ATS GCSE Biology - Digestive system & food Key words

• cells


  are the basic building blocks of all living organisms

  
• a tissue

  is a group of cells with a similar structure and function

  
• organs


  are aggregations of tissues performing specific functions

  
• aggregations

  the formation of a number of things into a cluster

  
• organ systems

  organs are organised into these which work together to form organisms

  
• organism


  any individual living thing that can react to stimuli, reproduce, grow, and maintain homeostasis

  
• unicellular organism


  made from one cell

  
• multicellular


  made from many cells

  
• muscular tissue

  contractfor movement

  
• cardiac muscle


  muscle in the heart

  
• glandular tissue


  contains secretory cellsproduce or release substances such as enzymes or hormones

  
• epithelial tissue


  covers surfaces outside and inside the body

  
• stomach


  organ involved with the digestion of foodmuscular tissue - to churn the food and digestive juices togetherglandular tissue - to produce the digestive juicesepithelial tissue - cover the inside and outside of the organ

  
• pancreas


  organ that monitors blood sugar levels, releasing insulin and glucagonproduces enzymes for digestion

  
• digestive system

  organ system to digest food

  
• circulatory system


  to circulate blood around the body

  
• respiratory system


  for gas exchange

  
• exchange surfaces


  large surface areamoist rich blood supplyshort diffusion distancemechanisms to increase concentration gradients (blood moving away from area of exchange)

  
• villi


  found in the small intestine adapted to absorb digested food into the blood plasma

  
• kidney


  organ to filter blood

  
• digestive system


  is an example of an organ system in which several organs work together to digest and absorb food

  
• digestive enzymes

  convert food into small soluble molecules that can be absorbed into the bloodstream

  
• bile

  is made in the liver and stored in the gall bladderalkaline to neutralise hydrochloric acid from the stomachemulsifies fat to form small droplets which increases the surface area for lipase to act

  
• food

  large insoluble molecules which can not be absorbed without being broken into smaller soluble moleculescarbohydrates, proteins and lipids

  
• carbohydrates

  contain carbon, hydrogen and oxygenprovide energy for metabolic reactions

  
• simple sugars


  small carbohydrate units glucose, sucrose

  
• glucose


  single sugarcontain only one sugar unit

  
• sucrose


  two sugar units joined togetherthe everyday sugar

  
• complex carbohydrates


  made up from long chains of simple sugar units bonded togetherstarchcelluloseglycogen

  
• carbohydrate rich food


  bread, pasta, potatoes, rice

  
• starch


  storage carbohydrate in plants

  
• cellulose


  complex carbohydrate that makes up plant and algal cell wallsgives strength

  
• glycogen


  carbohydrate store in animalsin liver and muscles

  
• lipids


  are fats (solids) and oils (liquid)most efficient energy storeused to make cell membranes, hormonesused in nervous system

  
• insoluble


  undigested foodlipids in water

  
• lipid molecule


  three fatty acids and a glycerol moleculeglycerol is always the samethe fatty acids varycarbon, hydrogen and oxygen

  
• lipid rich food

  olive oil, sunflower oil, butter, margarine, cheese, cream

  
• proteins


  used for building up cells and tissuesbasis of all enzymes, hair, nails and musclescarbon, hydrogen, oxygen and NITROGEN

  
• functions of proteins

  structural - muscles and tendonshormones - insulin, FSH, LH, oestrogen, testosteroneantibodies - destroy pathogensenzymes - act as catalysts

  
• protein molecule


  long chains of amino acidsdifferent arrangements of amino acids results in different proteinsspecific 3D shapes from folding chain