Lipids Flashcards
Lipids are compounds that are soluble in which type of solvents?
• A. Water
• B. Organic solvents such as acetone and ether
• C. Acidic solutions
• D. Salt solutions
B
The primary storage site for lipids in the body is:
• A. Muscle tissue
• B. Liver
• C. Adipose tissue (fat cells)
• D. Pancreas
C
What is the largest proportion of lipids consumed in the human diet?
• A. Phospholipids
• B. Cholesterol
• C. Triacylglycerols (TG)
• D. Free fatty acids
C
Lipids serve as precursors for:
• A. Carbohydrates
• B. Enzymes
• C. Hormones and signaling molecules
• D. Nucleotides
C
Which function is NOT associated with lipids?
• A. Energy storage
• B. Insulation of organs
• C. Cell membrane formation
• D. Acting as an enzyme
D
Which type of lipids act as carriers for fat-soluble vitamins?
• A. Steroids
• B. Phospholipids
• C. Triacylglycerols (TG)
• D. Free fatty acids
C
What is the main role of short-chain fatty acids (SCFAs)?
• A. They function as a structural component in cell membranes
• B. They act as a key energy source for colonic cells
• C. They aid in protein synthesis
• D. They act as neurotransmitters
B
SCFAs are primarily produced by:
• A. The liver
• B. The pancreas
• C. The fermentation of dietary fiber by gut bacteria
• D. The stomach lining
C
The three main short-chain fatty acids (SCFAs) include:
• A. Acetic, butyric, and propionic acids
• B. Stearic, oleic, and linoleic acids
• C. Palmitic, arachidonic, and linolenic acids
• D. Myristic, lauric, and eicosapentaenoic acids
A
Which of the following is not an effect of SCFAs on the gastrointestinal (GI) tract?
• A. Increase pH in the colon
• B. Enhance colonic blood flow
• C. Promote differentiation of mucosal cells
• D. Provide energy for colonic cells
A
How do SCFAs affect sodium (Na+) absorption in the colon?
• A. They inhibit Na+ absorption
• B. They stimulate Na+ absorption
• C. They replace Na+ with potassium (K+)
• D. They have no effect on Na+ absorption
B
How do SCFAs help protect against colon cancer?
• A. They increase bile solubility
• B. They reduce bile solubility and promote calcium (Ca+) binding to bile acids and fatty acids
• C. They increase pH in the colon
• D. They promote cholesterol synthesis
B
Which SCFA is the most important energy source for colonic cells?
• A. Acetic acid
• B. Butyric acid
• C. Propionic acid
• D. Linoleic acid
B
SCFAs inhibit the synthesis of which compound in the liver?
• A. Glucose
• B. Bile salts
• C. Cholesterol
• D. Protein
C
One of the effects of SCFAs is to:
• A. Reduce calcium binding
• B. Enhance immune function
• C. Decrease colonic blood flow
• D. Decrease water retention
B
Lipids contribute to cell signaling by:
• A. Acting as structural components in the pancreas
• B. Carrying oxygen molecules
• C. Modulating metabolic and immune responses
• D. Absorbing toxins from the bloodstream
C
What hormones are synthesized from lipids?
• A. Insulin and glucagon
• B. Cortisol and estrogen
• C. Epinephrine and norepinephrine
• D. Growth hormone and prolactin
B
How do lipids insulate the body?
• A. By forming a protective protein layer
• B. By generating electrical impulses
• C. By storing water in fat cells
• D. By providing a layer of fat under the skin and around organs
D
Which type of lipids are major components of cell membranes?
• A. Triacylglycerols
• B. Cholesterol
• C. Phospholipids
• D. Steroids
C
The primary function of cholesterol in cell membranes is to:
• A. Act as an energy source
• B. Increase membrane fluidity and stability
• C. Store excess carbohydrates
• D. Synthesize digestive enzymes
B
Lipids are stored for energy in the form of:
• A. Free fatty acids
• B. Cholesterol
• C. Triacylglycerols
• D. Phospholipids
C
When carbohydrates are unavailable, the body primarily uses:
• A. Lipids for energy
• B. Proteins for energy
• C. Nucleic acids for energy
• D. Minerals for energy
A
What is the role of phospholipids in digestion?
• A. They break down proteins
• B. They transport fat-soluble vitamins
• C. They act as an emulsifier in bile
• D. They digest carbohydrates
C
How do SCFAs affect immune function?
• A. They increase inflammation
• B. They suppress immune cell production
• C. They enhance immune response and prevent harmful cell growth
• D. They have no effect on immunity
C
Which of the following is NOT a function of lipids?
• A. Transport of fat-soluble vitamins
• B. Formation of cell membranes
• C. Storage of amino acids
• D. Insulation and organ protection
C
What is the primary function triacylglycerols (TG) in the human body?
- A. Structural support in cell membranes
- B. Energy storage
- C. Hormone synthesis
- D. Transport of proteins
B
Which of the following is NOT a function of lipids?
- A. Insulation and padding of organs
- B. Cell signaling
- C. carbohydrate synthesis
- D. Synthesis of hormones
C
Which of the following is a characteristic of a saturated fatty acid?
- A. Contains one or more double bonds
- B. Contains only single bonds
- C. Has a kinked structure
- D. Liquid at room temperature
B
The omega system of naming fatty acids starts counting from which end?
- A. Carboxyl end
- B. Methyl end
- C. Hydroxyl end
- D. Phosphate end
B
Which essential fatty acid is classified as an ω-3 fatty acid?
- A. Linoleic acid
- B. Arachidonic acid
- C. α-Linolenic acid
- D. Palmitic acid
C
Which fatty acid is considered ‘not good’ due to its role in promoting inflammation?
- A. ω-3 fatty acid
- B. ω-6 fatty acid
- C. Trans-fatty acid
- D. Short-chain fatty acid
B
Trans-fatty acids are produced artificially through which process?
- A. Hydrogenation
- B. Fermentation
- C. Esterification
- D. Hydrolysis
A
Which of the following is NOT an effect of trans-fatty acids?
- A. Increases LDL cholesterol
- B. Decreases HDL cholesterol
- C. Lowers blood pressure
- D. Induces inflammation
C
Which of the following is NOT a short-chain fatty acid?
- A. Acetic acid
- B. Butyric acid
- C. Linoleic acid
- D. Propionic acid
C
SCFAs are mainly produced in the gut through the fermentation of what?
- A. Lipids
- B. Dietary fiber
- C. Proteins
- D.Carbohydrates
B
Which of the following id NOT a function of SCFAs in the GI tract?
- A. Enhance colonic blood flow
- B. Increase bile solubility
- C. Provide energy for colonic cells
- D. Inhibit hepatic cholesterol synthesis
B
What is the ATP yield from triglycerides compared to glucose?
- A. 32 ATP for TG, 106 ATP for glucose
- B. 106 ATP for TG, 32 ATP for glucose
- C. 64 ATP for TG, 48 ATP for glucose
- D.48 ATP for TG, 106 ATP for glucose
B
Where are triglycerides primarily stored in the human body?
- A. Liver
- B. Adipose tissue
- C. Muscle cells
- D.Red blood cells
B
What makes phospholipids ideal components for cell membranes?
- A. They are fully hydrophilic
- B. They are amphiphilic
- C. There are fully hydrophobic
- D. They are electrically charged
B
Cholesterol is mainly synthesized in which organ?
- A. Heart
- B. Liver
- C. Kidney
- D. Pancreas
B
Which enzyme is the rate-limiting step in cholesterol synthesis?
- A. Lipase
- B. HMG-CoA reductase
- C. ATP synthase
- D.Phospholipase
B
What is the main function of the enterohepatic circulation?
- A. Transport fatty acids to muscles
- B. Reabsorb bile salts
- C. Store cholesterol in adipose tissue
- D. Regulate glucose metabolism
B
Which enzyme starts TG digestion in the mouth?
- A. Pancreatic lipase
- B. Lingual lipase
- C. Gastric lipase
- D. Bile salts
B
What is the role of bile salts in lipid digestion?
- A. Break down lipids into smaller droplets
- B. Hydrolyze TG into free fatty acids
- C. Transport lipids in the bloodstream
- D. Convert fatty acids into glucose
A
Which lipoprotein is responsible for transporting cholesterol to peripheral tissues?
- A. HDL
- B. LDL
- C. VLDL
- D. Chylomicrons
B
Which lipoprotein removes excess cholesterol from cells and transports it to the liver?
- A. HDL
- B. LDL
- C. VLDL
- D. Chylomicrons
A
What apoprotein is present in chylomicrons?
- A. ApoB-100
- B. ApoB-48
- C. ApoA-I
- D.ApoC-II
B
What enzyme hydrolyzes TG in chylomicrons?
- A. HMG-CoA reductase
- B. Lipoprotein lipase
- C. Pancreatic lipase
- D. Phospholipase A2
B
Which protein is responsible for degrading LDL receptors, leading to increased LDL in circulation?
- A. PCSK9
- B. ApoA-I
- C. CD36
- D. Niemann-Pick Type C
A
Which of the following lipids serves as a precursor for bile acids?
- A. Phospholipids
- B. Cholesterol
- C. TG
- D. Fatty acids
B
Which of the following conditions can result from an imbalance of ω-6 to ω-3 fatty acids in the diet?
- A. Increased risk of cardiovascular disease
- B. Decreased inflammatory response
- C. Enhanced insulin sensitivity
- D. Increased HDL cholesterol levels
A
Which if the following correctly describes the function of Niemann-Pick Type C protein in lipid absorption?
- A. It hydrolyzes TG in chylomicrons
- B. It facilitates the absorption of cholesterol into enterocytes
- C. It transport bile salts into circulation
- D. It regulates the rate of lipid oxidation into mitochondria
B
During lipid digestion, what happens to long-chain fatty acids after entering the enterocyte?
- A. They are directly absorbed into the bloodstream
- B. They are converted into TG and packed into chylomicrons
- C. They are stored into the cytoplasm of enterocytes
- D. They are used immediately as an energy source
B
Which of the following lipoproteins is formed in the liver and delivers endogenous lipids to peripheral tissues?
- A. Chylomicrons
- B. HDL
- C. VLDL
- D. LDL
C
Which statement below is correct?
- A. 18:2 Δ9,12 is an ω-9 fatty acid.
- B. Saturated fat is liquid at room temperature
- C. Hydrogenated fats are always saturated
- D. Fatty acids are attached to glycerol by ester bonds
- E. Saturated fat is the main component of canola oil
D
Which statement below is correct?
- A. Essential fatty acids belong to the ω-3 family.
- B. Phospholipids are transported on the surface of lipoproteins.
- C. Desaturates transform single bonds into double bonds.
- D. Trans-fatty acids make fat less creamy.
- E. LDL particles contain ApoB-48
B
Choose the incorrect statement below?
- A. A diet rich in ω-6 fatty acids limits the production of eicosanoids.
- B. Heart, muscle, and adipose tissue require LPL to extract fatty acids from VLDL and chylomicrons.
- C. Co-lipase supports TAG hydrolysis in the duodenum.
- D. Chylomicron remnants and IDLs are disassembled in the liver.
- E. The sterol nucleus is the basis for Vitamin D synthesis.
A
Which lipoprotein sequence below contains the highest to lowest phospholipid content relative to its mass?
- A. Chylomicron > VLDL > LDL
- B. HDL > Chylomicron > LDL
- C. LDL > HDL < Chylomicron
- D. HDL > VLDL > Chylomicron
- E. HDL > LDL > Chylomicron
E
Which is not a feature of HMG-CoA reductase?
- A. Its activity is regulated by intracellular cholesterol levels.
- B. Converts HMG-CoA into mevalonate.
- C. Is highly abundant in hepatocytes.
- D. Is rate-limiting for endogenous cholesterol production.
- E. Is the first enzyme in the endogenous cholesterol synthesis.
E
Which statement below is true?
- A. PCSK9 enhances cholesterol uptake by hepatocytes.
- B. HDL interacts with LDL to collect triglycerides.
- C. Cholesterol esters are formed in HDL by LCAT.
- D. Chylomicrons contain ApoB-100.
- E. Apo C-II is not necessary for VLDL to unload its cargo.
C
What is the function of LCAT?
- A. To esterify cholesterol moving from non-hepatic tissues into HDL
- B. To convert cholesterol into triglycerides within HDL particles
- C. To promote Apo-CII induced LPL activation
- D. To transfer cholesterol esters from hepatocytes to the HDL particle
- E. To allow the transfer of cholesterol from HDL to LDL particles
A
In which of the following situations would someone be in the negative nitrogen balance?
- A. When you are on a hypercaloric diet
- B. Pregnancy
- C. Disease states like sepsis or cancer
- D. When you are trying to build muscle mass
- E. None of these statements are correct
C
Which statement below is correct?
* A. HDL becomes spherical after interacting with non hepatic tissues
* B. LCAT converts cholesterol into cholesterol esters within HDL particles
* C. All options are correct
* D. Nascent HDLs are small and discoidal particles
* E. HDL particles pick up cholesterol from other lipoproteins and peripheral tissues
C
Which statement below is incorrect?
* A. Pepsin is responsible for digesting proteins in the stomach
* B. Bicarbonate is secreted by the pancreas
* C. HCl denatures pepsinogen in the stomach causing it to unfold and become activated
* D. Secretin stimulates the release of bicarbonate into the small intestine
* E. Trypsin and chymotrypsin are activated in the small intestine and work to break down peptide bonds in chyme
C
Which below are effects of short chain fatty acids?
* A. Promote peristalsis
* B. Enhance cholesterol synthesis by the liver
* C. Increase fecal volume
* D. Enhanced colonic blood flow
* E. Reduce bile acid excretion
D
Which fatty acids below are associated with increased LDL and reduced HDL?
* A. Short chain fatty acids
* B. Omega 6 fatty acids
* C. Cis fatty acids
* D. Omega 3 fatty acids
* E. Trans fatty acids
E
Which statement below is correct?
* A. PCSK9 is released when hepatic cholesterol content is low
* B. Interstitial fluid accounts for the majority of the extracellular water compartment
* C. Gastric juice contains HCl, pepsins, and mucus
* D. Intrinsic factor is produced by oxyntic cells in the duodenum
* E. Nonwater miscibility is a feature of essential amino acids
C
Which statement below is incorrect?
* A. The coiling/folding of one chain and the interaction of 2 or more peptide chain are the primary and quaternary structures of proteins, respectively.
* B. All polypeptide chains have a primary structure
* C. None of these statements are incorrect
* D. BCAAs contain nonpolar/hydrophobic side chains
* E. Polarity of an amino acid depends on its ability to interact with water and electrolytes
A
Which below are symptoms of hypothyroidism in an infant?
* A. Stunt growth
* B. Impaired fat and carbohydrate metabolism
* C. Impaired body temperature regulation
* D. All options are correct
* E. Cretinism and impaired protein synthesis
D
How does LDL donate its cholesterol content to peripheral tissues?
* A. By turning into IDL and interacting with HDL in the circulation
* B. By receiving apoE from HDL and undergoing endocytosis in hepatocytes
* C. By exchanging lipids with HDL upon binding to the LDL receptor
* D. By undergoing endocytosis after interacting with the LDL receptor
* E. By interacting with PCSK9 in the circulation
D
Which statement below is correct?
* A. Hydrogenation of unsaturated fatty acids causes rancidity in oils
* B. 22:6 delta 4,7,10,13,16,19 is an omega 3 fatty acid
* C. Lack of linoleic and linolenic fatty acids can lead to retarded growth in humans
* D. Bacteria in the colon ferment soluble fibers and produce long chain fatty acids
* E. The portal vein carries nutrients and insulin towards the pancreas
C
What is the function of LPL in the capillaries of the adipose tissue?
* A. The hydrolyze triacylglycerols in chylomicrons and VLDL
* B. To facilitate the formation of glycerol from glycolysis
* C. The hydrolyze triacylglycerols in LDL particles
* D. To esterify fatty acids in chylomicrons
* E. To transfer cholesterol esters from HDL to VLDL
A
What is the main fate of bile acids in the gut?
* A. Degradation by the liver
* B. Conversion into free cholesterol by gut bacteria
* C. Excretion in the feces
* D. Reabsorption in the terminal part of the ileum
* E. Degradation by colonic bacteria
D
What are chylomicrons composed of when they enter the lactal?
* A. Triglycerides, phospolipids, cholesterol, and apoB48
* B. 2MAGs, cholesterol, and apoB48
* C. Phospholipids, 1MAGs, and cholesterol
* D. Cholesterol, phospholipids and apoC2
* E. Cholesterol, phospholipids and apoB48
A
What effects are attributed to the intake of the n-3 fatty acids Eicosapentenoic (EPA) and docosahexaenoic (DHA) in the body?
* A. Enhanced inflammation
* B. Increased production of short chain fatty acids by the gut bacteria
* C. Attenuation of inflammation
* D. Increased oxidation of fatty acids by the liver
* E. Enhanced iron absorption
C
Which statement below is correct?
* A. HDL becomes spherical after interacting with non hepatic tissues
* B. LCAT converts cholesterol into cholesterol esters within HDL particles
* C. All options are correct
* D. Nascent HDLs are small and discoidal particles
* E. HDL particles pick up cholesterol from other lipoproteins and peripheral tissues
