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Introduction to Biochemistry > Exam 3 > Flashcards

Exam 3 Flashcards

1
Q

What is the main purpose of lipoproteins?

A

Transport lipids and cholesterol through the bloodstream

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2
Q

What are the four main types of lipoproteins?

A

Chylomicrons, VLDL, LDL, and HDL

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3
Q

What is the primary function of fatty acid catabolism?

A

Break down fatty acids to produce energy in the form of ATP

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4
Q

What is beta-oxidation?

A

The process of breaking down fatty acids into acetyl-CoA units

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5
Q

Where does fatty acid catabolism occur?

A

In the mitochondria of cells

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6
Q

What are ketone bodies?

A

Alternative energy source produced from fatty acids when glucose is limited

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7
Q

What triggers ketone body production?

A

Low glucose levels and high fatty acid breakdown

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8
Q

What is lipogenesis?

A

The process of creating fatty acids from acetyl-CoA

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9
Q

Where does fatty acid synthesis occur?

A

In the cytoplasm of cells

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10
Q

What is the rate-limiting enzyme in cholesterol synthesis?

A

HMG-CoA reductase

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11
Q

What regulates fatty acid synthesis?

A

Insulin levels and cellular energy status

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12
Q

How is cholesterol synthesis regulated?

A

Through feedback inhibition and hormonal control

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13
Q

What is the function of LDL?

A

Delivers cholesterol to peripheral tissues

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14
Q

What is the role of HDL?

A

Removes excess cholesterol from tissues and returns it to the liver

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15
Q

What are the three ways vertebrates utilize fat?

A

Dietary intake, mobilization from adipose tissue, and liver conversion of excess carbohydrates

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16
Q

What percentage of daily human energy requirements come from TAGs?

A

40% or more

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17
Q

What enzyme helps absorb fatty acids from diet?

A

Pancreatic lipase

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18
Q

Where is pancreatic lipase located?

A

Intestinal lumen

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19
Q

What is the function of lipoprotein lipase?

A

To absorb fatty acids from chylomicrons and VLDL

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20
Q

Where are lipoprotein lipases found?

A

Capillary walls

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21
Q

What is the purpose of hormone-sensitive lipase?

A

To break down cellular fat stores

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22
Q

Where is hormone-sensitive lipase found?

A

Intracellularly

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23
Q

What are bile salts derived from?

A

Cholesterol

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23
Q

What compounds help solve the problem of insoluble fat particles?

A

Bile salts

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24
Q

Where are bile salts produced?

A

In the liver

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25
Q

Where are bile salts stored?

A

In the gallbladder

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26
Q

What is the primary function of bile salts with TAGs?

A

They create mixed micelles

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27
Q

What are the four main components packaged with lipoproteins?

A

Triacylglycerols, cholesterol, cholesteryl esters, and specific proteins

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28
Q

What forms the exterior of lipoproteins?

A

Phospholipid head groups

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29
Q

What proteins coat the surface of lipoproteins?

A

Apolipoproteins

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30
Q

What are the five classes of lipoproteins in order of density?

A

Chylomicrons, VLDL, IDL, LDL, HDL

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31
Q

What does IDL stand for?

A

Intermediate-Density Lipoproteins

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31
Q

What does VLDL stand for?

A

Very Low-Density Lipoproteins

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32
Q

What does CM stand for in lipoprotein classification?

A

Chylomicrons

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33
Q

What does LDL stand for?

A

Low-Density Lipoproteins

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34
Q

What does HDL stand for?

A

High-Density Lipoproteins

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35
Q

What is the main function of the exogenous pathway?

A

Transport of dietary fat and cholesterol

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36
Q

What does the liver synthesize in the endogenous pathway?

A

TAGs and cholesterol

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36
Q

How are dietary lipids initially processed in the exogenous pathway?

A

They are packaged into chylomicrons

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37
Q

What lipoprotein packages liver-synthesized lipids?

A

VLDL

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38
Q

What are the three main products of β-oxidation?

A

Acetyl-CoA, FADH2, and NADH

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39
Q

What triggers the mobilization of stored TAGs?

A

Glucagon and epinephrine hormones

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39
Q

Where does fatty acid catabolism occur?

A

In the mitochondrial matrix through β-oxidation

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40
Q

What enzyme is responsible for releasing fatty acids from stored TAGs?

A

Hormone-sensitive lipase

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41
Q

How are fatty acids transported in the bloodstream?

A

By serum albumin

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42
Q

What are the four main ways fatty acid oxidation is regulated?

A

Cell energy state, hormonal regulation, malonyl-CoA regulation, and transcriptional regulation via PPAR receptors

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43
Q

Where does ketone body production exclusively take place?

A

In liver mitochondria

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44
Q

What are the five main functions of the liver in lipid metabolism?

A

Metabolizing dietary fatty acids, synthesizing fatty acids, synthesizing cholesterol, producing bile salts, and producing VLDLs/HDLs

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45
Q

Which lipoproteins does the liver produce?

A

VLDLs and HDLs

46
Q

What molecule regulates fatty acid oxidation at the metabolic level?

A

Malonyl-CoA

47
Q

What nuclear receptors are involved in transcriptional regulation of fatty acid oxidation?

A

PPAR receptors

48
Q

What are bile salts used for?

A

To aid in the digestion and absorption of dietary fats

49
Q

What key processes does ketogenesis provide energy for?

A

Brain, skeletal muscle, heart muscle, and kidney, especially during starvation

50
Q

Where does fatty acid synthesis occur and in which tissues?

A

In the cytosol, primarily in liver and adipose tissue

51
Q

What are the required components for fatty acid synthesis?

A

Acetyl-CoA, ATP, and NADPH

52
Q

What are the three main functions of cholesterol?

A

Cell membrane incorporation, steroid hormone precursor, and bile acid precursor

53
Q

What is the rate-determining enzyme in cholesterol synthesis?

A

HMG-CoA Reductase

54
Q

What factors regulate cholesterol synthesis?

A

Insulin, glucagon, and intracellular cholesterol levels

55
Q

What is hypercholesterolemia?

A

High blood cholesterol levels

56
Q

How do statins treat high cholesterol?

A

They reduce endogenous cholesterol synthesis and increase LDL receptors

57
Q

Where does protein digestion begin?

A

In the stomach and continues in the intestines

58
Q

What do salivary enzymes break down?

A

Starch to glucose

59
Q

What do gastric and pancreatic proteases break down?

A

Proteins into peptides and amino acids

60
Q

What do lipases release?

A

Fatty acids from triacylglycerol

61
Q

How are glucose and amino acids absorbed?

A

Through intestinal cell transporters

62
Q

Where do water-soluble substances go after absorption?

A

Enter portal vein to liver

63
Q

What is the activated form of trypsinogen?

A

Trypsin

64
Q

What is the activated form of chymotrypsinogen?

A

Chymotrypsin

65
Q

What are procarboxypeptidases A and B converted to?

A

Carboxypeptidases A and B

66
Q

What type of molecules are responsible for transporting nutrients in intestinal cells?

A

Transporters

67
Q

What is the main function of digestive proteases?

A

Breaking down proteins into smaller peptides and amino acids

68
Q

What are zymogens?

A

Inactive precursor forms of enzymes that must be activated

69
Q

Name the three main types of macromolecule digestive enzymes

A

Proteases, lipases, and amylases

70
Q

What is the primary site of nutrient absorption?

A

Small intestine

71
Q

Primary functions of protein turnover

A
  1. Energy production during metabolic needs 2. Elimination of abnormal proteins 3. Cellular metabolism regulation
72
Q

What are the two main protein degradation mechanisms?

A
  1. Lysosomal Degradation (CMA) 2. Proteasome Degradation
73
Q

Where is Lysosomal Degradation most important?

A

In liver and kidney during starvation

74
Q

What sequence do proteins need for CMA targeting?

A

KFERQ sequences

75
Q

What percentage of cytosolic proteins contain KFERQ sequences?

A

Approximately 30%

76
Q

What protein controls Lysosomal Degradation?

A

LAMP2A

77
Q

What are the three main functions of LAMP2A?

A
  1. Recognizes KFERQ proteins 2. Forms multimeric complexes 3. Transports proteins into lysosome
78
Q

What molecule tags proteins in Proteasome Degradation?

A

Ubiquitin

79
Q

What type of process is Proteasome Degradation?

A

ATP-dependent

80
Q

What specific modification is required for Proteasome Degradation?

A

Polyubiquitination

81
Q

E1 Activating Enzyme Function

A

Links ubiquitin to start protein degradation process

82
Q

E2 Conjugating Enzyme Role

A

Receives ubiquitin from E1 and carries it forward

83
Q

E3 Ligase Purpose

A

Transfers ubiquitin to specific protein targets for degradation

84
Q

Name 4 conditions linked to protein degradation:

A

Alzheimer’s, Parkinson’s, Huntington’s, ALS

85
Q

Step 1 of Nitrogen Removal

A

Transamination converting amino acids to L-Glutamate

86
Q

Step 2 of Nitrogen Removal

A

Oxidative deamination of glutamate

87
Q

Fish Nitrogen Excretion

A

Eliminates nitrogen waste as ammonia

88
Q

Birds and Reptiles Waste…

A

Excretes nitrogen waste as uric acid

89
Q

Terrestrial Vertebrates…

A

Removes nitrogen waste through urea

90
Q

Urea Cycle Location

A

Liver

91
Q

Primary Function of Ubiquitination

A

Tags proteins for degradation

92
Q

Protein Degradation Impact

A

Associated with various neurological disorders and disease progression

93
Q

Nitrogen Removal Purpose

A

Eliminates excess nitrogen from amino acid breakdown

94
Q

Organism Adaptation

A

Different species evolved various nitrogen excretion methods based on environment

95
Q

What happens to Glucogenic amino acids during metabolism?

A

They can be converted to glucose

96
Q

What is the end product of ketogenic amino acids?

A

They form acetyl-CoA or ketone bodies

97
Q

What type of genetic condition is PKU?

A

Autosomal recessive

98
Q

What are the two main complications of PKU?

A

Intellectual disability and metabolic complications

99
Q

What is the primary treatment approach for PKU?

A

Dietary control

100
Q

What is the genetic basis of Transcarbamylase Deficiency?

A

X-chromosome mutation

101
Q

What are the main symptoms of Transcarbamylase Deficiency?

A

Lethargy, vomiting, breathing problems, and potential brain damage if untreated

102
Q

What are the three main sources of carbon skeletons in amino acid biosynthesis?

A

Glycolysis intermediates, citric acid cycle, and pentose phosphate pathway

103
Q

What are the primary sources of amino groups in amino acid biosynthesis?

A

Glutamate and Glutamine

104
Q

How many nonessential amino acids exist?

A

11 types that the body can synthesize

105
Q

How many essential amino acids exist?

A

9 types that must be obtained from diet

106
Q

What is the role of glutamate and glutamine in amino acid synthesis?

A

They serve as donors of amino groups for the formation of other amino acids

107
Q

what arelipoproteins?

A

specific proteins which can transport the fat between organs

108
Q
A
109
Q
A
110
Q
A
111
Q
A
112
Q
A
113
Q
A
114
Q
A
115
Q
A
116
Q
A

Introduction to Biochemistry (5 decks)

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