electricity, digestive system, ecosystem Flashcards
what function does the mouth have
- breaks down food into smaller pieces
- salivary glands secrete saliva which contains the enzyme, salivary amylase
- tongue rolls the food into small balls and pushes it down to the oesophagus
oesophagus function
- a muscular tube measuring about 25cm
- transports food from the mouth to the stomach
- no secretion of enzymes in the oesophagus
stomach funtion
- churns to break down food into even smaller pieces
- secretes gastric juices containing; the enzyme, protease and hydrochloric acid that kills harmful microorganisms in food
large intestine function
- absorbs liquid and mineral salts from undigested food
- bacteria in the colon make vitamins for the body
small intestine functions
- food is mixed with intestinal juice, pancreatic juice, and bile to help digestion
- the liver and pancreas are connected to the small intestine
- the final products of digestion are absorbed into the bloodstream
rectum function
- temporarily stores the remaining undigested food
- faeces leaves the body through the anus
liver function
the cells in the liver secretes bile
gall bladder function
stores bile produced by liver
pancreas function and enzymes
secretes pancreatic juice containing enzymes which helps digest food
- pancreatic amylase
- pancreatic protease
- pancreatic lipase
carbohydrates nutrients
- large molecules: starch, cellulose, and glycogen
- small molecules: glucose, galactose, and fructose <- these are also known as sugars
- simplest building block -> glucose
carbohydrates function
- provides immediate source of energy
- cellulose makes up part of the fibre that passes out undigested and forms the bulk in our faeces
example foods of carbohydrates
starch, cellulose (plants, vegetables), sugars (sucrose found in sweet fruits, lactose in milk)
nutrients in proteins
- amino acids
- generally large molecules
- simplest building block -> amino acid
protein functions
- to make new cells for body growth and to repair worn out tissue
- to make complex proteins called enzymes
protein food examples
meat, fish, eggs, milk, yogurt
nutrients in fat
- made up of glycerol and fatty acids
- large molecules that are insoluble in water
fat function
- source and store of energy
- act as an insulating material to prevent excessive heat loss
fat food example
butter and cheese
why must food be digested
- the cell surface membranes of our cells in the body are partially permeable
- large molecules like starch, proteins, and fats cannot pass through the cell surface membranes
- digestion breaks down the large, insoluble molecules into small, soluble molecules
- these small molecules can pass through the cell surface membranes
what are enzymes
- complex proteins that speed up the rate of chemical reactions
- enzymes remain unchanged at the end of chemical reactions
- example of chemical reaction is large insoluble food molecules being broken down into smaller and soluble food molecules during digestion
- enzymes that act on food molecules are called digestive enzymes; which allow digestion to occur faster
what does amylase work on
starch (amylose)
what does maltase work on
maltose
what does protease work on
proteins (proteins digested by protease to form amino acids)
what does lipase work on
fats/lipids
what does sucrease work on
sucrose
what does saliva work on
saliva has salivary amylase
salivary amylase acts on starch
what does gastric juice act on
gastric juice contains protease
protease acts on proteins
what pancreatic juice act on
there is pancreatic amylase, pancreatic protease, and pancreatic lipase found in pancreatic juice
amylase works on starch
protease works on proteins
lipase works on fats
what does intestinal juice act on
intestinal juice has maltase, protease, and lipase
maltase acts on maltose
protease acts on proteins
lipase acts on fats
what does bile act on
it is made in the liver and acts on fats
it is not an enzyme and only helps with digestion, it does not digest anything
what is bile
bile is a yellow fluid produced by the liver, then stored in the gall bladder
bile physically breaks down large droplets of fat into smaller droplets of fat
this process is called emulsification
what does fat turn into
intestinal and pancreatic lipase act on fats and becomes fatty acids + glycerol
what does starch turn into
salivary amylase and pancreatic amylase act on starch, which becomes maltose
maltase then works on maltose and turns it into glucose
what do proteins turn into
protease acts on proteins, turning them into amino acids
absorption in the small intestine
- only small food molecules can pass through the walls of the small intestine and blood vessels
- the small food molecules enter the bloodstream and are transported throughout the body
- the small food molecules are absorbed by body cells to be used for respiration, cell repair and other processes
what physical digestion does the mouth do
teeth grinds food into smaller pieces
what chemical digestion does the mouth do
salivary amylase digests starch
what physical digestion does the stomach do
stomach muscles churn to digest food
what chemical digestion does the stomach do
protease digests proteins
hydrochloric acid kills harmful microorganisms
what physical digestion does the small intestine do
bile emulsifies fats
what chemical digestion does the small intestine do
starch and proteins are further digested and fat digestion begins
why cant fibre be digested
it forms the bulk in our faeces
