The Digestive System

Front 1

What is the function of the Oesophagus and how is it adapted?

Back 1

To transport food from the mouth to the stomach.
Thick muscular wall for peristalsis.
Mucus to lubricate the wall.

Front 2

Explain the Stomachs role in digestion?

Back 2

The stomach is a small sac where molecules of food are broken down.
Peristalsis churns the food to break it down physically.
Gastric Juice is produced.

Front 3

Gastric Juice?

Back 3

Enzymes- to break down food molecules.
HCL- to kill bacteria and provide optimum pH for enzymes.
Mucus- to protect the stomach walls from being digested.

Front 4

What are the two parts of the small intestine?

Back 4

The duodenum and the ileum.

Front 5

What happens in the duodenum?

Back 5

Bile and pancreatic juice neautralise the acidity of the chyme and break it down into smaller molecules. Bile increases the SA of fat as it is an emulsifier.

Front 6

What happens in the ileum?

Back 6

Small molecules are absorbed into the blood stream.

Front 7

How is the Small Intestine adapted for absorption?

Back 7

Villi and Micro-villi- large SA
Capillaries- Good blood supply maintain high concentration gradient
Short diffusion path

Front 8

function of the Large intestine?

Back 8

Absorbs water, salts and minerals to leave behind undigested food.

Front 9

The rectum is where...?

Back 9

Faeces are stored before exiting via the anus

Front 10

Physical Breakdown

Back 10

Food is broken down into smaller pieces by the teeth and the churning of the stomach. This gives the food a larger surface are for chemical digestion.

Front 11

Chemical Digestion

Back 11

Chemical digestion is carried out by enzymes functioning by hydrolysis. This is the splitting up of molecules by adding water.

Front 12

The role of the salivary gland in digestion?

Back 12

The salivary gland secretes mucus, mineral salts and salivary amylase.
The Amylase breaks down starch into maltose.
The mucus makes it easier to swallow.

Front 13

The role of the Pancreas in digestion?

Back 13

The pancreas secretes pancreatic juice into the duodenum. It contains enzymes (amylase, trypsin, chymotrypsin and lipase) to break down food molecules. It also contains sodium hydrogen carbonate to neautralsie the acidity.

Front 14

What is the process by which enzymes break down food?

Back 14

Hydrolysis. This is the breaking down of molecules by adding water.

Front 15

What are proteins made from(monomer)?

Back 15

Long chains of amino acids. Amino acids are the monomers of proteins.

Front 16

What is a dipeptide?

Back 16

When two amino acids are joined together?

Front 17

What is a polypeptide?

Back 17

When more than two amino acids join together

Front 18

A protein is made up of...?

Back 18

One or more polypeptides.

Front 19

What are the three groups that make up an amino acid and what are they attached to?

Back 19

Amino group- NH2
Carboxylic group- COOH
R group
Hydrogen atom
All attached to one central carbon atom.

Front 20

What type of reaction forms polypeptides?

Back 20

Condensation reaction.

Front 21

What is given off in a condensation reaction?

Back 21

Water- H2O.

Front 22

What is the new bond formed between the carbon atom and the nitrogen atom called?

Back 22

Peptide bond.

Front 23

What are the four structures of proteins?

Back 23

Primary, Secondary, Tertiary and quaternary.

Front 24

The primary structure is...?

Back 24

A sequence of amino acids in a polypeptide chain

Front 25

What happens in the secondary structure?

Back 25

Hydrogen bonds form between the -NH and the C=O in the amino acids causing the chain to bend or coil.

Front 26

What are the two types of secondary structure?

Back 26

Alpha helix coils.
Beta pleated sheets.

Front 27

Tertiary structure?

Back 27

The coiled or folded chains of amino acid are coiled and folded further to create a more complex 3D shape.

Front 28

What are the three types of bond in a tertiary protein?

Back 28

Hydrogen bonds
Disulphide bonds
Ionic bonds.

Front 29

Quaternary structures are made from...?

Back 29

several different polypeptide chains held together by bonds.

Front 30

What do Quaternary proteins often contain?

Back 30

Prosthetic groups.

Front 31

What are catalytic proteins?

Back 31

Enzymes are catalytic proteins as they catalyse biochemical reactions.

Front 32

Name a structural protein?

Back 32

Collagen is a structural protein. they are physically strong and make up the components of the body.

Front 33

Immunological proteins are...?

Back 33

things like antibodies and antigens.

Front 34

What are signalling proteins?

Back 34

Signalling proteins are the hormones and receptors in our bodies.

Front 35

Explain the test for protein?

Back 35

Add sodium hydroxide solution to sample and then add copper (II) sulphate solution.

Front 36

Turns Purple/lilac

Back 36

Protein present

Front 37

Stays Blue

Back 37

No protein present

Front 38

What are the monomers of carbohydrates?

Back 38

Monosaccharides

Front 39

What elements to carbohydrates contain?

Back 39

Carbon, Hydrogen and Oxygen

Front 40

Two monosaccharides are called...?

Back 40

Disaccharides

Front 41

What joins together monosaccharides?

Back 41

Glycosidic bonds that join during condensation reactions

Front 42

What are some examples of mono, di and polysaccharides?

Back 42

P
- Startch
- Glycogen
D
- Maltose
- Lactose
- Sucrose
M
- Glucose
- Galactose
- Fructose

Front 43

When is a disaccharide formed?

Back 43

When two monosacharides join together?

Front 44

Maltose is

Back 44

Glucose + Glucose

Front 45

Sucrose is

Back 45

Glucose + Fructose

Front 46

Lactose is

Back 46

Glucose + Galactose

Front 47

when is a polysaccharide formed?

Back 47

when more than two monosaccharides join together

Front 48

What causes lactose intolerance?

Back 48

Lack of the digestive enzyme latase. Lactose goes undigested and is fermented by bacteria to produce gas.

Front 49

Symptoms of lactose intolerance

Back 49

Cramps
Flatulence
Diarrhoea

Front 50

How can it be managed?

Back 50

Avoid milk
Add purified lactase to milk so lactose is already digested.

Front 51

Testing for reducing sugar

Back 51

Add an equal amount of Benedicts solution to a Sample and heat.
Blue>green>yellow>orange>red
Red means reducing sugar

Front 52

Testing for non reducing sugar

Back 52

Break down into monosaccharides
Boil test solution with dilute HCl and neutralise with NaHCO3
Then carry out benedicts test as normal
You must also carry out benedicts test to eliminate possibility of reducing sugar

Front 53

What are Enzymes?

Back 53

Enzymes are biological catalysts. They catalyse metabolic reactions(reactions that take place to maintain life).

Front 54

What two types of reactions do enzymes catalyse?

Back 54

Anabolic- building up
Catabolic- breaking down

Front 55

How do enzymes lower the activation energy for anabolic reactions?

Back 55

Anabolic reactions involve building up molecules. In anabolic reactions enzymes hold substrate molecules close together reducing the affects of repulsion and therefore meaning they can bond more easily.

Front 56

How do enzymes lower the activation energy for catabolic reactions?

Back 56

Catabolic reactions involve breaking down molecules. In catabolic reactions enzymes hold substrate molecules putting strain on the bonds in the substrate meaning they break more easily.

Front 57

Explain the lock and key model.

Back 57

The lock and key model is the idea where a specific substrate fits into a specific enzymes active site. The enzyme does not change shape throughout this process.

Front 58

Explain the induced fit model.

Back 58

The induced fit model is more commonly accepted now than the lock and key model. The idea is that the enzyme not only has to have a specific shaped active site but that it mus also change shape in the right way to catalyse the reaction.