cellular respiration and fermentation Flashcards
What is the purpose of cellular respiration? ** make sure you know EXACTLY what chad wants**
- to generate ATP
- cellular molecular chemical pathway in the presence of o2 to produce ATP
What are the four main steps in cellular respiration and the purpose of each?
- glycolysis: glucose is broken down into pyruvate
- pyruvate processing: pyruvate is processed to form acetyl-coA. acetyl-coa is used a fuel for next steps of CR
- krebs cycle: acetyl-CoA is oxidized to CO2. main function is to produce energy, stored and transported as ATP or GTP
- electron transport with oxidative phosphorylation: to create an electrochemical gradient that leads to the creation of ATP
How do positive and negative feedback loops ‘control’ cellular respiration.**
- cells are told what to do based on neg and pos feedback loops
- feedback loops allow for energy to not be expendend unecessarily
- if ATP levels are high, cr will stop
- dback mechanisms allow cells to adapt their energy production to their current needs, either by ramping up ATP production in response to increased demand or scaling it back when there is a surplus
- dynamic regulation is vital for the efficient functioning of cells and the organism as a whole.
What steps in the oxidation of glucose are primarily controlled positively versus negatively?**
GLYCOLYSIS: negative feed back loop; high levels of ATP inhibt the enzyme phosphofructokinase. produce of enxyme can only be used in glysolysis. enxyme binds in active site and the regulatory site. when atp conc high, atp also binds to reg site and enxyme changes shape, making reaction rate at active site drop dramatically
PYRUVATE PROCESSING: regulated under both positive and negative feeback control.
KREBS CYCLE: negative feeback; regulated by ATP and NADH abundance (at multiple sites in the cycle). shuts off by abundance of something
Outline an analogy to describe cellular respiration. Make sure to identify the importance of the bio-molecules ATP and NADH in your analogy.
bowling analogy
- the bowling ball is glucose
- the lane is the mitochonria, and knocking down the pins at the end is producing energy
- getting a strike is like producing ATP and getting a spare is like producing NADH
What is the fermentation?
- fermentation is an alternative pathway for producing energy
- occurs in anerobic conditions
- pyruvate, rather than oxygen accepts electron from NADH
- converts NADH back to NAD+ and allows glycolysis to continue
- 2 mechanism: lactic acid fermentation and alcohol fermentation
What is the purpose of fermentation in regard to cellular respiration?
- to regenerate NAD+ so that glycolysis can continue and produce some energy
- fermentation allows gyloysis to contine when the lack of an electron acceptor shuts own electron transport chain
what are the conditions necessary for alcohol fermentation to occur?**
- anerobic
- only some organisms can undergo alcohol fermentation
What does fermentation have to do with the generation of biofuels?
- allows fuel alcohol isolation from cellulose
- ethanol (produced in alcohol fermentation) is a usable fuel
- we dont use it/ use it less because fossil fuels are cheaper. i.e. takes time, energy, and money to grow organisms and have them undergo fermentation, vs drilling for fossil fuels which are already made
lactic acid fermentation vs alcohol fermentation
lactic acid fermentation
- pyruvate aceepts electron from NADH. lactate and NAD+ are produced
- occurs in most organisms
- what we do
- no intermediate; pyruvate accepts electron from NADH
- procudes 2 lactic acid (a 3 carbon molecule) and 2 ATP
alcohol fermentation
- pyruvate is converted to acetaldehyde and co2
- acetaldehyde accepts electrons from NADH. ethanol and NAD+ are produced
- occurs in yeast
- have an intermediary” acetayladhyde
- procudes 2 ethanol (a 2 carbon molecule) and 2 ATP
- applicable to sustainable energy
is fermentation efficent compared to cellular respiration
- not as efficent
- only produces 2 ATP molecules per glucose molecule
- organisms NEVER use fermentation if an appropriate electron acceptor is avalible for cellular respiration
what is glucose
- the hub of energy processing in cells
- a starch
- the end product of photosynthesis
- water insoluable
- it is energy and it is used by vast majority of organisms
- glucose is a key intermediatey in cell metabolism
- cells use glucose to build fats, carbs, and other compounds
- cells recover glucose by breaking down these molecules
glyolysis
- a series of ten chemical reactions
- first step in glucose oxidation
- glucose brokwn down into pyruvate, used to phosphorylate ADP to ATP
- NAD+ is reduced to NADH
- oxygen is not required
-a series of catalyzed enzymatic reactions - occurs in cytoplasm
- produced 2 ATP
which components are involved in the oxidatio of glucose
- glycolysis, pyruvate pricessing, and the krebs cycle
pyruvate processing
- second step in glucose processing
- in presence of oxygen, pyruvate undergoes a series of reactions producing acetly-CoA
- another molecule of NADH is generated
- one of carbon atoms in pyruvate is oxidized to CO2
- occurs in mitochoondrial matris (across the outer membrane)
- requires oxygen
- in bacteria and archea, ocurs in mitochonria
- pyrvuate dehydrogenaze converts pyruvate to acetly-CoA
