Exam 3 Flashcards
(120 cards)
1
Q
What is the main purpose of lipoproteins?
A
Transport lipids and cholesterol through the bloodstream
2
Q
What are the four main types of lipoproteins?
A
Chylomicrons, VLDL, LDL, and HDL
3
Q
What is the primary function of fatty acid catabolism?
A
Break down fatty acids to produce energy in the form of ATP
4
Q
What is beta-oxidation?
A
The process of breaking down fatty acids into acetyl-CoA units
5
Q
Where does fatty acid catabolism occur?
A
In the mitochondria of cells
6
Q
What are ketone bodies?
A
Alternative energy source produced from fatty acids when glucose is limited
7
Q
What triggers ketone body production?
A
Low glucose levels and high fatty acid breakdown
8
Q
What is lipogenesis?
A
The process of creating fatty acids from acetyl-CoA
9
Q
Where does fatty acid synthesis occur?
A
In the cytoplasm of cells
10
Q
What is the rate-limiting enzyme in cholesterol synthesis?
A
HMG-CoA reductase
11
Q
What regulates fatty acid synthesis?
A
Insulin levels and cellular energy status
12
Q
How is cholesterol synthesis regulated?
A
Through feedback inhibition and hormonal control
13
Q
What is the function of LDL?
A
Delivers cholesterol to peripheral tissues
14
Q
What is the role of HDL?
A
Removes excess cholesterol from tissues and returns it to the liver
15
Q
What are the three ways vertebrates utilize fat?
A
Dietary intake, mobilization from adipose tissue, and liver conversion of excess carbohydrates
16
Q
What percentage of daily human energy requirements come from TAGs?
A
40% or more
17
Q
What enzyme helps absorb fatty acids from diet?
A
Pancreatic lipase
18
Q
Where is pancreatic lipase located?
A
Intestinal lumen
19
Q
What is the function of lipoprotein lipase?
A
To absorb fatty acids from chylomicrons and VLDL
20
Q
Where are lipoprotein lipases found?
A
Capillary walls
21
Q
What is the purpose of hormone-sensitive lipase?
A
To break down cellular fat stores
22
Q
Where is hormone-sensitive lipase found?
A
Intracellularly
23
Q
What are bile salts derived from?
A
Cholesterol
23
Q
What compounds help solve the problem of insoluble fat particles?
A
Bile salts
24
Where are bile salts produced?
In the liver
25
Where are bile salts stored?
In the gallbladder
26
What is the primary function of bile salts with TAGs?
They create mixed micelles
27
What are the four main components packaged with lipoproteins?
Triacylglycerols, cholesterol, cholesteryl esters, and specific proteins
28
What forms the exterior of lipoproteins?
Phospholipid head groups
29
What proteins coat the surface of lipoproteins?
Apolipoproteins
30
What are the five classes of lipoproteins in order of density?
Chylomicrons, VLDL, IDL, LDL, HDL
31
What does IDL stand for?
Intermediate-Density Lipoproteins
31
What does VLDL stand for?
Very Low-Density Lipoproteins
32
What does CM stand for in lipoprotein classification?
Chylomicrons
33
What does LDL stand for?
Low-Density Lipoproteins
34
What does HDL stand for?
High-Density Lipoproteins
35
What is the main function of the exogenous pathway?
Transport of dietary fat and cholesterol
36
What does the liver synthesize in the endogenous pathway?
TAGs and cholesterol
36
How are dietary lipids initially processed in the exogenous pathway?
They are packaged into chylomicrons
37
What lipoprotein packages liver-synthesized lipids?
VLDL
38
What are the three main products of β-oxidation?
Acetyl-CoA, FADH2, and NADH
39
What triggers the mobilization of stored TAGs?
Glucagon and epinephrine hormones
39
Where does fatty acid catabolism occur?
In the mitochondrial matrix through β-oxidation
40
What enzyme is responsible for releasing fatty acids from stored TAGs?
Hormone-sensitive lipase
41
How are fatty acids transported in the bloodstream?
By serum albumin
42
What are the four main ways fatty acid oxidation is regulated?
Cell energy state, hormonal regulation, malonyl-CoA regulation, and transcriptional regulation via PPAR receptors
43
Where does ketone body production exclusively take place?
In liver mitochondria
44
What are the five main functions of the liver in lipid metabolism?
Metabolizing dietary fatty acids, synthesizing fatty acids, synthesizing cholesterol, producing bile salts, and producing VLDLs/HDLs
45
Which lipoproteins does the liver produce?
VLDLs and HDLs
46
What molecule regulates fatty acid oxidation at the metabolic level?
Malonyl-CoA
47
What nuclear receptors are involved in transcriptional regulation of fatty acid oxidation?
PPAR receptors
48
What are bile salts used for?
To aid in the digestion and absorption of dietary fats
49
What key processes does ketogenesis provide energy for?
Brain, skeletal muscle, heart muscle, and kidney, especially during starvation
50
Where does fatty acid synthesis occur and in which tissues?
In the cytosol, primarily in liver and adipose tissue
51
What are the required components for fatty acid synthesis?
Acetyl-CoA, ATP, and NADPH
52
What are the three main functions of cholesterol?
Cell membrane incorporation, steroid hormone precursor, and bile acid precursor
53
What is the rate-determining enzyme in cholesterol synthesis?
HMG-CoA Reductase
54
What factors regulate cholesterol synthesis?
Insulin, glucagon, and intracellular cholesterol levels
55
What is hypercholesterolemia?
High blood cholesterol levels
56
How do statins treat high cholesterol?
They reduce endogenous cholesterol synthesis and increase LDL receptors
57
Where does protein digestion begin?
In the stomach and continues in the intestines
58
What do salivary enzymes break down?
Starch to glucose
59
What do gastric and pancreatic proteases break down?
Proteins into peptides and amino acids
60
What do lipases release?
Fatty acids from triacylglycerol
61
How are glucose and amino acids absorbed?
Through intestinal cell transporters
62
Where do water-soluble substances go after absorption?
Enter portal vein to liver
63
What is the activated form of trypsinogen?
Trypsin
64
What is the activated form of chymotrypsinogen?
Chymotrypsin
65
What are procarboxypeptidases A and B converted to?
Carboxypeptidases A and B
66
What type of molecules are responsible for transporting nutrients in intestinal cells?
Transporters
67
What is the main function of digestive proteases?
Breaking down proteins into smaller peptides and amino acids
68
What are zymogens?
Inactive precursor forms of enzymes that must be activated
69
Name the three main types of macromolecule digestive enzymes
Proteases, lipases, and amylases
70
What is the primary site of nutrient absorption?
Small intestine
71
Primary functions of protein turnover
1. Energy production during metabolic needs 2. Elimination of abnormal proteins 3. Cellular metabolism regulation
72
What are the two main protein degradation mechanisms?
1. Lysosomal Degradation (CMA) 2. Proteasome Degradation
73
Where is Lysosomal Degradation most important?
In liver and kidney during starvation
74
What sequence do proteins need for CMA targeting?
KFERQ sequences
75
What percentage of cytosolic proteins contain KFERQ sequences?
Approximately 30%
76
What protein controls Lysosomal Degradation?
LAMP2A
77
What are the three main functions of LAMP2A?
1. Recognizes KFERQ proteins 2. Forms multimeric complexes 3. Transports proteins into lysosome
78
What molecule tags proteins in Proteasome Degradation?
Ubiquitin
79
What type of process is Proteasome Degradation?
ATP-dependent
80
What specific modification is required for Proteasome Degradation?
Polyubiquitination
81
E1 Activating Enzyme Function
Links ubiquitin to start protein degradation process
82
E2 Conjugating Enzyme Role
Receives ubiquitin from E1 and carries it forward
83
E3 Ligase Purpose
Transfers ubiquitin to specific protein targets for degradation
84
Name 4 conditions linked to protein degradation:
Alzheimer's, Parkinson's, Huntington's, ALS
85
Step 1 of Nitrogen Removal
Transamination converting amino acids to L-Glutamate
86
Step 2 of Nitrogen Removal
Oxidative deamination of glutamate
87
Fish Nitrogen Excretion
Eliminates nitrogen waste as ammonia
88
Birds and Reptiles Waste...
Excretes nitrogen waste as uric acid
89
Terrestrial Vertebrates...
Removes nitrogen waste through urea
90
Urea Cycle Location
Liver
91
Primary Function of Ubiquitination
Tags proteins for degradation
92
Protein Degradation Impact
Associated with various neurological disorders and disease progression
93
Nitrogen Removal Purpose
Eliminates excess nitrogen from amino acid breakdown
94
Organism Adaptation
Different species evolved various nitrogen excretion methods based on environment
95
What happens to Glucogenic amino acids during metabolism?
They can be converted to glucose
96
What is the end product of ketogenic amino acids?
They form acetyl-CoA or ketone bodies
97
What type of genetic condition is PKU?
Autosomal recessive
98
What are the two main complications of PKU?
Intellectual disability and metabolic complications
99
What is the primary treatment approach for PKU?
Dietary control
100
What is the genetic basis of Transcarbamylase Deficiency?
X-chromosome mutation
101
What are the main symptoms of Transcarbamylase Deficiency?
Lethargy, vomiting, breathing problems, and potential brain damage if untreated
102
What are the three main sources of carbon skeletons in amino acid biosynthesis?
Glycolysis intermediates, citric acid cycle, and pentose phosphate pathway
103
What are the primary sources of amino groups in amino acid biosynthesis?
Glutamate and Glutamine
104
How many nonessential amino acids exist?
11 types that the body can synthesize
105
How many essential amino acids exist?
9 types that must be obtained from diet
106
What is the role of glutamate and glutamine in amino acid synthesis?
They serve as donors of amino groups for the formation of other amino acids
107
what arelipoproteins?
specific proteins which can transport the fat between organs
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