THE CELL THEORY

• Cell – basic structural and functional unit classified as a living thing and is often called the "building block of life".
• The cell was discovered by Robert Hooke in 1665.
• The cell theory states:

  • All living things or organisms are made of cells and their products.
  • Cells are the basic building units of life.
  • New cells are created by old cells dividing into two.
• Eukaryotic Cell - complex, multicellular organism with membrane-bound nucleus and other membranous organelles; includes plants, animals, fungi, protists, and some algae.
• Prokaryotic Cell - simple, unicellular organism without membrane-bound nucleus and other membranous organelles; includes bacteria and archaea.
• Heterotrophs - derive their energy from other organism
• Autotrophs - photosynthetic organisms that produce food on their own using nonliving nutrients and sunlight.
• Major Parts of a cell

  • Cell Membrane
  • Cytoplasm
  • Nucleus

  
• Cell membrane/plasmalemma - a covering for the cell, impermeable to harmful substances and permeable to beneficial ones.
• it is composed of double layer of phospholipids and associated proteins - plasmalemma
• HYDROPHILIC head (water liking) is attracted to the water called Polar

  
• HYDROPHOBIC tails (water fearing) are not attracted to the water called Non Polar

  
• the largest part of the cell that has many cellular inclusions and organelles surrounded by plasma membrane - CYSTOPLASM
• the fluid portion of the cytoplasm that represents about 55% of cell volume - CYTOSOL
• CENTRIOLES - Pair of cylindrical organelles in the centrosome, consisting of triplets of parallel microtubules

  
• Microtubules are thin, hollow tube-like structures commonly found inside the plasma membrane. They regulate the addition of cellulose to the cell wall
• Microfilaments are long, protein filaments arranged in bundles. they play an important role in cyclosis, the streaming movement of the cytoplasm
• Spindle fibers are microtubules extending from the centrosome to chromosomes and other parts of the cell. Assist in the separation of chromosomes during cell division

  
• Cilia are the extensions of the plasma membrane containing doublets of parallel microtubules; 10 μm in length. It moves materials over the surface of cells

  
• Flagellum - an extension of the plasma membrane containing doublets of parallel microtubules; 55 μm in length. In humans, this is responsible for the movement of spermatozoa

  
• Microvilli - an extension of the plasma membrane containing microfilaments. This increases the surface area of the plasma membrane for absorption and secretion; modified to form sensory receptors

  
• Peroxisomes - contain the enzyme catalase, which detoxifies peroxide through chemical reactions, converting it to oxygen and water

  
• The inner membranes of the mitochondria has many tube-like in foldings called “cristae”
• Mitochondria - the process of cellular respiration takes place . Powerhouse of the cell

  
• Plastids are double membrane-bound organelles found inside plants and some algae.
• Types of Plastids (PPLEACCE 8)

  • Proplastid

  • Leucoplast

  • Elioplast

  • Amyloplast

  • Chromoplast

  • Elaioplast

  • Proteinoplast

  • Chloroplast

  
• the outer most membrane which is smooth is readily permeable to solutes — Mitochondria
• Amyloplasts are leukoplasts specialized for storage of starch granules.
• Chloroplasts are plastids that contain chlorophyll pigments and carry out photosynthesis.
• Elioplasts are colorless, nonphotosynthetic plastids that store lipids (oil droplets).
• Leucoplasts are colorless plastids that do not contain any pigment or perform photosynthesis.
• Proteinoplasts are plastids containing protein crystals or inclusions.
• Rough ER has ribosomes attached to its surface and functions in protein synthesis and modification.
• Ribosomes are small structures composed of RNA and proteins found in all living cells where protein synthesis occurs.
• Smooth ER lacks ribosomes on its surface and functions in detoxification reactions, lipid metabolism, and calcium ion homeostasis.
• It receive vesicles from the endoplasmic reticulum the secretory vesicle is exported to the outside of the cell for its own use. Golgi Bodies
• Endoplasmic Reticulum — is a system of narrow tubes and sheets of membrane forming a network throughout the cytoplasm
• It increase size and surface area of the cell. are also filled with a watery CELL SAP. Vacuoles
• Lysosomes • Suicide bag of the cell
• It is found along the central part of the cell control center where the chromatin material is found. Nucleus