Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
WORKBOOK 1 – CELLS & CELL TRANSPORT
Cells and simple cell transport
All living things are made up of cells. The structures of different types of cells are
related to their functions. To get into or out of cells, dissolved substances have to cross
the cell membranes.
Candidates should use their skills, knowledge and understanding to:
■ relate the structure of different types of cells to their function.
Subject content - Cells and cell structure
a) Most human and animal cells have the following parts:
■ a nucleus, which controls the activities of the cell
■ cytoplasm, in which most of the chemical reactions take place
■ a cell membrane, which controls the passage of substances into and out of the cell
■ mitochondria, which are where most energy is released in respiration
■ ribosomes, which are where protein synthesis occurs.
b) Plant and algal cells also have:
a cell wall made of cellulose, which strengthens the cell. Plant cells often have:
■ chloroplasts, which absorb light energy to make food
■ a permanent vacuole filled with cell sap.
c) A bacterial cell consists of cytoplasm and a membrane surrounded by a cell wall; the
genes are not in a distinct nucleus.
d) Yeast is a single-celled organism. Yeast cells have a nucleus, cytoplasm and a
membrane surrounded by a cell wall.
e) Cells may be specialised to carry out a particular function.
1
Revise with your teacher the basic structure & functions of animal & plant cells.
Watch the video or PowerPoint on cells.
Write the functions of these 8 structures:
All cells – cell membrane
encloses all cells; controls what enters & leaves
All cells – cytoplasm
site of all reactions of life
All cells – nucleus
controls activities of cell; contains chromosomes
All cells – mitochondria
releases energy for cell by aerobic respiration
All cells - ribosomes
site of protein synthesis
Plant cells only – cell wall
encloses plant cell, provides support to turgid
cells
Plant cells only – large vacuole
filled with sap, provides support to turgid cells
Plant cells only – chloroplasts
absorb light energy so plant can
photosynthesise
Resources:
Biology for You, page 17, Qs 2 and 3; page 40, Qs 1 and 2,.
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Wellsway school science dept.
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Curriculum 2011 – AQA Additional Science
Biology workbook
Prepare an onion epidermis (skin) slide using the worksheet/instructions provided:
Safety – take care with glass slides and cover slips. Place them in the container
provided at the end. Be careful with iodine, which stains hands, clothes, books, etc.
Ensure no stain gets on your microscope. Be careful when carrying and using your
microscope.
3
Look at your slide under your microscope (or use a Bio viewer and filmstrip).
You should be able to see:
Cell wall
Nucleus
Position of cell membrane
Position of vacuole.
Position of cytoplasm
One common structure often found in plant cells is not present in onion skin.
Write down which structure is missing, and suggest why this is (hint: onion bulbs grow
underground).
No chloroplasts – no sunlight available underground, so a waste of energy
producing structures which cannot be used.
4
Draw 2-3 onion epidermis cells in detail below, and label your drawing.
Cell wall
vacuole
Cell membrane
Nucleus
Position of cytoplasm
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Wellsway school science dept.
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Biology workbook
Observe some animal cells using a Microscope OR a Bio viewer OR a textbook.
Draw 2-3 animal cells in detail below, and label your drawing.
Cell membrane
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Curriculum 2011 – AQA Additional Science
Nucleus
Cytoplasm
Position of Mitochondria
Observe photographs or drawings of typical bacterial cells.
Draw and label a bacterial cell to highlight the key differences between it and an animal
and plant cell.
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Wellsway school science dept.
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Curriculum 2011 – AQA Additional Science
Biology workbook
Observe photographs or drawings of typical yeast cells.
Draw and label a yeast cell to highlight the key differences between it and an animal,
plant and yeast cell.
Yeast cells are much larger than bacteria (4 – 12 µm = 4/1000 –
12/1000 mm) – similar in size to a red blood cell. Fungal cells are
similar to plant cells BUT lack chloroplasts & chlorophyll.
8
Read your textbook or support material on specialised cells.
Draw 2 different animal cells and 2 different plant cells, and explain how they are
specialised to carry out their functions.
Specialised Animal & Plant Cells
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Wellsway school science dept.
Specialised Plant Cells
Curriculum 2011 – AQA Additional Science
Biology workbook
See previous diagram.
Dissolved substances
a) Dissolved substances can move into and out of cells by diffusion.
b) Diffusion is the spreading of the particles of a gas, or of any substance in solution,
resulting in a net movement from a region where they are of a higher concentration to a
region with a lower concentration.
The greater the difference in concentration, the faster the rate of diffusion.
c) Oxygen required for respiration passes through cell membranes by diffusion.
1
Watch the teacher demonstrations showing diffusion.
Read your textbook or support material on diffusion.
Write down a definition of diffusion:
Diffusion is the random movement of particles (of a liquid or
gas) from a region of high concentration to a region of low
concentration.
Write down some examples of diffusion of substances across membranes:
(a) in animal cells.
Oxygen into the blood; oxygen from blood to cells; glucose into
cells.
(b) in plant cells.
CO2 into leaves; O2 out of leaves
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Wellsway school science dept.
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Curriculum 2011 – AQA Additional Science
Biology workbook
Make a list of the factors which can affect the rate of diffusion:
Temperature (higher temperature = faster diffusion; particles
have more kinetic energy)
Concentration difference / gradient (greater conc difference =
faster diffusion)
Concentration of particles (higher concentration = faster
diffusion)
3
Investigating the effect of temperature and concentration on the rate of diffusion.
SAFETY: ammonia gas is an irritant.
wear eye protection & avoid inhaling ammonia vapour.
Apparatus:
Apparatus: (per group):
Glass diffusion tube
UI paper
Glass rod
Ruler
10 mls Ammonia solution in a small beaker
5 ml syringe
Stop watch
10 mls Distilled water in a small beaker
Method:
• Set up the apparatus as shown in the diagram.
• Syringe 3 mls of ammonia solution onto some cotton wool and immediately
push the cotton wool into the end of the glass tube.
• Start the stop watch.
• Record the time taken for the pieces of universal indicator paper to turn blue.
• Repeat the procedure using warm ammonia solution, and (if you have time)
dilute ammonia solution.
Variables: Write down:
(a) The independent variables (factors you are changing):
Concentration of ammonia / temperature of ammonia
(b) The dependent variable (factor you are measuring/finding out):
Time taken for UI paper to turn blue
(c) The main control variables (factors you will keep the same for fair testing):
Volume of ammonia (3 mls)
Size of cotton wool; how far cotton wool is pushed into the tube;
size and spacing of pieces of UI paper.
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
Predictions:
I think the fastest diffusion will take place with…
Hot ammonia
Because…
The gas particles have more kinetic energy and are moving
around faster
I think the slowest diffusion will take place with…
Dilute ammonia
Because…
There are less particles to diffuse, so they have less kinetic
energy
Carry out your investigation carefully, and record all your results in a neat clear table:
Results:
Typical answers – these can vary widely.
Time taken for UI paper to turn blue (mins + secs.).
UI paper no.
1 2 3 4 5
6
7
8
9 10
Full strength
Ammonia
10 11 30 40 50 1:00 1:20 1:40 2:10 3:00
Hot Ammonia
Dil. Ammonia
2
6
10 20 25
30
45
50 1:00 1:10
19 22 30 1:13 2:10 2:53 4:09 4:23 5:10 6:15
Conclusion: Write down:
(a) what you have found out:
Hot ammonia diffuses more quickly than cold.
Dilute ammonia diffuses more slowly than concentrated
ammonia.
(b) whether your predictions were correct:
(c) why you have obtained these results (i.e. a scientific explanation):
Ammonia is an alkaline gas & diffuses quickly – from high to low
concentration - onto the UI paper, turning it blue. Diffusion
slows down the further the UI paper is away from the cotton
wool.
Hotter gas particles have more kinetic energy and are moving
around faster, so they diffuse faster.
In dilute ammonia there are fewer particles to diffuse, so they
have less kinetic energy and diffuse more slowly.
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
Well done – you have finished the Cells & Cell Transport workbook!
Useful web links & clips:
General
http://www.bbc.co.uk/schools/gcsebitesize/biology/cellprocesses
Animal Cells: general structure
http://clipbank/espresso/clipbank/servlet/link?macro=setresource&template=vid&resourceID=1
542&taxonomyNodeID=721
Animal cells: types & functions
http://clipbank/espresso/clipbank/servlet/link?template=vid&macro=setResource&resourceID=1
543&taxonomyNodeID=721
Leaf & Plant Cell Structure
http://clipbank/espresso/clipbank/servlet/link?template=vid&macro=setResource&resourceID=1
544&taxonomyNodeID=721
Plant cells: general structure
http://clipbank/espresso/clipbank/servlet/link?macro=setresource&template=vid&resourceID=1
545&taxonomyNodeID=721
Plant cells: types & functions
http://clipbank/espresso/clipbank/servlet/link?template=vid&macro=setResource&resourceID=1
546
Glossary (muddled – sort them out!)
1
Carbon dioxide
2
Cell membrane
3
Cell wall
4
Chloroplast
5
Chromosomes
6
Cytoplasm
7
Diffusion
8
Diffusion (concentration) gradient
9
Mitochondria
10
Nucleus
11
Oxygen
12
Ribosomes
13
Vacuole
Jelly-like region in all cells, where reactions of life
take place.
Small green structure in some plant cells.
Absorbs light for photosynthesis.
Tiny threads inside the nucleus, which are
composed of lengths of DNA called genes. These
produce our inherited characteristics.
Outer boundary of all cells. Controls what enters
& leaves.
Extra boundary around plant cells. Made of
cellulose, for support.
Gas released from respiration & removed through
the cell membrane by diffusion.
Small structures in all cells which release energy
by aerobic respiration.
Tiny structures in all cells where protein synthesis
takes place.
Relatively large structure in all cells which
controls the cell’s activities. Contains
chromosomes.
Random movement of particle of gas or liquid
from a higher concentration to a lower
concentration.
Sap-filled bag in plant cells which provides
support to turgid (swollen) cells
Difference in concentration of a substance which
determines how quickly diffusion takes place.
Gas required for respiration absorbed through the
cell membrane by diffusion
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Additional Notes
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Questions.
a) Biology for You questions.
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
b) AQA Past paper questions.
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Biology workbook
Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
1 The diagram shows a cell from the lining of the lung. This cell is specialised to allow
gases to pass through quickly.
1 (a) Use words from the list to label structures A, B and C.
cell membrane
chloroplast
cytoplasm
(3 marks)
mitochondria
nucleus
1 (b) (i) Which feature of this cell allows oxygen to pass through quickly?
(1 mark)
Put a tick next to your choice.
It is thin.
It has a large nucleus.
It has many mitochondria.
1 (b) (ii) Complete the sentence by drawing a ring around the correct answer in the
box.
(1 mark)
Oxygen passes through this cell by
diffusion
osmosis
respiration
(F PAPER - JUN 2008)
2 The diagram shows a group of muscle cells from the wall of the intestine.
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
Biology workbook
(a) On the diagram, use words from the box to name the structures labelled A, B and
C.
cell membrane
cell wall chloroplast
cytoplasm
nucleus
(3 marks)
(b) How are these muscle cells adapted to release a lot of energy?
.......................................................................................................................................
.......................................................................................................................................
(2 marks)
(F PAPER – JAN 2008)
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Wellsway school science dept.
Curriculum 2011 – AQA Additional Science
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Biology workbook