P1: Biology- Organisation

• What is a specialised cell?

  When as an organism develops, cells differentiate to form different types of cells
• When do animal cells differentiate?

  Early in life
• When do plant cells differentiate

  throughout their life
• As a cell differentiates:


  -It may change shape

  -Different sub cellular structures develop to allow it to carry out a specific function
• A Sperm cell contains:

  -Tail: to propel the sperm to fertilise the egg

  -Nucleus: Contains one set of genetic material

  -Mitochondria: Provide energy for their journey

  -Acrosome: Contains enzymes to allow the sperm to penetrate the outer layer of the egg
• Sperm cell diagram:

  A) Tail

  B) Mitochondria

  C) Nucleus

  D) Middle Piece

  E) Acrosome

  
• Muscle Cell contains:

  -Nucleus

  -Protein fibres which can contract

  -Many mitochondria for energy
• What does a Motor Neurone cell contain?

  -Cell body

  -Dendrites

  -Axon

  -Sheath
• Label a motor neuron cell:

  .

  A) Dendrite

  B) Axon

  C) Nucleus

  D) Cell Body

  E) Myelin

  F) Axon terminal

  
• Examples of specialised cells in plants...

  -Phloem

  -Xylem

  -Root Hair cell
• How are xylem specialised?

  -Cell wall is strengthened by a substance called lignin

  -End walls break down to form hollow tubes
• How are phloem specialised?

  -End walls of cells allow sugars through but support cells

  -Phloem cells are organised into tubes

  -Have companion cells
• How are root hair cells specialised?

  -Have lots of mitochondria for active transport of materials

  -Long protection to increase surface area to absorb water of minerals
• What is a tissue?

  A tissue is a group of cells with a similar structure and function which all work together to do a job
• What job do muscle cells do?

  Contact to produce movement
• What do glandular tissues do?

  produces enzymes and hormones
• What does the epithelial tissue do?

  Covers organs
• What is an organ?

  A group of different tissues which all work together to preform a specific job
• What is an organ system?

  A group of organs which work together to do a specific job
• Lots of organ systems make up...


  an organism
• What tissues are in the stomach?

  -Epithelial tissue

  -Glandular tissue

  -Muscle tissue
• What is an enzyme?

  A biological catalysts made of proteins which speed up chemical reactions in living organisms
• Properties of an enzyme:

  -All large proteins

  -Contain a space called the active site

  -Each enzyme is specific to a substrate

  -Work best at a specific temperature and pH called the optimum
• The 'lock and key' theory:

  .

  A) Substrate

  B) Active site

  C) Enzyme

  D) Enzyme-substrate complex

  E) Products

  F) Enzyme

  
• What do high temperatures and extreme pH do to an enzyme?

  Make it change shape, called denaturing
• What happens after an enzyme has been denatured?

  They no longer work as the substrate no longer fits into the enzymes active site
• Where are enzymes produced in the body?

  In specialised cells in glands and in the lining of the gut
• Process of an enzyme:

  1.Pass out of cells into the digestive system

  2.Come into contact with food molecules

  3.Catalyse the breakdown of large insoluble food molecules into small soluble food molecules
• Digestive enzymes:

  -Protease

  -Lipase

  -Carbohydrase
• Where is amylase produced?

  In the salivary glands and the pancreas
• What is amylase?

  A carbohydrase
• What does amylase break down?

  Starch into sugar (maltose)
• Where is protease produced?

  In the stomach, pancreas and small intestine
• What does protease break down?

  Proteins into amino acids or peptides
• Where is lipase produced?

  pancreas and small intestine
• What does lipase break down?

  Lipids (fats) into fatty acids and glycerol
• Where is bile made and stored?

  Made in the liver and stored in the gall bladder
• What is bile?

  An alkaline to neutralise the hydrochloric acid from the stomach
• What does bile do?

  Breaks up fats to form small droplets, increasing the surface area for enzymes to act on which increases the rate fats are broken down by lipase
• What is blood?

  A tissue