what is a tissue?
group of similar cells working together to perform a specific function
what is an organ?
groups of tissues that work together (to make up an organ)
what is an organ system?
whole multicellular organism made up of a range of organ systems
what is an organism?
a body of living thing
why are major nutrients broken down?
too big to pass through membranes to go into bloodstream
what is carbohydrates and what is it broken down into?
source of energy
broken down into starch and sugars
what is glucose?
what is It used for?
what is stored glucose in animals?
what is stored glucose in plants?
- single sugar
- used for respiration
- animals: glycogen
- plants: starch
what is starch?
polymer of glucose
what is protein used for?
why is protein broken down into amino acids
- growth and repair
- too big to pass into bloodstream through gut wall, so broken down into amino acids and then reassembled into protein with a specific function
what are lipids used for?
what is lipids broken down into?
- provide energy, insulation to make cell membranes
- 2 pieces: glycerol and fatty acids
what does the mouth do in the digestive system?
- chews food, break down food by enzymes in salivary gland (amylase)
- starch –> sugar molecules
what does the oesophagus do in the digestive system?
- peristalsis (muscle contractions move food down)
- acidic environment
what does the stomach do?
- muscle that breaks down food
- contains hydrochloric acid; helps enzymes digest proteins
- churning turns food into fluid increase surface area for enzymes to digest
what does the small intestines do?
- absorb nutrients into the bloodstream
what does the liver do?
- bile neutralises stomach acid, speed up digestion of lipids
what does the pancreas do?
- pancreatic enzymes to break down food
what does the large intestine do?
- absorbs water into bloodstream
what does the rectum and anus do?
- feces
