Unit V Review Flashcards
Chapter 25 What is metabolism
All the chemical reactions that take place in an organism
What is cellular metabolism
Chemical reactions within cells, which create energy
What is catabolism
The breakdown of organic molecules
What is anabolism
Synthesis of new organic molecules
What are the four reasons why cells synthesize new organic components
- Maintenance and repair 2. Support growth 3. Produce secretions 4. Store nutrient reserves
Which fuel source is used first by a cell that has an excess of fats, carbohydrates, and proteins? Why?
Carbohydrates. Glucose is the most efficient energy source, as fats and proteins must first be converted to other things before they can be used. (Fats are second choice, and protein is third)
Which step in the catabolism of glucose takes place in the cytosol of the cell
Glycolysis
What is the difference between aerobic and anaerobic metabolism
Aerobic = uses O2, anaerobic = does NOT use O2 Note: Glycolysis is ANAEROBIC, while reactions inside the mitochondria are aerobic
What is glycolysis
Catabolism of one glucose (6 carbon) to two pyruvate (3 carbon). (Glucose –> Pyruvic Acid –> Pyruvate)
Where does glycolysis take place in the cell
In the cytosol
Why is glycolysis considered to be an anaerobic process
It doesn’t use oxygen
How many carbon, hydrogen, and oxygen atoms are found in one molecule of glucose
C6 H12 O6
How many molecules of pyruvic acid are produced from the catabolism of one glucose molecule
Two
What is pyruvate
At the normal pH inside cells, each pyruvic acid (C3H4O3) molecule loses a hydrogen ion and exists as a negatively charged ion (called pyruvate - C3H3O3)
Which atoms in a glucose molecule are “harvested” and used to drive the process that synthesizes ATP from ADP
Hydrogen (pyruvate = C3H3O3)
In order for pyruvate to enter the citric acid cycle, what gas has to be available
O2
The citric acid cycle takes place in which organelle
Mitochondria
How is acetyl-CoA produced
NAD and coenzyme A react with pyruvate (C3H3O3) to yield: 1x acetyl-CoA (CH3CO) 1x carbon dioxide (CO2) 1x NADH
What is the main function of the citric acid cycle
To remove hydrogen atoms from organic molecules and transfer them to coenzymes
What acid binds to the acetyl group carried by CoA to form citric acid
Oxaloacetic acid (4 carbons: C4H4O5)
What enzymes are responsible for “harvesting” the hydrogen atoms in the citric acid cycle
NAD or FAD
What is oxidative phosphorylation and where does it take place
Produced more than 90% of ATP used by bodily cells. Takes place in the ETS (electron transport system - a series of integral and peripheral proteins in the inner mitochondrial membrane)
What compound is a byproduct of ATP synthesis
The basis of oxidative phosphorylation is the formation of water, a very simple reaction: 2(H2) + O2 = 2(H2O)
Why is oxidative phosphorylation considered an aerobic process
It uses oxygen [2(H2) + O2 = 2(H2O)]