Cell Theory
States that all living organisms are composed of cells and that all cells arise from pre-existing cells.
Reductionist Biology
An approach to study living organisms by utilizing physico-chemical techniques and concepts.
Eukaryotic Cells
Cells that have a membrane-bound nucleus and organelles.
Prokaryotic Cells
Cells that lack a membrane-bound nucleus and organelles.
Nucleus
A membrane-bound structure that contains the genetic material and controls cellular activities.
Plastids
Organelles found in plants involved in the synthesis and storage of food.
Mitochondria
Double membrane-bound organelles responsible for energy production through aerobic respiration.
Golgi Apparatus
Cell organelle involved in the packaging and transport of proteins.
Ribosomes
Non-membrane bound organelles that are the site of protein synthesis in cells.
Cytoplasm
The semi-fluid matrix within a cell where cellular activities occur.
Cell Membrane
A selectively permeable membrane surrounding the cell that controls the movement of substances in and out.
Endoplasmic Reticulum (ER)
A network of membranous tubules in the cytoplasm involved in protein and lipid synthesis.
Lysosomes
Membrane-bound vesicles containing hydrolytic enzymes for digestion of macromolecules.
Active Transport
The movement of molecules across a membrane against a concentration gradient using energy.
Passive Transport
The movement of molecules across a membrane without the use of energy, typically along the concentration gradient.
Chromatin
The complex of DNA and proteins that forms chromosomes within the nucleus.
Centrosome
An organelle that serves as the main microtubule organizing center and is crucial during cell division.
Mesosome
An infolding of the plasma membrane in prokaryotic cells associated with various cellular functions.
Gram-positive Bacteria
Bacteria that retain the crystal violet stain used in the Gram staining procedure.
Gram-negative Bacteria
Bacteria that do not retain the crystal violet stain and are characterized by a thinner peptidoglycan layer.
Cell Wall
A rigid layer outside the cell membrane in plant cells, providing structural support and protection.
Chloroplasts
Organelles in plant cells that conduct photosynthesis, converting light energy into chemical energy.
Plasma Membrane
A flexible layer that surrounds the cell, controlling the passage of substances in and out.
Vesicles
Small membrane-bound sacs that transport substances within the cell.
Peroxisomes
Organelles that contain enzymes for oxidation reactions, breaking down fatty acids and detoxifying harmful substances.
Cytoskeleton
A network of fibers that maintains cell shape and aids in movement and anchoring organelles.
Nucleolus
A dense region within the nucleus where ribosomal RNA is synthesized and ribosome subunits are assembled.
Endocytosis
The process by which cells take in substances by engulfing them in vesicles.
Exocytosis
The process of vesicles fusing with the plasma membrane to release their contents outside the cell.
Transport Proteins
Proteins that assist in the movement of substances across a cell membrane.