unit 2 - prior knowledge

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Cell Size

The size of cells affects their efficiency, with smaller cells having a larger surface-to-volume ratio.

Plasma Membrane

A phospholipid bilayer with embedded proteins that regulates the movement of substances in and out of the cell.

Prokaryotic Cells

Cells without a membrane-enclosed nucleus, including bacteria and archaea.

Eukaryotic Cells

Cells with a membrane-enclosed nucleus and organelles, more complex than prokaryotic cells.

Endosymbiont Theory

The theory that chloroplasts and mitochondria originated from small prokaryotes that became incorporated into larger cells.

Membrane Bound Organelles

Organelles that compartmentalize cellular activities, allowing for specialized functions.

Cell Theory

The fundamental concept that all living things are composed of cells, which are the basic unit of structure and function, and that all cells arise from existing cells.

Light Microscope

A type of microscope that allows for the observation of living cells by passing light through lenses.

Scanning and Transmission Electron Microscopes

Advanced microscopes that reveal the ultrastructure of cells.

Nucleus

The organelle that houses the cell's DNA and directs protein synthesis.

Ribosomes

Cellular structures that synthesize proteins according to DNA instructions, composed of rRNA and proteins.

Chloroplasts

Organelles in plants and algae that perform photosynthesis, converting light energy into chemical energy.

Mitochondria

Organelles responsible for cellular respiration, found in nearly all eukaryotic cells.

Endomembrane System

A system of organelles that interact in the synthesis, distribution, storage, and export of molecules.

Smooth ER

A type of endoplasmic reticulum that synthesizes lipids and processes toxins.

Rough ER

A type of endoplasmic reticulum that produces membranes and secretory proteins.

Golgi Apparatus

An organelle that processes and packages products from the ER for distribution.

Lysosomes

Organelles that contain enzymes for breaking down ingested substances and damaged organelles.

Vacuoles

Large vesicles with various functions, including storage and maintaining water balance in cells.

Peroxisomes

Metabolic compartments that break down toxic hydrogen peroxide waste.

Fluid Mosaic Model

A model describing the structure of the plasma membrane as a mosaic of diverse protein molecules in a fluid phospholipid bilayer.

Selectively Permeable

A characteristic of the plasma membrane that allows certain substances to enter or exit the cell while blocking others.

Passive Transport

The movement of substances across a cell membrane without the use of energy, following the concentration gradient.

Osmosis

The diffusion of water across a selectively permeable membrane.

Tonicity

The ability of a surrounding solution to affect the water balance of a cell.

Facilitated Diffusion

The process by which hydrophilic substances move across the membrane with the help of transport proteins, without energy expenditure.

Active Transport

The movement of solutes against their concentration gradient, requiring energy (ATP).

Exocytosis

The process of exporting bulky molecules from the cell.

Endocytosis

The process of taking in large molecules by engulfing them with the cell membrane.

Phagocytosis

A type of endocytosis where the cell engulfs a food particle, forming a vacuole.