B3- organisation and the digestive system

Created by

Lissy

Cards (37)

How do muscle cells adapt
Can contract
Contain protein fibres that change length
packed with mitochndira - energy for contraction
form muscle tissue
Tissue definition
A group of cells with a similar structure and function
what is an organ
a group of tissues working together for a specific function
stomach contains muscle tissues and glandular tissues
what is an organ system
Organs grouped together
Work together to form organisms
order of organs
tissue
organ
organ system
organism
What nutrients are found in food
Carbohydrates
Protein
Lipids
All large molecules to large to be absorbed into blood stream so have to be digested
What happens during digestion
Large food molecules are broken down to small molecules by enzymes so they can be absorbed into the bloodstream
Role of mouth in digestion
Food is chewed
Enzymes in saliva digest the starch into smaller sugar molecules
role of oesophagus and stomach in digestion
Food passes down oesophagus into stomach
In Stomach enzymes begin digesting proteins
stomach contains hydrochloric acid to digest proteins
stays in stomach for several hours
churning action of stomach muscles turns food into a fluid increasing the surface area for enzymes to digest
Role of small intestine in digestion
Fluid passes to small intestine
Chemicals are released into small intestine from liver and pancreas
walls of small intestine release enzymes to digest proteins starch and lipids
small food molecules are absorbed into blood stream by diffusion or active transport
Role of pancreas in digestion
Releases enzymes to continue digestion starch and protein and to start digestion of lipids
role of liver/bile in digestion
liver releases bile to speed of digestion of lipids
bile neutralises stomach acid
role of large intestine in digestion
water is absorbed into blood
Stages of digestion
Mouth
Oesophagus
Stomach
Small intestine
Large intestine
Anus
What is the purepose of digestion
Large food molecules are digested and products are absorbed into bloodstream
The products of digestion are used by the body to build new carbs lipids and proteins
Some of the glucose Produced is used in respiration
What are enzymes
Catalysts
Large protein molecules
Have a groove on surface called the active site
Active site is where substrate (molecule enzyme breaks down) attatches too
Lock and key theory
If the enzyme can break down a substrate into products , it fits perfectly into the active site
If the substrate does not fit into the active site, the enzyme cannot break it down
enzymes are spacific and the substrate must fit perfectly into the active site
Proteases
Protease breaks down proteins
Found in stomach, pancreatic fluid and small intestine
structure of protein
Long chains of amino acids
role of protease
When digested the protease enzymes converts the protein back to individual amino acids which are absorbed into bloodstreamm
when amino acids are absorbed by cells they join together in a different order to make human proteins
Structure of starch
Consists of a chain of glucose molecules
Amylase breakdown starch
Breaks down starch
When starch is digested simple sugars are produced
Amylase is found in saliva and pancreatic fluif
lipid structure
molecule of glycerol attached to three molecules of fatty acids
Lipid digestion
Digested by enzyme lipase
Produces glycerol and fatty acids
Lipase in pancreatic fluid and small intestine
Also nvolves bile
what is bile
Made in liver stored in gall bladder
Speeds up digestion of lipids
Not an enzyme
alkaline that neutralises stomach acid
creates alkaline conditions in small intestine
biles involvement in breaking down lipids
Converts large lipid droplets to smaller droplets
Bile emulsifies lipid
Increases surface area of lipid droplet
Increases rate of lipid breakdown by lipace
Temperature effecting enzymes
As the temperature increases
the enzyme and substrate are moving faster
more collisions between substrate and active site
what is the optimum temperature of an enzyme
Where the enzyme is working at the fastest possible rate
maximum frequency of successful collisions between substrate and active site
After optimum the enzyme denatured
Enzyme can no longer catalyse reaction
Effect of ph on enzyme
The enzyme has an optimum ph where activity is maximum
If the ph is more acidic or alkaline activity drops to zero
The active site denatures
risks of effect of ph practice
iodine is an irritant - avoid skin
goggles
test for starch
Iodine
solution turns from brown to blue-black
test for reducing sugar
Benedict’s solution
Blue to brick red
protein test
biurets solution
blue to purple
lipids
ethanol
white emulsion formed on surface
adaptation of small intestine - length
5m
Large surface area for absorption of products in digestion
villi adaptations
Increase surface area for absorption of molecules
Microvilli on surface
good blood supply so bloodstream rapidly removes products of digestion which increases concentration gradient
Thin membrane for short diffusion path
Rapid rate of diffusion
enzymes required practical
determine optimum pH or temperature of an enzyme
measure out enzyme and substrate (starch and amylase)
place separately in water bath along with buffer solution to change pH
prepare spotting tile with iodine drops
mix reactants and start timer
every 10 seconds remove a drop of the mixture and place in dimple if iodine
if no colour change starch is broken down
repeat for diff temps or pH
draw a line of best fit