Lecture #10 - How cell gets energy from food Flashcards
Why does a cell need energy? (5 things)
- To do WORK
- CHEMICAL (to make things)
- CELLULAR transport
- MECHANICAL use of energy
- That’s all acheived through ENERGY COUPLING
What’s energy coupling?
- EXERGONIC processes: RELEASE energy
- The released energy drives ENDERGONIC processes which ABSORB energy.
- ATP provides the coupling mechanism
Fill in this diagram:
Here
What’s ATP involved in?
- ENERGY tranfer
- RNA synthesis - it’s a chemical component to make RNA
- NEUROTRANSMISSION - signals sent from one neuron to another
ATP hydrolysis:
- What kinda reaction is it?
- Large or small amount of energy realsed? Why?
- Generates what at a microscopic level?
- Couples to…..?
- ATP hydrolysis is an exergonic reaction (RELEASES energy)
- Relatively large amount of energy released due to the P-P-P bonds (lots of ene taken to put em together so releases heaps to break em)
- It generates heat - shivering
- It couples to endergonic cellular reactions
Coupling:
- Often achieved through what?
- Forms what?
- Which may be….
- And thus allows….
- Explain the image in terms of the above
- Coupling often acheived through the transfer of the phosphate
- Forms a PHOSPHORYLATED INTERMEDIATE
- Which may be MORE REACTIVE
- And thus allows a reaction to PROCEED
- Phosphorylated intemediate: P is transferred to glutamic acid after hydrolysis - more energy on molecule so more willing to react now. It’s an activated form of glutamic acid i.e. more reactive.
ATP forms a p_____ i______ which may …….. and allows the ……… and also allows ………
ATP forms a phosphorylated intermediate (transfer a P?) which may change shape of molecule and allows the active transport of molecules and also allows molecular movement to occur
Eg here, the transport protein changes shape and the motor protein changes shape (takes a step) to walk
In this image, label the left and right arrows with “exergonic” and “endergonic”
- How much ATP do we use per day?
- What is it regenerated from?
- Where is energy obtained from?
Left is endergonic (going from ADP + P to ATP) and right is exergonic
- We use nearly our body weight per day (a single muscle cell uses 10^6 ATP molecules/s)
- It is regenerated from ADP + P - an endergonic reaction
- The energy is obtained from cellular respiration
How do cells get energy out of glucose? (2 ways)
- Fermentation - catabolism without oxygen
- Aerobic respiration - catabolism with oxygen (some prokaryotes substitue eg sulfur for oxygen bc it’s near O on periodic table)
Chemical reactions involve transfer of ……. and what’s OIL RIG
Chemical reactions involce transfer of electrons whether that’s from one molecule to another or within a single molecule
OIL = Oxidation is LOSS of e-
RIG = Reduction is GAIN of e- (reduction of +ve charge)
- Redox reactions may also involve movement of e- ____ a molecule
- In this diagram, the e- move ____ from carbon therefore it’s been _____
- Also, e- move _____ to oxygen therefore it’s been ______
- Similar oxidation of organic molecules occurs in c____ r_____
(what’s another way to describe the redox?)
- Redox reactions may also involve movement of e- WITHIN a molecule
- In this diagram, the e- move AWAY from carbon therefore it’s been OXIDIZED (OIL)
- Also, e- move CLOSER to oxygen therefore it’s been REDUCED (RIG)
- Similar oxidation of organic molecules occurs in CELLULAR RESPIRATION
(For the redox; C had a ON of -4 in methane and it changed to +4 in CO2 so it went up therefore it was oxidised…….O2 has ON = 0 and then in H20, it became -2 so went down so reduced)
Energy is required to pull e- ____ from the positive a____ n_____
During r_____ electrons move n____ to the Oxygen nucleus
Therefore it r_____ energy
This is the energy the cell captures and puts to w____
Energy is required to pull e- AWAY from the positive ATOMIC NUCLEUS
During REDUCTION electrons move NEARER to the oxygen nucleus
Therefore it RELEASES energy
This is the energy the cell captures and puts to WORK
Cellular respiration harvests the energy in C-H bonds in food molecules by transferring the e_____ to O2
- Simple combustion generates too much h____
- The cell performs this o_____ in a series of
controlled steps
• Electrons stripped from glucose are transferred to N_____ (an electron carrier)
A d______ enzyme removes __ hydrogen atoms from glucose
- and transfers the 2 electrons plus 1 H+ to NAD+ forming N___
- N____ used to power electron transport chain
Cellular respiration harvests the energy in C-H bonds in food molecules by transferring the electrons to O2
- Simple combustion generates too much heat
- The cell performs this oxidation in a series of
controlled steps
• Electrons stripped from glucose are transferred to NAD (an electron carrier)
A dehydrogenase enzyme removes two hydrogen atoms from glucose
- and transfers the 2 electrons plus 1 H+ to NAD+ forming NADH
- NADH used to power electron transport chain
Fill in blanks
ATP Synthase:
- Makes what?
- Is a(n) __ ___ in reverse
- Uses the ___ gradient to power ____ formation
- Makes ATP from ADP + P
- Ion pump in reverse
Uses H+ gradient to power ATP formation
ATP Synthase:
- H+ ions flow into a h___ c___
- H+ ions bind to the r____ and change its s____
- rotor s___
- after o__ t___ of the rotor, H+ ions e___ to the m____
- rotor turns the r___ which activates c___ s____ to produce ATP
H+ ions flow into a HALF CHANNEL (channel only goes half way through the membrane)
H+ ions bind to the ROTOR and change its SHAPE
- rotor SPINS (H+ goes around rotor once - one notch with every one H+)
- after ONE TURN of the rotor, H+ ions EXIT to the MATRIX
- rotor turns the ROD which activates CATALYTIC SITES to produce ATP (top rotor turns and transfers the H+ to bottom rotor)
Appreciate this image
Yeah
