Download Equipment required per class: Starting off Images of proteins

Teacher and technician notes TB2.14
Lesson reference: B2.14 Proteins
Book links: Page 122
Specification links: B2.5.1 a–b
Proteins
Equipment required per class:
Notes on equipment:
Starting off
Images of proteins
Student activity AB2.14.1 Proteins
See the list on the next page for
suggestions.
Five test tubes
Test tube rack
White tile
Labels
To make the egg white
suspension, add egg white to an
equal volume of water and mix
gently. This makes the egg white
easier to handle.
Alternatively, make a solution of
dried albumen.
Allow one egg white per pair of
students.
Dropping pipette
Dilute sodium hydroxide solution
Dilute copper sulfate solution
Raw egg white suspension
Cooked chicken and raw chicken
1 mol dm-3 HCl
Access to water bath set at 90 °C
Timer
70% ethanol (highly flammable)
A3 paper
Poster pens
Access to the Internet
Biology books
Main ideas – Demonstration
Plasticine, beads or pipe cleaners
Extension activity Making jelly
Two packs of jelly cubes
Microwave oven
Water
Fresh pineapple
Tinned pineapple
Extension activity ATP and meat
Fibres of cooked and raw meat (beef skirt or chicken breast)
Microscope
Microscope slide
Graph paper
ATP solution
Practical activities have been checked for health and safety advice by CLEAPSS.
All users will need to review the risk assessment information and may need to adapt it to local circumstances.
© Oxford University Press 2011
This document may have been altered from the original.
400
Controlled Assessment:
B4.3.1
Health and Safety notes:
 Eye protection must be worn.
 Students should wash their hands with soap and water after handling raw chicken.
Starting off

Show a selection of the following images to demonstrate the importance of proteins:
 collagen (blood vessel walls, skin, tendons, bone)
 fibrin in a blood clot
 keratin (skin, hair)
 protease, carbohydrase, lipase
 elastin (lungs, blood vessel walls)
 actin and myosin in muscles (meat)
 haemoglobin
 transmitter substances at synapses
 antibodies
 hormones such as insulin
 antigens on cell surface membranes
 receptors on cell membranes.
 channel in a cell membrane

Ask students if they know what these have in common and establish that they are all proteins.

Explain to students that proteins make up a large proportion (about 75%) of our dry mass and
so form a large part of our body structure.

Introduce the idea that some proteins work like tools of the body, for example carrier proteins
such as haemoglobin, catalysts such as enzymes and antibodies for defence against diseases.
Plenary
True/false exercise
For each of the following statements ask students to decide whether it is true or false:
A Proteins are made of long chains of amino acids joined together.
True
B Proteins are made in the cell’s nucleus.
False
C There are 20 different types of proteins.
False
D You need to eat some protein every day as your body cannot store amino acids.
True
E Genes govern how proteins are assembled.
True
F All your proteins are assembled in mitochondria.
False
G Enzymes are proteins.
True
H Genes govern how other chemicals are made in cells because genes code for enzymes and
enzymes are needed to make other chemicals.
True
I Each chromosome contains many genes.
True
J Antibodies are proteins.
True
Differentiation/Extension
Making jelly
 The easiest way to prepare jelly is to cut the block of jelly into smaller cubes, add a little water,
and place in the microwave oven on low. Then add more water, slightly less than specified in the
instructions. Add tinned pineapple to one batch and fresh pineapple to the other.
 You could make these two jellies before the lesson and allow time for setting.
Practical activities have been checked for health and safety advice by CLEAPSS.
All users will need to review the risk assessment information and may need to adapt it to local circumstances.
© Oxford University Press 2011
This document may have been altered from the original.
401
 Show students the set jelly with tinned fruit and the fresh fruit jelly that has not set.
 Discuss why the jelly made with fresh pineapple does not set. Fresh fruit contains protease
enzymes and these digest the protein (gelatine) in jelly. It can no longer set.
 Ask students to predict what might happen if you made the fresh fruit jelly and then immediately
put it in the fridge at 0 °C?
 Ask students why cooking meat with fruit at low oven temperatures, such as in Moroccan
dishes, tenderises the meat.
ATP and muscle fibres
This demonstration is to show that cooked muscle can no longer function.
1 Add some ATP solution to fibres of raw meat on a microscope slide resting on graph paper.
2 Students measure the fibre lengths before and after ATP is added and see the contraction.
3 Repeat with muscle fibres from cooked meat.
Answers
Homework task HB2.14.1 Proteins
A
Name of
protein
Where found in your body
Function
Insulin
Made in your pancreas and then enters
your blood
Regulates blood sugar levels
Collagen
Bones, ligaments, and tendons, walls of
blood vessels
Part of your structure
Haemoglobin In red blood cells
Carries oxygen from lungs to
respiring cells/tissues
Protease
In stomach and small intestine
Digests proteins in food
Antibodies
Blood
Defence against infections/lock on to
antigens on surface of pathogens
B Amino acids, ribosomes, genes, gene, DNA, function, site, membrane, meat, collagen,
haemoglobin, enzymes.
Practical activities have been checked for health and safety advice by CLEAPSS.
All users will need to review the risk assessment information and may need to adapt it to local circumstances.
© Oxford University Press 2011
This document may have been altered from the original.
402