Biology Ch 3
Name the five levels of organisation
cells ➞ tissues ➞ organs ➞ organ systems ➞ organisms
What is a tissue?
group of cells with similar structures and functions
What is an organ?
group of tissues working together to perform a specific
function
What is the function of the liver in digestion?
produces bile, which neutralises hydrochloric acid from
the stomach and emulsifies fat to form small droplets
with a large surface area
What is the function of saliva in digestion?
lubrication to help swallowing – contains amylase to
break down starch
Name three enzymes produced in the pancreas.
amylase, protease, lipase
What are enzymes?
protein molecules that catalyse specific reactions in
organisms
Describe the function of amylase.
to break down starch into glucose
Describe the function of proteases.
to break down proteins into amino acids
Describe the function of lipases
to break down lipids into fatty acids and glycerol
What does denatured mean?
shape of an enzyme’s active site is changed by high
temperatures or an extreme pH, so it can no longer bind
with the substrate
What is an organ system?
a group of organs working together to perform a
speci昀椀c function