General Biology Yearly Notes

Cell Theory

All living things are made of cells; cells are the basic structural and functional units of organisms; all cells come from pre-existing cells.

Prokaryotes

Primitive, smaller, and simpler cells without a nucleus; include bacteria and archaea.

Eukaryotes

More complex cells with membrane-bound organelles; can be unicellular or multicellular.

Endosymbiotic Theory

Eukaryotic cells originated from prokaryotic cells that were engulfed but not digested, leading to mutualism.

Light Microscopes

Use light to magnify images up to 1500x with a maximum resolution of 200nm.

Electron Microscopes

Use electron beams for higher resolution; include Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM).

Organelles

Specialized structures within eukaryotic cells that perform specific functions; examples include mitochondria, chloroplasts, and ribosomes.

Cell Membrane

A selectively permeable barrier that controls the passage of substances in and out of the cell.

Diffusion

The passive movement of particles from an area of high concentration to an area of low concentration.

Osmosis

The net movement of water molecules across a semipermeable membrane along a water concentration gradient.

Active Transport

The process of moving substances against their concentration gradient using energy.

Endocytosis

The process by which cells take in materials by engulfing them in vesicles.

Exocytosis

The release of substances from a cell through vesicles that fuse with the cell membrane.

Surface-Area-to-Volume Ratio

Affects the efficiency of substance exchange in cells; smaller cells have a higher ratio.

Autotrophs

Organisms that produce their own food from inorganic substances; include photoautotrophs and chemoautotrophs.

Heterotrophs

Organisms that obtain organic compounds by consuming other organisms.

Unicellular Organisms

Single-celled organisms that carry out all life processes independently.

Colonial Organisms

Groups of cells that work together; can be unicellular or multicellular.

Multicellular Organisms

Organisms composed of many cells that work together to perform life processes.

Specialised Cells

Cells that have differentiated to perform specific functions within multicellular organisms.

Tissues

Groups of similar cells that work together to perform a specific function.

Organs

Structures made up of different tissues that perform specific functions.

Organ Systems

Groups of organs that work together to perform complex functions in an organism.

Ecosystems

Communities of living organisms interacting with their physical environment.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and reproduce.

Adaptations

Characteristics that enhance an organism's ability to survive and reproduce in its environment.

Structural Adaptations

Physical features of an organism that enhance its survival.

Physiological Adaptations

Internal processes that help an organism survive in its environment.

Behavioral Adaptations

Actions performed by organisms in response to environmental stimuli.

Biodiversity

The variety of life in a particular habitat or ecosystem, including genetic, species, and ecosystem diversity.