5.1.2.1 Give examples of macromolecules and their monomers Explain what polymerisation means Give...

5.1.2.1

Give examples of macromolecules and their monomers

Explain what polymerisation means Give the chemical and structural formulae for

hexose sugars.

The building blocks of life

4 most common elements in living things1. Hydrogen2. Carbon3. Oxygen4. Nitrogen

Together they make up more than 99% of atoms found in all living things

Carbon is the most important as it links with itself to form long chains or rings.

All organic molecules contain carbon.

Macromolecules

Macromolecule = ‘Giant molecule’ Three types of organic macromolecules

– Proteins (polypeptides)– Nucleic acids– Polysaccharides

For each one give an example of what it might do in the body and where it could be found.

Polymerisation

In your own words explain what polymerisation means, using the terms polymer and monomer in your explanation.

Polymer Monomer

Polypeptide

Nucleic Acid

Polysaccharide

Natural and synthetic

Group these polymers into natural and synthetic

Polyester Rubber Cellulose

PVC Nylon Polythene

Other organic molecules

The other type of organic molecule we will be looking at is lipids

This is made of fatty acids and glycerol but is smaller and simpler than the others

It is not a polymer

Carbohydrates

60 – 90% of plant dry mass. General formula Cn(H2O)m

Main groups are the Simple Sugars and the Polysaccharides.

Used as storage molecules, building blocks and for energy.

Sugars, starch, cellulose, glycogen and lignin are well known examples.

Monosaccharides

All Monosaccharides contain Carbon, Hydrogen and Oxygen in a ring structure.

They can have different numbers of Carbon atoms and different arrangements

The pentose sugars have 5 carbons The hexose sugars e.g. glucose have 6

carbons

Write the formulae for a pentose and a triose sugar

Draw the structure and write the formulae for -glucose

Monosaccharides cont.

Monosaccharides are sweet, soluble and have a low molecular mass

The two best known Hexoses are glucose and fructose

Hexoses have the same chemical formula (C6H12O6 ) but different structural formula - glucose and fructose are Isomers

Draw the structural formulae for - Glucose and for Fructose

Disaccharides

Monosaccharides can join together to form disaccharides

These are sugars

Using diagrams and bullet points describe how a disaccharide is made from two monosaccharides

Why is this called a condensation reaction? A C1-C4 glycosidic bond

is made

Polysaccharides

α and β glucose molecules produce different polymers

Starch and glycogen (storage) are polymers of the α form

Cellulose (structural) is a polymer of the β form

What is the main difference between cellulose and starch structure

Side chains

In some polysaccharides side chains are made.

A glycosidic bond is formed between C1 and C6

amylopectin

Using diagrams and bullet points explain how side chains are made.

Homework

What is the function of – Monosaccharides– Disaccharides– Polysaccharides

In living organisms? In your answer you should give at least 3

specific examples for each group and an overview of their function.

5.1.2.2

Look in detail at the structure of sugars and polysaccharides

Give the functions of these carbohydrates

Monosaccharides

Exist as straight chains when solid Hexoses and Ribose form rings in solution Names prefixed with a D or L depending on

which way the crystalline form bends light. L- Laveo rotatory (Left) D- Devo rotatory (Right) Only D forms found in multicellular organisms

Ketone and Aldehyde groups

Act as reducing agents Can donate electrons to other molecules

Ketone Aldehyde

H O

C O C

For each monosaccharide identify whether a ketone or aldehyde group is present

Trioses

D-Glyceraldehyde Intermediate produce of Respiration AND

photosynthesis Can be converted to glycerol for lipid synthesis Involved in intermediary metabolism

Glycerol Used in lipid synthesis A sugar alcohol

Pentoses

D-Ribose Formation of RNA, ATP, NADP, NAD

D- Deoxyribose Formation of DNA

Ribulose Carbon dioxide formation (photosynthesis)

Hexoses

Glucose Energy source for respiration Makes important polymers

Galactose Formation of lactose

Fructose In fruits and nectar- attracts animals

Show how the hexose sugars convert from chain to pyranose ring form in solution.

Disaccharides

Made by the formation of a glycosidic bond between two monosaccharides

If they have a free aldehyde or ketone group they are reducing agents

For each disaccharide record the monosaccharides it is made of, the bond made and whether it is a reducing agent

Disaccharide function

Maltose 1st product of starch digestion Important in germination

Lactose Energy source for new born mammals

Sucrose In vacuole-helps maintain turgor Transport in phloem (non-reducing)

Polysaccharides

Amylose- a soluble helix (hydrogen bonds with water).

Amylopectin- a chain with side branches every 10th glucose

Starch- amylose helix entangled in amylopectin branches.

Glycogen- similar to amylopectin but with more frequent side chains

Cellulose- long straight unbranched fibres. H-bonds between strands to make a regular lattice

For each polysaccharide record the subunit it is made of, the type of bond and whether its plant or animal.

Building starch and cellulose.

1. Using the sheet- what you need to do follow the instructions to build up a starch molecule.

2. make sure your work is stuck on and clearly labelled.

3. Complete the cellulose sections. You may need draw in OH and H to see where hydrogen bonds occur.

Complex carbohydrates

Monosaccharides joined to proteins/ lipids Glycolipids- myelin sheeth Glycoproteins – cell adhesion, immunological

markers Chitin- exoskeleton of insects. Hexoses linked

like cellulose with amino groups (NH2) every 2nd carbon added

Homework

Learn the structure of the biologically important carbohydrates.

Short test next lesson.

5.1.2.3

Carry out tests for carbohydrates Identify a mystery carbohydrate and the

properties of an enzyme.

Starch

Simple test- with iodine. Blue/black= iodine present.

Cellulose

Use Shultz solution- Turns purple in the presence of cellulose.

Reducing sugar

Add an equal amount of solution to be tested and Benedict's reagent to a test tube (about 4ml)

Heat in a water bath until it boils Green precipitate- a small amount of sugar Brown or red- greater amount of sugar

Non-reducing sugar

Test as for a reducing sugar first If no precipitate boil with Hydrochloric acid

(CAREFUL- EYE PROTECTION) Then neutralise with alkali. Test with Benedict’s as before,

Solutions E, F , G, H

Questions 4 on the back of the sheet Carry out and write all results and answers into

your book.

Homework

1. Write up the procedure for testing for– Starch– Cellulose– Reducing sugars– Non reducing sugars

2. For each test say how it works i.e. why does starch stain blue with iodine? Etc.

5.1.2.4

Make standard glucose solutions Use these solutions to find the reducing power

invertase on sucrose

Making standard dilutions

You have 2% glucose. You need to make 0.5%, 0.1% and 0.01 %.

1. Write down how you will make these dilutions (exact quantities of glucose solution and water you will use). Make sure all calculations are clearly recorded.

2. Make up your dilutions

Testing reducing power.

1. Using the standard test for reducing sugar test each solution for its reducing power (part a). Record all results

2. Devise a test for the two solutions J and K to find their reducing power.

Have you?

Written a method for both parts of the experiment?

Recorded all results neatly? Draw a graph from your standard results? Used your graph to calculate the reducing

power of invertase? Written a clear, detailed conclusion.

Homework

Qu 3- Solution M Write a Method for both parts of the

experiment. Write a rational for your method in both cases.