AP Bio Final- Semester 2

Steps to the Scientific Method

Observation → Question → Hypothesis (null vs. alternate) → Experiment → Data → Conclusion

Difference between variables

Independent Variable: What you change

Dependent Variable: What you measure

Control Group: Group without experimental variable

Vocab for Statistics

Error Bars: represent standard deviation or standard error

T-test: compares means of groups; significant if p < 0.05

Chi-Square Test: compares expected vs observed values

Water

Polarity: uneven charge (O is negative, H is positive)

Bonding: Hydrogen bonds between molecules, covalent within

Properties: cohesion, adhesion, high heat capacity, solvent abilities

Transpiration: water loss through leaves, heat helps water move

Water Potential: Ψ = Ψs + Ψp, water moves from high to low potential

Macromolecules

Carbs, lipids, proteins, nucleic acids

Dehydration Synthesis: forms bonds by removing water

Hydrolysis: breaks bonds by adding water

Prokaryotes vs Eukaryotes

Prokaryotes: no nucleus or organelles (bacteria)

Eukaryotes: nucleus, membrane-bound organelles

Cell Size

Surface Area-Volume Ratio: higher ratio = more efficient exchange

Cell Structure and Function

Organelles: nucleus, ER, Golgi, lysosomes, mitochondria, chloroplasts

Endomembrane System: ER —> Golgi —> Vesicles

Endosymbiosis: Mitochondria and chloroplasts were once free living

Cell Transportation

Passive: no energy required (diffusion, osmosis, facilitated diffusion)

Active: energy required (pump, endo/exocytosis)

Osmosis and Water Potential: water moves to a more negative Ψ

Metabolism

Endotherms vs Exotherms: endotherms maintain heat, higher O2 use

Exergonic: releases energy (Cell Respiration)

Endergonic: requires energy (Photosynthesis)

Anabolic: builds molecules

Catabolic: breaks down molecules

Photosynthesis and Respiration

Photosynthesis: Light + CO2 + H2O —> Glucose +O2

Pigments: Absorb light; chlorophyll most common

Cell Respiration: Glucose + O2 —> CO2 + H2O + ATP

Fermentation: Anaerobic, less efficient, produces lactate and alcohol

Enzymes:

Structure/Function: specific shape; active site

Rate Graphs: affected by temp, pH, concentration

Inhibitors: Competitive vs. Noncompetitive

Denaturation: Loss of structure = Loss of function

Cell Communication and Regulation

Signal Pathways: Ligand —> Receptors —> Cascade —> Response

• Ex: Epinephrine (fight or flight), insulin/glycogon (blood sugar)

Homeostasis:

• Negative Feedback: maintains set point

• Positive Feedback: Amplifies change

Mitosis

PMAT, identical cells, growth/repair

Cycling/CDKs: regulate cycle

Apoptosis: programmed cell death

How is cancer caused?

caused by uncontrolled mutations/division

Meiosis

Produces gametes, genetic variation via crossing over and independent assortment

Nondisjunction: causes chromosomal disorders (down syndrome)

Mendel’s Laws

Segregation: Alleles separate

Independent Assortment: Traits inherited separately

Non-Mendelian: incomplete dominance, codominance, polygenic genes

Linked Genes: inherited together

Sex-linked traits: Usually X-linked

Tools for Mendal’s Laws

punnet square, pedigrees, karyotypes, gel electrophoresis, cladograms

DNA and Gene Expression

Replication: semi-conservitive

Protein synthesis:

• Transcription: DNA —> mRNA

• Translation: mRNA —> protein (using codon chart)

Gene Regulation

Prokaryotes: Operons (Lac, Trp)

Eukaryotes: transcription factors, enhancers

Homeotic Genes: control body plan

Microbiology

Bacterial Process: transformation, transduction, conjugation

Viruses: infectious particles; use host machinery

Plasmids: Extra DNA in bacteria; often carry resistance genes

Evolution

Miller-Urey: simulated early earth; created organic molecules

Natural Selection: variation, inheritance, survival, reproduction

Types: Stabilizing (maintains status quo), directional (favors one extreme trait), disruptive (favors both extreme traits)

Hardy-Weinburg: p² + 2pq + q²

Cladograms: shows evolutionary relationship (diagram)

Speciation

Reproductive Barriers: prezygotic (stops diff species from mating) and postzygotic (leads to reduced variation and fertility)

Isolation: geographic (physical barriers separating populations), behavioral (differences in mating rituals or behavior), temporal (different breeding times)

Ecology

Animal Behavior: Innate vs. Learned

Food Webs: arrows = energy flow

Trophic Levels: 10% rule

Niche Partitioning: species avoid competition by specializing

Populations

Simpson’s Diversity Index: measures biodiversity

Symbiosis: mutualism (both species benefit), commensalism (one is harmed, one is helped), parasitism (the host suffers, the parasite benefits)

NPP vs. NSP: energy in producers vs consumers

Sustainability

Carrying capacity: maximum population an environment can support

Limiting factors: space, resources

Human impact: pollution, deforestation, climate change