energy transformation

Question 1

what is metabolism

Answer 1

• integrated network of biochemical reactions that support life, manage energy resources of a cell
• energy: capacity to cause change, cellular processes require energy, building, transport, division, growth and reproduction
• energy can be transferred / transformed but not created or destroyed
• catabolism: breaking down of organic matter (breaking bonds), produces energy
• anabolism: building molecules from smaller units, requires energy

Question 2

what are forms of energy

Answer 2

• kinetic: energy associated with motion (temp = change)
• potential: energy that matter possesses because of its location or structure (e-, ability to react, valence = highest)
• chemical: potential energy available for release in a chemical reaction (transfer of electrons)

Question 3

what are enzymes and how do they lower activation energy

Answer 3

• biological catalyst
• conformational shape change (functional shape, active site, affinity), enables it to stabilise a temporary association between reactants
• not consumed
• combines in correct orientation, stresses bonds and provides a surface to facilitate reactants coming together
• globular proteins with active site(s) for substrates to bind
  1. R-groups of AA interact chemically with substrate
  2. stress or distortion of a bond = lower activation energy
  3. product forms and dissociates from enzyme (due to lower affinity for enzyme)
• enzyme fits precisely into active site to form enzyme substrate complex, substrate binding induces shape change
• activates enzyme to produce a snug fit or receive other substrates
• activation energy: energy required to activate a reaction
• transition state: bonds are able to be broken, unstable

Question 4

what are energy sources

Answer 4

• autotrophic: using energy from the sun or the breakdown of inorganic substances (photosynthesis)
• heterotrophic: obtains energy from eating other organisms (cellular respiration)

Question 5

how does one harvest heat energy in cellular respiration

Answer 5

• takes in sugars / organic molecules to produce CO2, O2, H2O and energy
• mitochondria, cell respiration produce ATP via breakdown of glucose via aerobic / anaerobic
• C6H12O6 + 6O2 —> 6CO2 + 6H2O + heat + energy (ATP)
• redox: electron transfer, oxidation (C in C6H12O6) and reduction (O2 to become H2O), transfer is used to make energy (ATP)

Question 6

what is ATP

Answer 6

• adenine + ribose + 3 P groups
• intracellular battery of metabolic energy
• energy is stored in chemical bonds of P groups, ready to be released when molecule is split into its ADP or AMP
• cell respiration, chemical process uses O to oxidise sugars and fats to produce energy / ATP
• hydrolysis: reacting with water to form ADP + P + energy (e- released from third bond of P being damaged)
• function: transport work (phosphorylation), mechanical work (binds non-covalently to motor proteins = hydrolysed)

Question 7

how does one harvest light energy in photosynthesis

Answer 7

• takes in H2O, CO2 and energy from sun to produce O2 and sugars / organic molecules
• chloroplasts, similar to mitochondria, stroma geranum, thylakoid (organelle), thylakoid space / inter membrane space
• 6CO2 + 12H2O —> C6H12O6 + 6O2 + 6H2O
  1. split water into H and O, incorporating e- of H into sugar molecules
  2. photosynthesis = redox, H2O is oxidised, CO2 is reduced
  3. light reactions in thylakoid membranes (photo) produce O2 from H2O and light
  4. calvin cycle (synthesis) forms sugar from CO2, using ATP and NADPH from light reactions

Question 8

how are cell respiration and photosynthesis coupled

Answer 8

• light energy taken in
• photosynthesis (chloroplasts) - organic molecules + O2 = cellular respiration (mitochondria)
• ATP (powers most cellular work / heat energy as well as CO2 and H2O
• heat energy produced