Bio final

1. Scientific Method

• Steps:

  1. Ask a Question

  2. Do Background Research

  3. Make a Hypothesis

  4. Test with an Experiment

  5. Analyze Data

  6. Draw a Conclusion

  7. Share Results

• Variables:

  • Independent: What you change

  • Dependent: What you measure

  • Controlled: What stays the same

• Example: Testing how sunlight affects plant growth.

2. Human Body Systems

• Circulatory: Moves blood (heart, blood, vessels)

• Respiratory: Breathes in O₂, out CO₂ (lungs, trachea)

• Digestive: Breaks down food (stomach, intestines)

• Nervous: Sends signals (brain, nerves)

• Muscular: Helps movement (muscles)

• Skeletal: Supports body (bones)

• Excretory: Removes waste (kidneys, bladder)

• Immune: Fights disease (white blood cells)

• Endocrine: Hormones (glands like thyroid)

• Reproductive: Produces offspring

3. Biochemistry

• Elements in Life: CHON (Carbon, Hydrogen, Oxygen, Nitrogen)

• Macromolecules:

  • Carbohydrates: Quick energy (sugar, starch)

  • Proteins: Build body parts (amino acids)

  • Lipids: Store energy (fats)

  • Nucleic Acids: Store genetic info (DNA & RNA)

• Enzymes: Speed up reactions; work best at certain pH & temp

4. DNA & Enzymes

• DNA: Genetic code, double helix, made of A, T, C, G

• Base Pair Rules: A-T and C-G

• Replication: DNA copies itself

• RNA: Helps make proteins (A-U, C-G)

• Enzymes: Proteins that speed up chemical reactions

  • Lock & Key: Enzymes fit specific molecules

5. Ecology

• Levels: Organism → Population → Community → Ecosystem → Biosphere

• Biotic vs. Abiotic: Living vs. non-living

• Food Chain/Web: Shows energy flow

• Producers: Make their own food (plants)

• Consumers: Eat others (herbivores, carnivores)

• Decomposers: Break down dead stuff (fungi, bacteria)

• Cycles: Water, Carbon, Nitrogen

• Symbiosis:

  • Mutualism (+/+)

  • Commensalism (+/0)

  • Parasitism (+/−)

6. Genetics and Evolution

• Genes: Units of heredity

• Alleles: Different forms of a gene

• Dominant vs. Recessive: Dominant shows over recessive

• Punnett Squares: Predict offspring traits

• Genotype vs. Phenotype: Genes vs. traits you see

• Evolution: Change over time

• Natural Selection: Survival of the fittest

• Evidence: Fossils, DNA, anatomy similarities

7. Cells

• Cell Theory:

  1. All living things are made of cells

  2. Cells are the basic unit of life

  3. All cells come from other cells

• Prokaryotes: No nucleus (bacteria)

• Eukaryotes: Have nucleus (plants, animals)

• Organelles:

  • Nucleus: Controls the cell

  • Mitochondria: Makes energy

  • Ribosomes: Make proteins

  • Chloroplast: Photosynthesis (plants)

  • Cell Wall: Support (plants)

  • Membrane: Controls what goes in/out

• Mitosis: Cell division → 2 identical cells

• Osmosis: Water movement across membrane