Biology Review Flashcards

Flashcards covering key vocabulary from Biology Units 1-6.

Hypothesis

A testable prediction ("If… then… " statement).

Independent Variable

What you change in an experiment.

Dependent Variable

What you measure in an experiment.

Control Group

Group not exposed to the independent variable (used for comparison).

Constants

Conditions kept the same for all groups in an experiment.

Carbohydrates

Macromolecule for quick energy (e.g., glucose, starch).

Lipids

Macromolecule for long-term energy & insulation (e.g., fats, oils).

Proteins

Macromolecule that builds body structures, enzymes (e.g., meat, beans).

Nucleic Acids

Macromolecule that stores genetic info (DNA & RNA).

Cell Theory

1. All living things are made of cells. 2. Cells are the basic unit of life. 3. All cells come from pre-existing cells.

Prokaryotes

Cells with no nucleus (e.g., bacteria).

Eukaryotes

Cells with nucleus & organelles (e.g., plant and animal cells).

Nucleus

Organelle that controls the cell.

Mitochondria

Organelle; the powerhouse of the cell (makes ATP).

Ribosomes

Organelle that makes proteins.

Endoplasmic Reticulum

Organelle that transports materials.

Golgi Apparatus

Organelle that packages proteins.

Chloroplasts

Organelle; site of photosynthesis (plants only).

Cell Membrane

Structure that controls what enters/leaves the cell.

Cell Wall

Structure that provides structure in plants only.

Vacuole

Structure that stores materials.

Mitosis

One cell → two identical daughter cells. Used for growth, repair, asexual reproduction.

Cancer

Uncontrolled cell division.

Tumor

A mass of cells.

Benign

Not cancerous.

Malignant

Cancerous, can spread.

Metastasize

Spread of cancer cells.

Carcinogens

Cancer-causing substances.

Reactants

What you start with in a chemical reaction.

Products

What you end with in a chemical reaction.

Endothermic

A process that absorbs energy.

Exothermic

A process that releases energy.

ATP (Adenosine Triphosphate)

The energy currency of the cell.

Photosynthesis

Process in chloroplasts (plants) that converts CO₂ + H₂O + sunlight → C₆H₁₂O₆ + O₂.

Cellular Respiration

Process in mitochondria that converts C₆H₁₂O₆ + O₂ → CO₂ + H₂O + ATP.

Aerobic

With oxygen (more ATP).

Anaerobic

Without oxygen (less ATP, produces lactic acid or alcohol).

Trophic Pyramids

Representation of energy flow from producers → consumers → decomposers.

DNA

Double-stranded, has thymine (T), stays in nucleus.

RNA

Single-stranded, has uracil (U), can leave the nucleus.

DNA Replication

Copying DNA before cell division (semi-conservative).

Transcription

DNA → mRNA (in nucleus).

Translation

mRNA → protein (at ribosome).

Meiosis

One cell → four unique gametes (sex cells). Cuts chromosome number in half (haploid). Increases genetic variation.

Somatic Cells

Body cells (diploid).

Gametes

Sex cells (sperm/egg) (haploid).

Dominant

Trait that shows with one allele (A).

Recessive

Trait shows only if two alleles (aa).

Homozygous

Same alleles (AA or aa).

Heterozygous

Different alleles (Aa).

Genotype

The gene combo (Aa, AA, aa).

Phenotype

What it looks like (brown eyes, etc).

Monohybrid

Punnett square for 1 trait.

Dihybrid

Punnett square for 2 traits (use FOIL to cross).

Incomplete dominance

Blend (red + white = pink).

Codominance

Both show (black + white = speckled).

Polygenic

Many genes (skin color, height).

Gene mutation

Change in a single gene.

Chromosomal mutation

Large section of DNA changed.

Natural Selection

Best traits survive & reproduce. Requires genetic variation.

Adaptation

A helpful trait for survival.

Hardy-Weinberg Equilibrium

When allele frequencies don’t change = no evolution. Conditions: no mutation, random mating, no selection, large population, no migration.

Homologous Structures

Same structure, different function (human arm & whale fin).

Analogous Structures

Same function, different structure (bird & insect wings).

Vestigial Structures

No longer used (appendix, wisdom teeth).

Cell

The basic unit of life.

Allele

Different forms of a gene.

Haploid

Having a single set of chromosomes.

Diploid

Containing two complete sets of chromosomes, one from each parent.

mRNA

Messenger RNA, carries genetic code from DNA to ribosome.