Full set of revision notes for F211: Cells, exchange and transport

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Cells, Exchange and Transport F211
State the resolution and magnification that can be achieved by a light
Resolution: 200nm
Magnification: x1500
Explain the difference between magnification and resolution:
Explain the need for staining samples in light microscopy:
Allows the specimen to be seen. Also helps distinguish different cell structures.
Calculate the linear magnification of an image such as a photomicrograph or
electron micrograph: I AM
Actual Magnification
State the resolution and magnification that can be achieved with the electron
Transmission electron microscope:
Resolution: 0.1nm
Magnification: x 500 000
- 2D
Scanning electron microscope:
Magnification: x 100 000
Explain the need for staining samples for use in electron microscopy:
Helps distinguish different features.
Advantages of electron microscopes:
Resolution is 0.1nm. Can be used to produce detailed images of structures inside cells.
SEM produces 3D images. Can reveal detail of contours and cell arrangements.
Disadvantages of electron microscopes:
Electron beams deflected by molecules in the air so samples have to be placed in a
Very expensive.
To use them, you require a a high degree of skill and training.
Explain the importance of the cytoskeleton in providing mechanical strength to
cells, aiding transport within cells and enabling cell movement:
A network of fibres made of protein. Internal framework. Moves organelles inside cells
Actin filaments- cause movement (able to move against each other).
Microtubules- Made of protein called tubulin. May be used to waft a liquid past the cell.
Microtubule motors- use ATP to drive movements of cell contents along the fibres.

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Recognise the structure undulipodia (flagella) and cilia, and outline their
Hair like projections in the cell surface membrane.
Undulipodia are longer than cilia.
Use energy from ATP.
Cilia- short-less than 10um long. Often occur in large numbers. E.g. used in ciliated
epithelial tissue to waft mucus.
Undulipodia- long. Occur in ones and twos. E.g. used to move sperm.
Compare and contrast the structure and ultrastructure of plant cells and animal
Vesicles- membrane-bound sacs. Carry substances around cells.…read more

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Tiny. In cytoplasm, bound to ER. Consists of two subunits.
Protein synthesis occurs.
Spherical/ sausage. Inner membrane folded- cristae. Central part- matrix.
Where ATP is made.
- Spherical sacs, single membrane.
Contain digestive enzymes.
Break down material e.g. invading microorganisms.
In plant cells. Contain chlorophyll molecules.
Contains thylakoids. Stack of thylakoids= granum.
Site of photosynthesis.
Outline the interrelationship between the organelles involved in the production
and secretion of proteins:
The gene is the specific instruction for a hormone/protein.…read more

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ATP production in ATP production in
mitochondria mesosomes.
Don't have flagella. Some have flagella.
State that plasma (cell surface) membranes are partially permeable barriers:
Basic structure of the CS membrane- phospholipid bilayer. Consists of two layers of
phospholipid molecules.
Proteins embedded.
Cannot see through light microscope.
Can see through electron microscope.
7-10 nm thick.
Phosphate `head` - hydrophilic
Two fatty acid `tails' - hydrophobic
If surrounded by water forms stable bilayer. Hydrophobic `tails' held away fr
water molecules.…read more

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Describe the roles of the components of the cell membrane, including
phospholipids, cholesterol, glycolipids, proteins and glycoproteins:
form basic stable structure.
Mechanical stability.
Fits between fatty acid tails.
- Phospholipid molecules that have a carbohydrate part attached.
Protein molecules have a carbohydrate part attached.
Channel proteins:
Allow movement of some substances across membrane e.g. Glucose (too large and
hydrophilic to pass through phospholipid bilayer.
Carrier proteins:
Actively move substances using ATP. E.g. plant cells actively pump magnesium ions.…read more

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Enzymes and coenzymes:
Some photosynthesis and respiration reactions occur in membranes.
Outline the effects of changing temperature on membrane structure and
Increasing temp. gives molecules more kinetic energy, so they move faster.
Increased movement of phospholipids and other components:
Leads to increased permeability.
Explain the term `cell signalling':
Processes that lead to communication and coordination between cells. E.g. hormones
binding to their complementary receptors on the cell surface membrane.…read more

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Passive movement of molecules across membranes down their concentration gradient,
which is aided by transport (carrier) protein molecules. No metabolic energy is required.
Describe the role of membrane proteins in passive transport:
Channel proteins:
Pores in membrane.
May be `gated'.
Don't use ATP
Charged ions e.g. sodium/calcium ions.
Carrier proteins:
Shaped so a specific molecule can fit into then at membrane surface.
When it fits, protein changes shape to allow the molecule through to the other side of
the membrane.
Larger molecules e.g.…read more

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Recognise and explain the effects of solutions of different water potentials on
plant and animal cells:
Animal cells:
Water (high water potential)- haemolysed
Low water potential solution- crenated
Plant cells:
Water- Turgid
Low W.P.…read more

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Spindle breaks down.
Chromosomes break down, can no longer see under a light microscope.
Two cells split- cytokinesis.
Define the term stem cell:
Undifferentiated cells that are capable of becoming differentiated to a number of
possible cell types.
Explain the meaning of the term homologous pair of chromosomes:
Chromosomes that have the same genes at the same loci (position). Pair up during
meiosis.…read more

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Describe and explain how cells become specialised for different functions, with
reference to erythrocytes, neutrophils, epithelial cells, sperm cells, palisade
cells and root hair cells:
Erythrocytes (red blood cells):
Lose nucleus, mitochondria, Golgi apparatus, rough endoplasmic reticulum.
Haemoglobin filled.
Become biconcave discs.
Capable of transporting oxygen to the lungs.
Neutrophils (type of white blood cell):
Keep nucleus.
Many lysosomes are produced.
Able to ingest invading organisms. Enzymes in lysosomes capable of killing
microorganisms.…read more


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