Unit 1 Cells and Cell
Processes
1.1 Characteristics of living organisms
What you need to be able to do:
•
•
List and describe the characteristics of living
organisms
Define nutrition, excretion, respiration,
sensitivity, growth, reproduction and
movement
Starter
Read the definition and name the life
process
An action by an organism or part of an
organism causing a change of position or
place
MOVEMENT
The chemical reactions that break down
nutrient molecules in living cells
to release energy
RESPIRATION
The ability to detect or sense changes in the
environment (stimuli) and to make responses
SENSITIVITY
A permanent increase in size and dry mass by
an increase in cell number or cell size or both
GROWTH
The processes that make more of the same
kind of organism
REPRODUCTION
Removal from organisms of toxic materials, the
waste products of metabolism and substances
in excess of requirements
EXCRETION
The taking in of nutrients which are organic
substances and mineral ions, containing raw
materials or energy for growth and tissue
repair, absorbing and assimilating them
NUTRITION
Characteristics of living things
A mnemonic to help you remember:
Say what you see!
e
M ovement
R espiration
S ensitivity
G rowth
R eproduction
E xcretion
N utrition
Tasks
1. Match up the pictures and descriptions of the
life processes in your booklet.
2. Complete the Living Things crossword.
1.2 Classification systems
What you need to be able to do:
Define and describe the binomial system of
naming species
List the main features of the following
vertebrate groups - bony fish, amphibians,
reptiles, birds and mammals
Know of other classification systems,
e.g.cladistics
List the main features used in the
classification of viruses, bacteria and fungi
•
•
•
•
Starter
Watch the BrainPop video "Classification"
Biological Classification
Binomial Nomenclature
While you watch the video write down the rules
for naming organisms
Two names
What does binomial mean?
Rules for binomial classification
1. All organisms have a two part name
2. The first part of the name is the Genus and
starts with a capital letter
3. The second part of the name is the species
and starts with a lowercase letter
4. If the name is written by hand it is underlined
5. If the name is typed it is italicised.
Taxomomic Hierarchy
The binomial system gives each organism a two
part name showing the genus and species
Genus species Genus species Genus species
Panthera leo
Panthera tigris
Panthera onca
Other classification systems
Cladistics
A method of classification that relies upon lines of descent
(evolutionary history) rather than physical similarities
Other classification systems
Previously scientists used the morphology
(observable features) of organisms to put
them into groups.
Now many species are being reordered
because of similarites and differences in their
DNA
Tasks
1. Write a mnemonic to help you remember the
order of the taxonomic groups
2. Find the classification and the binomial name
for modern man
3. Complete past paper question 1
Starter
Watch BrainPop "The Six Kingdoms"
Tasks
1. Use your textbook and what you saw in the
video to complete the Key Features of the
Kingdoms table in your booklet.
Viruses
Watch the BrainPop video "Viruses"
Viruses are not included in the 5 kingdom
classification. Can you think why?
Viruses
Consist of:
•
•
An outer protein coat or capsid
Genetic material - a nucleic acid (DNA or
RNA)
•
May be helical, icosahedral in shape or
phages
•
e.g. HIV, influenza, measles, herpes simplex
Viral Structure
Tasks
1. Label the diagrams of the two viruses
2. Watch this video
3. Draw a storyboard to explain how viruses
use human body cells to replicate
Kingdom Fungi
Watch the BrainPop video "Fungi"
•
Fungi were originally classified as plants.
•
Why was this classification incorrect?
•
•
Fungi are eukaryotes with cells similar to
plants and animals.
They are usually saprophytes and feed on
dead or decaying plant and animals
Yeast
•
•
•
Sacchcaromyces
cerevisiae
Single celled
Reproduces by
budding
(asexual
reproduction)
Used in brewing
and baking
Yeast Structure
Mucor hiemalis
Consist of tubes called hyphae
Many hyphae make a mass
called a mycelium
Secrete enzymes to digest
•
•
•
Fungal Structure
Edible mushroom
•
•
•
Reproduce sexually
using fruiting bodies
which can be large (and
edible!)
New fungi are produced
from spores.
Spread via water which
is why fungi are found in
damp places
Mushroom and toadstools
Tasks
1. Draw and label a yeast cell and pin mould
2. Answer the questions in your booklet
3. Answer past paper question 2
Kingdom Bacteria
Watch the BrainPop video "Bacteria"
•
Prokaryotic organisms - made of simple
cells without a nucleus
•
Cause infectious diseases
•
Can be treated with antibiotics (against life)
•
e.g. Escherichia coli, Salmonella sp.
Bacterial Structure
Bacteria
•
•
Can be rods, spirals
or spheres
Reproduce asexually
by binary fission
Tasks
1. Draw and label a typical bacterial cell
2. Complete past paper question 3
Kingdom Animal - Vertebrate Groups
Starter
Watch the BrainPop video "Vertebrates"
Make a list of the features of each vertebrate
group
What is the common feature of all vertebrates?
Mammals
Mammals
•
•
•
•
•
•
Warm blooded (homeotherms)
Breathe using lungs
Body covered with hair or fur
Internal fertilisation
Viviparous
Offspring develop internally supported by
placenta
•
Feed young using milk (suckle)
Birds
Birds
•
•
•
•
•
•
•
Warm blooded
Bodies covered with feathers
Have beaks
Breathe using lungs
Internal fertilisation
Lay eggs with hard shells
e.g. penguins, owls, pigeon, sparrow
Reptiles
Reptiles
•
•
•
•
•
•
Cold blooded (ectotherms)
Breathe using lungs
Body covered with hard scales
Internal fertilisation
Lay soft shelled (leathery) eggs
e.g. crocodile, iguana, turtle
Amphibians
•
•
•
•
•
•
•
•
Amphibians
Cold blooded
Have lungs but small and not used much
Thin moist skin
External fertilisation
Eggs covered in jelly
Have an aquatic stage (tadpoles)
Metamorphosis (change) into adults
Adults live on land but breed in water
Fish
Fish
• Cold blooded
• Live entirely in water
• Breathe using gills
• Body covered in scales
• Have fins for locomotion
• External fertilisation
• e.g. herring (salt water), trout (freshwater)
Tasks
1. Complete the table of features of the
Vertebrate Groups in your booklet.
2. Watch BrainPop "Fish and Gills"
3. Dissect and draw a fish
4. Complete past paper question 3
Biological Drawing
•
Clear outline - no sketching (single lines, no
crossover)
•
•
•
•
Proportion - it should look like the object!
Size - fill the space given (half a page of A4)
No shading/colouring
Label - use a pencil and ruler to draw lines
(no crossed lines)
Spot the difference. What is wrong?
lines cross over
shading
thick lines
label lines cross over
l
Review
Which vertebrate group(s)?
1. Have scales?
fish and reptiles (and birds on their legs!
2. Breathe using lungs?
birds, mammals, reptiles, amphibians
3. Lay eggs?
birds, reptiles, fish amphibians (and duck billed platypuses)
4. Reproduce using internal fertilisation?
birds, mammals
5. Feed their young using milk?
mammals
6. Are warm blooded?
mammals and birds
1.3 Adaptations of organisms
What you need to be able to do:
•
List the main features used in the classification of:
- flowering plants (monocotyledons/dicotyledons)
- Arthropods (insects/crustaceans/arachnids/myriapods)
- annelids
- nematodes
- molluscs
Invertebrate Groups
Go to http://ngm.nationalgeographic.com/2011/01/sevenbillion/biodiversity-game
and play the diversity game.
Watch BrainPops video "Invertebrates"
Invertebrate = without backbone
Invertebrate Groups
As you have seen, there are many types of
invertebrate!
Luckily you only need to know these 4 groups:
Annelids
Nematodes
Molluscs
Arthropods
INVERTEBRATES
ANNELIDS
ARACHNIDS
MOLLUSCS
CRUSTACEANS
ARTHROPODS
INSECTS
NEMATODES
MYRIAPODS
•
•
•
•
Annelid
If all the material
s
that has ever passed
through earthworms
Bodies made of many segments.
was piled up, the
heap would be 30
May have a head and/or antennae
miles tall - more
than 5x the height
Chaetae (tiny hairs) for locomotion
of Everest!
e.g. earthworm
Mollusc
s
•
•
Soft unsegmented bodies
Internal or external hard shell (calcium
carbonate)
•
•
•
The
giant
squid
is
Muscular foot
the world's largest
invertebrate - it
Secretes mucus (for locomotion)
can grow to over 50
e.g. slug, snail, clam, octopus
feet with eyes the
size of
basketballs!
Nematodes
•
•
•
•
•
Bodies are not segmented
No obvious head
Long and thin
Never have chaetae
The 3 main human
Many are parasites of the digestive system!
diseases caused by
nematodes are
ascariasas,
hookwork infection
and elephatiasis!
Arthropods
Watch BrainPop "Arachnids" and "Insects"
Arthropod =
jointed legs
(Arthritis = inflammation of the joints)
All arthropods share three characteristics.
Look at the pictures on the next slide and tell
me what they are...
Did you get them?
•
Jointed legs
•
Exoskeleton
•
Body of two or more segments
How is each of these features beneficial to
arthropods?
Crustaceans
•
•
•
•
•
e.g. crabs, prawns, woodlice
Extra strong exoskeleton (calcium salts)
Many pairs of legs (5+)
2 pairs of antennae
2 main body parts
- cephalothorax (joined head and thorax)
- abdomen
Arachnids
•
•
•
•
e.g. spiders, scorpions, mites and lice
2 body parts (like crustacea)
4 pairs of legs
No antennae
Myriapods
Myria = ?
•
•
•
•
e.g. centipedes and millipedes
Many body segments
Many pairs of legs
1 pair of antennae
Pod = ?
Insects
•
•
•
e.g. ants, butterflies, bees, beetles
The biggest group of invertebrates
3 body segments
- head, abdomen and thorax
•
•
•
3 pairs of legs
1 pair of antennae
Many have wings (not an identifying
Tasks
1. Annotate the diagrams of each of the
invertebrate animals with their main features.
2. Complete the table of the arthropods groups.
3. Answer past paper questions 5 and 6.
Kingdom Plants - Flowering Plants
Starter
Watch BrainPops "Seed Plants"
Compare the two specimens you have in front
of you. Make a list of differences.
Monocotyledon
Dicotyledon
Monocotyledon
Dicotyledon
Monocotyledon
Dicotyledon
Tasks
1. Complete the table of differences between
monocots and dicots in your booklet.
2. Include some examples of each.
1.4 Simple Keys
What you need to be able to do:
•
Use simple dichotomous keys based on
easily identifiable features
http://www.district158.org/sdelorenzo/Biology/Foundations/
making_a_dichotomous_key.htm
Simple Dichotomous Keys
Dichotomous = two branches
The key to keys!
Observable features (what you can see!)
Either
Questions with yes/no answers
Answer questions and follow branches to the
end
or
Pairs of statements
Choose the most appropriate statement
Follow the instruction (go to...) until you get to
Making a key
1. Look at the drawings of the beetles.
2. Choose ONE observable characteristic and sort the beetles
3.
4.
5.
6.
into two groups based on whether they have the
characteristic or not.
Record the chosen characteristic and write the numbers of
the beetles under either Group 1 or Group 2 on your
diagram.
Select another characteristic of each subgroup, and repeat
step 3.
Repeat this process until you have only one beetle in each
group.
Once the diagram is complete, use it to create a
dichotomous key for the beetles.
1. Create a series of numbered steps with the first step
2.
3.
4.
showing the first characteristic you used.
At each step, offer two choices for classifying the beetle
based on a single characteristic.
e.g. you may have used the characteristic “antennae
longer than front legs” as your first dividing
characteristic.
The first numbered step in your key would be:
(1a) antennae longer than front legs................Go to 2
(1b) antennae not longer than front legs...........Go to 3
1.5 Cell Structure and Organisation
What you need to be able to do:
•
•
•
•
State that living organisms are made of cells
Identify and describe the structure of a plant
cell (palisade cell) and an animal cell (liver cell)
as seen under a light microscope
Describe the differences in structure between
typical animal and plant cells
Relate the structures seen under the light
microscope in the plant cell and the animal
cell to their functions
Starter Label the parts of the light
microscope.
What does each part do?
Try the echalk
microscope
labelling activity
revolving mount
objective lens
eyepiece lens
neck
stage
slide clips
diaphragm
coarse focus
fine focus
light source
base
Tasks
http://www.kscience.co.uk/animations/animal_c
ell.htm
http://www.kscience.co.uk/animations/plant_cell
.htm
Watch BrainPop video "Cells"
Cell Structure
Parts common to all cells
Nucleus - contains genetic material which
controls the activities of the cell
Cytoplasm - chemical reactions take place
here, controlled by enzymes
Cell membrane - partially permeable, controls
what comes in and out of the cell
Mitochondria - aerobic respiration occurs here
to release energy
Plant cells have these extra features
Cell wall - strengthens the cell and provides
support
Chloroplasts - contain chlorophyll which
absorbs light energy for photosynthesis
Large permanent vacuole - contains cell sap
to keep the cell turgid
Note: animal cells may contain small,
temporary food vacuoles
Looking at animal cells
Preparing a temporary mount of cheek cells
Try the echalk
activity preparing
cheek cells
Looking at plant cells
Preparation of onion skin temporary mount
Look at the echalk activity - preparing onion cells
Tasks
1. Make biological drawings of each of your
slides.
2. Remember the rules!
3. Add a title and label the parts you can see.
4. Answer past paper question 7.
Review Cells Revision Video
1.7 Size of Specimens
What you need to be able to do:
•
Calculate the magnification and size of
biological specimens using millimetres as
units
Starter
In Biology we study molecules to habitats. The size
of these things varies enormously!
Look here: http://www.cellsalive.com/howbig.htm
and here: http://scaleofuniverse.com/
In the last lesson we used microscopes to look at
cells. You used 10x and 40x lenses to magnify
them.
Magnification
How much an object is magnified under the
microscope is calculated as follows:
total magnification = eyepiece lens x objective lens
So, if we use a 10x eyepiece lens and a 10x
objective lens the total magnification is:
10 x 10 = 100x magnification
•
Calculating magnification of
biological drawings
The drawing you make of an object under a
microscope is usually much larger than the
object’s actual size
You need to indicate how much bigger
There are three things involved in magnification
calculations;
- the size of the drawing
- the actual size of the object
- the magnification of your drawing
(how much bigger your drawing is compared to
the real thing)
•
•
Magnification formula
To find the magnification of your drawing, the
formula is:
magnification =
size of drawing (mm)
size of the real thing (mm)
To find the size of your drawing is easy – just measure it with
a ruler (in mm)
The size of the real thing is usually given to you. BUT, you
must convert to mm to use the formula
Estimating Cell Size
We can use a clear plastic ruler to estimate the
size of cells.
Appearance of ruler at 100x
magnification
Appearance of onion cells at 100X
magnification
Estimating the size of cells
Imagine the
ruler lines!
1
2
Average cell width
12 cells = 1mm
so 1 cell = 0.083 mm
Remember
it is only an
estimate!
5
Count the
number of
cells in 1 mm
Average cell length
5 cells = 1 mm
so 1 cell = 0.2 mm
Tasks
1. Prepare an onion skin slide and estimate the
average length and width of the cells
2. Answer past paper question 8.
1.6 Level of Organisation
What you need to be able to do:
Relate the structure of the following
to their functions:
- ciliated cells
- root hair cells
- xylem vessels
- muscle cells
- red blood cells
Define: tissue, organ and organ system
•
•
Starter
Describe the cell shape and
say how it helps it do it's
job
Describe the cell's shape and say how it helps
it do it's job
Describe the cell's shape and say how it helps
it to do its job
Describe the cell's shape and say how it helps
it to do its job
Describe the cell's shape and say how it helps
it do its job
Describe the cell's shape and say how it helps
it do its job
Describe the cell's shape and say how it helps
it do its job
Tasks
Complete the specialised cell card sort and
complete the table.
Review
Watch BrainPop "Cell Specialisation"
Tissue, Organs and Organ Systems
Starter
Body organs game
Work in groups
On the large piece of paper draw around the
smallest person
Draw in the main body organs
1 point for position, 1 point for shape
Tasks
Define these terms:
Tissue
a group of cells with similar structure working
together to perform a shared function
Organ
a structure made up from a group of tissues,
working together to perform specific functions
Organ system
a group of organs with related functions,
working together to perform body
functions
A tissue is a group of cells of similar structure
that perform a shared function
Plants have tissues too!
Organs are structures made of a group of tissues,
working together to perform specific functions
Organ systems are groups of organs with related
functions, working together to perform body
functions
Levels of organisation
smallest
largest
cell
alpha
and beta
cells
tissue
organ
pancreatic
tissue
pancreas
organ system
digestive
system
organism
human
being
Tasks
1. Name each of the human organ systems A to K
2. Using the example on the previous slide, draw
a flowchart starting with a nerve cell.
Review
Play the game!
http://www.bbc.co.uk/science/humanbody/body/int
eractives/3djigsaw_02/index.shtml?organs
1.8 Diffusion
What you need to be able to do:
•
•
Define diffusion
Describe the importance of diffusion in
gases and of water as a solvent
What substances need to go in and
out of a cell and why?
Respiring animal cell:
oxygen
glucose
carbon
dioxide
water
Photosynthesising plant cell:
carbon
dioxide
glucose
water
oxygen
Substances can move in and out of cells in 3 ways
diffusion, osmosis and active transport
Diffusion
Starter
Watch BrainPops "Passive Transport"
Add potassium permanganate to hot and cold
water and observe
Tasks
Can you describe what happens using the
following words?
particles, low, concentration, down, high,
movement, random, concentration gradient.
Describe and explain how temperature affects
diffusion.
Watch the echalk diffusion animation
The importance of diffusion
Diffusion is the random movement of particles
from a region of high concentration to a region
of low concentration down a concentration
gradient.
Where in the human body is this important?
Watch this video and complete the table in your
booklet:
Review
Apart from temperature, what other factors affect the rate of
diffusion, how and why?
Particle size
Smaller size
= faster rate
Smaller particles move
faster than larger ones
(less energy needed)
Diffusion
distance
Shorter distance
= faster rate
Less distance takes
shorter time to
travel
Concentration
gradient
Bigger difference
= faster rate
Greater net movement
down concentration
gradient
What other important feature is often seen in parts of the body
where dffusion occurs?
A LARGE SURFACE AREA
1.10 Osmosis
What you need to be able to do:
•
•
•
Define osmosis
Describe the importance of osmosis in the
uptake of water by plants and its effects on
plant and animal tissues
Describe and explain the importance of a
water potential gradient in the uptake of
water by plants
Starter
Define the following and give an example:
Solute
the substance that dissolves in a
liquid to form a solution e.g. salt
Solvent
the liquid in which a solute
dissolves e.g. water
Solution
the mixture formed when a solute
has dissolved in a solvent
e.g. salt water
•
Water potential
Usually in cells/body fluids water is present
as part of a solution.
e.g. blood plasma is mostly water with
dissolved salts. gases and proteins.
Water potential is the tendency for water to
leave a solution
•
The more water in the solution (the more
dilute) the higher the water potential and the
greater the tendency for water to leave.
Water potential
partially permeable membrane
Dilute solution
Low solute
concentration
High water
potential
Concentrated
solution
High solute
concentration
Low water
potential
NET movement of water from left to right
Osmosis
Osmosis is the diffusion of water molecules from
a region of high concentration to a region of low
concentration through a partially permeable
membrane.
•
•
A partially permeable membrane will let
water (and other small molecules) pass
through but not solute molecules.
Cell membranes are partially permeable and
this allows cells to control what goes in and
out.
Tasks
1. Watch the echalk osmosis animation
1. Complete the potato chip experiment
Osmosis in potatoes experiment
Aim: to practically demonstrate osmosis at work
1. Take 6 boiling tubes and a test tube rack
2. Label the tubes 100%, 80%, 60%, 40% , 20% and 0%.
3. Measure out 20 ml of each solution into the appropriate
test tube.
4. Cut six equal sized pieces of potato, record the mass of
each one and add to the tubes.
5. Seal each tube with a bung.
6. Label your test tube rack and leave on the bench.
7. Results will be collected later in the week.
Tasks
Answer these questions about the practical
1. Write a hypothesis (what you think will happen
and why)
2. List the ways you have made it a fair test
3. What variables have you controlled?
4. What variable have you changed?
5. Why did we seal the tubes with a bung?
6. How could you make your results more
reliable?
Sample results
Concentration
of sugar
solution (%)
Mass at
start (g)
Mass at
end (g)
0
3.90
3.27
20
3.50
3.71
40
3.30
2.55
60
3.40
2.63
80
3.70
2.7
100
2.40
1.41
Change in
mass (g)
Percentage
change (%)
Describe and explain your results.
You should start by thinking about why some potato chips got
heavier and some got lighter.
Use the words: osmosis, water potential, water particles
Review
Answer past paper question 11.
What is the significance of osmosis
in plant and animal cells?
Starter
Watch this animation:
http://www.kscience.co.uk/animations/turgor.ht
m
and
http://www.kscience.co.uk/animations/plasmoly
sis.htm
Task
http://www.nuffieldfound
ation.org/practicalbiology/observingosmosis-plasmolysisand-turgor-plant-cells
A plant cell is placed in the following solutions:
a) one that is the same concentration as the cytoplasm
b) one that is more dilute
c) one that is more concentrated
Draw diagrams to predict what will happen.
Add arrows to show water movement.
More dilute
Same concentration More concentrated
The presence of the cell wall prevents a plant cell from
being damaged by water leaving and entering.
What do you think happens when an animal cell is placed
in same three solutions?
More dilute
Same concentration More concentrated
Review
Use the idea of water potential to explain what
happens with these visking osmometers
Explanation
In the first osmometer:
The water potential in the beaker is high while the
water potential in the visking tubing is low.
Water moves by osmosis down the concentration
gradient from the beaker into the visking tubing
through the selectively permeable membrane.
Now write your own explanation for the second
osmometer.
1.9 Active Transport
What you need to be able to do:
•
•
Define active transport
Discuss the importance of active
transport, e.g. ion uptake by root hair
cells and the uptake of glucose by
epithelial cells of villi
Starter
Osmosis and diffusion both occur when
substances move down the concentration
gradient.
What happens when the cell needs to move
substances in the opposite direction (against
the concentration gradient)?
Can you think of any places where this might
occur?
Active Transport
Active transport is the movement of ions in or out
of a cell through the cell membrane, from a
region of low concentration to a region of high
concentration against their concentration
gradient using energy released from respiration
(in the form of ATP)
Examples of active transport include the uptake
of mineral ions by root hair cells and the
absorption of glucose in the small intestine
Where is active transport important?
Mineral ions
Soil particle
There is a low
concentration of mineral
ions dissolved in soil
water.
The plant needs a
constant supply of
minerals (why?).
There is a higher
concentration of minerals
inside the root hair cell
than in the soil.
Where is active transport important?
Villus of small intestine
Initially, glucose
is absorbed by
diffusion. The
concentration of
glucose in the
small intestine is
high and the
concentration in
the capillaries of
the villi is low.
glucose molecule
As glucose is
absorbed the
concentration in the
capillaries increases.
Active transport is
used to ensure that
all of the glucose is
absorbed.
Tasks
1. Watch BrainPop video "Active Transport"
1. Look at the animation here :
http://www.bbc.co.uk/schools/gcsebitesize/scie
nce/add_ocr_pre_2011/homeostasis/importa
ncerev6.shtml
1. In your booklet produce a labelled diagram
to explain how active transport works.
1.11 Enzymes (1)
What you need to be able to do:
Define the term catalyst
Define enzymes
Investigate and describe the effect of
changes in temperature and pH on enzyme
activity
Explain enzyme action in terms of the
'lock and key' model
Explain the effect of changes in
temperature and pH on enzyme activity
•
•
•
•
•
Starter
Enzymes take part in these reactions.
Where do they occur? Can you name the enzymes?
amylase
Starc
h
+ water
Glucose
protease
Protein
+ water
Amino acids
lipase
Fats
+ water
Fatty acids and glycerol
Task
Carry out this experiment:
1
2
3
4
5
10 ml
hydrogen
peroxide
raw
potato
boiled
potato
copper (II) manganese
oxide
(VII) oxide
Read this information
•
•
Hydrogen peroxide is a toxic waste product
found in living things.
It has to be broken down (decomposed) to
prevent it from harming cells and tissue.
hydrogen peroxide
•
•
water
+ oxygen
This is a chemical reaction (metabolism).
Look at the results of your experiment, and
describe what happened.
Description of results
•
•
•
•
•
Decomposition of hydrogen peroxide
normally happens very slowly (tube 1).
Manganese (VII) oxide makes the reaction
happen faster (tube 5).
Copper (II) oxide does not make the reaction
faster (tube 4).
The raw potato makes hydrogen peroxide
decompose quickly (tube 2).
The boiled potato does not make the
reaction faster (tube 3)
Information
A substance which speeds up chemical
Catalyst reactions and is not changed by the
reaction
A protein which functions as a
Enzyme biological catalyst (i.e. it is found in
living things)
Both catalysts and enzymes are usually
specific (they will only speed up one type of
reaction)
Tasks
Look back at your results.
Can you explain what is happening using the
information given to you?
•
•
•
•
•
The manganese (VII) oxide is a catalyst for the
decomposition of hydrogen peroxide.
Copper (II) oxide is not a catalyst for this
reaction.
The potato is a living thing and so contains
enzymes.
The boiled potato is no longer living, therefore no
enzymes.
Tube 1 contains neither catalyst or enzyme (it is
a control) and the reaction is very slow.
Tasks
1. Watch this and make your own notes.
1. Now complete the paragraph on the next
slide by adding the key words.
Review - Properties of enzymes
biological ____________.
catalysts
Enzymes are_________
They speed up chemical reactions in _________
things. Each
living
enzyme catalyses one reaction, we say they are
specific
____________,
e.g. protease breaks down ___________
proteins
and ________
breaks down lipids (fats and oils). Their
lipase
names end in "___".
ase The enzymes are not ______
used up___ but
can be used many times to catalyse the same reaction.
The substance that the enzyme breaks down is called the
__________. The substance that is made is called the
substrate
lock and ____
key _____
________.
product They work by the ________
pH and
mechanism. Enzymes are affected by ___
____________.
temperature
temperature They have an ___________
optimum
and pH at which they work best.
slowly but at high
At low temperatures enzyme work ________
temperatures they may become ______________.
denatured
•
Factors affecting enzymes
Starter
Go to the kscience animation:
http://www.kscience.co.uk/animations/model.swf
•
Change each of the following conditions and
then write a few sentences to describe what is
happening:
- temperature
- pH
- enzyme concentration
- substrate concentraion
Factors affecting enzymes
Task
Describe and explain the shape of these
graphs:
Experiments involving enzymes
1. Amylase and starch
http://www.nuffieldfoundation.org/practicalbiology/investigating-effect-ph-amylaseactivity
2. Catalase and hydrogen peroxide
http://www.nuffieldfoundation.org/practicalbiology/investigating-enzyme-controlledreaction-catalase-and-hydrogen-peroxideconcentrat
1.11 Enzymes (2)
What you need to be able to do:
Describe the role of enzymes in the
germination of seeds, their uses in
biological washing products and in the
food industry (including pectinase and
fruit juice)
Outline the use of microorganisms and
fermenters to manufacture the antibiotic
penicillin and enzymes for use in
biological washing products
Describe the role of the fungus Penicillium
in the production of antibiotic penicillin
•
•
•
Starter
What is the difference between a biological and
a non biological washing powder?
A biological washing powder contains
enzymes
•
•
•
•
Enzymes are important in many processes
The germination of seeds is one example
They have been used by man for thousands of
years in brewing, baking and leather tanning
They can also be used in industry to make
foods and biological washing powder
Seed germination
Will grow
into plant
Starch
STARCH
amylase
MALTOSE
maltase
Water is needed for
germination
It activates the
enzyme amylase.
GLUCOSE
Amylase breaks
down starch into
maltose. Maltose is
broken down into
glucose by
maltase.
Glucose is used for
respiration.
Industrial uses of enzymes
•
Biological washing powders
•
Making soft centred chocolates
•
Pre-digesting baby food so babies can eat it
more easily
•
Making diet foods
•
Lactose free milk
•
•
•
Soft centred chocolates
A chocolate coating is poured over a solid
mixture which contains sucrose
The enzyme sucrase is injected into the
centre
Sucrase breaks down sucrose into glucose
and fructose
Baby foods
•
•
•
Proteins can be difficult for babies to digest
Proteases are added to baby food to predigest the proteins
Babies can get the amino
acids they need without
an upset stomach
Diet foods
•
•
•
Carbohydrases are used to
convert starch into glucose
syrup.
Starch is very cheap as it is
made by plants like corn.
Using enzymes to convert
starch into sugar is a cheap
source of sweetness
Diet foods
•
•
•
Glucose syrup can be converted to fructose
syrup by the enzyme isomerase
Glucose and fructose contain exactly the
same amount of energy but fructose is much
sweeter
Smaller amounts
of fructose are
needed to make
food taste sweet
Biological washing powders
•
•
•
In the past, people boiled
and scrubbed clothes to
get them clean
Now we use biological
detergents
These contain enzymes which
work at quite low temperatures
Biological washing powders
Are considered to be more "environmentally
friendly" - why?
What type of stains do we get on clothes?
What enzymes might biological detergents
contain?
Why is it recommended to wash at 30 degrees?
Apple juice
•
•
•
•
Plant cell walls are
made of cellulose
Cellulose fibres are
held together by pectin
Pectinase enzymes
are added to apple
juice
This helps to produce
Immobilised Enzymes
•
•
•
•
Enzymes are expensive to manufacture.
They also need to be removed from the
product.
To solve this problem
enzymes can be
immobilised.
The enzyme is trapped
in a jelly bead
Lactose free milk
•
Lactose is a sugar found in milk
•
Lactose is digested using lactase
•
•
•
Many adults are unable to make
the enzyme lactase
Drinking milk causes nausea and diarrhoea
Milk is passed over immobilised lactase to
produce lactose free milk
Medical Uses
•
Thrombosis - blood clot
•
Build up in damaged blood vessels.
•
•
Danger of travelling to the heart (resulting in
a heart attack) or the brain (resulting in a
stroke).
Digested away by proteases which dissolve
fibrin, from which the clot is built up.
Review
Tasks
Make a list of advantages and disadvantages of
using enzymes in industry.
Advantages
Disadvantages
Specific - produce only wanted
product
Can be denatured easily - need
to carefully control conditions
Biodegradable - less
environmental pollution
May contaminate the product product needs processing
Work at low temperatures - use
less energy
Expensive to produce initially
Efficent - only a small amount
needed and can be reused
Making enzymes for industry
•
•
•
Many enzymes are made by microbes
Can you think of a reason why?
Most industrial enzymes are made by a
process called fermentation in a piece of
apparatus called a fermenter (or bioreactor)
Other useful products, such as medicines
can also be made in this way.
Making penicillin in a fermenter
Penicillium
mould
Mixture of
carbohydrates
and amino
acids
Steam or cold
water out
Bubbles of
oxygen
air supply
Steam or
cold water in
Mixture removed and
processed
Tasks
1. Label the diagram of the fermenter in your
booklet.
2. Explain why each of the labelled items in the
diagram is necessary.
3. Complete past paper question 12.
Topic Review
1. Look back at the learning outcomes.
2. Use them to produce a revision booklet or
mind map.
3. Make sure you include the keywords and
their definitions.
4. If you are not sure about anything you have
studied ASK the teacher!