Comprehensive Biology: DNA, Cells, Genetics, Evolution, and Ecology

Observation

Notice something.

Hypothesis

Educated guess.

Experiment

Test the hypothesis.

Data

Information collected.

Conclusion

What the results mean.

Independent Variable

What YOU change.

Dependent Variable

What you measure.

Control Group

The normal group for comparison.

Theory

Idea supported by lots of evidence.

Qualitative Data

Words/descriptions.

Quantitative Data

Numbers.

DNA

Genetic instructions.

Gene

DNA for one trait.

Chromosome

Coiled DNA.

Genome

All of an organism's DNA.

Nucleotide

DNA building block.

Replication

Copy DNA.

Transcription

DNA → RNA.

Translation

RNA → Protein.

mRNA

Carries DNA instructions.

tRNA

Brings amino acids.

Codon

Three RNA letters = one amino acid.

Ribosome

Makes proteins.

Cell

Smallest unit of life.

Prokaryote

No nucleus.

Eukaryote

Has nucleus.

Cell Membrane

Controls what enters and leaves.

Cytoplasm

Jelly inside the cell.

Nucleus

Control center; holds DNA.

Organelle

Cell part with a job.

Mitochondria

Makes ATP (energy).

ATP

Cell's energy.

Diffusion

High → Low.

Osmosis

Water moves.

Active Transport

Low → High (uses ATP).

Enzyme

Speeds up reactions.

Homeostasis

Stable internal conditions.

Selectively Permeable

Lets some things through.

Cell Cycle

Grow, copy DNA, divide.

Mitosis

Makes two identical cells.

Cytokinesis

Cell splits.

Sister Chromatids

Identical chromosome copies.

Centromere

Holds chromatids together.

Cancer

Uncontrolled cell division.

Meiosis

Makes sex cells.

Gametes

Sperm or egg.

Diploid

Two chromosome sets (2n).

Haploid

One chromosome set (n).

Crossing Over

Chromosomes swap DNA.

Independent Assortment

Chromosomes mix randomly.

Homologous Chromosomes

Matching chromosome pair.

Fertilization

Sperm + Egg = Zygote.

Zygote

Fertilized egg.

Allele

Version of a gene.

Genotype

Your genes.

Phenotype

What you look like.

Dominant

Shows if present.

Recessive

Hidden unless two copies.

Homozygous

Same alleles (AA or aa).

Heterozygous

Different alleles (Aa).

Punnett Square

Predict offspring.

Monohybrid

One trait.

Dihybrid

Two traits.

Test Cross

Find unknown genotype.

Evolution

Populations change over time.

Mutation

DNA changes.

Natural Selection

Best traits survive.

Gene Flow

Genes move between populations.

Genetic Drift

Random population change.

Adaptation

Trait that helps survival.

Fitness

Ability to survive and reproduce.

Convergent Evolution

Different ancestors, similar traits.

Homologous Structures

Same ancestor.

Analogous Structures

Same job, different ancestor.

Vestigial Structures

Leftover body parts.

Fossil Record

Evidence from fossils.

Biogeography

Where organisms live.

Population

Same species together.

Community

Different species together.

Ecosystem

Living + nonliving things.

Biosphere

All life on Earth.

Biotic

Living.

Abiotic

Nonliving.

Producer

Makes food.

Consumer

Eats other organisms.

Decomposer

Breaks down dead organisms.

Food Chain

One feeding path.

Food Web

Many connected food chains.

Keystone Species

Species that holds ecosystem together.

Biodiversity

Variety of life.

Trophic Level

Position in food chain.