IB Biology SL Unit 1

Functions of Life:
MR SHENGE

Metabolism, Reproduction, Sensitivity, Homeostasis, Excretion, Nutrition, Growth, Evolution

Metabolism

Sum of chemical reactions, responsible for all actions

Reproduction

Sexual: 2 parents, offspring is unique, fusion of haploid sex cells, meiosis
Asexual: 1 parent, offspring is identical, mitosis and binary fission

Sensitivity and Response

All life responds to changes in environment

Homeostasis

Keeps internal environment within the range of stable internal conditions despite external environments

Excretion

Metabolic waste is eliminated

Nutrition

Autotrophs: Normally plants, abiotic source into chemical energy
Heterotrophs: Chemical energy found in matter

Growth and Development

Growth: Size and mass change
Development: Transformation over lifespan

Evolution and Adaptation

Evolution: Ratio of different genetic types change
Revolution: Fitted to environment

Paramecium
Metabolism

Cytoplasm contains dissolved enzymes, digestion

Paramecium
Reproduction

Mitosis, asexually

Paramecium
Sensitivity

Cilia to move

Paramecium
Nutrition

Eats smaller unicellular organisms, heterotroph, eats YEAST

Paramecium
Homeostasis

Contractile Vacuole, swells and expels water through opening in cell membrane

Paramecium
Excretion

Anal pore

Chlamydomona
Metabolism

Cytoplasm and Chloroplast contains dissolved enzymes, digestion, photosynthesis, cellular respiration

Chlamydomona
Reproduction

Asexual, mitosis

Chlamydomona
Sensitivity

Eye spot to sense light and 2 flagella to move around

Chlamydomona
Nutrition

Autotroph, photosynthesis

Chlamydomona
Homeostasis

Contractile Vacuole, swells and expels water

Chlamydomona
Excretion

Oxygen deposited from photosynthesis through cell membrane

Levels of biological organization

Atom
Simple molecules
Macro molecules
Sub cellular structures
Cells
Tissues
Organ
Organ system
Organism
Population
Community
Ecosystem
Biome
Biosphere

Emergent Properties

Property that comes from parts interacting with the whole

Cell Theory

1. Cell is the basic unit of life
2. All living things are made of cells
3. Cells come from preexisting cells

Evidence of Cell Theory

1. Sub cellular cannot perform functions of life
2. Tissues of plant and animal contains at least 1 cell
3. Never observed spontaneous generation

Implications

1. Trace origin of cells in our body back to zygote
2. First cell can be traced back to evolution of LUCA
3. 1st cell must've come from non-living material

Trend

Prevailing tendency, generalization
Leads to development of predictions

Discrepancy

Doesn't fit the trend
Lead to scientific questions

Trends in Cells

Cells are small
All living things are made of cells

Discrepancies in Cells

Red Blood Cells- No nucleus or mitochondria
Giant Algae- Big single celled organism
Skeletal Muscles- More than 1 nucleus
Fungal Hyphae- Not made of clear, individual cells

Development of Cell Theory

Jansen- Compound microscope
Hooke- Discovered cells
Leeuwenhock- Discovered unicellular
Schleiden- All plants are made of cells
Schwann- All animals are made of cells
Vichow- All cells come from other cells
Abbe & Zeiss- Modern compound microscope
Scanning electron microscope