AP bio type shite

Biology

scientific study of life.

themes that organize biological info

Information

Interactions

Organization
Energy & matter
Evolution

Organization

All living things are made of cells.

Prokaryotic

simple, no nucleus, no membrane-bound organelles.

Eukaryotic

more complex, have nucleus & organelles.

Metabolism

All life carries out countless chemical reactions.
Catabolic- break down, release energy (exergonic).
Anabolic- build up, require energy (endergonic).
Enzymes- catalyze reactions.
Viruses- don’t have metabolism → not considered living.

Growth & Development

Growth- increase in size/mass.
Development- transformation during lifespan (ex

Reproduction

Sexual- two parents → genetically unique offspring (variation).
Asexual- one parent → clones (binary fission, mitosis).

Response to Environment

Cells sense environment using receptors (chemical, light, temperature, pressure).
Ex- E. coli uptake of arabinose → activates genes for metabolism.

Energy & Matter Use

Autotrophs:organisms, such as plants, algae, and some bacteria, that produce their own food and energy

Homeostasis

Maintain stable internal conditions.
Ex- Paramecia use contractile vacuoles to expel excess water.
Ex- Jackrabbits’ ears release heat; human kidneys regulate water/salt.

Adaptation & Evolution

Individuals don’t adapt; populations evolve via natural selection.
Adaptations- heritable traits that increase survival.

Emergent properties

arise when parts interact (heart tissue vs. full heart).

Structure & function

shape matches role (elephant trunk = many muscles → flexibility & strength).

Genetic information

DNA → proteins; inherited from parents.

Interactions

organisms affect each other & environment (mutualism, parasitism, commensalism).

Domains of Life

Bacteria (prokaryotes)
Archaea (prokaryotes, often in extreme environments)
Eukarya (plants, animals, fungi, protists)

Scientific method

systematic way of understanding nature.

Steps of scientific method

Observation → Question
Hypothesis (testable explanation)
Prediction (if…then…)
Experiment (controlled conditions)
Data collection & analysis
Conclusion (support/refute hypothesis)
Communicate (peer review, journals, conferences)

Reasoning

Inductive Reasoning- specific observations → general principle.
Deductive Reasoning- general principle → specific prediction.

Hypotheses & Experiments

Hypothesis = tentative explanation, can be supported/refuted, never proven 100%.
Null hypothesis = no effect/difference.
Alternative hypothesis = there is effect/difference.
Controlled experiment

Example Mouse Coat Color Study

Beach mice = light fur; inland mice = dark fur.
Hypothesis- coloration = camouflage to reduce predation.
Test- placed light & dark models in both habitats.
Result- camouflaged models attacked less → supports natural selection.

Placebo Effect

Health improvement after fake treatment (sugar pill).
Driven by expectation & mind-body connection.
Used in clinical trials to test drug effectiveness.

Laws vs. Theories

Law- describes what happens (e.g., gravity, conservation of mass).
Theory- explains why/how it happens (e.g., cell theory, evolution).

3. Atoms, Elements, Isotopes and matter

Matter = has mass & takes up space.
Elements = pure substances, can’t be broken down.
Compounds = 2+ elements combined in fixed ratio, with new properties (emergent).

Elements of Life

C, H, O, N = 96% of living matter.

Abundance of elements in the human body

H - 10%
O - 65%
N - 3%
C - 18%
Other essential elements

Subatomic particles

Protons (+, nucleus)
Neutrons (0, nucleus)
Electrons (–, orbitals/cloud)
Atomic number = protons.
Mass number = protons + neutrons.

Isotopes

Same element, different neutrons.
Stable isotopes- nuclei don’t decay (C-12, C-13).
Radioactive isotopes- nuclei decay spontaneously (C-14 → N-14).

Beta decay

Neutron → proton + electron (beta particle).
Mass stays same, atomic number increases.

Uses of beta decay

Fossil dating (carbon dating with C-14).
Tracing atoms in metabolism.
Medical imaging/diagnosis (PET scans).
Hazards

Structure of water

Polar molecule- O = δ–, H = δ+.
Forms hydrogen bonds → unique emergent properties.

Four Life-Sustaining Properties

Cohesion & Adhesion
Temperature Moderation
Expansion Upon Freezing
Versatile Solvent

Cohesion & Adhesion

Cohesion- water sticks to itself → surface tension.
Ex- paperclip floats, insects walk on water.
Adhesion- water sticks to other surfaces.
Ex- water climbing xylem walls in plants.

Temperature Moderation

High specific heat- resists temp change.
High heat of vaporization- evaporation cools organisms.
Ex- sweating in humans; transpiration in plants.

Expansion Upon Freezing

Ice less dense than liquid → floats, insulates.
Water densest at 4°C.
If ice sank, aquatic life wouldn’t survive winter.

Versatile Solvent

Dissolves ionic & polar molecules (hydration shells).
Hydrophilic = dissolves (polar/ionic).
Hydrophobic = does not dissolve (nonpolar, oils).

Nonpolar vs polar

Nonpolar Covalent Bond | Covalent Bond | Ionic |
0 0.4 1.4 2+
Cation

Water Properties

High point of vaporisation/boiling
Surface Tension
Cohesion = Water + Water (Surface tension)
Adhesion = Water + Other Polar Molecule
Freezing Structure (Hexagon with space in the middle = floats in water)
Universal solvent
Can work as a base/acid (H+/OH-)