Question 1

Explain the cause of hereditary diseases of sphingolipid metabolism, such as Tay-Sachs and Niemann-Pick diseases.

Accepted Answer

Hereditary diseases of sphingolipid metabolism, such as Tay-Sachs and Niemann-Pick diseases, are caused by genetic mutations that affect the enzymes responsible for breaking down sphingolipids. Sphingolipids are a type of lipid found in cell membranes and are involved in various cellular functions.

In Tay-Sachs disease, a mutation in the HEXA gene leads to a deficiency in the enzyme hexosaminidase A, which is responsible for breaking down a specific sphingolipid called GM2 ganglioside. As a result, GM2 ganglioside accumulates in the nerve cells of the brain, leading to progressive neurodegeneration and ultimately, death.

Similarly, in Niemann-Pick disease, mutations in genes such as SMPD1 or NPC1/NPC2 lead to deficiencies in enzymes involved in the breakdown of sphingomyelin, another type of sphingolipid. The accumulation of sphingomyelin in various tissues, particularly in the liver, spleen, and brain, leads to the characteristic symptoms of the disease, including hepatosplenomegaly, lung and neurological problems.

These hereditary diseases of sphingolipid metabolism are inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the mutated gene (one from each parent) to develop the disease. The severity and specific symptoms of these diseases can vary depending on the specific genetic mutation and the extent of enzyme deficiency. Currently, there is no cure for these diseases, and treatment focuses on managing symptoms and improving quality of life for affected individuals.

Question 2

Fatty acids are a component of:

Accepted Answer

A)  carotenes. 
B)  cerebrosides. 
C)  sterols. 
D)  vitamin D. 
E)  vitamin K. 
A)  carotenes. 
B)  cerebrosides. 
C)  sterols. 
D)  vitamin D. 
E)  vitamin K. B

Question 3

Match the compounds on the left with the important roles they play listed on the right. (Answers are used only once.)
(a) prostaglandins
___ blood clotting
(b) vitamin E
___ intra-tissue messengers
(c) sphingolipids
___ necessary for sight
(d) thromboxanes
___ mediates pain and inflammation
(e) vitamin A
___ important component of myelin membranes
(f) steroids
___ reducing agent

Accepted Answer

To match the compounds with their roles:(a) prostaglandins - mediates pain and inflammation
(b) vitamin E - reducing agent
(c) sphingolipids - important component of myelin membranes
(d) thromboxanes - blood clotting
(e) vitamin A - necessary for sight
(f) steroids - intra-tissue messengers
So the full answer would be:
(a) prostaglandins - (d) mediates pain and inflammation
(b) vitamin E - (f) reducing agent
(c) sphingolipids - (e) important component of myelin membranes
(d) thromboxanes - (a) blood clotting
(e) vitamin A - (c) necessary for sight
(f) steroids - (b) intra-tissue messengers

Question 4

If a patient you are treating has asthmatic attacks due to the overproduction of leukotrienes, which drug would you prescribe to help treat that condition?

Accepted Answer

A)  testosterone 
B)  ibuprofen 
C)  aspirin 
D)  prednisone 
E)  warfarin 
A)  testosterone 
B)  ibuprofen 
C)  aspirin 
D)  prednisone 
E)  warfarin

Question 5

Which statement is TRUE of sphingolipids?

Accepted Answer

A)  Cerebrosides and gangliosides are sphingolipids. 
B)  Phosphatidylcholine is a typical sphingolipid. 
C)  They always contain glycerol and fatty acids. 
D)  They contain two esterified fatty acids. 
E)  They may be charged, but are never amphipathic. 
A)  Cerebrosides and gangliosides are sphingolipids. 
B)  Phosphatidylcholine is a typical sphingolipid. 
C)  They always contain glycerol and fatty acids. 
D)  They contain two esterified fatty acids. 
E)  They may be charged, but are never amphipathic.

Question 6

You are working in a laboratory trying to design a drug that specifically binds to the surface of certain cells. To which membrane lipid constituents should your drug bind in order to achieve this specificity?

Accepted Answer

A)  sphingomyelins 
B)  phosphatidylcholines 
C)  gangliosides 
D)  triacylglycerols 
E)  sterols 
A)  sphingomyelins 
B)  phosphatidylcholines 
C)  gangliosides 
D)  triacylglycerols 
E)  sterols

Question 7

Which technique is NOT commonly used to analyze lipid composition?

Accepted Answer

A)  selective extraction using apolar solvents 
B)  adsorption chromatography 
C)  x-ray crystallography 
D)  hydrolysis using enzymes with specificity for certain linkages 
E)  mass spectroscopy 
A)  selective extraction using apolar solvents 
B)  adsorption chromatography 
C)  x-ray crystallography 
D)  hydrolysis using enzymes with specificity for certain linkages 
E)  mass spectroscopy

Question 8

Which statement is NOT true of sterols?

Accepted Answer

A)  Cholesterol is a sterol that is commonly found in mammals. 
B)  Sterols are commonly found in bacterial membranes. 
C)  Sterols are more common in plasma membranes than in intracellular membranes (mitochondria, lysosomes, etc.). 
D)  Serols are precursors of steroid hormones. 
E)  Sterols have a structure that includes four fused rings. 
A)  Cholesterol is a sterol that is commonly found in mammals. 
B)  Sterols are commonly found in bacterial membranes. 
C)  Sterols are more common in plasma membranes than in intracellular membranes (mitochondria, lysosomes, etc.). 
D)  Serols are precursors of steroid hormones. 
E)  Sterols have a structure that includes four fused rings.

Question 9

Describe how vitamin A1 (all-trans-retinol) is altered to produce the visual pigment used in rhodopsin to absorb visible light. Include in your description what is structurally altered in this visual pigment upon light absorption.

Accepted Answer

Vitamin A (all-trans-retinol) is altered

Question 10

What feature do Tay-Sachs disease, Fabry disease, and Niemann-Pick disease have in common?

Accepted Answer

A)  defects in enzymes responsible for synthesizing membrane lipids 
B)  defects in enzymes responsible for breaking down membrane lipids in the lysosomes 
C)  hyperactive membrane lipid degradation enzymes 
D)  defects in enzymes responsible for cholesterol synthesis 
E)  All of the answers are correct. 
A)  defects in enzymes responsible for synthesizing membrane lipids 
B)  defects in enzymes responsible for breaking down membrane lipids in the lysosomes 
C)  hyperactive membrane lipid degradation enzymes 
D)  defects in enzymes responsible for cholesterol synthesis 
E)  All of the answers are correct.

Question 11

Bile acids are derived from which lipid?

Accepted Answer

A)  cholesterol 
B)  sphingomyelin 
C)  ceramide 
D)  digalactosyldiacylglycerol 
E)  phosphatidylcholine 
A)  cholesterol 
B)  sphingomyelin 
C)  ceramide 
D)  digalactosyldiacylglycerol 
E)  phosphatidylcholine

Question 12

Which feature allows certain lipid molecules to be used as colorful pigments in plants and animals?

Accepted Answer

A)  Their high oxygen content helps electrons circulate, which allows absorption of visible light. 
B)  Their conjugated bond structures allow absorption of visible light. 
C)  Their four-fused ring structure allows visible light reflection. 
D)  Their hydrophobicity bends light around them. 
E)  Their low specific gravities cause light to reflect from their surfaces. 
A)  Their high oxygen content helps electrons circulate, which allows absorption of visible light. 
B)  Their conjugated bond structures allow absorption of visible light. 
C)  Their four-fused ring structure allows visible light reflection. 
D)  Their hydrophobicity bends light around them. 
E)  Their low specific gravities cause light to reflect from their surfaces.

Question 13

Which term BEST describes the cholesterol molecule?

Accepted Answer

A)  amphipathic 
B)  nonpolar, charged 
C)  nonpolar, uncharged 
D)  polar, charged 
E)  polar, uncharged 
A)  amphipathic 
B)  nonpolar, charged 
C)  nonpolar, uncharged 
D)  polar, charged 
E)  polar, uncharged

Question 14

Which statement is TRUE about fatty acids?

Accepted Answer

A)  Fatty acids with longer chains have higher melting points. 
B)  Fatty acids with longer chains have lower solubility in water. 
C)  Fatty acids with more double bonds have higher melting points. 
D)  Fatty acids with longer chains have higher melting points and lower solubility in water. 
E)  None of the statements is true. 
A)  Fatty acids with longer chains have higher melting points. 
B)  Fatty acids with longer chains have lower solubility in water. 
C)  Fatty acids with more double bonds have higher melting points. 
D)  Fatty acids with longer chains have higher melting points and lower solubility in water. 
E)  None of the statements is true.

Question 15

Which compound can be cleaved in half to generate a molecule important in vision?

Accepted Answer

A)  calcitol 
B)  beta-carotene 
C)  arachidonic acid 
D)  tocopherol 
E)  isoprene 
A)  calcitol 
B)  beta-carotene 
C)  arachidonic acid 
D)  tocopherol 
E)  isoprene

Question 16

Describe the dependence of the melting point of a fatty acid upon (a) chain length and (b) unsaturation; (c) explain these dependencies in molecular terms.

Accepted Answer

The melting point of a fatty acid is dep

Question 17

_____ is NOT a biological use of waxes.

Accepted Answer

A)  Energy storage 
B)  Lubrication 
C)  Structure 
D)  Insulation 
E)  Waterproofing 
A)  Energy storage 
B)  Lubrication 
C)  Structure 
D)  Insulation 
E)  Waterproofing

Question 18

Which types of signaling lipids are produced by platelets to aid in the formation of blood clots?

Accepted Answer

A)  prostaglandins 
B)  thromboxanes 
C)  arachidonates 
D)  lipoxins 
E)  leukotrienes 
A)  prostaglandins 
B)  thromboxanes 
C)  arachidonates 
D)  lipoxins 
E)  leukotrienes

Question 19

Which statement BEST describes why lipids typically float on water?

Accepted Answer

A)  Lipids are nonpolar, while water is polar. 
B)  Lipids have lower specific gravities than water does. 
C)  Lipids have higher melting temperature than water does. 
D)  Lipids store more energy than water does. 
E)  Lipids contain carbon, while water does not. 
A)  Lipids are nonpolar, while water is polar. 
B)  Lipids have lower specific gravities than water does. 
C)  Lipids have higher melting temperature than water does. 
D)  Lipids store more energy than water does. 
E)  Lipids contain carbon, while water does not.

Question 20

Tay-Sachs disease is the result of a genetic defect in the metabolism of:

Accepted Answer

A)  gangliosides. 
B)  phosphatidyl ethanolamine. 
C)  sterols. 
D)  triacylglycerols. 
E)  vitamin D. 
A)  gangliosides. 
B)  phosphatidyl ethanolamine. 
C)  sterols. 
D)  triacylglycerols. 
E)  vitamin D.

Exam 10: Lipids

Explain the cause of hereditary diseases of sphingolipid metabolism, such as Tay-Sachs and Niemann-Pick diseases.

Fatty acids are a component of:

If a patient you are treating has asthmatic attacks due to the overproduction of leukotrienes, which drug would you prescribe to help treat that condition?

Which statement is TRUE of sphingolipids?

You are working in a laboratory trying to design a drug that specifically binds to the surface of certain cells. To which membrane lipid constituents should your drug bind in order to achieve this specificity?

Which technique is NOT commonly used to analyze lipid composition?

Which statement is NOT true of sterols?

Describe how vitamin A1 (all-trans-retinol) is altered to produce the visual pigment used in rhodopsin to absorb visible light. Include in your description what is structurally altered in this visual pigment upon light absorption.

What feature do Tay-Sachs disease, Fabry disease, and Niemann-Pick disease have in common?

Bile acids are derived from which lipid?

Which feature allows certain lipid molecules to be used as colorful pigments in plants and animals?

Which term BEST describes the cholesterol molecule?

Which statement is TRUE about fatty acids?

Which compound can be cleaved in half to generate a molecule important in vision?

Describe the dependence of the melting point of a fatty acid upon (a) chain length and (b) unsaturation; (c) explain these dependencies in molecular terms.

_____ is NOT a biological use of waxes.

Which types of signaling lipids are produced by platelets to aid in the formation of blood clots?

Which statement BEST describes why lipids typically float on water?

Tay-Sachs disease is the result of a genetic defect in the metabolism of:

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

Describe how vitamin A₁ (all-trans-retinol) is altered to produce the visual pigment used in rhodopsin to absorb visible light. Include in your description what is structurally altered in this visual pigment upon light absorption.