Flashcards in Chapter 9 Deck (51)
Energy enters most ecosystems as...
Energy leaves most ecosystems as...
chemical energy stored in organic molecules that the mitochondria and eukaryotes use as fuel for cellular respiration
yield energy by OXIDIZING and BREAKING down organic molecules
an exergonic process
a catabolic process
-a partial degradation of sugars that occurs in the absence of oxygen
the most prevalent and efficient catabolic pathway
- consumes Oxygen and organic molecules such as glucose and yields ATP
Cells must regenerate ATP...
in order to keep working
Catabolic pathways yield energy based on ...
their ability to cause a transfer of elections
transfer elections from one reactant to another by oxidation and reduction
i.e. redox of table salt: Na+ is oxidized, Cl- is reduced
a substance loses elections, or is oxideized
a substance gains elections, or is reduced
the "fall" of electrons during respiration is...
stepwise and occurs by an electron transport chain
Electron Transport Chain
found in inter membrane counter of mitochondria
During cellular respiration...
glucose is oxidized
oxygen is reduced
done through a series of steps, each of which is catalyzed by a specific enzyme
at Key Steps during cellular respiration
electrons are stripped from glucose and the electrons are transferred with a proton as a hydrogen atom
glucose + 6oxygen => 6CO2 + 6water + Energy
O: glucose => 6CO2
R: 6oxygen => 6water
During cellular respiration, glucose is oxidized in a...
series of steps and
the H atoms are not directly transferred to oxygen but are ...
passed to a coenzyme called NAD+
nicotinamide adenine dinucleotide
2 H atoms from glucose are removed by this enzyme and then it transfers 2 electrons and 1 H+ (proton) to NAD+ (creating NADH) and the other proton is released into the solution
NADH => NAD+
NADH: the reduced form
passes e- to the "top" or high energy end of the electron transport chain
If the electron transfer is not stepwise...
a large release of energy occurs as in the reaction of hydrogen and oxygen to form water
Electron Transport Chain location
in the mitochondria membranes
Electron transport chain
"breaks the fall" of electrons by passing them in a controlled series of steps, and uses the energy from the electron transfer to form ATP
a the "bottom" or lower-energy end, oxygen captures the electrons along with hydrogen to form water
During cellular respiration, electrons follow a
Stages of cellular respiration
2) Citric Acid Cycle
3) Oxidative phosphorylation
occurs in the cytoplasm
- breaks down glucose into two molecules of pyruvate (produces some ATP)
glucose => 2 pyruvate + 2 H2O + 2ATP + 2 NADH
Citric Acid Cycle
occurs in the mitochondrial membrane
- utilizes pyruvate and completes the breakdown of glucose
2 pyruvate => ATP, CO2, NADH, FADH2
occurs in the inner mitochondrial membrane
- drives the synthesis of ATP by the transfer of electrons from NADH in electron transport chain
NADH + FADH2 => ATP
Glycolysis and the citric acid cycle can generate ATP by
substrate level phosphorylation
an enzyme transfers a phosphate group from an organic substrate to ADP, forming ATP
i.e. Pyruvate Kinase: transfers a phosphate (phosphorylates) ADP from phosphoenolpyruvate (PEP) to make ATP and pyruvate