Biology paper 1 - organisation

What is a tissue

a group of cells with a similar structure and function

what is an organ

A group of tissues working together for a specific function

What are the 3 large nutrients found in food

Carbohydrates , protein, lipids - these are large molecules that are too large to be absorbed in the bloodstream so they are digested into smaller molecules to be absorbed

what is the function of the digestion system

Large food molecules are broken down into smaller molecules by enzymes. And the products of digestion can then be absorbed into the bloodstream, the new products of digestion can then be used by the body to build new carbohydrates, lipids and proteins

describe how digestion across the body happens

food is chewed in the mouth, enzymes in the saliva begin to digest the starch into smaller sugar molecules for easier swallowing

Food is passed from oesophagus into the stomach. In the stomach, the enzymes being digestion of proteins as the stomach contains hydrochloric acid which aids the enzymes to break food . And the churning action of the stomach muscles turns the food into fluid, increasing the surface area for enzymes to digest

The fluid passes into the small intestine - at this point chemicals are released into the small intestine from the liver and pancreas

The pancreas releases enzymes which continue the digestion of starch and protein, and also start the digestion of lipids

The liver releases bile which speeds up the digestion of lipids as bile also neutralises the acid released from the stomach

The wall of the small intestine release enzymes to continue the digestion of proteins and lipids

In the small intestine the small food molecules produced by digestion are absorbed into the bloodstream either by diffusion or active transport

The fluid makes its way through the large intestine where water is absorbed into the bloodstream

Faeces is released from body

What are enzymes

Enzymes are biological catalysts that speed up chemical reactions in the body by lowering the activation energy, allowing processes like digestion to occur more efficiently.

Describe the lock and key enzyme theory

The substrate molecule is complimentary to the active site found on the enzyme, once the substrate and active site bind, the enzyme now breaks down the substrate into products

What is an organ system

Food is passed from oesophagus into the stomach. In the stomach, the enzymes being digestion of proteins as the stomach contains hydrochloric acid which aids the enzymes to break food . And the churning action of the stomach muscles turns the food into fluid, increasing the surface area for enz

What enzyme are proteins , lipids and carbohydrates broken down by

Proteins - protease

Lipids - lipase

Carbohydrates - carbohydrases

Where are proteases found in the body

stomach , small intestine , pancreas

What are proteins

long chains of amino acids

What happens during digestion of proteins

the protease enzymes convert proteins back into individual amino acids which are then absorbed into the bloodstream

When the amino acids are absorbed by the body cells, they are joined together in different order to make human proteins

What is starch

a type of carbohydrate consisting of chains of glucose molecules

What enzymes breaks down starch

Amylase

what is produced when carbohydrates like starch are digested

simple sugars such as glucose and fructose

where is amylase found

in the saliva and pancreatic fluid

What is a lipid molecule consisted of

a molecule of glycerol attached to 3 molecules of fatty acids

Describe how lipids are digested

lipid molecules are digested by enzyme lipase, this produces glycerol and fatty acids. Bile helps to speed up digestion of lipids however bile is not an enzyme

Where is lipase found

in pancreatic fluid and in small intestine

Where is bile produced and stored

made in the liver and stored in gall bladder

What is the function of bile in relation to digestion of lipids

converts large lipids droplets into smaller droplets and emulsifies the lipid which increases the surface area of the lipid droplet = increases the rate of lipid breakdown by lipase

Bile is also alkaline which neutralises stomach acid = creating alkaline conditions in the small intestine = increase the rate of lipid digestion

How is the rate of lipid digestion increased

by emulsification of lipids by bile, which increases the surface area for lipase action, and by creating alkaline conditions in the small intestine which alows for nuetralisation of stomach acid = creates alkaline conditions in the small intenstine

What happens to enzyme activity when temperature is increased and why

the rate of enzyme activity increases → As temperature increases, the kinetic energy of the enzyme and substrate molecules increases, so they move faster and collide more frequently. This leads to more successful collisions per second between the substrate and the active site, increasing the rate of enzyme activity.”

at which temperature does enzyme activity work the fastest

at optimum temperature as there is the maximum frequency of successful collisions between the substrate and active site

What happens to enzyme activity using PH if it is made more acidic or alkaline

enzyme activity drops to zero → because the active site denature if the conditions are too acidic or alkaline