Lab midterm #1 1-4 Flashcards
What is a Spectrophotometer?
An instrument that measures the amount of light absorbed by molecules in a solution.
Amount of light absorbed is known as the “Absorbance” (A)
The magnitude of absorbance is proportional to the concentration of the absorbing molecule (solute) in the solution.
**The darker and more concentrated the solution = the light light that is absorbed.
Why do you need to “Blank” a spectrophotonometer?
It ensures that any background measurement is cancelled out and that a solution with a concentration of 0 gives an absorbance value of 0.
What is an enzyme?
A protein that catalyzes a chemical reaction. (lowers the activation energy required)
It has direct contact with a substrate (active site) forming an”enzyme substrate complex”.
After the reaction occurs the products are released and the enzyme is available to repeat this reaction.
In lab 2 “Enzymes” what is the enzyme being used and what is it doing?
Amylase (saliva).
Its breaking (via hydrolysis) the polysaccharide starch Amylose into Maltose.
What happens in lab 2 “Enzymes” amylase experiment?
Come back to this
What are positive and negative controls?
Positive control: used to assess the tests validity by producing an expected result. (positive result)
Negative control: Does not give a response to the test being done (negative result)
What does the Benedict’s reagent do?
It contains copper sulfate and appears blue in a solution of sucrose (disaccharide)
If there is sugar (monosaccharide, fructose and glucose) present the solution will change to yellow orange or red.
What is sucrose and what does it break down to and how?
Sucrose is a disaccharide. Breaks down into Glucose and Fructose (monosaccharides)
Invertase (enzyme) uses hydrolysis to break down sucrose into glucose so it can be used for fuel in Glycolysis.
What is the chemical equation for cellular respiration?
C6H12O6 + 6O2 ——> 6CO2 + 6H2O + 32 ATP
What is the importance of “normalizing” data?
To eliminate redundant data
What is the chemical equation for photosynthesis?
6CO2 + 6H2O ——–> C6H12O6 + 6O2
More blue = DCPIP. Clear = Reduced 2 DCPIP + 2H
Happens in the light reactions before the calvin cycle
What do soda lime crystals do?
They absorb the CO2 so that we can just measure the O2
Why did we add dye to the respiarometer?
To measure the O2. more dye moving inwards means more O2 being used = increases cellular respiration
Arar is?
Starch
