Studied by 2 people
Topics covered: White/Black - Organisation in living Organisms Yellow - Human Digestive System Red - The Chemistry of Food Blue - Food Tests Purple - Enzymes Green - Factors affecting Enzyme Action
Organ System
Group of organs with related functions working together to perform body functions. (Circulatory System, Respiratory System)
Organ
Structure made up of a group of tissues, working together to perform specific functions.
Tissue
Group of cells with similar structures, working together to perform a shared function (Epidermal Tissue - Covers surfaces and protects them)
Cell
Basic structural and functional unit of a living organism.
Tissues Found in the Stomach and their Role
Muscular Tissue - To churn food and digestive juices that break down food
Glandular Tissue - To produce the digestive juices that break down food
Epithelial Tissue - Covers the outside of the stomach
Heart (Organ System, Functions, Other organs in that System)
Circulatory & Cardiovascular System
The system pumps blood and hormones around the body
The heart pumps and oxygenates blood
Arteries, veins and capillaries are also involved
Brain (Organ System, Functions, Other organs in that System)
Nervous System
The system carries electrical signals, allowing the body to react
The brain processes information and sends out impulses to coordinate response
Nerves and the Spinal chord are involved
Lungs (Organ System, Functions, Other organs in that System)
Respiratory System
The system takes in oxygen and transports it
The lungs allow air to move in and out of the blood
The trachea, diaphragm, nose and mouth are also involved
Physical Digestion
Breaking large pieces of food into smaller pieces of food (teeth)
Chemical Digestion
Breaking large, insoluble molecules into smaller soluble molecules to increase surface area
Mouth
Digestion begins here. The smell of food triggers salivary glands in your mouth to secrete saliva. Mechanical digestion takes place as chewing breaks food into pieces.
Oesophagus
Carries food to the stomach. It is a long muscular tube. Food is pushed through the oesophagus and into the stomach by means of a series of contractions called peristalsis.
Liver
Processes absorbed food and detoxifies the blood. Makes bile.
Gallbladder
Stores excess bile, before it is released into the small intestine.
Stomach
Contains hydrochloric acid which kills off any excess bacteria. Produces protease enzymes. The muscular walls contract to churn food.
Pancreas
Produces digestive enzymes secreted into the small intestine
Large Intestine
Connects the small intestine to the rectum. Highly specialised organ, responsible for processing waste.
Small Intestine
Produces amylase, protease, and lipase that continue digestion. Soluble products of digestion are absorbed through the walls.
Rectum
Received stool from the large intestine
Uses of proteins in the body
Used to make structural components, hormones, antibodies and enzymes
15-16% of your body mass is proteins
Build up all of the cells and tissues in your body
Structure of Proteins
Long chains make amino acids in different orders. The chains are coiled into specific 3D shapes that enable other molecules to fit into the protein. Made up of Carbon, Hydrogen, Oxygen, and Nitrogen.
Word Equation for the digestion of Proteins
Protein —-(protease)—→ Amino Acids
Uses of lipids in the body
The most efficient source of energy and energy store in your body. Important in cell membranes, as hormones, and in your nervous system. Insulate organs.
Structure of lipids
Made up of Carbon, Hydrogen, and Oxygen. Insoluble in water. Made up of 3 molecules of fatty acids joined to a molecule of glycerol. Different combinations affect state.
Word equation for the digestion of Lipids
Lipids —-(lipase)—→ Fatty acids + Glycerol
Uses of carbohydrates in the body
Provide us with the fuel that makes all the reactions in life possible. They contain the chemical elements Carbon, Hydrogen, and Oxygen
Structure of carbohydrates
All carbohydrates are made out of units of sugar. Glucose and Sucrose are known as simple sugars, and some carbohydrates contain only one of these. Complex carbohydrates such as starch or cellulose are made up of long chains of sugar units bonded together.
Word equation for the digestion of carbohydrates
Carbohydrase + Carbohydrates —→ Sugar Molecules
Stacrh —-(amylase)—> Maltose —-(maltase)—> Glucose
Testing for Glucose
Add Benedicts Solution and heat
Positive result - Brick Red
Negative result - Blue
Testing for Starch
Add Iodine solution
Positive result - Blue black
Negative result - Yellow orange
Testing for Protein
Add Biuret reagent and shake after each drop
Positive result - Lilac
Negative result - Blue
Testing for Lipids
Shake with ethanol then add to water
Positive result - White emulsion
Negative result - No emulsion
Enzymes
Enzymes are biological catalysts. This means that they speed up the rate of a biological reaction but they are not used up in the process. Each type of enzyme has a very specific shape. Only specific molecules will fit into this shape. The molecule has to be complementary. The molecules fit together like a lock and key.
Process of an enzyme working
Enzymes break down ‘substrates’
The substrate bonds to the active site of the enzyme, forming an enzyme-substrate complex
When the complex is formed, the substrate is broken down
Activation Energy
The energy needed for a chemical reaction to take place (enzymes lower the activation energy)
Active Site
The special site in the structure of an enzyme where the substrate binds.
Catalyst
A substance that changes the rate of a chemical reaction without being changed itself.
Complementary
The word used to describe molecules that fit together like pieces of a jigsaw.
Enzyme Denaturation
If the temperature gets too high, or the pH is too high/low for that particular enzyme, the shape of the enzyme’s active site changes. The enzyme is denatured.
Consequence of Enzyme Denaturation
Bonds within the enzyme will break. The active site will change state and the substrate is no longer complementary.
Enzyme Temperature Practical
The enzyme tested worked best around 40 degrees C. Above 40, the enzyme would begin to fail and denature. This would be the same for most enzymes in the body, as the average body heat is 37 degrees C.
Enzyme pH Practical
The enzyme tested had an optimum pH of around 7. This would not be the same for all enzymes in the body, as different places in the body have different pH levels. (e.g Enzymes in the stomach have an optimum pH of 2)
Note
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