Comprehensive Overview of Biology Concepts

Characteristics of Life

Order, reproduction, growth & development, metabolism, homeostasis, response to stimuli, evolutionary adaptation.

Scientific Method

Observation → Question → Hypothesis → Experiment → Data → Conclusion.

Quantitative data

Numbers.

Qualitative data

Descriptions.

Hypothesis

Testable explanation.

Experimental group

Receives treatment.

Control group

No treatment (baseline).

Independent variable

Changed.

Dependent variable

Measured.

Constants

Kept the same.

Biotic

Living things.

Abiotic

Non-living factors (e.g., temperature, water).

Mutualism

Both benefit (bee & flower).

Parasitism

One benefits, one harmed (tapeworm).

Commensalism

One benefits, other unaffected (barnacle on whale).

Competition

Organisms fight for the same resources.

Predation

Predator eats prey.

Herbivory

Animal eats plants.

Producers (autotrophs)

Make their own food (plants).

Consumers (heterotrophs)

Eat others for energy.

Decomposers

Break down dead matter (fungi, bacteria).

Food Web

Interconnected food chains.

Energy Flow

10% of energy passes to next level.

Matter Cycles

Carbon, nitrogen, water cycles.

Invasive species

Non-native, disrupt ecosystems.

Exponential Growth

J curve (unlimited).

Logistic Growth

S curve (limited by carrying capacity).

Organic molecules

Contain carbon.

Monomer

Building block.

Polymer

Chain of monomers.

Monosaccharides

Sugars (glucose).

Polysaccharides

Starch, cellulose.

Lipids

Fats & oils.

Hydrophobic

Repels water.

Hydrophilic

Attracts water.

Amino acids

Monomers of proteins.

Polypeptide

Chain of amino acids.

Enzymes

Speed up reactions.

Active site

Binds substrate.

Denaturation

Loss of function (heat/pH).

Nucleic acids

DNA & RNA.

Nucleotide

Monomer (sugar + phosphate + base).

Prokaryotic

No nucleus (bacteria).

Eukaryotic

Has a nucleus.

Plant Cells

Cell wall, chloroplast, large vacuole.

Animal Cells

Lysosome, small vacuoles.

Nucleus

Controls cell.

Plasma membrane

Regulates entry/exit.

Cell wall

Support (plants only).

Cytoplasm

Jelly-like fluid.

Ribosomes

Make proteins.

ER (rough)

Protein transport.

ER (smooth)

Lipid production.

Vacuoles

Storage.

Mitochondria

Powerhouse (ATP production).

Chloroplast

Photosynthesis (plants only).

Golgi apparatus

Packages proteins.

Lysosome

Digests waste.

Passive Transport

No energy (diffusion, osmosis).

Active Transport

Uses energy.

Diffusion

Particles move from high to low concentration.

Osmosis

Water diffusion.

Equilibrium

Balanced concentration.

Cellular Respiration

Purpose: Make ATP from glucose.

Cellular Respiration Steps

Glycolysis, Krebs Cycle, ETC.

Anaerobic

No O₂: fermentation (lactic acid/alcohol).

Aerobic

Uses oxygen.

Photosynthesis Equation

CO₂ + H₂O + sunlight → O₂ + glucose.

Light reactions

Use sunlight, make ATP.

Calvin Cycle

Uses CO₂ to make sugar.

Asexual Reproduction

1 parent, clone.

Mitosis

somatic cell division (growth, repair)

PMAT

Prophase, Metaphase, Anaphase, Telophase

Meiosis

makes gametes (sperm/egg)

Crossing over

variation

Somatic cells

body cells

Gametes

sex cells

Chromosome

DNA + protein

Chromatin

loose DNA

Chromatids

copied chromosomes

Homologous chromosomes

same genes, different versions

Autosomes

non-sex chromosomes

Sex chromosomes

X, Y

Fertilization

sperm + egg → Zygote

Haploid

1 set of chromosomes

Diploid

2 sets of chromosomes

Cancer

uncontrolled cell division

Genotype

genetic makeup

Phenotype

physical trait

Allele

gene variant

Homozygous

same alleles

Heterozygous

different alleles

Punnett Square

predicts traits

Incomplete dominance

blended (red + white = pink)

Codominance

both show (AB blood)

Multiple alleles

more than two options (A, B, O)

Sex-linked

traits on X chromosome

Pedigree

family trait chart

DNA

double helix, made of nucleotides (A-T, C-G)

Replication

process of copying DNA