Chapter 6- Harvesting Cellular Energy Flashcards
A molecule is oxidized when what happens to it?
When it loses one or more electrons
Reduction is ______.
The addition of electrons to a substance
What occurs in cellular respiration?
02 is consumed as organic molecules are broken down to CO2 and H2O
The cell captures the energy released in ATP
Photosynthesis occurs in chloroplasts of plants/algae and some ______.
Prokaryotes
Cellular respiration occurs in the mitochondria of _____ and almost all _____.
Many prokaryotes
Almost all eukaryotes (plants, animals, fungi, and protists
Matter is ______ but energy _____.
Recycle
Is not recycled
Respiration refers to _____.
An exchange of gases
Biologists also define respiration as _____.
The aerobic harvesting of energy from food molecules
Cellular respiration harvests energy from _____ and _____.
Glucose
Other organic molecules
In cellular respiration, O2 is used to _____.
Help cells breakdown glucose and other molecules to obtain ATP
C6H12O6 + 6O2 ———> _______.
6CO2 + 6H2O + ATP + heat
What do cells use most often for fuel?
Simple sugar, glucose
In the Exergonic reaction of breaking down glucose, some of the energy released is stored as _____.
ATP
How many ATP molecules are produced from each glucose molecule?
Up to 32 ATP molecules
How much energy is captured from the breakdown of glucose?
About 34%
What occurs to the rest of the energy released in the Exergonic reaction of cellular respiration?
It is lost as heat
What helps maintain body temperature?
Heat released from cellular respiration
The unit of measurement of energy is _____.
Kilocalories (kcal)
The human brain consumes how much glucose per day for energy? This accounts for what % of the body’s total energy consumption?
120g
20%
What is a kcal?
The quantity of heat required to raise the temperature by 1 degree Celsius
How man jacks does the human body need?
1300-1800 kcal
What is the basal metabolic rate? (BMR)
The energy requirement for the human body (1300-1800 kcal/day)
The US National Academy of Science says the average human needs how many kcal per day?
2,200
What affects your daily calorie intake?
Age, sex, activity level
What is a redox reaction?
The transfer of electrons from one molecule to another
An oxidation-reduction reaction
In a redox reaction, the loss of one or more electrons from a substance is called _____.
Oxidation
In a redox reaction, the addition of electrons to another substance is called _____.
Reduction
What is the important coenzyme used in oxidizing glucose?
The enzyme NAD+ (nicotinamide adenine dinucleotide
What does NAD+ do?
It accepts electrons, becoming REDUCED (reduction: adding electrons to a substance)
Shuttles electrons
An enzyme called ______ strips _____ from the organic ______.
Dehydrogenase
Two hydrogen atoms
Food molecule
Once hydrogenase removes 2 hydrogen atoms from the food molecule, what does it do?
Hydrogenase transfers two electrons and one proton to NAD+, reducing it to NADH.
The second proton is released into the surrounding solution.
Once NAD+ is reduced to NADH, it carries the electrons and drops them off at the _______.
Electron transport chain
The electron transport chain is composed of what?
Carrier molecules (mostly all proteins)
At the end of the electron transport chain, what occurs?
An oxygen atom accepts two electrons, picks up 2H+, and is REDUCED to H2O
What is released through the electron transport chain?
Controlled release of energy for ATP synthesis
Glycolysis is the process of _____.
Oxidizing glucose through redox reactions (?)
What are the 3 stages of cellular respiration?
- Glycolysis
- Pyruvate oxidation and citric acid cycle
- Oxidative phosphorylation
Glycolysis basically does what?
Splits glucose into two molecules of a three carbon compound called pyruvate
What is pyruvate?
The product of glycolysis, glucose broken down to form two molecules of a 3 carbon chain compound
Where do pyruvate oxidation and the citric acid cycle take place?
Within the mitochondria
What does the citric acid cycle do?
Breaks down the rest of glucose, after pyruvate oxidation, to CO2
In the _____ stage of cellular respiration, CO2 is formed through the _____ cycle in the _____.
Second
Citric acid cycle (process of breaking down glucose to form CO2)
Mitochondria
What occurs to pyruvate exiting glycolysis, once it enters the mitochondria?
It is oxidized to a two carbon compound after which the citric acid cycle takes over
A small amount of _____ produced during _____ and _____.
ATP
Glycolysis
Citric acid cycle
A cell produces most of it’s _____ during _____.
Oxidative phosphorylation
What is oxidative phosphorylation?
Occurring after the citric acid cycle, electrons are transported to an electron transport chain embedded in the inner mitochondrial membrane.
Oxidative phosphorylation captures the energy of the redox reactions occurring once NADH and FADH carry electrons to the inner mitochondrial membrane.
The electrons are eventually dropped off at O2, where two H+ atoms joins to form water.
During oxidative phosphorylation, what does the electron transport chain ALSO do?
Pumps H+ ions across the intermembrane space resulting in a high concentration of H+ ions
What is chemicals?
Creating ATP from the H+ rich concentration within the mitochondrial intermembrane space.
Pyruvate itself does/does not enter the citric acid cycle?
Does not
What actually enters the Citric Acid cycle (Krebs cycle)?
Two molecules of acetyl CoA
How is pyruvate prepared to enter the Krebs cycle?
A carboxyl group (—COO-) is removed and given of as CO2
The two carbon pyruvate is oxidized
A molecule of NAD+ is reduced to NADH
The two carbon group then joins with a compound, coenzyme A (CoA), to form acetyl coenzyme A (acetyl CoA)
