enzymes and digestion

define tissue

a group of similar specialized cells that work together to carry out a specific function

define organ

a structure of different tissues that work together to perform a specific function

define organ system

a group of organs that work together to perform a specific function

function of the mouth

Amylase released from the salivary glands breaks down carbs and starches

function of the esophagus

transports food (bolus) from the pharynx to the stomach via wave-like muscular contractions called peristalsis

function of the stomach

breaks down protein into amino acids. Protease breaks down the protein and the stomach acid balances the ph for easier and quicker digestion

function of the liver

produces bile for digestion. Bile regulates protein and hormone levels

function of the gall bladder

stores bile

function of the bile duct

transport bile from liver to small intestine

function of the pancreas

makes all enzymes:

-protease

-amylase

-lipase

function of the small intestine

contains villi, protease, and amylase that break down the remaining carbs and proteins. and lipase for fats

function of the large intestine

absorbs water and compacts waste

function of the anus

expells poo from body

function of the rectum

temporarily stores feces (undigested waste) before egestion (removal) via the anus

function of the brain

coordinate everything from automatic bodily processes like heartbeat and breathing to conscious actions like movement, speech and thought

function of the heart

pump blood throughout the body, delivering oxygen and nutrients while removing carbon dioxide and waste products

function of the skin

protects the body by acting like a barrier protecting it from stuff like pathogens, physical damage and uv radiation

function of the kidneys

filter waste products and excess water from the blood to produce urine

function of the lungs

facilitate gas exchange

function of the bladder

store urine produced by the kidneys and expel it from the body

function of the digestive system

to break down food into smaller absorbable nutrients to fuel the body for energy, growth, and repair

all the organs involved in the digestive system

mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus, along with accessory organs (liver, gallbladder, pancreas) that aid digestion.

the summary of the process of digestion

the multi-stage process of breaking down food into nutrients for energy, growth, and repair.

• Mouth & Esophagus: Teeth mechanically grind food, while saliva (containing amylase) begins breaking down carbohydrates. Food is formed into a bolus and moves down the esophagus via peristalsis.

• Stomach: The stomach churns food, mixing it with gastric acid and enzymes (like pepsin) to break down proteins. The mixture becomes a liquid called chyme.

• Small Intestine (Primary Digestion/Absorption): The pancreas releases enzymes to break down carbs, fats, and proteins. The liver provides bile to emulsify fats. Nutrients are absorbed into the bloodstream through the walls of the small intestine.

• Large Intestine & Elimination: Water and vitamins are absorbed from remaining waste in the colon. The remaining solid waste is stored in the rectum and expelled through the anus.

Key accessory organs include the liver (bile production), gallbladder (bile storage), and pancreas (enzyme production).

food is broken down in two ways

mechanical digestion - teeth grinding and our stomach churning up food

chemical digestion - where enzymes help break down food.

function of the circulatory system

to transport oxygen, nutrients, and hormones to the body's cells and remove waste products

function of the reproductive system

to produce offspring to ensure the survival of species

enzymes

- An enzyme is a protein that acts as a biological catalyst

- This means they speed up a reaction in living things, but are not used up themselves

- They are also affected and damaged in certain conditions

starch simple structure

All of the glucose together is starch

They are long molecules, made out of lots of smaller molecules/it is a polymer made out of lots of monomers

protein simple structure

Lots of DIFFERENT amino acids altogether make protein

lipids simple structure

a glycerol molecule bonded to 1, 2 or 3 fatty acid chains

sugars simple structure

a chain of chemically bonded glucose and fructose molecules chemically bonded to make sucrose

how are enzymes used in digestion

they are proteins that speed up the breakdown of large food molecules into smaller, more absorbable ones that the body can use

why are enzymes needed in digestion

they act as biological catalysts that speed up the breakdown of large, complex, insoluble food molecules into small, simple, and soluble molecules. These smaller molecules—such as amino acids, glucose, and fatty acids—can then be absorbed into the bloodstream for energy, growth, and repair.

why is the lock and key theory vital for the enzyme to function

because the active site has a unique 3D shape that is complimentary to the shape of the substrate

independent variable

what we change

dependent variable

what we measure

control variable

What stays the same

(always put 2)

Why do high temperatures prevent enzymes from catalyzing reactions

because it denatures the enzyme, because it is not at its optimum temperature

-That's why our body heat is around 37 degrees, because that is the optimum temperature for enzymes to catalyse reactions

Why does the pH change how well enzymes catalyse reactions

because it denatures the enzyme and the active site, so it is not at the optimum pH

- That's why we have stomach acid, so it can create the right environment for the enzymes to work at their best

function of bile

- to neutralize the acid from the stomach, otherwise, the enzymes in the small intestine would denature

- to emulsify fats, which means to break down the fats into fat droplets, increasing the surface area so lipase can break them down more easily.

What enzyme acts on carbs

-carbohydraise

-amylase (starch)

What enzyme acts on lipids

-lipase

What enzyme acts on protein

-protease

Where are enzymes produced

-carbohydraise

-lipase

-amylase

-protease

all made in the pancreas

lipase can be produced in the small intestine

protease can be produces in the stomach and small intestine

amylase can be produced in the salivary glands and small intestine all

enzymes in the digestive system summary

what is product from carbs breaking down

glucose

what is the product from lipids breaking down

fatty acids and glycerol

what is the product from proteins

amino acids

food test for presence of starch

- place a small amount of the food on a spotting tile

- add a few drops of iodine

- if the colour changes from yellow-red to blue-black

food test for presence of sugars/glucose

- place a small amount of the food into a test tube

- add water

- add a small amount of blue benedicks solution

- heat test tube in a warm water bath

- if colour changes from nlue to brick red, sugar is present

food test for presence of protein

- place a small amount of food onto a spotting tile

- add a few drops of bieuret solution

- if colour changes from blue to purple, protein is present

food test for fats (lipids)

- place a small amount of food into the test tube

- add a few drops of clear ethanol to the solution

- shake the test tube and leave for 1 minute

- pour the ethanol into a test tube of water, or add water to the ethanol

- a cloudy white layer will appear on top of the water if fats are present

what are vitamins needed for

maintain bodily function

what is fat needed for

insulation, protection, and emergency energy

what is protein needed for

growth and repair

what is glucose needed for

quick release energy

what is starch needed for

slow release energy

How to calculate the mean rate of

an enzyme-catalysed reaction.

- quantity of product formed / time taken

or

- quantity of reactant used / time taken

How is starch broken down

starch is broken down into maltose. then maltose is broken down by maltase into simple sugars and glucose. starts as a polymer and ends as monomers

investigating enzymatic reactions - investingating the effect of ph on amylase

the enzyme amylase catalyses the breakdown of starch to maltose. Its easy to detect starch using iodine solution, if starch if present, the iodine will change from browny orange to blue black

1. put a drop of iodine solution in every well of a spotting tile

2. put a beaker of water on a tripod stand with a gauze with a bunsen underneath until the water is 35 degrees. Try to keep the temp of the water constant through the experiment

3. with a syringe add 1cm³ of amylase solution and 1cm³ of a buffer solution with a ph of 5 to a boling tube. Put the tube into the beaker of warm water for 5 mins.

4. add 5cm³ of a starch solution to the boiling tube

5. use continous sampling to record how long it takes for the amylase to break down all the starch. to do this take a dropping pipette to take a sample from the boiling tube every thirty seconds to put a drop into a well. the idonie solution remains browny orange when starch is no longer present

6. repeat the whole experiment with buffer solutions to different ph values to see how ph effects the time taken for the starch to be broken down

7. remember to control any variables each time to make it a fair test

calculating the rate of reaction

rate = 1000 // time