Lab 6,7 and 8 Flashcards
(24 cards)
What does a Spectrophotometer do?
reads the color intensity in terms of absorbance.
Higher the
absorbance (reading on the machine) more is the amount of protein in
the tube.
(Absorb) Beer Lamberts Law
absorbance is directly proportional to concentration
Diffusion
the movement of molecules from a region of high concentration to a region
of low concentration.
Cell membrane is composed of ?
phospholipids
Cell membranes are selectively permeable meaning
they allow only
certain types of molecules to pass through while they don’t allow certain other types of molecules to go across the membrane making them selectively permeable or semi-
permeabl
What does cell membrane not allow to cross and does allow to cross
they don’t allow polar or charged molecules to cross the membrane.
Cell membranes allow some small
polar molecules like water, and small non polar molecules like CO2 and O2 to go across the membrane
Osmosis
movement of water molecules from a region of low solute concentration to a region of high solute concentration
Water molecules moves from most water concentration to less
Hypertonic solutions: (Grape in glucose)
When the solute concentration is HIGHER outside the cell compared to inside the cell
water molecules will move from inside the cell
to outside (low to high solute concentrations).
Cells shrink in size
because they lose water
Enzymes
Enzymes are made of proteins and they help speed up a chemical reactions or act as catalysts
Enzymes are called biological catalysts that increase the rate of chemical reactions in the cells without undergoing any change themselves. Enzymes accelerate the chemical reactions by LOWERING the activation energy of a chemical reaction.
What is a substrate and a product?
Substrate is the substance that enzymes act upon initially. Enzymes convert substrate to product.
What are different factors that affect enzyme activity?
Temperature, pH, substrate concentration and enzyme concentration
How does Temperature affect enzymes
Enzymes work best at a certain temperature called the optimal temperature.
For most enzymes in the human body, this is around 37°C (normal body temperature).
If it’s too cold, enzymes work more slowly.
If it’s too hot, enzymes can lose their shape and stop working.
How does pH affect enzymes
(Most enzymes in the body work best at pH 7.4 (close to neutral).
Some enzymes work better in acidic or basic conditions.
For example, pepsin (Stomach) works best at pH 2 in the stomach (very acidic),
while trypsin (small intestine) works best at pH 8 i
How does substrate concentration affect enzymes
Substrate Concentration
The substrate is the molecule the enzyme works on.
When there’s more substrate, the enzyme can make more product—up to a point.
After a certain amount, adding more substrate won’t increase activity because all enzyme molecules are already working. This is called saturation.
How does enzyme concentration affect enzymes
If there is more enzyme, there is more product formation and there is more enzyme activity. However if there is too much enzyme then the activity reaches a maximal level and does not increase anymore.
Catalyst
Substances that increase the rate of a chemical reaction without themselves undergoing any change.
Ex: Enzymes
What role does Guaiacol play in the experiment that we performed in the lab?
Guaiacol acts as a substrate (or electron donor) in the peroxidase reaction. Changes color when it oxidizes to brown red
It’s used to help us visually measure enzyme activity because it changes color during the reaction.
Why does Guaiacol change from colorless to brown color during the enzymatic reaction?
The brown color intensity increases as the reaction proceeds.
By measuring the absorbance of the brown color using a spectrophotometer, we can track the rate of the enzymatic reaction.
More color = more reaction = higher enzyme activity.
Hypotonic solutions (gummy bear)
When the solute concentration outside the cell is lower than inside the cell. In hypotonic solutions, water molecules move from outside to inside the cell (low solute to high solute concentrations). In hypotonic solutions cells swell up.
hypotonic solution has a lower concentration of solute compared to the solution it’s being compared to
what does solvent do?
Does the dissolving
Bond breaking
requires energy
What is ATP?
energy currency of cells
Passive transport
movement that does NOT require energy
Active transport
USES energy
