The effect of sodium chloride concentration of the activity of yeast cells.

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  • Created by: Steff06
  • Created on: 03-02-16 17:23
IV and DV of the experiment.
Independent variable = NaCl concentration. Dependent variable = The rate of respiration/yeast cell activity.
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Why are the test tubes kept in the water bath at 33 degrees?
This is to give them time to equilibriate and reach the same temperature and so that things had time to take effect such as osmosis.
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Where should units go in a table and how should the table be organised?
The units should be in the headings only, none in the body of the table. The IV should be in the 1st column and the DV should be in the columns to the right.
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Why replicate?
To identify any anomalies which do not fit the trend that the data shows, to calculate the mean and to improve the accuracy and reliability of the results - if it is replicable, then it is reliable.
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What is the purpose of controls?
To establish cause and effect and to compare the results with the controls.
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Improvements?
Use a pH buffer which will be resistant to slight changes in pH meaning the results will not be affected by this. Use a gas syringe to measure the carbon dioxide produced/respiration. Use a graduated pipette with a scale for increased precision.
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Osmotic effects?
Similar to plant cells. Water potential lower outside of the cell so water will move out of the cell from high to low concentration. The cell will become plasmolysed and the cell wall will separate from the cell surface membrane.
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CO2 and respiration?
CO2 produced in aerobic+anaerobic respiration. Also produced in fermentation. 2 molecules produced in link reaction when pyruvate is converted to Acetyl CoA. 4 molecules produced Krebs Cycle when 6C citric acid ->5C Keto Glutaric -> 4C succinic acid.
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Dissolved CO2 on pH?
Dissolving CO2 in water will lower pH, because CO2 will react with water to produce carbonic acid. This will dissociate to from H+ ions and bicarbonate (HCO3).
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Protein structure and how it will be affected?
Tertiary protein structure will be disrupted. Tertiary structure is complex 3D structure and holds shape. Has ionic, disulphide + hydrogen bonds + hydrophilic/phobic interactions. Ionic bonds affected between different R groups of amino acids.
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Primary, secondary and quaternary structure?
Primary = Sequence of amino acids and peptide bonds. Secondary = Coiling of sequence. Main types=alpha helix/beta pleated sheet. Quaternary=Proteins with 2+ polypeptide e.g. haemoglobin.
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Other cards in this set

Card 2

Front

Why are the test tubes kept in the water bath at 33 degrees?

Back

This is to give them time to equilibriate and reach the same temperature and so that things had time to take effect such as osmosis.

Card 3

Front

Where should units go in a table and how should the table be organised?

Back

Preview of the front of card 3

Card 4

Front

Why replicate?

Back

Preview of the front of card 4

Card 5

Front

What is the purpose of controls?

Back

Preview of the front of card 5
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