Download B2.12.2 Cells Diffusion SOW May 2013

Unit 2.1
Cells & Diffusion and
Unit 2.2 Tissues,
organs and systems
Scheme of Work
(updated by PDa
September 2011)
Prior Knowledge
Key Stage 1
none
Key Stage 2
By the end of Year 6 pupils will have some understanding of life processes, such as growth
and reproduction, nutrition and movement. They will also have been taught about microorganisms and should have some idea that these are too small to be seen easily. Their
understanding of just how small that might be is likely to be limited.
Key Stage 3
In Year 7 Pupils should be taught:
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That animal and plant cells can form tissues, and tissues can from organs. (KS3,
Sc2, 1a)
The functions of chloroplasts and cell walls in plant cells and the functions of the
cell membrane, cytoplasm and nucleus in both plant and animal cells. (KS3, Sc2,
1b)
To relate cells and cell functions to life processes in a variety of organisms. (KS3,
Sc2, 1e)
Ways in which some cells, including ciliated epithelial cells, sperm, ova, and root
hair cells, are adapted to their functions. (KS3, Sc2, 1c)
B2.1 Cells and simple cell transport
B2.1.1 Cells and cell structure
Pupils should:
1. Know that 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 is where most energy is released in respiration
 ribosomes, which is where protein synthesis occurs.
2. Know that 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.
3. Know that a bacterial cell consists of cytoplasm and a membrane surrounded by a
cell wall; the genes are not in a distinct nucleus.
4. Know that yeast is a single-celled organism. Yeast cells have a nucleus, cytoplasm
and a membrane surrounded by a cell wall.
5. Know that cells may be specialised to carry out a particular function.
B2.1.2 Dissolved substances
Pupils should:
1. Know that dissolved substances can move into and out of cells by diffusion.
2. Know that 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.
3. Know that oxygen required for respiration passes through cell membranes by
diffusion.
B2.2 Tissues, organs and organ systems
B2.2.1 Animal organs
Pupils should:
1. Know that large multicellular organisms develop systems for exchanging materials.
during the development of a multicellular organism, cells differentiate so that they
can perform different functions
2. Know that a tissue is a group of cells with similar structure and function. Examples
of tissues include:
 muscular tissue, which can contract to bring about movement
 glandular tissue, which can produce substances such as enzymes and
hormones
 epithelial tissue, which covers some parts of the body.
3. Know that organs are made of tissues. One organ may contain several tissues. The
stomach is an organ that contains:
 muscular tissue, to churn the contents
 glandular tissue, to produce digestive juices
 epithelial tissue, to cover the outside and the inside of the stomach.
4. Know that organ systems are groups of organs that perform a particular function.
The digestive system is one example of a system in which humans and other
mammals exchange substances with the environment. The digestive system
includes:
 glands, such as the pancreas and salivary glands, which produce digestive
juices
 the stomach and small intestine, where digestion occurs
 the liver, which produces bile
 the small intestine, where the absorption of soluble food occurs
 the large intestine, where water is absorbed from the undigested food,
producing faeces.
B2.2.2 Plant organs
Pupils should:
1. Know that plant organs include stems, roots and leaves.
2. Know that examples of plant tissues include:
 epidermal tissues, which cover the plant
 mesophyll, which carries out photosynthesis
 xylem and phloem, which transport substances around the plant.
Lesson 1&2 Animal Cell structures
Starter
Crossword quiz on cell parts and function. OR
Worksheet available on Cells, tissues and organs to refresh this in their
minds. Sheet has six fairly simple questions and a brief summary.
Introduce that the new topic is on cells and how molecules pass across their
membrane. Use the human torso to build on the work achieved in Year 7 on
the definition of organism, organ systems, organs, tissues and cells. Do
summary notes.
Notes
Pupils to draw and annotate an animal cell to include ribosomes. Get
across the idea of organelles.
Recall the fact that cells are small and can only be seen properly with a light
microscope. Bring in the idea that electron microscopy is now also used to
enhance scientists knowledge about the cell and cell processes.
Microscopy
Revise the parts of the microscope and do summary notes on resolution and
magnification. Use the analogy of a distant luminous object in space
thought to be a star. The star can be magnified to be a much larger sphere,
but only through enhanced resolution can it actually be seen to be three stars
not one.
Using various animal cell slides pupils inspect the slides and draw and label
cells and tissues.
Plenary
Review the structure of a cell and the requirements needed for a cell to
survive. Cover protein synthesis and respiration
Homework
Do a research piece to produce an information sheet on a specialised
cell.
Lesson 3&4 Making Slides
Starter
Ask students to complete the table of magnification vs diameter of field of
view. I.e. revise Magnification. Give students a scrpa of graph paper. Use
the maths of magnification to work out field of view rather than try to
attempt to estimate the proportion of a small graph paper square observable.
Practical
Demo at the front how to make slides properly using tissue at the edge of the
cover slip to remove excess dye and how to minimise the number of air
bubbles produced.
Pupils can then make slides of their own cheek cells.
Rst found useful to add a drop of water to cell sample before adding dye.
Pupils can then attempt to draw, label and using the starter activity, estimate
the diameter of these cells. cheek cell image.bmp to show.
**Card for this available.
Perhaps ask students to pluck a head hair out and examine follicle – not
necessarily to see cells (dismiss misconception that the actual hair itself is
made of cells!)
Using pages 138-139 give summary notes of the differences between animal
and plant cells with reasons.
Questions
You may want to use q 1-4 on page 139 AQA text book
Homework
Complete worksheet questions. See new 2013.Cell measuring
worksheet.pdf
Lesson 5&6 Plant cells, tissues, organs, systems
Starter
Project an animal and plant cell and get pupils to recall differences and
similarities. Revise ribosomes, but also the fact that plants also have
mitochondria alongside chloroplasts.
Demo
Demo various plants on the desk for pupils to recall the four main
organs. Do notes on the roles of stems, roots and leaves.
/
Discussion
Microscopy
Elicit the idea that plant organs are also made of tissues and get pupils
to recall tissues they know.
Use Ligustrum slides to get pupils to identify and do notes on plant
tissues, including epidermal tissues, which cover the plant, mesophyll
which carries out photosynthesis, and the xylem and phloem, which
transport substances around the plant.
Lesson 7 Specialised Cells
Starter
Banta
Viewers
Get pupils to present some of their homework pieces on specialised cells.
Then, hand out Year 7 Cell models and Red blood cell models we have.
Discuss what the function of each cell is and how they are adapted for this
function. Link to the idea that cells may be specialised to carry out a
particular function.
Pupils to use these investigate the shape and contents of three different
specialised cells. Pupils need to draw and label each with a description of
how each is specialised for its function. If there is time you may want to get
pupils to complete a poster of a specialised cell, either using the laptop to
research, or use pages 140-141.
Notes
as below or try this w/s Systems, Organs, Tissues etc.doc
Notes
Know that large multicellular organisms develop systems for exchanging
materials. During the development of a multicellular organism, cells
differentiate so that they can perform different functions Use the following
examples:
- muscular tissue, which can contract to bring about movement
- glandular tissue, which can produce substances such as enzymes
and hormones
- epithelial tissue, which covers some parts of the body.
Do notes on the fact that animal organs are also made of tissues, and that
one organ may contain several tissues. Use the example of the stomach as
an organ that contains:
- muscular tissue, to churn the contents
- glandular tissue, to produce digestive juices
- epithelial tissue, to cover the outside and the inside of the
stomach.
Do notes on the fact that organ systems are groups of organs that
perform a particular function. Use the digestive system as one example
of a system in which humans and other mammals exchange substances
with the environment, and one that includes:
- glands, such as the pancreas and salivary glands, which produce
digestive juices
- the stomach and small intestine, where digestion occurs
- the liver, which produces bile
- the small intestine, where the absorption of soluble food occurs
- the large intestine, where water is absorbed from the undigested
food, producing faeces.
Plenary
Get pupils to give further examples from the use of Banta viewers
Homework
Are Bacteria or Yeast more useful for humans? Discuss
Lesson 8 Algae, Yeast and Bacteria
Starter
Recall kingdom classification and the differences between Monera and
Protoctista. Use pupil homework to identify which kingdom bacteria
and yeast belong to.
Elicit from their homework that a bacterial cell consists of cytoplasm and a
membrane surrounded by a cell wall and that the genes are not in a distinct
nucleus. Whereas yeast is a single-celled organism whose cells have a
nucleus, cytoplasm and a membrane surrounded by a cell wall.
Microscopy
Use pond algae and plant matter for pupils to make slides and look at
the differences between algae and plants
Notes
Do notes on that plant and algal cells also have a cell wall made of
cellulose, which strengthens the cell, but that plant cells often have
chloroplasts, which absorb light energy to make food and a permanent
vacuole filled with cell sap.
Lesson 9&10 Introduction to Diffusion
Starter
Show diffusion cartoon. Discuss what is happening to the ‘smell particles’.
Elicit the idea that the particles are moving at random, but there is net flow
of particles from an area of high concentration to low concentration.
Practical
Set up Experiment from worksheet B8C using different sized jelly cubes
dipped in potassium manganate solution. Pupils answer questions from the
sheet.
(An alternative experiment involves timing how long it takes for acid to
penetrate jelly cubes. See SA to Vol sheets- tried in 2007 – not very
successfully). Questions related to this practical are useful to get pupils to
think of the biological significance of larger organisms and diffusion.
Worksheet
Practice ISA table drawing skills on SA:Volume worksheet.
Textbook
Pages 142-143 (AQA) or p 298 (new McKean) are useful to cover the
general principles of diffusion.
Plenary
Discuss what can increase the rate of diffusion and use the hair dryer to test
pupil predictions.
Homework
Read P142-143 and answer Summary questions.
or
Worksheet B7E : size and gas exchange
ISA skills
ISA skills – The effect of temperature on diffusion sheet tables and
controls– new 2013 and ISA skills worksheet – graphing and planning – also new 2013
Lesson 11 Diffusion in cells
Starter
Draw a cell and discuss what is diffusing into and out of the cell and why.
Use the mitochondria to review diffusion of oxygen towards the
mitochondria with carbon dioxide diffusing away and reasons for this.
Demo
Set up visking tubing at the start of the lesson which contains a starch
solution. Add a very small volume of Iodine to the water in the test tube and
leave for 10-15 minutes. Pupils to observe changes later in the lesson.
Notes:
Revise that the function of the cell membrane is to control what enters and
exits the cell. Outline that this occurs due to proteins in the membrane.
These specific shaped proteins are used for actively transporting substances
across the membrane using ATP from aerobic respiration. Elicit the reasons
why this would be required: too large or against a concentration gradient.
Worksheet
Use ‘Movement across membrane’ sheets to elicit answers to questions.
This revises the idea that cell membranes are selectively permeable.
Worksheet
‘In and out of cells’ worksheet to discuss the exchange of substances across
the membrane of living cells.
Worksheet
“some principle of biology” good summary worksheet, in absence of an
EOUT.
NO END OF UNIT TEST FOR THIS UNIT
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