4.1 - Intro to Cellular Respiration and Fermintation

Aerobic Cellular Respiration

uses oxygen to harvest energy from food

Energy harvest from food is used to convert what?

ADP and Pi (inorganic phosphate) into ATP

Converted ADP and Pi is used to supply what?

energy to cells to carry out their function

Aerobic Cellular Respiration is the catabolism of what 2 molecules?

CO₂ and H₂O

define catabolism

the breakdown of large molecules into smaller molecules

cellular respiration equation (molecules)

C_6H_{12}O_6+6O_2\to6CO_2+6H_{2_{}}O

cellular respiration word equation

glucose + oxygen → carbon dioxide + water

what is the delta g (free energy) of the cellular respiration equation?

△G = -2870 kJ/mol

how is the free energy released in the breakdown of glucose be useful?

it can be useful elsewhere such as the phosphorylation of ADP

obligate aerobe

organism that cannot live without oxygen and uses cellular respiration most of the time (euk)

what is the most widely used pathway to produce ATP?

oxidation of ATP

can proteins and lipids also be oxidized?

yes

what is oxidation in terms of hydrogen and oxygen?

• loss of H+ molecules

• gain of O2 molecules

how many stages can aerobic cellular respiration be divided into?

4 stages

each stage in aerobic cellular respiration involves the…

transfer of free energy to produce ATP

what are the 2 ways free energy can be transferred to produce ATP

1. substrate-level phosphorylation

2. oxidative phosphorylation

what is substrate-level phosphorylation?

• type of way to transfer free energy to produce ATP

• forms ATP through an enzyme catalyzed reaction where a phosphate group is transferred from a molecule to ADP

what is oxidative phosphorylation?

• type of way to transfer free energy to produce ATP

• forms ATP indirectly through a series of redox reactions involving O2 as the final electron acceptor

what are the 4 steps of cellular respiration?

1. Glycolysis

2. Pyruvate Oxidation

3. Citric Acid Cycle

4. Electron transport and oxidative phosphorylation

simplified definition of glycolysis

a series of reactions where a glucose is broken into 2 pyruvate molecules and energy is released

simplified definition of pyruvate oxidation

pyruvate is oxidized by NAD+, CO₂ is removed forming an acetyl group and releasing NADH

simplified definition of citric acid cycle

a cyclic series of reactions that transfers energy from organic molecules to ATP, NADH, and FADH₂

simplified definition of electron transport and oxidative phosphorylation

the NADH and FADH₂ are oxidized, free energy that is released is used to synthesize ATP by oxidative phosphorylation

Where does glycolysis occur?

occurs in cytosol

• fluid surrounding all of the organelles and occurs out mitochondria

What steps occur in the mitochondrion?

pyruvate oxidation, citric acid cycle, electron transport chain

why are mitochondria considered to be the powerhouse of the cell?

the citric acid cycle and electron transport chain occur here and generate most of the ATP that is used by the cell

how many membranes does a mitochondrion have?

2; one inner and one outer membrane

intermembrane space

space between the inner and outer membranes of the mitochondrion

matrix

internal aqueous environment of the organelle

can some prokaryotic cells undergo cellular respiration without a mitochondria?

no

in cells without a mitochondria, where do the 4 steps occur?

glycolysis, pyruvate oxidation, and citric acid cycle → occur in the cytosol of the cell

electron transport → internal membrane

label the parts of the mitochondria:

1. inner membrane

2. outer membrane

3. cristae

4. matrix

5. intermembrane space

what is “cristae”?

the folds of the inner membrane

what are the 2 processes that are used to generate ATP without oxygen?

1. anaerobic respiration

2. fermentation

anaerobic respiration

• one of the processes that can generate ATP without oxygen

• series of electron transferring steps with an inorganic molecule as the final oxidizing agent (other than oxygen)

fermentation

• one of the processes that can generate ATP without oxygen

• does not use an electron transport system and relies on an organic compound as the final oxidizing agent to produce energy (break down of an organic comopound)

are the 2 processes that can generate ATP without oxygen catabolic or anabolic?

catabolic

does aerobic or anaerobic cellular respiration release more free energy?

aerobic cellular respiration releases more free energy

obligate anaerobe

an organism that does not survive in the presence of oxygen

• does not use oxygen but uses inorganic substances

facultative anaerobe

an organism that can live with or without oxygen