AP biology Chapter 9- Cellular Respiration

Photosynthesis

generates O₂ and organic molecules, which are used in cellular respiration

regenerate ATP

Cells use chemical energy stored in organic molecules

OILRIG

Oxidation Is Losing Reduction is Gaining

Fermentation

is a partial degradation of sugars that occurs without O₂

Aerobic respiration

consumes organic molecules and O₂ and yields(makes) ATP

Anaerobic respiration

is similar to aerobic respiration but consumes compounds other than O₂

Cellular respiration

includes both aerobic and anaerobic respiration but is often used to refer to aerobic respiration; Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace it with the sugar glucose

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP + heat)

What is the formula for Cellular Respiration?

Inner mitochondrial membrane

Where does the electron transport chain take place in?

gains an electron, but a hydrogen can follow

what does a oxidizer gain?

transfer of electrons

• during chemical reactions releases energy stored in organic molecules

• This released energy is ultimately used to synthesize ATP

redox reactions

Chemical reactions that transfer electrons between reactants

oxidation

a substance loses electrons, or is oxidized

reduction

a substance gains electrons, or is reduced (the amount of positive charge is reduced)

reducing agent

The electron donor

oxidizing agent

The electron receptor(steals electrons)

the oxidizing agent would want more electrons since they are already electronegative or can be positively charged, and would want to pull from their neighbor, causing the products for the one with more electrons originally in the reactants to be oxidized and the oxidizing agent would be reduced and have more electrons; Ex: in CH4 + 2O2 ——> CO2 + 2H2O; the 2O2 is the oxidizing agent that wants electrons from CH4, which causes CH4 to be the reducing agent, giving electons to O2,making CH4 being oxidized(losing electrons) and 2O2 gains electrons, being reduced.

On the reactants side of a reaction, why does the oxidizing agent want more electrons and how?

NAD+ is a reactant, that wants to gain electrons, being the oxidizer agent, that pulls from other reactants, that when its in the products, it gains an electron, being reduced, followed by having a proton H+.

in a reaction, what is NAD+?

NAD+

coenzyme and electron acceptor, functions as an oxidizing agent during cellular respiration

Each NADH(the reduced form of NAD⁺) represents stored energy that is tapped to synthesize ATP

electron transport chain

NADH passes electrons here; Unlike an uncontrolled reaction, the electron transport chain passes electrons in a series of steps instead of one explosive reaction

• O₂ pulls electrons down the chain in an energy-yielding tumble

The energy yielded is used to regenerate ATP

The tree stages of Cellular Respiration

1. Glycolysis (breaks down glucose into two molecules of pyruvate)

2. The citric acid cycle (completes the breakdown of glucose) (KREBS, TCA)

3. Oxidative phosphorylation (accounts for most of the ATP synthesis)

oxidative phosphorylation

accounts for almost 90% of the ATP generated by cellular respiration

substrate-level phosphorylation

A smaller amount of ATP is formed in glycolysis and the citric acid cycle

Glycolysis

• can produce ATP with or without O₂ (in aerobic or anaerobic conditions)

• In the absence of O₂, couples with fermentation or anaerobic respiration to produce ATP

• Occurs in nearly all organisms

• (“splitting of sugar”) breaks down glucose into two molecules of pyruvate

• occurs in the cytoplasm and has two major phases:

  • Energy investment phase

  • Energy payoff phase

They have no membrane-bound organelle

Why can only prokaryotes do Glycolysis?

2 ATP

How much ATP is used in Glycolysis?

G-3-P; it is eventually going to be pyruvate, huge majority energy molecule

What is made that the end of the Glycolysis Investment phase, and what does it turn into after the payoff phase?

2 NADH product from the redox reactions and 4 ADP phosphorylation redox reactions; and 2 pyruvates with a net gain of 2 ATP

How many redox reactions take place at the end of glycolysis and what energy molecules are made?

it gets converted into Acetyl CoA, and releases some carbons, being CO2

what happens to Pyruvate in the start of the Kreb cycle and why?

During the Kreb cycle and when Pyruvate turns into Acetyl CoA

How much CO2 gets released in the Kreb cycle and where?

twice; once per pyruvate

How many times does the Kreb cycle run per pyruvate?

6

How much NADH is made Total in the Kreb cycle?

2

How much FADH2 is made Total the Kreb cycle?

2

How much Total ATP is made in the Kreb cycle?

The cristae of the mitochondrion

Where does the electron transport chain take place in?

After the forming of NADH and FADH; they carry the electrons to the chain, and the electrons are passed through a # of proteins including Cytochromes to go to O2. Generates no ATP, but the ultimate function is to break the large free-energy drop from food to O₂ into smaller steps that release energy in manageable amounts

What does the electron transport chain do?

allosteric regulation of PFK; regulate form a site not from the active site; citric acid and ATP, can inhibit or slow down PFK, which can slow down the production of ATP; AMP can increase PFK to produce more ATP

How can the process of glycolysis be regulated?

TCA, citric acid cycle

what are the different names of the Kreb cycle?

intermembrane space of the mitochondria

Where are the H+ ions pumped during the electron transport chain?

acts as a passageway of the protons to enter into the mitochondria; due to the high concentration of H+ in the innermembrane, so the H+ need a passageway where there is less concentration of H+ (exergonic flow of H⁺ to drive phosphorylation of ATP

• This is an example of chemiosmosis, the use of energy in a H⁺ gradient to drive cellular work)

What is the role of ATP synthase?

• The energy stored across a membrane couples the redox reactions of the electron transport chain to ATP synthesis

• referred to as a proton-motive force, emphasizing its capacity to do work

What is the H+ gradient referred to as?

• NADH and FADH₂ account for most of the energy extracted from food

• These two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation

How does NADH and FADH2 power ATP synthesis?

No, About 33% of the energy is transferred, making about 32 ATP

Is 100% of energy of the energy in a glucose molecules transferred in ATP molecule?

speeds up when there is a low concentration of ATP; slows down when there is a lot of ATP

what happens with respiration when ATP concentration fluctuates?

• fermentation or anaerobic respiration to produce ATP

In the absence of O₂, glycolysis couples with?

Fermentation

• consists of glycolysis plus reactions that regenerate NAD⁺, which can be reused by glycolysis

• Two common types are alcohol fermentation and lactic acid fermentation

• uses phosphorylation instead of an electron transport chain to generate ATP

alcohol fermentation

• pyruvate is converted to ethanol in two steps, with the first releasing CO₂

• this fermentation by yeast is used in brewing, winemaking, and baking

lactic acid fermentation

• pyruvate is reduced by NADH, forming lactate as an end product, with no release of CO₂

• the fermentation by some fungi and bacteria is used to make cheese and yogurt

• Human muscle cells use lactic acid fermentation to generate ATP when O₂ is scarce

Obligate anaerobes

• carry out fermentation or anaerobic respiration and cannot survive in the presence of O₂

facultative anaerobes

yeast and many bacteria is this; that they can survive using either fermentation or cellular respiration

Anceint prokaryotes before oxygen was in the atmosphere

where did Glycolysis evolve in?

cytosol

where does glycolysis take place in?