(module2-lecture) ANAPHY-CELL STRUCTURES AND THEIR FUNCTIONS

• Cells- the basic living unit of all organisms; each cell is a highly organized unit
• Organelles- specialized structures in cells that perform specific functions
• Cytoplasm- jelly-like substance that holds organelles and is enclosed by cell membrane (plasma membrane)
• Enumerate the functions of the cell:

  • cell metabolism and energy use
  • synthesis of molecules
  • communication
  • reproduction and inheritance
• Cell membrane/Plasma membrane- it is the outermost component of the cell that forms a selective barrier between intracellular (materials inside the cell) and extracellular substances (materials outside the cells)
• Enumerate 2 major molecules

  • phospholipids
  • protein
• Phospholipids- forms a double layer that contains 2 regions:

  • Polar region- "heads", exposed to H2O (hydrophilic)
  • Nonpolar region- "tails", away from H2O (hydrophobic)
• Protein

  • floats among the phospholipid molecules and in some, extend from inner to the outer surface of cell membrane
  • function as membrane channels, carrier molecules, receptor molecules, enzymes, or structural supports in membrane
• Other components

  • Cholesterol
  • Carbohydrates
• Cholesterol- provide added strength & stability by limiting the amount of movement of phospholipids
• Carbohydrates- may be bound to some CHON molecules, modifying their functions
• Enumerate the 14 organelles

  • nucleus
  • ribosomes
  • rough endoplasmic reticulum
  • smooth endoplasmic reticulum
  • Golgi apparatus
  • secretory vesicle
  • lysosome
  • peroxisome
  • mitochondria
  • microtubule
  • centrioles
  • cilia
  • flagella
  • microvilli
• Nucleus

  • contains of genetic material of cell (DNA) and nucleoli
  • site of RNA synthesis & ribosomal subunit assembly
• Ribosome- site of protein synthesis
• Rough endoplasmic reticulum

  • has may ribosomes attached
  • site of protein synthesis
• Smooth endoplasmic reticulum

  • site of lipid synthesis
  • participates in detoxification
• Golgi apparatus- modifies CHON structure & packages CHON in secretory vesicles
• Secretory vesicle

  • contains materials produced in cell
  • formed by the golgi apparatus
  • secreted by exocytosis
• Lysosome- contains enzymes that digest material taken into the cell
• Peroxisome- breaks down fatty acids, amino acids, and hydrogen peroxide
• Mitochondria- powerhouse of the cell; site of aerobic respiration and the major site of ATP synthesis
• Microtubule

  • supports cytoplasm
  • assists in cell division and forms components of cilia & flagella
• Centrioles- facilitate the movement of chromosomes during cell division
• Cilia- located on cell surface that move substances over surfaces of certain cells
• Flagella- proper sperm cells
• Microvilli- increase surface are of a certain cells
• Passive membrane transport- does not require the cell to expend energy, this includes; diffusion, osmosis, and facilitated diffusion
• Active membrane transport- does require the cell to expend energy, usually in the form of ATP. This includes active transport, secondary active transport, endocytosis, and exocytosis
• Diffusion- is the movement of a solute from an are of high concentration to an area of lower concentration within a solvent. At equilibrium, the distribution of molecules is uniform
• Concentration gradient- is the concentration of a solute at one point in a solvent minus the concentration of that solute at another point in the solvent divided by the distance between the points
• Osmosis- is the diffusion of water across a selectively preamble membrane. Osmotic pressure is the force required to prevent movement of water across a selectively preamble membrane
• Facilitated diffusion- this moves substances from a higher to lower concentration and does not require energy in the form of ATP
• Carrier-mediated transport- the movement of a a substance across a membrane by means of a carrier molecule. The substances transported tend to be large, water-soluble molecules or ions
• Active transport- moves substances from a lower to higher concentration and requires ATP
• Secondary active transport- uses energy from one substances moving down its concentration gradient to move another substance across the cell membrane. In co-transport, both substances move in the same direction; in counter-transport, they move in opposite directions
• Endocytosis- movement of materials into cells by the formation of a vesicle

  • receptor-mediated endocytosis- involves cell receptors attaching to molecules
  • phagocytosis- movement of solid material into cells (cell-eating)
  • pinocytosis- the materials ingested is much smaller and is in solution (cell-drinking)
• Exocytosis- the selection of materials from cells by vesicle formation
• Cytoskeleton- is a cell's framework. This is vital for providing support, holding organelles in place and enabling the cell to change shape
• Enumerate the 3 types of cytoskeletal

  1. microtubules
  2. intermediate filaments
  3. microfilaments
• Microtubules- largest diameter; provide structural support, assist in cell division, forming essential components of certain organelles (cilia and flagella)