Science: Organisms Flashcards
What is GAS EXCHANGE?
Where does it occur?
Gas exchange is the process of taking in oxygen and giving out carbon dioxide
This occurs in the respiratory system
What happens when you breathe in?
• muscles between the rubs contract • ribs are pulled up and out
• diaphragm contracts and flattens
• volume of the chest increases
• pressure inside the chest decreases
• air rushes into the lungs
What happens when you breathe out?
• muscles between ribs relax
• ribs are pulled in and down
• diaphragm relaxes and moves up
• volume in the chest decrease
• pressure inside the chest increases
• air is forced out of the lungs
What does the liver do?
Produces bile, which helps with digestion
What does the stomach do?
Adds acids and it is where digestion occurs
What does the pancreas do?
Produces a digestive juice, which is added into the small intestine
What happens in the small intestines?
Here digestion is completed, and absorption of soluble food occurs
What happens in the large intestines?
Water is absorbed from the undigested food, which then produces faeces
What are enzymes (re. Digestion)?
Enzymes are biological catalysts, they speed up the digestion of nutrients
What is LOCK AND KEY MODEL (re. Digestion?)
The way the enzyme and nutrient bind with each other is called a lock and key model
Each enzyme is specific to a nutrient
What enzyme breaks down each of:
Carbohydrates
Proteins
Lipids (fats)
Carbohydrases break carbohydrates down into simple sugars
Proteases break proteins down into amino acids
Lipase breaks lipids (fats) down into fatty acids and glycerol
What do each of the following do in your body?:
Carbohydrates
Proteins
Vitamins&minerals
Water
Fibre
carbohydrates: main source of energy
lipids: fats and oils provide energy
proteins: growth and repair of cells and tissues
vitamins and minerals: essential in small amounts to keep you healthy
water: needed in all cells and body fluids
fibre: provides bulk to food to keep it moving through the gut
