Location of Fatty Acid Synthesis
In which part of the cell does fatty acid synthesis mainly occur?
Cytoplasm (cytosol)
What enzyme converts acetyl-CoA into malonyl-CoA?
Acetyl-CoA Carboxylase (ACC)
What is the main purpose of the TCA cycle?
To produce energy by oxidizing acetyl-CoA.
Which molecule provides the reducing power for fatty acid synthesis?
NADPH
A healthy 20-year-old student eats a large meal high in carbohydrates. A few hours later, insulin levels are high and the body begins making fatty acids.
Which metabolic pathway is being activated?
Fatty acid synthesis
Fatty acid synthesis primarily takes place in the cytoplasm of what type of cells?
Eukaryotic cells
What molecule does ACC use as a cofactor?
Biotin
Which molecule enters the TCA cycle?
Acetyl-CoA
What is the main source of NADPH in cells?
Pentose phosphate pathway
A researcher gives a drug that blocks Acetyl-CoA Carboxylase (ACC) in liver cells.
What molecule will no longer be produced efficiently?
Malonyl-CoA
Which organ is the major site of fatty acid synthesis in humans?
Liver
What energy molecule is required by ACC to convert acetyl-CoA into malonyl-CoA?
ATP
Approximately how many NADH molecules are produced during one turn of the TCA cycle?
Three
What is NADPH mainly used for in metabolism?
Biosynthetic (anabolic) reactions.
A patient has a genetic disorder that greatly reduces NADPH production from the pentose phosphate pathway.
Which process would be directly affected?
Fatty acid synthesis, because NADPH provides the reducing power needed for the pathway.
Which tissue also performs fatty acid synthesis to store excess energy?
Adipose tissue
Is ACC considered the rate-limiting enzyme of fatty acid synthesis?
Yes
What role does oxygen play in relation to the TCA cycle?
Oxygen is the final electron acceptor in the electron transport chain, allowing NADH and FADH₂ to be recycled.
During fatty acid synthesis, what does NADPH donate?
Electrons (reducing power)
A patient has uncontrolled type 1 diabetes and very low insulin levels. Laboratory tests show increased fat breakdown and very little fat production.
Why is fatty acid synthesis decreased?
Low insulin fails to activate Acetyl-CoA Carboxylase (ACC), reducing fatty acid synthesis.
Why is fatty acid synthesis separated from β-oxidation into different cellular compartments?
To prevent the two pathways from occurring simultaneously and wasting energy.
Which hormone activates fatty acid synthesis by activating ACC?
Insulin
Besides NADH, name one other energy-rich molecule produced during the TCA cycle.
FADH₂ or GTP
Why can't NADH replace NADPH during fatty acid synthesis?
Because fatty acid synthesis specifically requires NADPH as its reducing agent.
A pharmaceutical company is testing a new medication that inhibits Fatty Acid Synthase (FAS) in rapidly growing cancer cells. After treatment, the cancer cells stop making palmitate and their growth slows.
Why would blocking Fatty Acid Synthase slow cancer cell growth?
Cancer cells require newly synthesized fatty acids to build cell membranes and support rapid cell division. Inhibiting Fatty Acid Synthase prevents palmitate production, limiting their ability to grow and divide.