Cells

• Lysosomes contain digestive enzymes that break down waste materials inside the cell.
• Nucleus Is the Control centre for the cell
• Lysosome Is an Organelle containing digestive enzymes which break down waste material inside the cell.
• Peroxisomes is Degrade toxic molecules inside the cell
• Nucleus

  Control centre for the cell, contains DNA which is the genetic material and blueprint for cell activity, surrounded by the nuclear envelope with nuclear pores for molecule movement
• Cells compartments

  • Nucleus
  • Cytoplasm
  • Plasma membrane
• Cytoplasm organelles

  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes
  • Peroxisomes
  • Mitochondria
• Cytoplasm

  Consists of organelles which are cellular "organs" mostly surrounded by a membrane, cytosol is a jelly-like fluid, inclusions are chemical substances like stored nutrients and pigments
• Rough ER packages and transports proteins to the Golgi apparatus in transport vesicles
• DNA ➔ RNA ➔ Protein


  DNA is the genetic code, mRNA is produced from DNA blueprint and directs protein production, proteins carry out biological functions
• Ribosomes

  • Needed for protein synthesis, free ribosomes in cytosol make proteins for cytosol function, membrane-bound ribosomes create proteins for membrane or outside cell function
• Lysosomes & peroxisomes

  Membrane-bound vesicles containing enzymes, lysosomes break down organic material inside the cell, peroxisomes degrade toxic molecules inside the cell
• Golgi apparatus


  Series of curved sacs that modify, sort, and transport proteins to their final destinations
• Endoplasmic reticulum (ER)


  Extensive network of membranes joining the nucleus, two types: rough ER covered in ribosomes making proteins and smooth ER with specialized functions in certain cells
• Smooth ER has specialized functions like detoxification, hormone production, and calcium release
• Which proteins are made in the rough ER?


  Proteins
• Mitochondria are the power plant of the cell carrying out aerobic cellular respiration
• Adenosine triphosphate (ATP) stores released energy from nutrient conversion as chemical bonds
• Adenosine triphosphate (ATP)


  • The chemical bond between the last two phosphate groups is broken
  • Energy is released when terminal phosphate group is removed
• Aerobic cellular respiration

  1. Nutrients in food converted to CO2 and H2O

  2. Released energy is stored as ATP (adenosine triphosphate)
• Mitochondria is the power plant of the cell
• Mitochondria carries out aerobic cellular respiration
• Protein synthesis

  1. Proteins are modified within the Golgi compartments

  2. Proteins are then packaged within different vesicle types, depending on their ultimate destination
• ATP is used for Synthesis of new compounds (eg. proteins), Transport of molecules across membranes, Mechanical work (eg. contraction of muscle cells)
• The plasma membrane has a double layer of phospholipids with embedded proteins
• Plasma membrane functions: Forms a mechanical barrier, Selective permeability, Electrochemical gradient, Communication & cell signalling
• Phospholipids

  • Two layers of phospholipids
  • Phospholipids have a “head” and two “tails” - The phosphate head is hydrophilic, The fatty-acid tails are hydrophobic
• Hydrophilic (lipophobic) - Loves water, Mixes with water like soap, detergent
• The hydrophilic heads of phospholipids face the watery environment of the ECF and ICF. The hydrophobic tails are sandwiched in the middle, away from water
• Hydrophobic (lipophilic) - Hates water, Don’t mix with water like oil and water
• Osmolarity is the number of solute particles in the solution (i.e., the concentration)
• Diffusion across plasma membrane

  1. Simple diffusion: Penetrating solutes can diffuse through the plasma membrane unaided

  2. Facilitated diffusion: Non-penetrating solutes can only diffuse across the plasma membrane through carriers or channels
• Transport of molecules across the plasma membrane

  Can be passive or active
• Concentration gradients are differences in concentration across two areas
• Molecules that can pass across the plasma membrane

  • Gases (O2 & CO2)
  • Water
  • Ethanol
  • Ions
  • Glucose & proteins
• The plasma membrane is selectively permeable - only some molecules can pass freely across the membrane
• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration (down the concentration gradient)
• Types of membrane transport

  • Passive transport: Simple diffusion, Facilitated diffusion (channels & carriers), Osmosis
  • Active transport: Primary active transport, Secondary active transport, Vesicular transport (endocytosis & exocytosis)
• Movement of a molecule across the plasma membrane depends on its size and if it can pass through the lipid core of the membrane (i.e., if it is hydrophobic)
• Facilitated diffusion - channel


  Molecules are transported across the cell membrane through a channel protein