A LEVEL BIOLOGY VIRTUAL

INDUCTION You will need a pen and paper to make notes and complete the activities as you go along!

Any technical problems or questions then please email Dr Cawthorne at

jennycawthorne@eswick.cumbria.sch.uk

A L L L I F E O N E A R T H S H A R E S A C O M M O N C H E M I S T R Y

C A N Y O U T H I N K O F A N Y O F T H E M O L E C U L E S F O U N D I N L I V I N G

T H I N G S ?

C L U E : T H I N K A B O U T W H A T W E E A T !

C A R B O H Y D R A T E S

P R O T E I N S

L I P I D S

N U C L E I C A C I D S

( A N D , O F C O U R S E … ) W A T E R

A L L L I F E O N E A R T H S H A R E S A C O M M O N C H E M I S T R Y…

e.g. sugars, and storage compounds like starch and glycogen

e.g. enzymes

Have many uses , including making cell membranes

DNA and RNA

D E S P I T E T H E I R V A R I E T Y , A L L C E L L S O F A L L L I V I N G O R G A N I S M S C O N T A I N O N L Y

A F E W G R O U P S O F C A R B O N - B A S E D C O M P O U N D S

BIOLOGICAL MOLECULES

One of the first topics you will study in A Level Biology is this chemistry of life.

You will learn about the chemical structure of these molecules, how they bond together and how these structures link to the job they do in living things.

BIOLOGICAL MOLECULES

The video should start automatically. You may need to give it a moment to load.

or follow this link...

CARBOHYDRATES

In this virtual lesson, we will begin to look at the structure of carbohydrates. It might feel a little bit like a chemistry lesson because it’s BIOCHEMISTRY!

This will hopefully give you a taster of what to expect from A Level Biology in September. We hope you enjoy ‘getting your teeth into’ something a bit more challenging!

CARBOHYDRATES• Carbohydrates are made up of Carbon (C),

Hydrogen (H) and Oxygen (O)

• There are usually twice as many Hydrogen as

there are Carbon and Oxygen with a ratio of

1C:2H:1O

• E.g. C6H12O6 or C5H10O5

CARBOHYDRATES• Carbohydrate monomers are called

monosaccharides

• Two monosaccharides can join together to form

a disaccharide

• Monosaccharides and disaccharides are both

sugars

CARBOHYDRATES• Many monomers join together to make a polymer

• A polymer of monosaccharides is called a

polysaccharide

• Polysaccharides can be used for storage (e.g. starch

or glycogen) or can be structural (e.g. cellulose)

INTRODUCING ALPHA GLUCOSEThe video should start automatically. You may need to give it a moment to load.

If the video isn’t working then try this link or email sammcdonald@keswick.cumbria.sch.ukand I can share it with you directly.

INTRODUCING ALPHA GLUCOSE

• Have a look at the molecule and try to memorise it’s structure. Watch the video again, if you like!

• Learn the full version including the numbered carbon molecules

• In September you will be learning the chemical structure of all of the biological molecules!

INTRODUCING ALPHA GLUCOSE

• On a scrap piece of paper, try to draw alpha (α)

glucose from memory.

• Then, look at the next slide to critique what you have

done.

MARKING POINTS /10

1. The molecule has 6 carbons

2. Full formula is correct (C6 H12 O6)

3. Each carbon has 4 bonds clearly shown

4. Correct number of OH’s (should be 5)

5. OH’s are in the correct position

6. Correct number of lone H’s (should be 6)

7. Only 5 Carbons in the ring

8. Linking O in correct place in ring

9. The carbons are numbered correctly 1-6

10. ALL bonds and letters are neat and unambiguous

INTRODUCING ALPHA GLUCOSE

• Repeat your drawings of alpha (α) glucose a couple of

times to really solidify it in your memory

…check back at the diagram after each attempt!

Extension:

• Can you do the ‘full’ and simpler versions of alpha (α)

glucose?

• Can you do the ‘full’ and simpler versions of beta (β)

glucose?

MONOSACCHARIDES• There are three common monosaccharides: glucose,

galactose and fructose.

• Their structures are slightly different but they are all

monomers (single units) which can be building blocks

for larger carbohydrates.

DISACCHARIDES

glucose + glucose → maltose

glucose + fructose → sucrose

galactose + glucose → lactose

Two monosaccharides are joined together to form a disaccharide.

This happens via a condensation reaction which also releases water.

There are 3 common disaccharides:

DISACCHARIDESThe bond which is formed is called a glycosidic bond

DISACCHARIDESTwo monosaccharides are joined together by a glycosidic bond… how does this happen?

The video should start automatically You may need to give it a moment to load.

If the video isn’t working then try this link or email sammcdonald@keswick.cumbria.sch.ukand I can share it with you directly.

DISACCHARIDE FORMATION

• On a scrap piece of paper, try to draw the formation

of maltose from memory

• Remember there are 2 stages:

1. Showing the 2 molecules of α glucose side by side

and illustrating where water is formed

2. Showing the resulting disaccharide which is formed

FORMATION OF SUCROSE

• One glucose and one fructose molecule join together in a condensation reaction to form sucrose

• Can you predict what the structure of sucrose would be?

Sucrose

CONDENSATION & HYDROLYSIS REACTIONS• Condensation reactions occur when a

molecule of water is lost.

• Two monosaccharides join in a

condensation reaction to form a

disaccharide.

• A glycosidic bond forms between the two

molecules.

• The opposite of this would be a hydrolysis

reaction involving the addition of water

and the splitting of the two molecules.

• Can you think of when (in biology) the

hydrolysis of a carbohydrate might take

place? …during digestion!

CAN YOU REMEMBER…1. …the biological molecules common to living things (there are 5)?

2. …the general name for a carbohydrate monomer?

3. …an example of a carbohydrate monomer? (there are 3)

4. …how to draw α glucose from memory?

5. …what type of bond is formed when a disaccharide is produced?

6. … an example of a disaccharide? (there are 3)

7. …how to draw the formation of maltose?

8. … the difference between a condensation and hydrolysis reaction?

Extension:

Glucose (C6H12O6) combines with fructose (C6H12O6) to form the disaccharide sucrose. From your knowledge of how disaccharides form, work out the formula of sucrose.