BIO101 Study Guide

Steps of the scientific method

Observation → Question → Hypothesis → Experiment → Data collection → Conclusion → Repeat

Independent variable

What you change

Dependent variable

What you measure

Control

Baseline comparison

Hypothesis

Testable prediction

Theory

Well-supported explanation based on lots of evidence

Can they be proven?

No, only supported or rejected. Hypotheses can contribute to theories over time

Good experiments

1. Control group

2. Only one variable changed

3. Reproducible

4. Large sample size

 Characteristics of Life

1. Made of cells

2. Use energy (metabolism)

3. Maintain homeostasis

4. Grow/develop

5. Reproduce

• Ex: Movement alone ≠ life

Population

Same species

Community

All species

Ecosystem

Community + environment

Carrying capacity

Max population

Density-dependent

Competition, disease

Density-independent

 Weather, disasters

Exponential

Rapid (J-shaped)

Logistic

Levels off (S-shaped)

Competition

(-/-)

Predator-prey

(+/−)

Parasite-host

(+/−)

Commensalism

(+/0)

Mutualism

(+/+)

Predator-prey adaptations

1. Camouflage

2. Warning colors

3. Chemical defenses

4. Physical defenses

5. Behavior

Competitive exclusion

One species outcompetes another

Resource partitioning

Divide resources

Biomes

Earth shape + wind + ocean currents → climate → biomes

Carbon cycle

Atmosphere, fossil fuels

Nitrogen cycle

Atmosphere, soil bacteria

Phosphorus

Rocks, soil

The more sunlight, the more….

Larger food webs are

10% Rule

Only ~10% energy transfers to next trophic level

Biodiversity

Variety of life

Hotspots

High diversity + threatened

Releasing pets/plants that non native sometimes

Can become invasive species → disrupt ecosystems

Human impact on biodiversity

1. Pollution

2. Deforestation

3. Climate change

4. Habitat loss

Succession

Gradual ecosystem change → increases biodiversity

Fossil fuels

CO₂, SO₂ → climate change, acid rain

Global warming

1. Caused by greenhouse gases

2. Deforestation reduces CO₂ absorption

Proteins

Structure, enzymes

Lipids

Membrane, long energy

Carbs

Quick energy

Nucleic acids

Genetic Information

Which has the most energy

Lipids

Primary sourcees of these things

Carbs

Proteins: amino acids

Polypeptides

Carbs: monosaccharides

Polysaccharides

Nucleic acids

Nucleotides → DNA/RNA

Primary structure

Sequence

Secondary structure

Local

Tertiary structure

Global

Quaternary

Assembly

Cell Theory

1. All living things made of cells

2. Cells = basic unit of life

3. Come from pre-existing cells

Prokaryotes

No nucleus

Eukaryotes

Nucleus + organelles

Compartmentalization

Optimizing metabolic efficientcy

Nucleus

DNA

ER

Protein/lipid production

Golgi

Packaging

Mitochondria

Energy

Chloroplast

Photosynthesis

Lysosome

Digestion

Endosymbiosis theory

Mitochondria/chloroplasts

Invagination theory

Other organelles

Protein pathway

Rough ER → Golgi → vesicle → membrane → outside

Enzymes

Proteins that speed reactions

Properties

1. Specific

2. Reusable

3. Work best at optimal conditions

Membrane proteins

1. Transport

2. Communication

3. Structure

4. Recognition

Membrane structure

1. Phospholipid bilayer

2. Hydrophilic heads, hydrophobic tails

 DNA structure

1. Double helix

2. A-T, C-G

 Replication

1. Helicase = unzips

2. Polymerase = builds

When?

S phase

Mutation

DNA change

Causes: radiation, errors

Are all mutations harmful?

 Not all harmful, some neutral or beneficial

Chromosome

DNA + proteins

Genes

Segments of DNA

Mitosis

Identical cells (2)

Meiosis (reproductive)

Gametes (4 unique)

Chromosome number

Stays 14 (mitosis preserves number)

Homologous Chromosomes

From parents

Sister chromatids

Identical copies

 Meiosis (Reproductive) Pt 2.

1. Makes gametes

2. Occurs in reproductive organs

3. Reduces chromosome number

4. Crossing over increases variation
   

RNA vs DNA

RNA:  single strand, uracil

DNA: double stranded thymine

Replication

DNA

Transcription

DNA → RNA

Translation

RNA → protein

mRNA

message

tRNA

brings amino acids

rRNA

ribosomes

Protein production

DNA → mRNA → ribosome → protein

Proteins & traits

Proteins determine phenotype

DNA universality

Found in all living organisms

Cancer

Uncontrolled cell division

Treatments

Target fast-dividing cells → affects healthy cells

Tumor

Mass

Metastasis

Spreads

Cloning

1. Reproductive = whole organism

2. Therapeutic = tissues

3. DNA cloning = genes

Clone issues

Shortened telomeres

Stem cells

Undifferentiated → can become many cell types

Embryonic Stem Cells

More flexible