Organisation
Cell organisation
Cell Organisation:
- Cells – the basic building blocks of all living organisms The digestive system
- Tissues – groups of cells with similar structure and functions Enzymes
- Organs – groups of tissues that perform a specific function
Food groups and tests
- Organ systems – organs are organised into organ systems
- Organisms – the different organ systems make up organisms The heart and blood vessels
Heart disease
The Digestive System:
- Salivary Glands The lungs
o The saliva acts as a lubricant, making it easier to swallow food. Disease
o It contains amylase, a carbohydrase that breaks down starch.
Cancer
- Oesophagus
o Moves food along to the stomach by peristalsis. Plant cell organisation
o The lining of the tube secretes mucus to lubricate the bolus of Transpiration and translocation
food. Transpiration rates
- Stomach
o A muscular bag that churns the food and mixes it with Guard cells
hydrochloric acid and protease enzyme.
o The protease (pepsin) breaks down proteins
o The acid kills bacteria and creates good conditions for the enzyme to work in.
- Small Intestine
o This tube produces the 3 types of enzymes itself to break down fat, starch and protein, but it
also gets chemicals from the pancreas and the gall bladder.
o This is also where the digested food is absorbed out of the digestive system into the blood.
- Pancreas
o Produces 3 types of enzymes (carbohydrase, protease and lipase), which break down starch,
protein and fat.
o The liquids secreted pass down the pancreatic duct into the small intestine
o No food goes into this organ.
- Liver
o Produces bile, which emulsifies fat.
o The bile is stored in the gall bladder
o Bile neutralises stomach acid and emulsifies fats.
- Gall Bladder
o Bile is stored here
o It passes down the bile duct into the small intestine
- Large Intestine
o Any food that has not been digested or absorbed enters this wide tube.
o Water is absorbed from this waste into the blood, and the waste is dried out.
- Rectum
o Waste is stored here before egestion
o More water is absorbed from the waste, creating faeces.
- Anus
o Faeces are egested from the body here.
o The exit is controlled by 2 rings of muscles called the sphincters.
1
, Enzymes:
Enzyme Substance Broken down into
- Every enzyme has an active site with
Carbohydrase Carbohydrate Sugars
a unique shape that fits onto the
Protease (e.g. pepsin) Proteins Amino acids
substance involved in a reaction.
Lipase Lipids (fats and oils) Fatty acids and
- The substrate forms a complex with glycerol
the active site, and then the enzyme
breaks down the substrate into products.
- Factors that affect the rate of enzyme actions:
o Temperature
§ If it is too hot, the enzyme will denature
§ The higher the temperature, the faster the reaction
o pH
§ depends on the enzyme; they all have different optimum pHs
§ The further from ideal pH, the slower the reaction
o Surface area of substrate
§ The larger the surface area, the faster the reaction
o Concentration of enzyme and substrate
§ The higher the concentration the faster the reaction
Food Groups and Tests:
- Carbohydrates: Sugars
o Made from monosaccharides such as glucose, fructose, and galactose.
o Used as the main respiratory substrate.
- Carbohydrates: Starch
o Made from a polymer of glucose
o Used as energy storage in plants, digested to glucose in animals so it is a source of energy
- Protein
o Made of a chain of amino acids
o Required for growth and repair, makes enzymes, some hormones and structural components
like collagen.
- Lipids
o Made from three fatty acids and glycerol
o Used for energy storage.
Food tests:
- Starch – iodine solution
o Use a pipette to add 2 drops of the test solution to a well in a spotting tile
o Add 2 drops of iodine to the solution and record the colour observed.
o The positive test for starch is a blue-black colour
- Sugars – benedict’s reagent
o Add 1cm³ of the test solution to a test tube
o Add 1cm³ of Benedict’s reagent to this. Place the test tube
o Place the test tube into the hot water bath for 5 minutes.
o Observe and record the colour produced.
o The positive test for sugar is a change from clear blue to brick red precipitate (with various
colours through green à brick red)
2
Cell organisation
Cell Organisation:
- Cells – the basic building blocks of all living organisms The digestive system
- Tissues – groups of cells with similar structure and functions Enzymes
- Organs – groups of tissues that perform a specific function
Food groups and tests
- Organ systems – organs are organised into organ systems
- Organisms – the different organ systems make up organisms The heart and blood vessels
Heart disease
The Digestive System:
- Salivary Glands The lungs
o The saliva acts as a lubricant, making it easier to swallow food. Disease
o It contains amylase, a carbohydrase that breaks down starch.
Cancer
- Oesophagus
o Moves food along to the stomach by peristalsis. Plant cell organisation
o The lining of the tube secretes mucus to lubricate the bolus of Transpiration and translocation
food. Transpiration rates
- Stomach
o A muscular bag that churns the food and mixes it with Guard cells
hydrochloric acid and protease enzyme.
o The protease (pepsin) breaks down proteins
o The acid kills bacteria and creates good conditions for the enzyme to work in.
- Small Intestine
o This tube produces the 3 types of enzymes itself to break down fat, starch and protein, but it
also gets chemicals from the pancreas and the gall bladder.
o This is also where the digested food is absorbed out of the digestive system into the blood.
- Pancreas
o Produces 3 types of enzymes (carbohydrase, protease and lipase), which break down starch,
protein and fat.
o The liquids secreted pass down the pancreatic duct into the small intestine
o No food goes into this organ.
- Liver
o Produces bile, which emulsifies fat.
o The bile is stored in the gall bladder
o Bile neutralises stomach acid and emulsifies fats.
- Gall Bladder
o Bile is stored here
o It passes down the bile duct into the small intestine
- Large Intestine
o Any food that has not been digested or absorbed enters this wide tube.
o Water is absorbed from this waste into the blood, and the waste is dried out.
- Rectum
o Waste is stored here before egestion
o More water is absorbed from the waste, creating faeces.
- Anus
o Faeces are egested from the body here.
o The exit is controlled by 2 rings of muscles called the sphincters.
1
, Enzymes:
Enzyme Substance Broken down into
- Every enzyme has an active site with
Carbohydrase Carbohydrate Sugars
a unique shape that fits onto the
Protease (e.g. pepsin) Proteins Amino acids
substance involved in a reaction.
Lipase Lipids (fats and oils) Fatty acids and
- The substrate forms a complex with glycerol
the active site, and then the enzyme
breaks down the substrate into products.
- Factors that affect the rate of enzyme actions:
o Temperature
§ If it is too hot, the enzyme will denature
§ The higher the temperature, the faster the reaction
o pH
§ depends on the enzyme; they all have different optimum pHs
§ The further from ideal pH, the slower the reaction
o Surface area of substrate
§ The larger the surface area, the faster the reaction
o Concentration of enzyme and substrate
§ The higher the concentration the faster the reaction
Food Groups and Tests:
- Carbohydrates: Sugars
o Made from monosaccharides such as glucose, fructose, and galactose.
o Used as the main respiratory substrate.
- Carbohydrates: Starch
o Made from a polymer of glucose
o Used as energy storage in plants, digested to glucose in animals so it is a source of energy
- Protein
o Made of a chain of amino acids
o Required for growth and repair, makes enzymes, some hormones and structural components
like collagen.
- Lipids
o Made from three fatty acids and glycerol
o Used for energy storage.
Food tests:
- Starch – iodine solution
o Use a pipette to add 2 drops of the test solution to a well in a spotting tile
o Add 2 drops of iodine to the solution and record the colour observed.
o The positive test for starch is a blue-black colour
- Sugars – benedict’s reagent
o Add 1cm³ of the test solution to a test tube
o Add 1cm³ of Benedict’s reagent to this. Place the test tube
o Place the test tube into the hot water bath for 5 minutes.
o Observe and record the colour produced.
o The positive test for sugar is a change from clear blue to brick red precipitate (with various
colours through green à brick red)
2
