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Cells, Exchange and Transport F211

State the resolution and magnification that can be achieved by a light
microscope:
Resolution: 200nm
Magnification: x1500

Explain the difference between magnification and resolution:
Magnification-

Resolution-

Explain the need for staining samples in light microscopy:
Allows the specimen to be seen. Also helps distinguish different…

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Recognise the structure undulipodia (flagella) and cilia, and outline their
functions:
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…

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Tiny. In cytoplasm, bound to ER. Consists of two subunits.
Protein synthesis occurs.


Mitochondria:
Spherical/ sausage. Inner membrane folded- cristae. Central part- matrix.
Where ATP is made.

Lysosomes:
- Spherical sacs, single membrane.
Contain digestive enzymes.
Break down material e.g. invading microorganisms.

Chloroplasts:
In plant cells. Contain chlorophyll molecules.
Contains…

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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…

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Describe the roles of the components of the cell membrane, including
phospholipids, cholesterol, glycolipids, proteins and glycoproteins:
Phospholipids:
form basic stable structure.

Cholesterol:
Mechanical stability.
Fits between fatty acid tails.

Glycolipids:
- Phospholipid molecules that have a carbohydrate part attached.

Glycoproteins:
Protein molecules have a carbohydrate part attached.

Channel proteins:…

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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
permeability:
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…

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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…

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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. solution- Plasmolysed

State that mitosis occupies only a small percentage of the cell cycle and that…

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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…

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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…

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