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Unit One: Cell Biology

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Title: Unit One: Cell Biology


1
Unit One Cell Biology
2
National 4/5
  • Units
  • Complete Life on Earth mid Sept
  • Cell Biology Sept - Dec
  • Multicellular Animals Jan - April

3
How is the course assessed?
  • Course work
  • 3 end of unit tests (one for each unit) can
    have resits if necessary
  • One Practical investigation
  • One mini research project (100 words)
  • One LARGE research project (Added Value) (500-800
    words)
  • NATIONAL 5 Final exam!

4
Work
  • Classwork to be done in jotter.
  • Remember it every day!
  • You will get set homework sometimes but
    expected to learn the work done each day as you
    go along!!!

5
What is in Unit One?
  • Cell Biology
  • Cell Structure
  • Transport across membranes
  • Producing new cells
  • DNA and protein production
  • Genetic engineering
  • Proteins and enzymes
  • Aerobic respiration
  • Photosynthesis

6
1 Cell Structure
7
Cell structure
  • LI 1. Identify and name the structures found in
    an animal cell.
  • 2. State the function of the structures in an
    animal cell.
  • 3. Identify and name the structures found in an
    plant cell.
  • 2. State the function of the structures in an
    plant cell.

8
Cell Structure
  • Cells are the building blocks of all life.
  • Cells video

9
Cell Structure
  • We will be looking at 4 different cell types-
  • Animal cells
  • Plant cells
  • Bacterial cells, and
  • Fungal cells.
  • You have already looked at the basic structure of
    animal and plant cells in S1- S3. We will be
    looking at all of these cells in greater detail.

10
What can you remember from last year?
  • Task One Complete the revision worksheet on
    cells.

11
Cell Structure
  • Task 2 Prepare slides for examination under a
    light microscope.
  • Using the help sheets provided prepare one type
    of slide cheek cell, onion cell or Elodea
    pondweed. After you have examined your own slide
    share your slide with a group that has prepared a
    different slide . You should look at all 3 cell
    types.

12
Cheek Cells
  • These are cheek cells viewed at 100x
    magnification using a light microscope.

http//www.stancoe.org/patterson/cms/staff/humanch
eekcellwebpage.htm
13
Onion Skin Cells
These are onion skin cells viewed at 40x
magnification using a light microscope.
http//www.baileybio.com/plogger/images/biology/la
b_-_plant___animal_cells/onion_cells.jpg
14
Elodea Pondweed Cells
These are Elodea pondweed cells viewed at 100x
magnification using a light microscope
http//seys-science.wikispaces.com/elodeag
15
Cell Structure
  • We will now look in more detail at the structure
    of animal and plant cells.
  • To see more detail or the ultra structure of
    cells we need to use and electron microscope.

Image from Wikipedia commons http//en.wikipedia.o
rg/wiki/FileElectron_Microscope.jpg
16
Cell Structure - Organelles
  • Organelle is the name given to the structures
    found inside the cell e.g. Nucleus, vacuole,
    chloroplasts etc.
  • You need to know about 2 more organelles.
  • Mitochondria and Ribosomes

17
Mitochondria
  • Mitochondria are the power houses of cells. They
    convert energy into forms that are usable by the
    cell. They are found in the cytoplasm and are the
    sites of cellular respiration which generates
    fuel for the cell's activities.

Mitochondria are found in the cytoplasm of the
cell.
18
  • Electron microscope image of a mitochondrion
  • (credit Tom Deerinck and Jeff Martell/MIT)

http//people.eku.edu/ritchisong/ritchiso/mitochon
drion2.gif
19
Ribosomes
  • Ribosomes can be found floating free in the
    cytoplasm or attached to another type of
    organelle called Rough Endoplasmic Reticulum or
    R.E.R. for short. (you dont have to know about
    R.E.R!)

20
Ribosomes are responsible for protein synthesis,
i.e. this is where amino acids are assembled into
proteins.
Electron Microscope image of ribosomes.
http//www.cbv.ns.ca/bec/science/cell/page11a.gif
http//bioweb.uwlax.edu/genweb/molecular/theory/tr
anslation/ribosome.jpg
21
Cell Structure Organelles
  • Task 3 Collect the diagram sheets of the animal
    cell and the plant cell. Label any structures you
    recognise.
  • You will need to include- Cell membrane,
    nucleus, cell wall, vacuole, chloroplast,
    cytoplasm, ribosome and mitochondria.

22
Animal Cell Diagram
Cytoplasm
Nucleus
Ribosomes
Mitochondrion
Cell Membrane
23
Plant Cell Diagram
Ribosomes
Mitochondria
Cell Membrane
Cytoplasm
Cell Wall
Chloroplast
Nucleus
Vacuole
24
Cell Structure - Organelles
  • Task 4 Collect and complete the worksheet
  • Cell structures and functions.

25
Bacteria and fungi
  • LI 1. Identify and name the structures found in
    a bacterial cell.
  • 2. State the function of the structures in a
    bacterial cell.
  • 3. Identify and name the structures found in a
    fungal cell.
  • 4. State the function of the structures in a
    fungal cell.

26
Bacterial Cells
  • For the first half of geological time our
    ancestors were bacteria. Most creatures still are
    bacteria, and each one of our trillions of cells
    is a colony of bacteria.
  • Richard Dawkins

27
Bacteria
  • TThey are the oldest living organisms on earth.
    They are everywhere. We find them on and in the
    human body, in the air we breathe, on the
    surfaces we touch, in the food we eat. Almost 99
    of these bacteria are helpful, whereas the
    remaining are the notorious ones. Some are
    essential for proper growth of other living
    beings. They are either free-living or form a
    symbiotic relationship with animals or plants.

http//en.wikipedia.org/wiki/FileGram_Stain_Anthr
ax.jpg
28
Structure of Bacteria
  • Bacteria can occur in different shapes. However
    their basic structure is the same.
  • Task Collect the bacterial cell diagram handout
    and the information sheet.
  • Use the information to complete the labels on the
    diagram and to complete the table.

29
Cytoplasm
Cell Wall
Capsule
Plasmid
Genetic material
Cell Membrane
30
Structure Function and importance
Capsule
Cell Wall
Cell Membrane
Genetic Material
Plasmid
Cytoplasm
Provides additional protection from the
environment
It strengthens and supports the cell
Controls the movement of substances into and out
of the cell
Made of DNA and controls the activities of the
cell
Circular genetic material. Can convey special
abilities, e.g. a resistance to certain
antibiotics. They can be manipulated by man to
produce bacterial cells that produce useful
products e.g. Insulin, hormones and enzymes.
Most chemical processes take place here
controlled by enzymes
31
Structure of a fungal cell
  • Task Collect the diagram sheet and label any of
    the structures and organelles you recognise.

32
Structure of a fungal cell
Nucleus
Cell Wall
Cytoplasm
Vacuole
Cell Membrane
33
  • All the cell parts are now familiar. You should
    be able to compare all the cell types and
    identify which parts are similar and which are
    not. While all the cell parts have the same
    functions as before there is one difference.

The fungal cell wall.
Just as the bacterial cell wall has a different
chemical structure from a plant cell wall, so
does the fungal cell wall. The fungal cell wall
is made from a chemical called chitin.
34
It is important that you know
  • The cell walls in plant, bacterial and fungal
    cells is structurally and chemically different.

35
Measuring cell size
  • LI 1. Be able to calculate the length and
    breadth of cell seen through a microscope.

36
Just how tiny are cells?
  • How big?
  • This link will show you how tiny cells are.
  • Cells can be seen more clearly using a microscope.

37
Magnification
  • Total magnification is worked out by multiplying
    the eyepiece lens magnification by the objective
    lens magnification.

Eyepiece Lens
Objective Lens
38
Copy and complete this table
Eyepiece lens magnification Objective lens magnification Total magnification
X 10 X 4
X 10
X 100
39
Working out the size of a cell
The field of view is the area you can see down
the microscope.
Field of view
Length of each cell (mm)

Number of cells
e.g. 2 5 0.4 mm So each cell measures 0.4 mm.
40
Field of view 2 mm
Collect a version of this diagram. Your teacher
will tell you how many cells to draw in the
circle. Calculate the length of your cell in
millimetres (mm). Swap with other and calculate
the length of their cells.
41
2. Transport across cell membranes
42
The cell membrane
  • LI 1. Describe the composition of the cell
    membrane
  • 2. Describe how the structure of the membrane
    relates to its permeability.
  • 3. Define the term passive transport

43
The Cell Membrane
  • The cell membrane (or plasma membrane) is made up
    of a bilayer of lipids with protein scattered
    throughout and is selectively permeable.
  • Proteins can
  • be attached to the surface
  • be embedded within the bilayer
  • span the whole bilayer
  • form channels in the lipid bilayer

44
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45
  • Small molecules can pass through pores in the
    membrane made by channel forming proteins and
    enter or leave the cell. This is why the plasma
    membrane is selectively permeable.
  • This transport of molecules is passive and
    requires no energy as it is with the
    concentration gradient.

46
Diffusion
  • LI 1. Define the term diffusion
  • 2. Explain how the process of diffusion occurs
    across a selectively permeable membrane.

47
Diffusion
  • Diffusion is the name given to this movement of
    the molecules of a substance from a region of
    high concentration of that substance to a region
    of low concentration of that substance until the
    concentration becomes equal.

48
Diffusion Activity
  • Cut a 20cm piece of visking tubing and tie a knot
    in one end.
  • Soak the tubing in water and never let it dry out
    during the experiment.
  • Fill the visking tubing with 5-10cm3 starch and
    glucose solution and seal with another knot.
  • Place this in a boiling tube of water completely
    submerged and leave until the next lesson.

49
  • Take a small sample of the water from around the
    test tube. Test for starch and sugar

3. If starch is present it goes from brown to
black
50
Activity
  • Perform Benedicts test and starch test on the
    water in the boiling tube from Diffusion in a
    Model Cell experiment you set up last lesson.
  • Explain your results in terms of diffusion. (LO1
    assessment).

51
Importance of diffusion to cells
  • In an animal cell, food (such as glucose), oxygen
    and carbon dioxide will diffuse like this

52
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53
Substances which diffuse in or out of cells
Diffuse IN Diffuse OUT
Oxygen (raw material for respiration) Carbon dioxide (waste from respiration)
Carbon dioxide (PLANTS ONLY, raw material for photosynthesis) Oxygen (PLANTS ONLY, made in photosynthesis)
Glucose (raw material for respiration) Urea (a cell waste product)
Amino acids (raw materials to build the cell)
54
Osmosis
  • LI 1. Define the term osmosis
  • 2. Explain how the process of osmosis occurs
    across cell membranes.
  • 3. Describe the effects of osmosis on animal and
    plant cells.

55
Gummi bears in water
  • Take a gummi bear (Haribo works best) and measure
    its height and width.
  • Place in a 50 ml beaker of water.
  • Leave for several days.
  • Carefully remove from the water, and measure the
    height and width.
  • What has happened to the Gummi bear? Why has this
    happened?

56
Osmosis the diffusion of water
57
Osmosis
  • The diffusion of water through a
    selectively-permeable membrane from an area of
    high concentration of water molecules to an area
    of low concentration of water molecules is called
    osmosis.

58
Effects of Osmosis on Plant Cells
Cells in a dilute solution become turgid
Cells in concentrated solutions become flaccid.
Cells in the same solution stay the same.
Plasmolysed cell cytoplasm is pulled away from
the cell wall.
59
Turgid Cells
  • Osmosis makes plant cells swell. Water moves into
    the plant cell vacuole and pushes against the
    cell wall. The cell wall stops the cell from
    bursting. We say that the plant is turgid. This
    is useful as it gives plant stems support.

60
Flaccid Cells
  • If a plant lacks water, it wilts and the cells
    become flaccid as water has moved out of the
    cell. If alot of water leaves the cell, the
    cytoplasm starts to peel away from the cell wall.
    We say the cell has undergone plasmolysis.

61
Osmosis in Animal Cells
62
Active transport
  • LI
  • Define the term active transport
  • Explain how active transport occurs across cell
    membranes.

63
Active Transport
  • Active transport is the movement of molecules
    across a cell membrane from a low to a high
    concentration i.e against a concentration
    gradient.
  • Active transport works in the opposite direction
    to the passive transport of diffusion and always
    requires energy.
  • This energy is released during respiration.

64
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65
3. Producing New Cells
66
Producing new cells
  • LI
  • Describe the stages of mitosis.
  • Describe the maintenance of the diploid
    chromosome complement by mitosis.
  • Explain why mitosis is used by cells.

67
Everyone in this room started life as a single
cell, a fusion of a sperm and egg cell. What
processes must have happened to develop you from
that single cell?
68
How many new cells do you think you will make in
a day?
  • Cell Division throughout Life

69
330 000 000 in 20 minutes so
  • 23,760,000,000 new cells every day!

70
What do these pictures all have in common?
71
They are all examples of Cell Division in action
for growth or repair!
72
How do Cells Divide?
  • Mitosis watch this clip on the process of
    mitosis and answer the following questions
  • How are new cells produced?
  • What are chromosomes? Where are they found?
  • What kind of cells undergo mitosis?
  • What are the only kind of cells that do not
    undergo mitosis?

73
Put the following stages of mitosis in the
correct order
  • New nuclear membranes form around the
    chromosomes, followed by new cell membranes,
    creating two new identical cells.
  • Chromosomes replicate to form identical
    chromatids.
  • Spindle fibres then pull the matching chromatids
    apart, to opposite poles of the cell.
  • The membrane around the nucleus breaks down, and
    spindle fibres attach to the chromatids and line
    them up in the centre of the cell - equator.

74
Why do chromosomes need to be copied so carefully
and put into each new cell?
  • Chromosomes carry GENES, which are stretches of
    DNA.
  • Each GENE codes for one protein e.g. one gene
    codes for haemoglobin, the substance in red blood
    cells that carries oxygen. Other genes will code
    for other molecules that make up the body.

75
Chromosome Complement
  • The number of chromosomes that a species of
    animal or plant possesses.
  • Why so you think it is important that each new
    cell has the same chromosome complement as the
    parent cell?

76
  • During growth and development of an organism will
    be able to provide the animal or plant with all
    the characteristics of its species.
  • Losing any chromosome would mean a loss of
    genetic information the information that forms
    the code allowing the cell to function correctly!

77
What goes wrong in Cancer?

Decreased cell death more cells
Ability to invade surrounding tissues
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Increased cell division more cells
Loss of contact inhibition the cells no longer
stay in one place
Ability to move - metastasis
Escape from immune surveillance cells not
destroyed
Loss of DNA Repair
78
Cancer cells Research Task
  • 1. Find out the meaning of the following terms
  • Benign
  • Malignant
  • Metastasis
  • 2. Research a type of cancer and find out the
    following
  • What part of the body does this cancer affect?
  • What are the clinical symptoms?
  • How common is this cancer (in the UK)?
  • What is the treatment given for this cancer?
  • What research is being done on this cancer?
  • Is there a charity fundraising to help support
    people affected by this type of cancer?

79
Cell culture
  • LI
  • Describe how cells are produced using
    cell-culture techniques.
  • Describe the aseptic techniques that are used
    when culturing cells.

80
Cell culture
  • Growing cells in the laboratory is known as cell
    culture.
  • To grow cells in the lab you need
  • A suitable growing medium
  • Availability of oxygen
  • A suitable temperature
  • A suitable pH level

81
Cells can be grown in nutrient broth in
fermenters or flasks. Or the broth can be mixed
with agar to make a solid agar plate.
82
To provide ideal growing conditions cultures are
grown in incubators. These allow temperature,
humidity, pH, carbon dioxide and oxygen levels to
be controlled.
83
Aseptic techniques
  • In order to work with cell cultures you have to
    use aseptic techniques in order to prevent
    contamination.
  • Your teacher will then show you how to streak out
    bacterial colonies using aseptic techniques.

84
  • Read page 45 of the textbook. Using what you
    learned streaking out the bacteria, take a page
    in your jotter and create a Guide to being
    aseptic.

85
4. DNA and Protein Production
86
DNA
  • LI
  • Describe the structure of DNA.
  • State the names of the four bases that make up
    the genetic code.

87
What is DNA?
Watch the following video that introduces DNA and
its importance. DNA video
88
DNA, genes and chromosomes
Chromosomes The cells nucleus contains
chromosomes made from long DNA molecules.
DNA DNA molecules are large and complex. They
carry the genetic code that determines the
characteristics of a living thing. Genes Think
back to the last section!

89
DNA, genes and chromosomes
The diagram shows the relationship between the
cell, its nucleus and the chromosomes in the
nucleus that are made up of DNA, and genes.
Collect the handout sheet and stick it into your
jotters.
90
From Genes to Proteins?
Watch the following video that gives a basic
definition of a gene and what genes do. What
exactly is a gene?
91
DNA Structure
  • DNA consists of two molecules that are arranged
    into a ladder-like structure called a Double
    Helix.
  • A molecule of DNA is made up of millions of tiny
    subunits called Nucleotides.

92
Nucleotide Structure
  • Each nucleotide consists of

Copy this diagram into your jotters.
93
DNA Structure
  • The phosphate and sugar form the backbone of the
    DNA molecule, whereas the bases form the rungs.
    Collect the handout and stick it into your
    jotters.

94
The Genetic Code
  • The genetic code determines the order in which
    amino acids are joined together to produce a
    specific protein.
  • The code itself is determined by the order of the
    organic bases in the DNA molecule.
  • There are 4 different bases.
  • Guanine Cytosine Adenine and Thymine

95
  • Each base can only join with one other type of
    base-

Guanine always pairs with Cytosine Adenine always
pairs with Thymine
G-C and A-T
These are called complementary base pairs.
96
Complementary Base Pairs
97
Build your own DNA Molecule
Task 1 Collect the handout sheets DNA origami
instructions and template Follow the
instructions to complete your own model DNA!
98
DNA and proteins
  • LI
  • Explain the relationship between DNA and
    proteins.
  • Explain the relationship between the order of
    bases on DNA and the amino acids in a protein.
  • Describe the role of mRNA in protein production.
  • Name the basic units that proteins are made from
    and where protein synthesis takes place.

99
Protein Structure
Proteins are made up of amino acids. The order
of the amino acids determines the proteins
molecular structure, its shape and its function.
The order of the amino acids is determined by
the order of the bases in the DNA molecule the
genetic code.
100
So how does the genetic code get translated into
a protein?
101
Watch Again
Watch the What is DNA? video again. This time
try to answer the following questions- Video
  • How is the genetic code from the DNA molecule
    copied?
  • What happens to the copy of the genetic code?
  • Where does it go?
  • In which organelle is the copy of the genetic
    code
  • translated to form proteins?
  • How are the proteins formed?

102
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103
Translating the genetic code
Task 1 Using the information in the video, the
questions and discussion with your teacher write
a short paragraph to describe how the genetic
code from the DNA is translated into a protein.
You could use a diagram to help illustrate you
description.
104
Translating the genetic code
The genetic code in the DNA is copied or
transcribed by another molecule called Messenger
RNA (mRNA). The mRNA carries the code out of
the nucleus to the ribosomes in the
cytoplasm. The ribosomes then translate the code
from the mRNA into the specific protein using
amino acids found free in the cytoplasm.
105
mRNA
  • The DNA for the gene being turned into a protein
    is copied into a mRNA molecule.
  • It is different from DNA, it is
  • Shorter
  • Single stranded
  • Have URACIL instead of THYMINE.

106
How does mRNA become a protein
  • Every 3 letters in the mRNA tell the ribosome
    which amino acid to add to the protein.
  • A U G C G A U G G A C G mRNA
  • Alanine Serine Glycine Proline

107
Translating the genetic code
  • Task 3 In groups produce an A4 poster to
    illustrate protein synthesis.
  • Your poster should contain the following
    information-
  • DNA carries the genetic code for producing
    proteins
  • mRNA copies the code
  • mRNA carries the copy of the code to the
    ribosomes
  • The ribosomes translate the copy of the code to
  • produce proteins

108
5. Genetic Engineering
109
Genetic engineering
  • LI
  • Describe how genetic information can be
    transferred from one cell to another.
  • Explain the process of genetic engineering and
    the stages involved.

110
What is genetic engineering? What is it used
for?
111
  • Watch the following clip on Genetic Engineering
    and in pairs answer the following questions
  • What 3 things are produced by genetically
    modifying microbes?
  • Name the first organisms to be genetically
    modified and when this was done.
  • What does insulin normally do? What condition
    arises from not making insulin?

112
GMO Defined
  • An organism that is generated through genetic
    engineering is considered to be a genetically
    modified organism (GMO).
  • The first GMOs were bacteria in 1973 GM mice
    were generated in 1974. Insulin-producing
    bacteria were commercialized in 1982 and
    genetically modified food has been sold since
    1994.

113
The process of Genetic Engineering
  • The control of all the normal activities of a
    bacterium depends upon its single chromosome and
    small rings of genes called plasmids.
  • In genetic engineering pieces of chromosome from
    a different organism can be inserted into a
    plasmid. This allows the bacteria to make a new
    substance.

114
Task 1 Use the cut out sheet and put the stages
of genetic engineering in the correct order.
  • Use the following diagram to help you.

115
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116
Uses of Genetic Engineering 1
  • Genetic engineering is used for the production of
    substances which used to be both expensive and
    difficult to produce. Examples include
  • insulin for the control of diabetes
  • antibiotics such as penicillin
  • various vaccines for the control of disease
  • enzymes for laundry detergent

117
Uses of Genetic Engineering 2
  • Genetic engineering is a way of producing
    organisms which have genotypes best suited for a
    particular function. In the past man has used
    selective breeding to achieve this. This was done
    by choosing only his most suitable animals and
    plants for breeding.

118
  • Genetic engineering has several advantages over
    selective breeding. Some are
  • particular single characteristics can be selected
  • the selection may be quicker
  • a desirable characteristic can be transferred
    from one species to another

119
Genetic Engineering now and the future?
  • It is not just bacteria that can be genetically
    modified, plants and animals can be modified too.
  • It is therefore possible to genetically engineer
    people!
  • It holds the promise of curing genetic diseases
    like cystic fibrosis, and increasing the immunity
    of people to viruses.

120
  • It is speculated that genetic engineering could
    be used to change physical appearance,
    metabolism, and even improve mental faculties
    like memory and intelligence, although for now
    these uses seem to be of lower priority to
    researchers and are therefore limited to science
    fiction.

121
Issues?
  • There are dangers involved with genetic
    engineering since it involves creating completely
    new strains of bacteria. There is a possibility
    of creating some which are harmful to animal or
    plant life.
  • What is your opinion on GM Food (plant and
    animal), GM organisms for research and GM People?

122
Task 2 Genetically Engineering the Future
  • Thinking about the possibilities and issues
    surrounding genetic engineering, I want you to
    imagine 50 years from now. Technology has moved
    on and GMO is commonplace in agriculture,
    medicine and all organisms.
  • Write a letter to your present self, describing
    this new world. Be honest in this letter, what
    are the good and bad points about GMO in the
    future?

123
6. Proteins and Enzymes
124
Protein structure
  • LI
  • Explain how the variety of protein shapes and
    functions arises.
  • Describe some of the main functions of proteins.

125
Protein structure
  • Proteins are made up of sub-units called amino
    acids.
  • There are 21 amino acids.
  • The order of amino acids in a protein is dictated
    by the genetic code.
  • Every protein has different amino acids in
    different orders.

126
  • The order of the amino acids affects the shape of
    the protein.
  • Proteins can be fibrous or globular
  • GLOBULAR enzymes
  • FIBROUS keratin (hair)

127
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128
Protein functions
  • Read pages 58 60.
  • Make a mind-map showing the 5 main functions of
    proteins.

129
Enzymes
  • LI
  • State what enzymes are and where they can be
    found.
  • Describe the main function of an enzyme.
  • Define the terms active site and substrate.
  • Explain the relationship between the active site
    of an enzyme and its substrate.

130
Catalysts
  • A catalyst speeds up a chemical reaction, but is
    unchanged in the process and can be used over and
    over again.
  • In living things, catalysts are known as enzymes.

131
  • If cells did not have enzymes in their cytoplasm,
    then the chemical reactions which happen in our
    cells would happen so slowly that life would be
    impossible!

132
An example of an enzyme CATALASE
  • Hydrogen peroxide (H2O2) is a liquid similar to
    water (H2O), but with one extra oxygen.
  • Over a long period of time hydrogen peroxide
    naturally breaks down into water and oxygen.

133
  • The word equation for this reaction is
  • Hydrogen peroxide water oxygen
  • This process can be sped up using an enzyme.

134
Into each test tube measure out 5 ml of
Hydrogen peroxide AND 5 drops of detergent.
CAUTION!! Hydrogen peroxide is a dangerous
chemical. Safety goggles must be worn!!
  • Add nothing 2. Potato 3. Carrot
    4. Liver
  • Leave for 10 minutes. Measure the height of the
    foam bubbles.

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Test tube contents Height of foam (mm)
Nothing CONTROL
Potato
Carrot
Liver
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Conclusion
  • Only the plant and animal tissues speed up the
    breakdown of hydrogen peroxide.
  • This is because the cells contain catalase.
    Catalase is an enzyme found in living cells.

137
  • Catalase
  • Hydrogen peroxide water oxygen
  • The tissue which contained the most catalase was
    ______________.

138
Breakdown and Synthesis
  • Catalase is an enzyme involved in chemical
    breakdown.
  • Breakdown means chopping up larger molecules
    into smaller molecules.

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  • Other enzymes do the opposite the build large
    molecules from smaller molecules. This is called
    synthesis.

140
An example of a synthesis enzyme Phosphorylase
  • Glucose-1-phosphate is a chemical made by plants
    during photosynthesis. It is stored in plant
    cells be converting it into a large molecule
    called starch.

141
Phosphorylase
  • Phosphorylase
  • Glucose-1-phosphate Starch

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Substrates and products
  • The substrate is the substance the enzyme works
    on.
  • The product is the substance the enzyme makes.
  • Enzyme
  • Substrate Product

143
Enzyme Substrate Product
Catalase
Phosphorylase
Amylase
Pepsin
Lipase
144
How enzymes work
  • Enzymes are made of protein. This protein has a
    special shape which is unique to each enzyme.

Enzyme
Active site
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Substrate
Enzyme
The active site is the correct shape to fit the
substrate.
Substrate
Turned into the products
Enzyme
146
Substrate
Enzyme
Other substrates are the wrong shape to fit in
the active site of the enzyme. Therefore the
enzyme will only work with one substrate. This is
described as being SPECIFIC.
147
Specific
  • When talking about enzymes, SPECIFIC means that
    the ENZYME WILL ONLY WORK WITH ONE SUBSTRATE.

148
One enzyme one substrate
5 ml Starch 5 ml Starch 5 ml Starch 5 ml
Starch
3 ml Water 3 ml Amylase 3 ml Pepsin 3 ml
Lipase
Put in waterbath for 10 minutes. Test all 4
test-tubes with Benedicts Solution
149
Results
Sugar present?
Starch water
Starch amylase
Starch Pepsin
Starch Lipase
150
Conclusion
  • The test-tube containing Starch and Amylase had
    the most sugar.
  • This shows that only Amylase can convert starch
    to sugar.
  • Amylase is said to be SPECIFIC to starch.

151
Factors affecting enzyme activity
  • LI
  • Explain the meaning of the term optimum as
    applied to enzymes.
  • Give factors that affect enzymes and their
    proteins, and describe their effect.
  • Explain the meaning of the term denatured and
    why it happens to enzymes.

152
Effect of temperature on enzymes
153
5 ml Starch 5 ml Starch 5 ml
Starch 3 ml Cold Amylase 3 ml Amylase 3 ml 80oC
Amylase
Iced water 37oC
80oC
Put in waterbath for 10 minutes. Test all 3
test-tubes with Benedicts Solution
154
Temperature Was sugar present?
0 oC
37 oC
80 oC
155
  • All enzymes have a temperature at which the work
    fastest.
  • This is called the optimum temperature.
  • In humans the optimum temperature for all enzymes
    is 37oC.

156
  • Enzymes work slowly at cold temperatures.

157
  • At very high temperatures enzymes become changed
    and do not work.
  • This is called being denatured.
  • Once an enzyme is denatured it will never work
    again.

158
The effect of pH on enzymes
Into all 5 test tubes put 5ml Hydrogen Peroxide
and 5 drops of soap
3ml pH1 buffer 3ml pH4 buffer 3ml pH7
buffer 3ml pH9 buffer 3ml pH 14 buffer
LAST Add 1 cm cylinder of potato to each test
tube. Measure height of foam after 10 minutes.
159
Results
pH Height of foam (mm)
1
4
7
9
14
160
Conclusion
  • The optimum pH for the catalase enzyme is pH
    _______.
  • All enzymes have a different optimum pH depending
    on where they are found in the body.

161
Uses of enzymes
  • Yoghurt and cheese making
  • Biological detergents

162
Yoghurt and cheese
  • Yoghurt and cheese making depend on the
    activities of enzymes in bacteria.
  • Bacteria used lactose sugar in milk as a source
    of energy.

163
  • They make the waste product called lactic acid
    which makes the milk increasingly acidic and sour
    tasting.
  • Lactose energy lactic acid

164
  • This is another example of fermentation.

165
  • Yoghurt making
  • Milk is heated to kill microbes
  • Special yoghurt bacteria are added
  • The lactose in the milk is fermented by the
    bacteria.
  • The milk becomes acidic and so it
  • Thickens
  • Tastes sour

166
  • 2. Cheese making
  • The process is similar to yoghurt making, but
    after the fermentation, rennet is added which
    curdles the milk.
  • The solid curds are separated from the liquid
    whey.
  • The curds are then pressed into hard cheese.

167
Task 3 Note Taking
  • The following slides will tell you about
    biological detergents how they are made, why
    they are useful and their environmental impact.
  • Your task is to take notes from the slides this
    could be mind mapping key words and concepts
    under the headings above or a table of
    information or bullet point. Decide quickly which
    method you find most useful when revising and try
    it this way.

168
How Biological Detergents are produced
  • Biological detergents contain enzymes such as
    protease, amylase and lipase to digest proteins,
    starch and fats respectively.
  • Enzymes can be produced using bacteria that have
    been genetically engineered to make these
    enzymes. They are grown in industrial fermenters
    in vast quantities. This equipment ensures that
    the bacteria receive food and oxygen so that they
    grow well. The bacteria will produce the enzymes
    and pass them out into the culture liquid. The
    bacteria and the filtered off and the enzymes
    extracted from the liquid. The enzymes are
    purified and added to washing powder.

169
Value and Use of Product
  • Advantages of using biological detergents include
    reducing fuel costs as clothes can be washed at
    lower temperatures reducing the electricity
    consumption Less damage to delicate fabrics such
    as acrylic and wool whilst still cleaning
    effectively and the ability to remove difficult
    stains such as grass and blood. These will be
    completely removed by biological washing powder
    but not by non-biological even at high
    temperatures.

170
Environmental Impact 1
  • Reduced Fuel Consumption - using Biological
    Detergents has a positive impact on our
    environment as it reduces CO2 and SO2 production
    from burning fossil fuels in Power Stations to
    generate electricity.

171
Environmental Impact 2
  • Detergents are rich in chemicals called
    phosphates. This chemical passes from waste water
    from peoples homes to sewage works.
    Unfortunately it is hard to remove during
    processing and can end up in local rivers where
    they cause algal bloom. This single celled plant
    can overwhelm the balance of the ecosystem and
    when it dies can cause bacterial numbers to
    increase. The bacteria use up oxygen in the water
    which leads to the death of other organisms.

172
Task 3 Note Taking
  • Your task was to take notes from the slides it
    would be useful to check your notes with a peer.
    Have you covered similar key areas?
  • If you are not sure, the check with your teacher!

173
7. Respiration
174
Cellular respiration
  • LI
  • Explain what is meant by the term respiration.
  • Describe the build up and break down of ATP in
    cells.
  • Name the cellular uses of ATP.
  • Give the summary word equation for aerobic
    respiration.

175
Why do cells need energy?
176
Respiration Why do cells need energy?
Living cells need energy to carry out a variety
of cell functions.
177
energy from food
178
  • The three main food groups are _____,
    ____________, and __________.
  • _____ contains the most energy.

179
Aerobic Respiration

Energy in a cell is produced by a chemical
reaction called aerobic respiration.
carbon dioxide
glucose

oxygen

water
energy released
180
ATP
  • The energy produced during aerobic respiration is
    stored in a molecule called ATP (Adenosine
    triphosphate).
  • Every molecule of glucose that is burned in the
    cell produces 38 ATP molecules.

181
ATP structure
  • ATP is made up of one Adenosine and three
    phosphates

182
  • ATP is made by joining ADP (Adenosine
    diphosphate) and phosphate.
  • ADP ? Pi ATP

183
  • As a molecule to transfer energy in cells

184
Aerobic respiration
  • LI
  • Describe the stages of aerobic respiration with
    reference to the number of ATP molecules
    produced.
  • State the location of aerobic respiration in
    cells.

185
Glycolysis
  • Respiration should be seen as a series of
    enzyme controlled reactions in which
  • 6-carbon glucose is oxidised (broken down) to
    form carbon dioxide
  • this is accompanied by the synthesis of ATP
    from adenosine diphosphate (ADP) and inorganic
    phosphate (Pi).

186
(6C)
Glucose
2ADP 2Pi
2ATP
Pyruvic Acid
(2x3C)
187
  • The first stage of respiration is called
    Glycolysis.
  • This process takes place within the cytoplasm.
  • does not require oxygen
  • involves the step by step breakdown of a
    6-carbon sugar such as glucose to form two
    3-carbon pyruvic acid units
  • Glycolysis results in a production of 2ATP.

188
  • What happens next?
  • If there is oxygen available ( the normal
    situation), then the pyruvic acid produced by
    glycolysis diffuses into an organelle called
    mitochondrion for further breakdown if oxygen
    becomes available.

189
Structure of a Mitochondrion
Outer Membrane
Inner Membrane
Cristae
Matrix Fluid
190
  • Pyruvic acid from glycolysis diffuses into
    central matrix fluid
  • Pyruvic acid is broken down further in the
    presence of oxygen by a cycle of reactions called
    the Krebs cycle releasing most of the 38 ATP
    produced during respiration

191
Anaerobic respiration
  • LI
  • State when anaerobic respiration occurs.
  • Describe what happens in anaerobic respiration in
    animal cell.
  • Describe what happens in anaerobic respiration
    (fermentation) in yeast/plant cells.

192
Anaerobic respiration
  • If there is no Oxygen- Anaerobic Respiration
    occurs.
  • Anaerobic respiration occurs in human after heavy
    exercise.

193
  • Pyruvic acid is converted to either
  • (i) Lactic Acid (in animal and bacterial cells)
  • (ii) Ethanol and carbon dioxide (in plant and
    fungal cells)
  • No further ATP is made so only the net 2 ATPs
    are produced.
  • In animal cells the Lactic Acid is converted back
    to Pyruvic Acid when oxygen becomes available.

194
Complete this summary table
Aerobic respiration Anaerobic respiration Humans Yeast/Plant Anaerobic respiration Humans Yeast/Plant
Site in the cell
Number of ATP
Final products
195
Complete this summary table
Aerobic respiration Anaerobic respiration Humans Yeast/Plant Anaerobic respiration Humans Yeast/Plant
Site in the cell Cytoplasm Mitochondria Cytoplasm Cytoplasm
Number of ATP 38 2 2
Final products Carbon dioxide water Lactic acid Ethanol Carbon dioxide
196
8. Photosynthesis
197
The importance of plants
  • LI
  • Explain why plants are important.
  • Give examples of plants that are useful to man,
    and explain what they are used for.

198
Photosynthesis
  • Why are plants important?
  • What is photosynthesis?
  • What do plants need for photosynthesis?

199
The importance of plants
200
Raw materials
201
Food
202
Medicines
203
Photosynthesis Importance of plants
FOOD RAW MATERIALS MEDICINES
Wheat for bread Wood for building Poppy pain killers
Grapes for wine Cotton for clothes Foxglove heart medicine
Sugar cane for sugar Flowers for perfumes Mint menthol for cough sweets
204
Photosynthesis
  • LI
  • Give the summary word equation for
    photosynthesis.
  • Describe what happens during the light reaction.
  • Describe what happens during carbon fixation.
  • State the possible uses of the sugar made in
    photosynthesis.

205
Photosynthesis
Green plants make their own food using light
energy
Green plants convert light energy to chemical
energy (food) using a green pigment in the
leaves called chlorophyll.
206
Carbon Dioxide taken up from air
Glucose used for energy or stored as starch
Light energy - from sun
Oxygen given off as waste
Water - from soil
207
This can be summarised by the following equation
Light energy
Carbon dioxide
Water
Glucose
Oxygen
Chlorophyll
Energy source and pigment which traps it
Products Glucose is used for energy, stored
as starch or built up into cellulose Oxygen is
waste gas
Raw Materials
208
Chloroplast structure
209
Stages of Photosynthesis biochemistry
  • There are two stages of photosynthesis. The
    equation you have just learned is actually more
    complex and occurs at two separate stages.

210
Stage 1
  • The first stage is called PHOTOLYSIS.
  • This stage involves using energy from the
    sunlight to split water molecules into hydrogen
    and oxygen.

211
WATER
Oxygen
Hydrogen
ATP ENERGY
Released to the air as oxygen gas
Passed on to second stage
Passed on to second stage
212
Light energy
Chlorophyll
ADP Pi
Water
Chemical energy
ATP
Hydrogen Oxygen
Passed on to second stage
Passed on to second stage
Released to the air as oxygen gas
213
Stage 2
  • The second stage is known as the Carbon Fixation
    stage
  • Here the energy and hydrogen from stage one are
    used along with the carbon dioxide.
  • It is at this stage where glucose molecules are
    produced.

214
From the first stage
From the first stage
ADP Pi
ATP
Hydrogen
Glucose
Carbon dioxide
Enzyme controlled reactions
From the air
215
  • This stage is energy consuming so that is where
    the ATP comes in.
  • This stage is also controlled by enzymes.
  • Carbon dioxide and hydrogen join to give us
    glucose

216
What happens to the glucose?
  • Glucose which are used for energy
    (respiration)
  • Storage carbohydrates such as starch - these
    can be broken
  • down to simple sugars if needed
  • Structural carbohydrates such as cellulose -
    these are used to build
  • the cell wall

217
Limiting factors
  • LI
  • Describe the limiting factors of photosynthesis.
  • Explain the impact of limiting factors on
    photosynthesis and growth.

218
Limiting factors
Three possible factors can limit the rate of
photosynthesis in a plant when they are in short
supply -
  • Light intensity this limits the energy
    available.
  • Carbon dioxide concentration this is an
    essential raw material
  • Temperature this limits the rate at which the
    enzymes controlling photosynthesis work.

219
Effect of light on the rate of photosynthesis We
can use the rate of production of oxygen bubbles
by pond weed to measure the rate of
photosynthesis Diagram bubbler
220
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221
  • A large water trough or sheet of glass stops the
    heat from the lamp from affecting the experiment.
  • Lamp moved away -gt less oxygen bubbles produced
  • The amount of light therefore limits the rate of
    photosynthesis. It is called a limiting factor.

222
Point X Optimum
Increasing rate of photosynthesis
Increasing light intensity
Part B Further increases in light causes no
further increase in the rate of photosynthesis
since the rate is limited by a shortage of some
other factor e.g. carbon dioxide or temperature
Part A As light intensity increases the rate of
photosynthesis increases.
223
Point X Optimum
Increasing rate of photosynthesis
Carbon Dioxide Concentration
Part B Further increases in CO2 conc. causes no
further increase in the rate of photosynthesis
since the rate is limited by a shortage of some
other factor e.g. light or temperature
Part A As CO2 conc. increases the rate of
photosynthesis increases.
224
0.4 CO2
0.3 CO2
Increasing rate of photosynthesis
0.2 CO2
Increasing light intensity
light intensity is limiting factor
CO2 is limiting factor
225
Point X Optimum
Increasing rate of photosynthesis
Increasing temperature
Part A As temperature increases the rate of
photosynthesis increases.
Part B Further increases in temperature results
in a drop in the rate due to the denaturing of
the enzymes that carry out photosynthesis
226
Photosynthesis and horticulture
227
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228
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229
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230
Photosynthesis and horticulture Horticulture is
the cultivation of plants in gardens and
greenhouses. The use of a greenhouse helps remove
limiting factors
231
  • (a) Lighting and heat
  • By increasing the light, the rate of
    photosynthesis increases and leads to an increase
    in the growth rate of the crop
  • crop is ready to be picked earlier.
  • increased crop yield.

232
(b) Carbon dioxide enrichment Increased carbon
dioxide in the atmosphere increases the yield
(size) of crops. This happens because the rate of
photosynthesis is increased.
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