Food Biochemistry Quiz

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Questions and Answers

What is the primary function of lipoprotein lipase?

To convert free fatty acids into triglycerides

To synthesize triglycerides in the liver

To transport cholesterol to peripheral tissues

To break down chylomicrons into free fatty acids and glycerol (correct)

What happens to chylomicrons after they deliver triglycerides to tissues?

They are converted into VLDLs

They are excreted in the urine

They are taken up by the liver as chylomicron remnants (correct)

They are broken down into glycerol and free fatty acids

What is the main function of VLDLs?

Transporting cholesterol to peripheral tissues

Storing triglycerides in adipose tissue

Breaking down triglycerides into free fatty acids

Transporting triglycerides to peripheral tissues (correct)

How are free fatty acids utilized in muscle tissue?

They are used for energy production Signup and view all the answers

What is the process of breaking down triglycerides in adipose tissue called?

Lipolysis Signup and view all the answers

What are the two main products of lipolysis?

Glycerol and free fatty acids Signup and view all the answers

Which of the following is NOT a type of lipoprotein?

Hemoglobin Signup and view all the answers

What happens to VLDLs as triglycerides are removed?

They become IDLs and eventually LDLs Signup and view all the answers

Which enzyme is responsible for the breakdown of triglycerides in adipose tissue?

Adipose triglyceride lipase (ATGL) Signup and view all the answers

What is the role of albumin in the process of fatty acid transport?

Albumin acts as a carrier protein, binding to free fatty acids and transporting them in the blood. Signup and view all the answers

What is the primary function of coenzyme A (CoA) in fatty acid metabolism?

CoA is required for the breakdown of fatty acids into acetyl-CoA during beta-oxidation. Signup and view all the answers

Where does beta-oxidation take place?

Mitochondrial matrix Signup and view all the answers

What is the primary product of each cycle of beta-oxidation?

Acetyl-CoA Signup and view all the answers

What is the role of the citric acid cycle in the process of fatty acid oxidation?

The citric acid cycle oxidizes acetyl-CoA, producing electron carriers NADH and FADH2, which contribute to ATP production. Signup and view all the answers

Which of the following molecules directly contributes to the proton gradient that drives ATP synthesis in oxidative phosphorylation?

NADH and FADH2 Signup and view all the answers

Which of the following statements is NOT true about the process of fatty acid oxidation?

Fatty acid oxidation occurs in both the cytoplasm and mitochondria. Signup and view all the answers

Which enzyme is NOT involved in the carnitine shuttle for fatty acid transport?

Acetyl-CoA carboxylase Signup and view all the answers

During which process do fatty acids get broken down into acetyl-CoA?

Beta oxidation Signup and view all the answers

What is the primary energy currency produced during the citric acid cycle?

ATP Signup and view all the answers

Triglycerides are composed of which molecular structure?

One glycerol and three fatty acid chains Signup and view all the answers

What happens to triglycerides after they are digested and absorbed in the small intestine?

They are re-esterified and packaged into chylomicrons. Signup and view all the answers

How are chylomicrons transported from the intestines to the bloodstream?

Via the thoracic duct in the lymphatic system Signup and view all the answers

Which statement about triglycerides is incorrect?

Triglycerides are primarily used for immediate energy. Signup and view all the answers

Which component is synthesized alongside triglycerides during their formation?

Apolipoproteins Signup and view all the answers

What is the primary function of hormone-sensitive lipase in the transport of fatty acids?

Break down triglycerides into free fatty acids and glycerol Signup and view all the answers

Why do free fatty acids bind to albumin for transport in the blood?

Albumin makes fatty acids water-soluble Signup and view all the answers

What is the role of fatty acid translocase (FAT/CD36) in fatty acid transport?

It facilitates the uptake of free fatty acids by cells Signup and view all the answers

What is the purpose of activating fatty acids to form fatty acyl-CoA?

To enable fatty acids to enter mitochondria for beta oxidation Signup and view all the answers

Which of the following is NOT a key step in the transport of fatty acids within the body?

Synthesis of new fatty acids Signup and view all the answers

What is the primary function of fatty acid binding proteins (FABPs)?

To facilitate the entry of fatty acids into mitochondria Signup and view all the answers

What is the role of acyl-CoA synthetase in the transport of fatty acids?

It activates fatty acids to form fatty acyl-CoA Signup and view all the answers

Where does the breakdown of triglycerides into free fatty acids and glycerol occur?

Adipose tissue Signup and view all the answers

Study Notes

Fatty Acids

Long chains of hydrocarbon molecules with a carboxyl group (-COOH) at one end.
Key components of fats and oils in plants and animals, classified by the number of double bonds.

Transport of Fatty Acids

Release from Adipose Tissue: Hormone-sensitive lipase breaks down triglycerides into free fatty acids and glycerol when energy is needed.
Transport in Blood: Free fatty acids are not water-soluble, so they bind to albumin for transport in the bloodstream.
Uptake by Cells: Cells utilize specific transport proteins like fatty acid translocase (FAT/CD36) and fatty acid binding proteins (FABPs) to absorb free fatty acids.
Transport into Mitochondria: Fatty acids convert to fatty acyl-CoA via acyl-CoA synthetase, requiring the carnitine shuttle for transport into mitochondria.
Beta Oxidation: In mitochondria, fatty acids are oxidized, producing acetyl-CoA, which enters the citric acid cycle (Krebs cycle) for ATP production.
Energy Production: ATP generated from the citric acid cycle and electron transport chain powers various cellular functions.

Triglycerides

Composed of one glycerol molecule bonded to three fatty acid chains; the most common fat type in the body.
Formed when excess calories are converted to fat for storage in fat cells.

Transport of Triglycerides

Absorption and Packaging:
- Digestion: Dietary triglycerides break down into monoglycerides and free fatty acids in the small intestine by pancreatic lipases.
- Absorption: These products are absorbed by enterocytes and re-esterified into triglycerides.
- Chylomicron Formation: Packaged into chylomicrons with cholesterol, phospholipids, and apolipoproteins.
Transport via Lymphatic System and Bloodstream: Chylomicrons enter the lymphatic system and are transported to the bloodstream via the thoracic duct.
Uptake by Tissues:
- Lipoprotein lipase on endothelial surfaces breaks down triglycerides in chylomicrons into free fatty acids and glycerol for cellular uptake.
- Free fatty acids are used for energy or storage, while glycerol returns to the liver.
Liver Processing:
- Chylomicron remnants are taken up by the liver to form very-low-density lipoproteins (VLDL) for further transport.
Very-Low-Density Lipoproteins (VLDL) Transport:
- Released into the bloodstream to transport triglycerides to peripheral tissues.
- VLDL is acted upon by lipoprotein lipase, forming intermediate-density lipoproteins (IDL) and low-density lipoproteins (LDL) over time.
Storage and Utilization:
- Free fatty acids can be re-esterified in adipose tissue or oxidized in muscle for energy.

Release of Energy from Triglycerides and Fatty Acids

Lipolysis: Breakdown of triglycerides into glycerol and free fatty acids, catalyzed by hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL).
Transport: Free fatty acids are transported by albumin to various tissues.
Fatty Acid Activation: Free fatty acids are activated to acyl-CoA in the cytoplasm, a process requiring ATP.
Beta Oxidation: Acyl-CoA enters mitochondria for beta-oxidation, producing acetyl-CoA, NADH, and FADH2.
Citric Acid Cycle (Krebs Cycle): Acetyl-CoA undergoes further oxidation, producing additional NADH, FADH2, ATP, and carbon dioxide.
Electron Transport Chain (ETC) and Oxidative Phosphorylation: NADH and FADH2 donate electrons to the ETC, creating a proton gradient that drives ATP synthesis through oxidative phosphorylation.

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Description

A quiz on food biochemistry for fourth-year students, covering various aspects of food science and nutrition. This quiz is designed to test knowledge and understanding of food biochemistry concepts. Prepare to answer questions on food chemistry and nutrition!