The nature and variety of living organisms

• What are the 8 life processes?

  movement

  respiration

  sensitivity

  Homeostasis

  growth

  reproduction

  excretion

  nutrition
• What are the 5 different living organisms?

  1. prokaryote 2. Fungi 3. Plants 4. Animals 5. Protoctists
• Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
• Osmosis is the movement of water molecules from an area of high concentration of water molecules to an area of low concentration of water molecules through a partially permeable membrane
• How is active transport different from osmosis and diffusion?

  • it is an active process
  • it goes against the concentration gradient
• What is active transport?

  • It is an active process
  • the movement of substances from an area of low concentration to an area of high concentration against the concentration gradient
  • uses energy from respiration
  • involves a protein in the cell membrane
• What do you find in an animal cell?

  • nucleus
  • cell membrane
  • mitochondria
  • ribosomes
  • cytoplasm
• What do you find in a plant cell?

  • Cell membrane
  • cytoplasm
  • cell wall
  • vacuole
  • chloroplasts
  • mitochondria
  • nucleus
  • ribosomes
• Plant features:

  • multicellular
  • have chloroplasts meaning they can photosynthesise
  • Their cells have cell walls made from cellulose
  • they store carbohydrates as sucrose or starch
• Animal cell features:

  • multicellular
  • cant photosynthesise and don’t have chloroplasts
  • their cells don’t have cell walls
  • have nervous coordination meaning they can respond rapidly to changes in their environment
  • can move from one place to another
  • store carbohydrate in the form of glycogen
• Fungi


  • Some are single-celled
  • Others have a body called a mycelium, which is made up of hyphae (thread-like structures)
  • Hyphae contain lots of nuclei
  • Can't photosynthesise
  • Cells have cell walls made of chitin
  • Most feed by saprotrophic nutrition - they secrete extracellular enzymes into the area outside their body to dissolve their food, so they can then absorb the nutrients
  • Can store carbohydrate as glycogen
• Examples of fungi: yeast or Mucor
• Protoctists:

  • Single Celled and microscopic
  • some have chloroplasts and are similar to plant cells
  • others are more like animal cells
• protoctists examples:

  chlorella or Amoeba
• Bacteria:

  • single Celled and microscopic
  • don't have a nucleus
  • have A circular chromosome of DNA
  • some can photosynthesise
  • feed off other organisms, both living and dead
• Viruses

  • smaller than bacteria, particles rather than cells
  • can only reproduce inside living cells
  • a virus is a parasite- depends on another organism to grow and reproduce
  • infect all types of living organism
  • come in different shapes and sizes
  • dont have a cellular structure - have a protein coat around some genetic material
• Example of a virus: Influenz, HIV
• Pathogens are organisms that cause disease. They include some fungi, protoctists and bacteria. Viruses are also pathogens even though they’re not living organisms
• Cells can be eukaryotic or prokaryotic. eukaryotic cells are complex and include animal and plant cells. Prokaryotic cells are smaller and simpler like bacteria
• Organelles are tiny structures within cells that you can only see through a microscope
• Nucleus

  • an organelle that contains the genetic material that controls the cell’s activities. It is surrounded by its own membrane
• Cell membrane

  • forms the outer surface of the cell and controls the substances that go in and out
• Cytoplasm

  • a gel like substance where most of the cells chemical reactions happen. It contains enzymes which control these reactions
• Mitochondria

  • small organelles where most of the reactions for anaerobic respiration take place. respiration transfers energy that the cell needs to work
• Ribosomes

  • small organelles where proteins are made in the cell
• Chloroplasts

  • where photosynthesis occurs. Chloroplasts contain a green substance called chlorophyll which is used in photosynthesis
• Cell wall

  • a rigid structure made of cellulose which surrounds the cell membrane. it supports the cell and strengthens it
• Vacuole

  • a large organelle that contains cell sap, it helps to support the cell
• Plant cells


  • Usually have all the organelles
• Chloroplasts


  Where photosynthesis happens, which makes food for the plant. Contain chlorophyll used in photosynthesis.
• Cell wall


  A rigid structure made of cellulose, which surrounds the cell membrane. It supports and strengthens the cell.
• Vacuole


  A large organelle that contains cell sap (a weak solution of sugars and salts). It helps to support the cell.
• Tissue


  A group of similar cells that work together to carry out a particular function
• Plant tissues


  • Xylem (for transporting water and mineral salts)
  • Phloem (for transporting sucrose and amino acids)
• A tissue can contain more than one cell type
• Organ


  A group of different tissues that work together to perform a function
• Organs


  • Lungs in mammals
  • Leaves on plants
• Organ system


  Organs working together to do a different job e.g the digestive system in mammals
• Most cells are specialised to carry out a certain function so their structures can vary

  e.g red blood cells for carrying oxygen and white blood cells for defending the body against disease
• Cell differentiation is the process by which a cell changes to become specialised for its job, as cells change they develop different organelles and turn into different types of cells. this allows them to carry out specific functions