Chapter 13: How Cells Obtain Energy from Food Flashcards
During respiration, energy is retrieved from the high-energy bonds found in certain organic molecules. In addition to energy, what are the ultimate products of respiration?
CO2 and H20
During photosynthesis, what are the products?
O2 and Sugars
Essentially, what photosynthesis produces are the reactants for cellular respiration.
During photosynthesis, what are the reactants (inputs)?
CO2 and H20
During cellular respiration, what are the reactants (inputs)?
sugars + O2
Remember you need food and oxygen to survive and have energy!
Which groups of organisms undergo photosynthesis?
Plants, Algae, some bacteria
Which groups of organisms undergo cellular respiration?
most living organisms
Energy released during anabolism was acquired from the sun during photosynthesis. True or false?
False. It’s during catabolism.
Energy released during catabolism was acquired from the sun during photosynthesis. True or false?
True
A chemical reaction is defined as spontaneous if there is a net loss of free energy during the reaction process. However, spontaneous reactions do not always occur rapidly. Favorable biological reactions require ______ to selectively speed up reactions and meet demands of the cell.
enzymes
Your body extracts energy from the food you ingest by catalyzing reactions that essentially “burn” the food molecules in a step-wise fashion. What is another way to describe this process?
oxidation
If you weigh yourself on a scale one morning, then eat 4 pounds of food during the day, will you weigh 4 pounds more the next morning?
NO, because only a small portion of the mass of the food will form components of the body. Much of the mass of food is either released as CO2 and H20 that are breathed out into the atmosphere or converted into materials excreted as waste products.
What is the group carried in high-energy linkage for the activated carrier ATP?
Makes sense. You attach a phosphate to the ADP to activate ATP.
phosphate
What is the group carried in high-energy linkage for the activated carrier NADH, NADPH, FADH2?
electrons and hydrogens
What is the group carried in high-energy linkage for the activated carrier ACetyl CoA?
acetyl group
What is the activated carrier for the phosphate?
ATP
What are the activated carriers for the electrons and hydrogens?
Think… I rather sing in the sun…. FA-NA-NA:
FADH2, NADH, NADPH,
Also, remember all of them HAVE hydrogens in them!
What is the activated carrier for the acetyl group?
Acetyl CoA
For delta G < 0….
a) Is the process spontaneous or non-spontaneous?
b) Exergonic or endergonic?
a) spontaneous;
b) exergonic?
For delta G > 0….
a) Is the process spontaneous or non-spontaneous?
b) Exergonic or endergonic?
a) non-spontaneous;
b) endergonic
For delta G = 0….
a) Is the process spontaneous or non-spontaneous?
b) Exergonic or endergonic?
a) Neither. It’s in equilibrium;
b) Neither. It’s in equilibrium;
Catabolism is a energetically ______ reaction.
favorable
Anabolism is a energetically _______ reaction.
unfavorable
What is the cool mnemonic for redox reactions?
LEO the lion says GER!!!
Loss of electrons is ______.
oxidation
Gain of electrons is _______.
reduction
Give an example of a nonspontaneous, endergonic, favorable reaction.
condensation
Give an example of a spontaneous, exergonic, unfavorable reaction.
hydrolysis
A readily available source of energy that cells use to drive reactions is stored in the ______ bond.
phosphoanhydride
A common type of reaction that is needed for ______ is one which two molecules, A and B, are joined together by a _____ bond, to produce A-B in the energetically unfavorable ______ reaction.
biosynthesis; covalent; condensation
NADH, NADPH, and FADH2 are ____ carriers.
activated
NADH, NADPH, and FADH2 carry __ electrons and a ___.
2; H+
Although ATP and NADH are both important activated carrier molecules, ATP Hydrolysis provides the direct molecular energy for most biochemical reactions. Why do the mitochondria also need to generate high levels of NADH?
NADH is an activated carrier molecule used as
- a cofactor for many enzymes that catalyze redox reactions;
- NADH also donates electrons to the electron-transport chian, which is essential for the production of ATP.
When NAD+ receives the high electron energy from the food, it becomes ___.
NADH
When NADH does to the _______, it will donate the electron and then becomes ___ again.
electron transport chain; NAD+
Acetyl coenzyme A (acetyl CaO) is a ____ carrier.
activated
Coenzyme A (CoA) can be converted to _____ when it has the acetyl group.
Acetyl CoA
Which activated carrier molecule has a central role in metabolism and can be used to add two carbons in each successive cycle of fatty acid synthesis?
Acetyl CoA
What is the name of the high energy bonds in Acetyl CoA?
thioester bonds
What happens when the thioester bonds breaks?
It releases high energy
In animals, the breakdown of food molecules occurs in __ stages.
3
What is the first stage of the breakdown of food molecules in animals?
Break down of large food molecules in the mouth and the gut - occurs outside cells.
Where does glycolysis take place?
cytosol
Where does the conversion of pyruvate to acetyl groups on acetyl CoA take place?
mitochondrial matrix
What is stage 2 of the breakdown of food molecules in animals?
Intracellularly with glycolysis and ends with the conversion of the pyruvate to acetyl groups on acetyl CoA
Several types of organic molecules are converted to Acetyl CoA in the ____.
mitochondrial matrix
Where does the citric acid cycle take place?
Mitochondrial matrix
Where does oxidative phosphorylation take place?
Inner membrane
What is stage 3 of the breakdown of food molecules in animals?
Begins with the citric cycle and concludes with the phosphorylation.
What is the net result of the breakdown of food molecules in animals?
You CAN finish this! Hurray!
Food + O2 —> CO2 + ATP + NADH + H20
What are the inputs (reactants) for the breaking down of food molecules?
Food + O2
What are the products (outputs) for the breaking down of food molecules?
You go to the CAN and flush with water.
CO2 + ATP + NADH + H20
The 3 stages in breaking down food molecules in animals occurs only when what?
Food and OXYGEN are available
Stage 1 for breaking down food is _____. Proteins are converted to _____. Polysaccharides are converted to _____. And fats are converted to __________.
digestion; amino acids; sugars; fatty acids & glycerol
________ is the process in which cells break down glucose, release the stored energy, and use it to make ATP.
Cellular respiration
The reactions of cellular respiration can be grouped into three stages. What are those stages?
glycolysis, the Krebs cycle (also called the citric acid cycle), and electron transport.
In stage II of cellular respiration, what are the products of glycolysis? Where does glycolysis occur?
Think…. Time 2 take a NAP.
2 NADHs + 2 ATPs + 2 pyruvate; cytoplasm
What does glucose need to activate itself?
It’s TWO to TANGO.
2 ATPs
During energy harvest in glycolysis, 2 ____ are made. This generates a sum of ____ and ____.
pyruvates; 4 ATP; 2 NADH
Think… After eating sugary snacks, you want to take a nice N-A-P or te comes un P-A-N
2-4-2
during 10 steps of ______, none of the steps required oxygen. So this is the anaerobic condition.
glycolysis
The net products of glycolysis is
Think. TIme 2 take a NAP.
2 NADH + 2 ATPs + 2 pyruvate
Glycolysis requires ___ steps and ___ enzymes.
10; 10
In step 6 of glycolysis, what enzyme is used to convert glyceraldehyde 3-phosphate + NAD+ ———> 1,3 bisphosphglycerate + NADH + H+
glyceraldehyde 3-phosphate dehydrogenase
Glycolysis requires a constant supply of what?
NAD+
Without ___ to pick up high-energy electrons from the splitting of glucose, _____ would stop.
NAD+; glycolysis
If you run out of NAD+, NAD+ can get the high energy electron from glucose. True or False?
False. Glucose can not produce NADH. To produce NADH, you must have NAD+.
What occurs by the transfer of a phosphate group directly from a substrate molecule - one of the sugar intermediates - to ADP?
substrate level phosphorylation
What is the difference between oxidative phosphorylation and substrate level phosphorylation?
- Oxidative phosphorylation requires a proton gradient;
- Substrate level phosphorylation occurs by the by the transfer of a phosphate group directly from a high energy molecule to the ADP
Substrate level phosphorylation occurs in ____ and ____.
glycolysis; citric acid cycle
What is the general function of the kinase enzyme?
Catalyzes the addition of a phosphate group to molecules
What is the role in glycolysis for the kinase?
A kinase transfers a phosphate group from ATP to a substrate in steps 1 and 3; other kinases transfer a phosphate to ADP to form ATP in steps 7 and 10.
A ______ transfers a phosphate group from ATP to a substrate in steps 1 and 3; other kinases transfer a phosphate to ____ to form ___ in steps 7 and 10.
kinase; ADP; ATP
When oxygen is not present (anaerobic), cells use ______ to regenerate ___.
fermentation; NAD+
Microorganisms do alcoholic ______.
fermentation
In fermentation, there are ___ steps and ___ carbon ___ as the starting material.
10; 6; glucose
Fermentation is an ___ process.
anaerobic
After the 10 fermentation steps, you have 2 ___.
Think… After seeing wine, I want to have some “2 pies”.
pyruvate
Each pyruvate has __ carbon, and you produce ___.
Think “P” rhymes with 3. +1 give you the ATPs.
3; Sum of 4 ATPs (net sum: 2 ATP)
In glycolysis step 6, ___ is required; otherwise glycolysis will ___ immediately.
NAD+; stop
How many ATP are produced during fermentation?
2 ATPs
When oxygen is not available, the process will go through fermentation to regenerate ___.
NAD+
Yeast alcoholic fermentation produces ___ and ___.
CO2 and ethanol
During the fermentation process, ___ is released.
NAD+
In anaerobic conditions, skeletal muscle produces
lactate only
____ and ____ are converted to acetyl CoA in the ____.
Think… I learned about “pi” and getting “fat” when attending MIT.
pyruvate; fatty acids; mitochondria matrix
_______ complex catalyzes the transformation of pyruvate to acetyl CoA in the matrix generating ___ in the process.
pyruvate dehydrogenase ; NADH
Pyruvate dehydrogen complex catalyzes the transformation of pyruvate to acetyl CoA in the matrix when ____ is available.
oxygen
Beta oxidation takes places where?
Mitochondria matrix
What is the term that describes the breakdown of fatty acyl CoA to generate acetyl CoA, FADH2, and NADH?
Think… If you are breaking down fatty acyl CoA, then you must be BEEEFY and TALLLLLLL.
beta oxidation
Beta oxidation breaks down fatty acyl CoA to generate ____, _____, and _____.
Thank FAN!
FADH2, acetyl CoA, and NADH.
The citric acid cycle generates ____ by oxidixing acetyl groups to ___.
Think…. Citric Acid reminds me of NAranjas Delicioosas en Hawaii.
Acetyl me da gas (CO2).
NADH; CO2
What are the citric acid cycle inputs per 1 glucose molecule?
Think…To ACE, I need to scream NAD-FAD-ADP!
2 acetyl groups; 6 NAD+; 2 FAD; 2 ADP + 2P
What are the citric acid cycle inputs per 1 turn?
1 acetyl groups; 3 NAD+; 1 FAD; 1 ADP + 1P
What are the citric acid cycle outputs per 1 glucose molecule?
4 CO2; 6 NADH; 2 FADH2; 2 ATP
What are the citric acid cycle outputs per 1 turn?
2 CO2; 3 NADH; 1 FADH2; 1 ATP
Where does the citric acid cycle take place?
Mitochondrial matrix
In the matrix, acetyl CoA is oxidized by the _____ to produce ___ and activated carrier molecules.
citric acid cycle; CO2
Acetyl CoA (2C) combines with _____ (4C) to create _____ (6C).
To Ace her, you need to understand AOC.
oxaloacetate; citrate
____ is converted back to oxaloacetate producing what in the process.
Citrate;
Think the Fibonacci Sequence: 1, 1, 2, 3
FADH2 + GTP + 2 CO2 + 3 NADH
Many biosynthetic pathways begin with ____ or _____.
glycolysis; citric acid cycle
____ drives the synthesis of the majority of ATP in most cells.
Electron transport
NADH and FADH2 donate their high energy electron to electron transport chain. Where does this occur?
Inner mitochondrial matrix
Oxidative phosphorylation takes place in________ as part of a multistage
mitochondria
Oxygen is ____.
electron acceptor
Final electron acceptor is _____.
oxygen
When oxygen is not available, the citric acid cycle immediately stop. Why?
Electron must be received by oxygen. NADH cannot drop the electron. That means what? the shortage of NAD+. Citric acid cycle requires three NAD+ per one turn so it will stop.
Cellular respiration occur when ______ is available.
oxygen
What term describes the synthesis of glucose from pyruvate?
gluconeogenesis
When glucose is being used up and not replaced from food intake, the blood sugar level can be maintained by synthesizing glucose from smaller molecules such as pyruvate or lactate. This process is called gluconeogenesis. Which organ is principally responsible for supplying glucose to the rest of the body when glucose reserves are low?
liver
Catabolic and anabolic reactions are ____ and ______.
organized; regulated
Feedback regulation allows cells to switch from glucose ____ to glucose ____.
breakdown; synthesis
Cells store food molecules in special ____ to prepare for periods of need.
reservoirs.
Long-term storage in animals: fatty acids are stored as ____ in ____ in ___ cells.
triacylglycerols; fat droplets; adipose
Energy storage in plants: fats and ____ are stored in ____.
starches; chloroplasts
Short-term storage in animals: sugars are stored as ____.
glycogen
What is the function of a kinase?
to add a phosphate group to a molecule
If cells were undergoing glycolysis but could not carry out fermentation, what products would build up in the cytosol?
NOTE: Glycolysis produces pyruvate, ATP, and NADH. Fermentation converts pyruvate to ethanol or lactic acid and recycles NADH back to NAD+, so in the absence of this process, the products of glycolysis would accumulate, right?
NADH and pyruvate
Why is the presence of oxygen required for the citric acid cycle to operate?
because the NADH passes its electrons to oxygen in the electron transport chain to renew NAD+
Each molecule of acetyl-CoA entering the citric acid cycle produces two ___________ and four ___________.
CO2; activated carriers
What is the role of oxygen in the electron transport chain?
final electron acceptor
Glycolysis is a(an) _____ process.
anaerobic
Enzymes change the equilibrium point for reactions by lowering the activation energy. True or False?
False. Enzyme can NOT change the equilibrium point.
____ store energy in an easily exchangeable form, either as a readily transferable chemical group or as readily transferable (“high energy”) electrons.
Active carriers
What is the most widely used used activator in cells?
ATP
ATP is synthesized in an energetically unfavorable _____ reaction.
phosphorylation
What do you call the process in which the energy from other activated carriers are used to drive ATP production?
oxidative phosphorylation
Where does oxidative phosphorylation take place?
inner mitochondrial membrane
In the initial stage of breaking down food, where does this take place?
Outside cells in the mouth and gut.
Glycolysis splits a molecule of glucose to form two molecules of ____.
pyruvate
