CC2

• Roles of membranes

  • Internal transport system
  • Separation from area of cytoplasm
  • Large surface area to attached enzymes
  • ATP synthesis
• Nucleus

  • Contains DNA which codes for protein synthesis
  • Nuclear envelope is a double membrane
  • Nuclear pore allows mRNA, rRNA and nucleotides out
  • Nucleoplasm contains chromatin which is made up of DNA and histone proteins
  • Nucleosome is less than 2 strands of DNA wrapped around histone proteins
  • Nucleolus synthesis rRNA
• Mitochondria

  • Rod shaped
  • Double membrane
  • Most reaction for aerobic respiration happen
  • ATP is produced on the cristae
  • Matric contains proteins, lipids and DNA
• Endoplasmic reticulum

  • Double membrane
  • Has folds called cisternae
  • Extends from the nuclear membrane
• Rough endoplasmic reticulum

  • Studded with ribosomes
  • Site of protein synthesis
  • Transport system
• Smooth endoplasmic reticulum

  • No ribosomes
  • Site of phospholipid synthesis
  • Packages protein into vesicles
• Golgi body

  • Formed by the Rough ER pinching off and fusing with the golgi membrane
  • Transports and modifies proteins
  • Secretes enzymes and carbohydrates
  • Transports and stores lipids
  • Forms lysosomes
• Exocytosis

  1. DNA codes for protein synthesis
  2. mRNA leaves the nucleus and goes to RER
  3. Proteins are synthesised
  4. A membrane forms around the protein
  5. Transport vesicle fuses with the the golgi membranes and sheds its contents inside
  6. Golgi body modifies proteins
  7. Protein is packaged into a vesicle
  8. Vesicle travels to cell membrane, fuses with it and sheds its content outside of the cell by exocytosis
• Lysosomes

  • Vesicles which contain hydrolytic enzymes that can digest and destroy worn out organelles and pathogens
• Ribosomes

  • Found in eukaryotes (80S) and prokaryotes (70S)
  • Found on the rough endoplasmic reticulum and singly in the cytoplasm
  • Made of a large and small subunit
  • Manufactured from rRNA
  • Important in protein synthesis
• Centrioles

  • Only in animal cells
  • Located just outside the nucleus in the centrosome
  • 2 tubules at 90 degrees
  • In cell division, they divide and move to opposite poles of the nucleus where they synthesise the microtubules of the spindle fibres which separate the chromosomes
• Chloroplast

  • Double membrane
  • Contains thylakoids arranged in stacks
  • Each stack is known as a granum
  • Reactions for photosynthesis take place in the membranes and stroma
• Vacuole

  Fluid-filled sacs that act as storage areas for chemicals

  keep the cell rigid by taking in water,

  large

  permanent
• Cell wall

  Made of cellulose,

  provides strength

  permeable to water,

  contains pores called plasmodesmata
• Tissue

  Aggregation of similar cells carrying out the same function
• Organ

  Aggregation of several tissues carrying out a function
• Organ system

  Groups of organs working together to carry out a function
• Organism

  Collection of organ systems, tissues, and cells working together to form an independent living thing
• Types of muscle tissue

  • Smooth
  • Cardiac
  • Skeletal
• Virus

  So small they can only be seen by electron microscope, not cells, no cytoplasm/organelles/chromosomes, invade living cells to replicate
• Virus structure

  • Contain DNA or RNA (not both), nucleic acid surrounded by protein coat (capsid)
• The nuclear envelope that surround the nucleus is a double membrane and contains pores to allow mRNA, rRNA and nucleotides out.
• Nuclear pores allow mRNA, rRNA and nucleotides out.
• The nucleolus synthesises rRNA which will be used to make ribosomes
• Nucleoplasm contains chromatin which is made up of histone proteins and DNA.
• The nucleosome is composed of less than 2 strands of DNA which are wrapped around 8 histone proteins.
• What is chromatin made out of?

  DNA & Histone proteins
• Epithelial tissue is made of cells sitting on a basement membrane an is the site of exchange and protection.
• Name 5 types of epithelial tissue

  • Columnar
  • Cuboidal
  • Ciliated
  • Squamous
  • Statified
• Columnar epithelium are tall cells. They line the small intestine and contain microvilli to increase the surface area for absorption.
• Cuboidal epithelium are wide cells. They line the proximal coulated tubules of the kidney and are found in the slaivary ducts to reabsorb useful products.
• Squamous epithlium is very thin. They line the alveoli to create a short diffusion distance
• Stratified epithelium is made of layer of cells where the bottom layer is attached to the basement membrane and the top layers are dead. This means the layers can be worn away easily without causing damage. It is found in skin and the oesophagus
• Cilliated epithelium contain a border of cilia which can move mucus up the trachea and move eggs through the fallopian tubes.
• Connective tissue connects, supports and separates tissues and organs.
• Name 6 types of connective tissue

  • Loose connective tissue
  • Fibrous connective tissue
  • Adipose tissue
  • Cartilage
  • Blood
  • Bone
• Loose connective tissue is found between layers of tissue
• Fibrous connective tissue is found in tendons
• Bones make up the skeleton
• Adipose tissue is a store of fat that is used for energy, protection and insulation. In aquatic animals it can be used for buoyancy.