Biology

• ANIMALS

  • Multicellular organism
  • Stores carbohydrates as Glycogen
  • Has nervous coordination to move from one place to another
  • Structure:
  • Nucleus - membrane-bound organelle containing chromosomes
  • Mitochondria - protein to carry out cell respiration 
  • Cytoplasm - fills the cell to facilitate chemical reactions and holds organelles in place
  • Cell membrane - phospholipid bilayer that controls movement of substances into and out of cells
  • Example: Mammals, Insects 
• PLANTS

  • Multicellular organism
  • Stores carbohydrates as Starch
  • Structure: 
  • Nucleus - membrane-bound organelle containing chromosomes
  • Chloroplast - protein to carry out Photosynthesis 
  • Mitochondria - protein to carry out cell respiration 
  • Cytoplasm - fills the cell to facilitate chemical reactions and holds organelles in place
  • Vacuole - storage organelle for Water and dissolved substances 
  • Cell membrane - phospholipid bilayer that controls movement of substances into and out of cell
  • Cell wall - made of Cellulose to protect and maintain the shape of cell 
  • Example: Herbaceous Legume
• Fungi


  • Both multicellular and unicellular
  • Stores carbohydrates as Glycogen
  • Organised into a Mycelium - thread-like structure called Hyphae that contains many Nuclei
  • Feeds by extracellular secretion - the release of digestive enzymes onto food to absorb organic products (saprotrophic nutrition)
• Fungal cell structure


  • Nucleus - membrane-bound organelle containing chromosomes
  • Mitochondria - protein to carry out cell respiration
  • Cytoplasm - fills the cell to facilitate chemical reactions and holds organelles in place
  • Cell membrane - phospholipid bilayer that controls movement of substances into and out of cell
• Fungi


  • Mucor
  • Yeast
• PROTISTS

  • Microscopic unicellular organism
  • Structure of protists are varied
  • Example: Amoeba (animals)
  • Chlorella (plants)
• BACTERIA

  • Unicellular organism
  • Feeds on living or dead organisms
  • Structure:
  • Nucleoid - single circular strand of DNA
  • Plasmid - independent small circle of DNA
  • Plasma membrane - phospholipid bilayer that controls movement of substances into and out of cell 
  • Cell wall made of Peptidoglycan to protect and maintain shape of cell 
  •  *Pili protein filmanets that facilitates cell adhesion and conjugation 
  •  *70S Ribosomes site of protein synthesis 
  •  *Flagellum elongated inflexible structure that rotates to move cell
• VIRUS

  • Non-living organism
  • Parasitic as they can only reproduce inside living host cells
  • Structure:
  • Capsid - contains genetic material (DNA or RNA)
  • Viral Envelope - made from fatty lipid molecules taken from host cells to avoid host immune system
  • Surface Protein - proteins that help recognise and bind to host cells for infection
• ORGANELLESCell structures specialised with a specific function CELLSBasic functional and structural units in a living organismTISSUESComposed of same cells carrying out same functionORGANSComposed of different tissues carrying out a particular functionSYSTEMSComposed of organs carrying out body function
• Nucleus


  Membrane-bound organelle that contains genetic material
• Cytoplasm


  Material that fills cell to facilitate chemical reactions and hold organelles in place
• Cell membrane


  Phospholipid bilayer that controls the movement of substances into and out of cell
• Cell wall


  External to cell membrane that protects and maintains the shape of cell (prevents cell from bursting)
• Mitochondria


  Membrane-bound organelle that carries out cellular respiration
• Chloroplast


  Plastid in plants that carries out photosynthesis
• Ribosomes


  Site of protein synthesis
• Vacuole


  Storage organelle in plants to store Water and dissolved substances
• Plant cell structure 


  Fixed shape, Large vacuole, Cell wall, Stores carbohydrates as Starch, Contains Chloroplasts to conduct photosynthesis, Multicellular organism, Nucleus, Mitochondria, Cytoplasm, Cell membrane
• Animal Cell structure 


  No fixed shape, Little or no vacuole, No cell wall, Stores carbohydrates as Glycogen, Does not contain Chloroplasts (cannot conduct photosynthesis),Multicellular organism, Nucleus, Mitochondria, Cytoplasm, Cell membrane
• STEM CELLS: Unspecialised cells that has two key qualities:s

  • Self-renewal: capable of continuous division and replication
  • Potency: capacity to differentiate into specialised cell type
• 
  

  • Cell types that are not capable of self-renewal are non-stem cells (e.g tissues)
  • As these tissues cannot be regenerated or replaced, stem cells are a viable therapeutic option when these tissues are damaged
• Advantages to stem cells in medicine

  • Medical benefits in therapeutic cloning to heal diseases and chronic illnesses.
• Advantages to stem cells in medicine

  • Potential in discovering treatments and cures for diseases such as Parkinson's disease and cancer.
• Advantages to stem cells in medicine

  • Ability to test potential drugs and medicine without the use of animals or human simulation.
• Advantages to stem cells in medicine

  • Reduced risk of rejection as patient's own cells can be used.
• Disadvantages to stem cells in medicine

  • Ethical issues surrounding the use of embryonic stem cells involving the destruction of human embryos.
• Disadvantages to stem cells in medicine

  • Uncertainties regarding long-term effects
• Disadvantages to stem cells in medicine

  • Rejection by patient's body as certain stem cells are obtained from embryos instead of their own cells.
• Disadvantages to stem cells in medicine

  • Difficulty in controlling differentiation of pre-specialised cells into desired cell.
• Stem cells have been used to treat conditions such as Parkinson’s disease, diabetes, heart failure, spinal cord injuries, burns, blindness, deafness, osteoarthritis, multiple sclerosis, Alzheimer’s disease, stroke, cancer, kidney damage, liver cirrhosis, lung diseases, skin grafts, bone marrow transplants, blood disorders, immune system deficiencies, infertility, and HIV/AIDS.
• Cell differentiation

  • All specialised cells and organs constructed from them have developed as a result of cell differentiation
  • Undifferentiated cells receive signals which stimulates the expression of genes for cell to undergo change in metabolism and shape, enabling them to carry out specialised functions - forming a specialised cell
  • Therefore, this allows organism to develop cells necessary to grow and develop as specialised cells can undertake specific functions
  • For example, stem cells can differentiate into nerve cells to carry electrical impulses, hence allowing muscle movement
• CELL DIFFERENTIATION: Process involving the development of newly formed cells into more specialised and distinct cells as they mature
• Chemical elements


  CARBOHYDRATE-Carbon, Oxygen and Hydrogen
• Chemical elements


  PROTEIN-Carbon , Oxygen, Hydrogen, Sulfur and Nitrogen
• Chemical elements 


  LIPIDS-Carbon, Oxygen and Hydrogen