Flagella

Help cells move.

Cytoskeleton

Gives shape/support to cell.

Peroxisome

Breaks down fats and toxins.

Diffusion

Movement from high to low concentration.

Osmosis

Water moving across membrane.

Passive Transport

No energy needed.

Active Transport

Needs energy (ATP).

Endocytosis

Cell takes in materials.

Exocytosis

Cell releases materials.

Isotonic

Same solute concentration inside and out.

Hypotonic

Lower solute outside; cell swells.

Hypertonic

Higher solute outside; cell shrinks.

Photosynthesis

Plants use sunlight to make food.

Chlorophyll

Green pigment in chloroplasts.

Light Reaction

First part of photosynthesis.

Calvin Cycle

Second part of photosynthesis.

Cellular Respiration

Breaks down food for energy.

Glycolysis

First step; happens in cytoplasm.

Krebs Cycle

Second step; makes CO2.

Electron Transport Chain (ETC)

Final step; makes most ATP.

ATP

Energy molecule.

Anaerobic

No oxygen needed.

Aerobic

Needs oxygen.

Fermentation

Makes energy without oxygen.

Mitosis

Cell division for growth/repair.

Meiosis

Makes sex cells (sperm, egg).

Chromosome

DNA wrapped up.

Gene

Section of DNA with instructions.

DNA

Holds genetic info.

RNA

Helps make proteins.

Replication

Copying DNA.

Transcription

DNA to RNA.

Translation

RNA to protein.

Mutation

Change in DNA.

Allele

Different versions of a gene.

Genotype

Genetic makeup.

Phenotype

Physical traits.

Homozygous

Same alleles.