Chapter 7
What are the three major ways that molecules and waste are transported throughout the cell membrane?
Bulk, Active, Passive Transport
What is the difference between a catabolic and an anabolic reaction? Which is endergonic and exergonic?
Catabolic - reactions that occur spontaneously as a result of a breakdown of reactants (exergonic)
Anabolic - reactions that occur non-spontaneously as a result of building up a product that requires energy to produce (endergonic)
What are the products and reactants of cellular respiration?
Reactants:
- C6H12O6 (Glucose)
- 6 O2 (Oxygen)
Products:
- 6 CO2 (Carbon Dioxide)
- 6 H2O (Water)
- Energy (ATP + heat)
What is feedback inhibition?
In feedback inhibition:
- The end product of a metabolic pathway shuts down the pathway
- prevents a cell from wasting chemical resources by synthesizing more product than is needed
What are the three different types of endocytosis?
Receptor-Mediated, Pinocytosis, Phagocytosis
What is the difference between carrier and channel transport proteins?
Carrier - Changes shape to transport small, hydrophilic/ionic molecules (primarily in active transport; can partake in passive transport)
Channel - Has a hydrophilic interior that creates an opening for small, hydrophilic molecules (passive transport)
What are the two laws of thermodynamics?
1st: Energy can be transferred and transformed, but it cannot be created or destroyed.
2nd: Every energy transfer or transformation increases the entropy of the universe
What are the four stages of cellular respiration?
1) Glycolysis
2) Pyruvate Oxidation
3) Citric Acid Cycle
4) Oxidation Phosphorylation
What is phosphorylation?
Phosphorylation, transfer of a phosphate group from ATP to another molecule, is typically used to power endergonic reactions
What is energy coupling?
The process of anabolic and catabolic reactions working together to break down and produce the same component repeatedly. (ATP Regeneration)
What is the equilibrium solute concentration condition that occurs in plant cells? What is it called when the cell is in this state?
Hypotonic; Turgid
What is the Gibbs-Free Energy Equation, and what do its components represent?
ΔG = ΔH – TΔS
–ΔG = change in free energy
–ΔH = change in enthalpy (total energy)
–ΔS = change in entropy
–T = Temperature in Kelvin (K)
What is the importance of NAD+/NADH?
NAD+/NADH is a coenzyme that functions as an electron carrier that transfers electrons to the ETC (electrons need carriers as they are volatile).
What is cooperativity?
In cooperativity, substrate binding to one active site triggers a shape change in the enzyme that stabilizes the active form for all other sites
How many molecules of ATP are produced per glucose?
30 - 32 molecules
What is the difference between unsaturated and saturated fatty acids structurally/physically? What role does cholesterol play?
Saturated - solid at room temperature; more favorable in warmer climates; packed together
Unsaturated - liquid at room temperature; more favorable in colder climates; kinked
Cholesterol maintains the fluidity of the membrane, ensuring its consistency is not too thin (molecules can slip past) or too stiff (molecules cannot slip past when they need to).
Does a non-competitive inhibitor affect the efficiency of the substrate in the active site? Why or why not?
Yes, the non-competitive inhibitor diminishes the substrate's effectiveness with its corresponding enzyme because although it bonds with the allosteric site, it will still change the shape of the substrate.
What are the two phases of glycolysis?
Bonus: What is so special about the second phase?
1) Energy Investment
2) Energy Payoff
The energy payoff phase occurs twice, while the energy investment phase only occurs once.
What is co-transport?
Cotransport occurs when active transport of a solute indirectly drives transport of other substances
What is the importance of the proton pump?
- Plant cells use proton pumps to generate an H+ gradient across the cell membrane
- A cotransporter couples the movement of H+ back down its concentration gradient to the active transport of sucrose into the cell
What is the importance of the sodium-potassium pump? What process enables the pump to work?
Transfer of a phosphate group from ATP to the sodium-potassium pump energizes the transport of K+ into the cell and Na+ out of the cell. This creates an electrochemical charge (voltage) across the membrane to use as storage for cellular work.
How do enzymes affect a chemical reaction?
Enzymes lower the activation energy required to reach the transition phase (DOES NOT LOWER ΔG).
Methods of how this can happen:
–Substrates orientation
–Bonds can be changed to be more easily broken
–The active site may provide a microenvironment that favors the reaction
–Amino acids in the active site may participate in the reaction
What is the difference between lactic acid and alcohol fermentation?
Alcohol Fermentation: The first step releases CO2 from pyruvate, and the second step produces NAD+ and ethanol
Lactic Acid Fermentation: Pyruvate is reduced directly by NADH to form lactate and NAD+
The difference is that lactic acid fermentation does not release CO2.
What is the difference between obligate and facultative anaerobes?
- Obligate anaerobes: carry out fermentation or anaerobic respiration and cannot survive in the presence of O2
- Facultative anaerobes: can survive using either fermentation OR cellular respiration
What is the first step of the TCA cycle?
The acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate, forming citrate