C1.2 - Cell Respiration Flashcards
What is cell respiration as a process?
Converting organic molecules to chemical energy of ATP
What are nucleotides?
Subunits of DNA, RNA. Made of 3 parts - nitrogenous base, sugar, phosphate groups
What is ATP?
Adenosine triphosphate, a nucleotide made of adenine base, 5-carbon ribose sugar, and 3 phosphate groups that are negatively charged in chain
What qualities of ATP make it good for being the ‘energy currency’?
- ATP is soluble in water
- 3rd phosphate group of ATP can be easily removed/replaced to make energy
- ATP doesn’t pass freely through phospholipid bilayer
What 3 processes do cells need the energy of ATP for?
- Making macromolecules
- Active transport
- Cell movements
Where can energy to change ADP to ATP come from?
- Cell respiration
- Photosynthesis
- Chemosynthesis
Are energy transfers from ATP-ADP and ADP-ATP completely efficient?
No - some energy changed to heat
What carbon compounds can be used in cell respiration?
Mainly glucose and fatty acids - but others can also be used
What is gas exchange?
When oxygen enters the cells and at the same time carbon dioxide exits the cells
Distinguish between gas exchange and cell respiration? (how are they connected to each other?)
Different processes but are interdependent.
- Without gas exchange, there would be too much co2 and not enough o2 for cell respiration to happen
- Without cell respiration, the concentration gradient of the gases wouldn’t form to let it diffuse in and ount
State 3 word equations to show the different types of cell respiration?
[animals, plants] 1. glucose + oxygen -> (adp-atp) -> co2 + water
[animals, some bacteria] 2. glucose -> (adp-atp) -> lactate
[yeast, fungi] 3. glucose -> (adp-atp) -> co2 + ethanol
Contrast anaerobic and aerobic cell respiration?
Anaerobic:
- Oxygen is not used
- Co2, ethanol, lactate waste products
- Low ATP yield (2 ATP/glucose)
- Reactions in cytoplasm only
Aerobic:
- Oxygen is used
- Co2 and H2O waste products
- High ATP yield (30 ATP/glucose)
- Reactions in cytoplasm + mitochondria
When is anaerobic respiration usually used in humans?
To maximize power of muscle contractions -> anaerobic releases ATP really fast. Historically used for prey/predator stuff, now used for exercise.
Describe the waste product of anaerobic respiration in human muscles?
Waste = lactate which has a max concentration that a human can tolerate so anaerobic respiration is limited
Describe the factors that limit rate of cell respiration?
- Temperature -> optimum temp 20-30
- Substrate Concentration (too much Co2 = bad, too less O2 = bad)
- Type of cell -> some cells need more so rate is faster
What is oxidation?
Loss of electrons from a substance
What is reduction?
A substance experiences gain of electrons
What are electron carriers? What is cell respiration’s electron carrier?
Substances that link the oxidation reactions and the reduction reactions. NAD (nicotinamide adenine dinucleotide) is cell respiration’s carrier
Describe the structure of NAD?
Two nucleotides - one has an adenine base, one has a nicotinamide base. Each base has a ribose sugar connected, the ribose sugars are connected to the phosphate groups which are connected which joins the two nucleotides
How is NAD reduced for cell respiration?
Through substances being oxidized to give NAAD 2 electrons and 1 proton
What does NAD reduction show about reduction/oxidation in general?
Reduction can happen by losing accepting hydrogen atoms and oxidation can happen by losing hydrogen atoms
Are there any examples of reduction/oxidation through loss/gain of oxygen atoms?
Oxygen can be used
Fewer examples, maybe b/c oxygen was scarce on primitive Earth.
Ex: Bacteria oxidizing hydrocarbons with oxygen
What is glycolysis? (Basic overview!)
Glycolysis is 1st step in aerobic cell respiration -> changes glucose into pyruvate to make ATP and reduced NAD. In cytoplasm.
What is the first stage of glycolysis?
Phosphorylation to make fructose 1,6 biphosphate
- Phosphate is added to glucose to make glucose 6 phosphate.
- Glucose 6 phosphate to split fructose 6 phosphate
- Phosphate is added to fructose 6 phosphate to make fructose 1,6 biphosphate
What is the second stage of glycolysis?
Lysis
- Fructose biphosphate is split into 2 molecules of triose phosphate
What is the third stage of glycolysis?
Oxidation
- Each triose phosphate is oxidized / looses electron
- The NAD’s are reduced by the electrons from triose getting oxidized
- Makes glycerate and 2 biphosphate molecules