Content from Exam 3 Flashcards
Know the differences between exergonic and endergonic reactions
Exergonic proceeds with a net release of free energy and is spontaneous (ex. cellular respiration)
Negative Delta G (ex. -686 kcal/mol is a release of free energy)
Endergonic absorbs energy from surroundings and is non-spontaneous (ex. photosynthesis)
Positive Delta G (ex. +686 kcal/mol is an absorption of free energy)
What is Gibbs Free Energy?
Gibbs Free Energy (G) is the energy that can be used by a system for work
- the change in free energy determines if a reaction happens spontaneously
What is the equation for Delta G? (triangle)
Delta (triangle) G = G final - G initial
What is energy coupling and what is the benefit of it
Bonds between ATP’s phosphate groups can be broken down by hydrolysis (- 7.3 kcal/mol)
- Endergonic reaction do not happen spontaneously so when the exergonic process of hydrolysis of ATP is coupled with it, the overall reaction is exergonic, which means energy is released as heat
Calculate Delta G (must know the delta G for ATP hydrolysis!!!!!)
-7.3 kcal/mol for hydrolysis of ATP
What are the differences between autotrophs and heterotrophs?
Autotrophs are organisms that make organic molecules from inorganic molecules and do not need to eat other organisms for energy; can make their own food
Heterotrophs are organisms that cannot make their own food so they must obtain organic molecules from eating autotrophs or other heterotrophs (eat other organisms)
What are the differences between catabolic and anabolic pathways?
Catabolism is the breakdown of complex molecules into simpler ones; produces ATP (ex. cellular respiration)
Anabolism is the synthesis of complex molecules from simpler ones; uses ATP (ex. protein synthesis or DNA synthesis)
What are the differences between aerobic and anaerobic respiration?
Aerobic respiration breaks down sugars completely in the presence of oxygen and yields the most ATP. Anaerobic respiration partially breaks down sugars in the absence of oxygen and yields less ATP
What are the phases of aerobic respiration and where does each occur within a cell? How much ATP is produced by each???
1.) Glycolysis- occurs in cytoplasm; makes 2 net ATP
2.) Citric acid cycle- occurs in the mitochondria and produces 2 ATP
3.) Oxidative phosphorylation- occurs in mitochondria inner membrane and produces 24-28 ATP
What happens if there is not enough oxygen present after glycolysis? Where would this occur?
Anaerobic respiration (Fermentation)
- pyruvate converted to a molecule that can be easily excreted from cell
- couples glycolysis with fermentation to produce a small amount of ATP (does not require oxygen)
- occurs in cytosol??
What are the 2 types of anaerobic organisms? Know the differences of each
1.) Obligate anaerobes- only carry out anaerobic respiration
- cannot survive in the presence of oxygen
- many microorganisms (bacteria and archaea)
2.) Facultative anaerobes- perform either aerobic or anaerobic respiration
- many yeast and bacteria
What are pigments?
Pigments are substances that absorb photons of visible light
- wavelengths not absorbed are reflected or transmitted, hence why chlorophyll has a green color
What major pigments are used during photosynthesis and what color are they? (why?)
1.) Chlorophyll- green because those wavelengths are not absorbed and so the green light is reflected
- Chlorophyll a and b
Accessory pigments
2.) carotenoids- orange because those wavelengths are not absorbed, giving off an orange color
3.) anthocyanins- red because those wavelengths are not absorbed, giving off a red color
- both absorb excessive light that would damage chlorophyll
What are the 2 major stages of photosynthesis and what happens during each?
1.) light-dependent reactions:
- where photo comes from
- occurs in the thylakoid membrane
- split water
- release oxygen
- reduce NADP+ to NADPH
- Generate ATP from ADP by photophosphorylation
2.) light-independent reactions (aka. Calvin cycle):
- where synthesis comes from
- occurs in the stroma
- forms sugar from carbon dioxide
- begins with carbon fixation
For microtubules: what protein comprises them? How does it assemble into a microtubule? What are the two ends/which grows or shrinks, which is stable, which is near the plasma membrane, and which is near the nucleus???
Microtubules are made of a tubule dimer- alpha tubulin and beta tubulin
- assembles end to end forming 13 protofilaments and wrap around to form a small tube
- The plus end is the rapid assembly and disassembly
- The minus end is relatively stable and usually capped
- The plus end would be near the plasma membrane while the minus end which is stable would be near the nucleus
