5.1.2.1 Give examples of macromolecules and their monomers Explain what polymerisation means Give...
-
Upload
henry-garrett -
Category
Documents
-
view
240 -
download
0
Transcript of 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.