Midterm 2 (Lectures 11-23) Flashcards
Catabolism
- breaking down of high energy molecules into simple molecules
- generate energy
Anabolism
- building of complex molecules from simple ones
- require energy
ATP- adenosine triphosphate
- intermediate energy carrying molecules where energy is stored
- fuels many endergonic enzymatic processes
- diffuse or transported to where energy is needed and deliver chemical energy from breaking of phosphate bond
When ATP is hydrolyzed, what part of the molecule is released to provide energy?
y-phosphate or terminal phosphate
Explain the combustion of glucose with oxygen that forms water and CO2.
- a large molecule is converted into many small molecules
- products has more entropy (more disorder) than reactants
How do enzymes catalyze a reaction by increasing the rate of the reaction?
- reducing free energy of activation (Ea)
- reactant molecules absorb energy to reach transition state
When enzymes catalyze a reaction, there is a reaction rate plateau at higher reactant concentrations. Why?
most enzymes are already occupied
What is needed for any reaction to occur?
energy
What is Ea or energy of activation?
- energy needed to start the reaction
- is like a barrier preventing reactions to occur without the input of energy
What is the role of an enzyme in metabolic reactions?
- allow cells to overcome Ea quickly and precisely
- biological catalyst
- increases rate of reaction by lowering Ea
- does not add energy to reaction
How does the shape of an enzyme affect metabolic reactions?
- 3D shape
- very selective
- each enzyme can only catalyze one type of reaction with specific substrates
- lock and key analogy
- shape is maintained after reaction
What kind of molecule is an enzyme?
- proteins
- organic catalysts
When enzymes catalyze a reaction, what is the name of the reactants involved?
substrates
What is end-product inhibition for feedback-regulated enzymatic pathway?
P0-E1-P1-E2-P2-E3-P3-E4-P4
P4 binds to E1 and deactivates it
Lab-Explain what would happen if you placed a dialysis sac containing a 5% salt solution into a beaker containing a 10% salt solution.
Water leaves the dialysis sac through osmosis, causing an increase in salt concentrations inside the dialysis sac. After a certain amount of time, dynamic equilibrium will be reached.
Lab-Explain what should happen when you add a salt water solution to living onion cells.
The onion cells lose water due to the hypertonic solution, which causes the inner content to shrivel up and distance itself from the cell wall.
Lab- Explain the roles of the four test tubes in Lab 4 where :
Tube 1 has 1 mL of H20
Tube 2 has 1 mL of 1% Glucose
Tube 3 has 1 mL of Culture Medium Before Fermentation
Tube 4 has 1 mL of Culture Medium After Fermentation
Tube 1 = Negative control group (no reaction expected)
Tube 2 = Positive control group (reaction is expected)
Tube 3 = Experimental group to prove presence of glucose before fermentation
Tube 4 = Experimental goup
Lab-Which are the four pigments involved in photosynthesis (order from left to right on the paper chromatography)?
carotene, xanthophyll, chlorophyll a, chlorophyll b
Lab- Explain the roles of the four test tubes in Lab 5 where :
Tube 1 has 5 mL of H20
Tube 2 has 5 mL of 50% Ethyl Alcohol
Tube 3 has 5 mL of Culture Medium Before Fermentation
Tube 4 has 5 mL of Culture Medium After Fermentation
Tube 1 = Negative control group (no reaction expected)
Tube 2 = Positive control group (reaction is expected)
Tube 3 = Experimental group
Tube 4 =Experimental group with yellow precipitate due to ethanol being a product of fermentation
Lab-What type of substances would enter and leave cells by simple diffusion?
H2O
CO2
O2
Lab-Three lengths of dialysis tubing containing 2.0M sucrose solution are put in three different solutions:
Solution A: distilled water
Solution B: 2.0M sucrose
Solution C: 4.0M sucrose
Which solution is isotonic, hypotonic and hypertonic?
Solution A = hypotonic
Solution B = isotonic
Solution C = hypertonic
What are the chemical constituents of the plasma membrane and how are they arranged?
1) phospholipid bilayer = hydrophilic heads outside the membrane and hydrophobic tails inside the membrane
2) proteins = embedded in bilayer
3) carbohydrate side chains = attached to proteins and lipids outside of membrane