B3 Organisation and the Digestive System Flashcards
What are tissues
Groups of cells that act together to perform a function
What are some examples of plant tissues
Mesophyll
Capable of photosynthesis
Epithelial/epidermal tissue
Waxy covering of plants
What are some examples of animal tissues
Epithelial/epidermal tissue
Outer surface of organs and blood vessels and human skin
Muscular tissue
Contract to bring about force and motion
What are organs
Groups of tissues that work together to perform a function
What does glandular tissue in the stomach do
Produces digestive juices that break down the stomach’s contents
What does epithelial tissue in the stomach do
Lines the stomach
What does muscular tissue do in the stomach
Moves the content of the stomach during digestion
What are organ systems
Groups of organs that work together to perform a function
What does the small intestine do in the digestive system
Digests foods
Absorbs soluble food molecules
What does the liver do in the digestive system
Produces bile
What do glands do in the digestive system
Produce digestive enzymes
What does the stomach do in the digestive system
Digests food
What does the large intestine do in the digestive system
Absorbs water molecules from remaining undigested food
Produces faeces
What is an organism
A multicellular organism consisting of several organ systems
What are enzymes
Proteins that are biological catalysts, increasing the speed of chemical reactions
What is an enzyme’s active site
To catalyse a reaction, the substrate must bind to the enzyme’s active site
Here, substrates are broken up or bonded together
Only specific substrates fit an enzyme’s active site
What is the lock and key model
The active site is like a lock and the substrate is like a key
Only the right substrate fits the active site
What does denatured mean
When an enzyme’s structure is altered and it can no longer catalyse a reaction
How do you calculate the rate of reaction from a graph of mass of product against reaction time?
Rate of reaction is equal to the gradient of the graph
What causes denaturing
High temperature
Non-optimum pH
How does temperature affect rate of reaction
Increasing the temperature of a working enzyme initially increases the reacting activity
Enzymes have an optimum temperature
Once this temperature is reached, the activity decreases
Past a certain temperature, the enzyme is denatured
How does pH affect rate of reaction
Enzymes have an optimum pH
If the pH changes away from the optimum pH, the enzyme activity decreases
If the pH is too low or too high, the enzyme is denatured and will not function
How to calculate rate of reaction
change in mass divided by change in time
What do digestive enzymes do
Digestive enzymes catalyse the breaking down of large and insoluble molecules of food into smaller, soluble molecules that can be absorbed into the bloodstream
Digested molecules can be used to construct new carbohydrates, proteins and lipids in the body
Some glucose produced by digestion is used for respiration
What are the three main digestive enzymes
Amylase
Protease
Lipase
What is bile
An alkaline substance produced in the liver and stored in the gallbladder
How is bile used in emulsification
Bile breaks up fats into droplets through emulsification
The droplets have a higher surface area than the original fat drop
This increases the rate of the lipase-catalysed reactions that break fats down
Where are digestive enzymes produced
Specialised cells in the glands and the lining of the gut
They are then secreted out of the body cells and into the cavity of the digestive system
Where are amylase action sites
Small intestine
Mouth
What does amylase do
Breaks down starch into its constituent simple sugars (mainly maltose)
Where is amylase produced
Pancreas
Salivary glands
What are carbohydrases
Enzymes that break down carbohydrates into sugars
What are proteases
Enzymes that break down proteins into amino acids
Where are proteases produced
Pancreas
Stomach
Where are protease action sites
Small intestine
Stomach
What are lipases
Enzymes that break down lipids into glycerol and fatty acids
Where are lipases produced
Small intestine
Pancreas
How are sugars tested for
Add Benedict’s reagent
Heat in a water bath for 2 minutes
If the solution is green, yellow or red, sugar is present
Colour depends on concentration
How is starch tested for
Add iodine solution
Blue-black if starch is present
How are proteins tested for
Add biuret solution
Mauve or purple is protein is present
How are lipids tested for
Add ethanol
Add water and shake
Cloudy if lipids are present
What are the control factors when investigating the rate of enzyme activity
pH
Temperature
Enzyme concentration
Substrate concentration
What are carbohydrates
C, H & O
Made up of simple sugars
What are lipids
Molecules of fatty acids joined to molecules of glycerol
What function do carbohydrates have in the body
Most carbohydrates will be broken down into glucose and used in cellular respiration to provide energy for metabolic reaction
What function do lipids have in the body
Most efficient energy store
Important source of energy
Used as hormones and in cell membranes and the nervous system
What are proteins
Made of C, H, O & N
Chains of amino acids
What function do proteins have in the body
Building cells, tissues and enzymes
Structural components
Hormones
Antibodies
What do catalysts do
Increase the rate of chemical reactions without changing chemically themselves
What is metabolism
The sum of all the reactions in a cell or the body
What does hydrochloric acid do in the stomach
Causes a low pH suitable for the effect functioning of protease
How does bile affect pH
Neutralises acid
Causes a high pH for the effective functioning of enzymes from the pancreas and small intestine
