Cellular Components and Organelles
- Cytoplasm: A colloidal system consisting primarily of water and other cellular components. It contains organelles and the cytoskeleton, responsible for structuring and storing.
- Cytoskeleton: A complex network of actin filaments and microtubules composed of tubulin. It is responsible for cellular movement.
- Rough Endoplasmic Reticulum (RER): Composed of flattened sacs; its external surface presents many ribosomes. It synthesizes proteins and produces ribosomes.
- Smooth Endoplasmic Reticulum (REL): Composed of flattened sacs; it synthesizes lipids and carbohydrates and lacks ribosomes.
- Lysosomes: Membrane-bound vesicles containing digestive enzymes synthesized in the RER. They function in the degradation of nutritional compounds, bacteria, and damaged organelles.
- Centrioles: Non-membranous structures formed by microtubules. A pair of centrioles is called a diplosome and is involved in cell division.
- Ribosomes: Formed by the RER; they synthesize proteins.
- Mitochondria: Responsible for cellular respiration. They possess their own DNA and have internal and external membrane folds.
- Vacuoles: Bounded by a membrane (tonoplast); these are mature lysosomes. They contain water, reserve substances, and metabolic waste.
- Peroxisomes: Contain oxidase and catalase; they degrade purines and other compounds.
- Golgi Apparatus: Composed of flattened sacs and vesicles; it handles the packaging and distribution of substances produced by the cell.
- Chloroplasts: Responsible for photosynthesis.
- Amyloplasts: Double-membrane vesicles that store starch.
- Chromatin: The complete set of chromosomes found in the nucleus and mitochondria, consisting of DNA wrapped around proteins.
- Glyoxysomes: Contain enzymes that convert fatty acids into sugars.
- Nucleolus: A set of DNA, RNA, and proteins that synthesizes RNA.
- Plastids: Includes leucoplasts, chromoplasts, and chloroplasts; they store substances and provide color.
- Nucleus: Consists of chromosomes and DNA strands; it contains the genetic material.
Cell Theory
- Robert Hooke: Observed cork plant cell structure (cell wall).
- Antonie van Leeuwenhoek: Discovered animal cells in blood and bacteria.
- Matthias Schleiden: Studied plant cells.
- Theodor Schwann: Concluded that all living things are composed of one or more cells and that the cell is the fundamental unit of all living organisms.
- Rudolf Virchow: Established that the cell is the basic unit of life and that all cells come from pre-existing cells.
