Exam 4: Lipids and Carbs Flashcards
1
Q
What are some properties we can use to classify carbohydrates?
A
Size and base of carbon chain, location of C=O functional group, number of sugar units, stereochemistry of the compound
2
Q
What is the primary function of carbohydrates?
A
Serve as a source of energy
3
Q
What are the monosaccharide components of sucrose?
A
Glucose + Fructose
4
Q
What are the monosaccharide components of lactose?
A
Glucose + Galactose
5
Q
What are the monosaccharide components of maltose?
A
Glucose + Glucose
6
Q
D-Glucose vs L-Glucose
A
D glucose has hydroxyl groups on the right side, L glucose has hydroxyl groups on the left side
7
Q
Examples of polysaccharides
A
Starch, glycogen, cellulose, chitin
8
Q
What are proteoglycans?
A
Protein core that is heavily glycosylated - found in connective tissues and can provide hydration to tissues and enable tissues to endure compressional forces
9
Q
Examples of glycoproteins
A
Antibodies, hormones, coagulation factors
10
Q
Examples of reducing sugars
A
All monosaccharides, all disaccharides except sucrose
11
Q
What is the criteria to be a reducing sugar?
A
Must have a free aldehyde or ketone group
12
Q
What enzyme breaks down carbohydrates?
A
Amylase
13
Q
Amylopectin vs amylose
A
Amylopectin is branched form of starch
Amylose is unbranched form of starch
14
Q
What is the body’s primary source of energy?
A
Glucose metabolism (carbs)
15
Q
What system relies on a steady supply of glucose because it cannot store it?
A
Nervous system
16
Q
What is the end product of Embden-Meyerhof Pathway?
A
Pyruvate, ATP (aerobic glycolysis)
Lactate, ATP (anaerobic glycolysis)
17
Q
What is the end product of the hexose monophosphate shunt?
A
NADPH and ribose-5-phosphate
18
Q
What is the end product of glycogenesis?
A
Glycogen
19
Q
What is the storage form of glucose?
A
Glycogen
20
Q
What metabolic pathway for glucose can produce the sugar used in nucleotide synthesis?
A
Hexose-monophosphate shunt
21
Q
What tissues are capable of glycogenolysis?
A
Liver tissues only
22
Q
What tissues are capable of glycogenesis?
A
Liver and muscle tissue
23
Q
Glycolysis
A
Metabolism of glucose molecule to pyruvate or lactate for production of energy
24
Q
Gluconeogenesis
A
Formation of glucose-6-phosphate from noncarbohydrate sources
25
Glycogenolysis
Breakdown of glycogen to glucose for use as energy
26
Glycogenesis
Conversion of glucose to glycogen for storage
27
Lipogenesis
Conversion of carbohydrates to fatty acids
28
Lipolysis
Decomposition of fat
29
How are blood glucose levels maintained in short fasting periods?
Glycogenolysis and Gluconeogenesis
30
How are blood glucose levels maintained in prolonged fasting periods?
Gluconeogenesis
31
How are blood glucose levels maintained in postprandial periods?
Glycogenesis, Lipogenesis
32
What cells secrete glucagon?
alpha cells of islets of Langerhans in the pancreas
33
What does glucagon do ?
Increase glycogenolysis and increase gluconeogenesis (raises blood sugar)
34
What secretes epinephrine? How does epinephrine affect blood glucose?
Adrenal cortex; increased blood glucose rapidly
35
Where is growth hormone produced? What affect does it have on blood glucose levels?
Anterior pituitary; increases blood glucose
36
Where is ACTH produced? What affect does it have on blood glucose levels?
Anterior pituitary; increases blood glucose
37
Where is somatostatin produced? What affect does it have on blood glucose levels?
Delta cells of the pancreas; increases blood glucose and acts as an intermediate between insulin and glucagon
38
Where is cortisol produced? What affect does it have on blood glucose levels?
Adrenal cortex; increases blood glucose
39
Where is thyroxine produced? What affect does it have on blood glucose levels?
Thyroid gland; increases glucose
40
Where is human placental lactogen produced? What affect does it have on blood glucose?
Placenta; increases blood glucose by breaking down fats
41
Where is insulin secreted from? How does it affect blood glucose?
Secreted by beta cells of islets of langerhans in the pancreas; only hormone that decreases blood glucose
42
What are the major targets of insulin?
Liver, skeletal muscle, adipose tissue
43
Insulin should be 1:1 with _______.
C-peptide
44
What four symptoms can be seen in diabetes patients?
Hyperglycemia
Polydipsia
Polyuria
Polyphagia
45
Type 1 Diabetes
Complete lack of insulin production; autoimmune condition that is typically juvenile-onset
46
Type 2 Diabetes
No response to insulin/insulin-resistant (Adult-onset) associated with obesity
47
Is Type 1 or Type 2 diabetes more common?
Type 2
48
Treatment for type 1 vs type 2 diabetes
type 1: insulin injections
type 2: lifestyle changes
49
Beta cells in type 1 vs type 2 diabetes
type 1: beta cells are destroyed
type 2: beta cells are in tact
50
Symptoms of type 1 vs type 2 diabetes
type 1: polydipsia, polyphagia, polyuria, DKA
type 2: minimal symptoms --> difficult to detect
51
What are some causes of secondary diabetes mellitus?
Pancreatic disease, genetic defects of Beta cell function, Endocrine disease (cushing's, acromegaly, hyperthyroidism), drug or chemical induced insulin receptor abnormalities (phenytoin)
52
The breakdown of what compounds result in the production of ketones?
Breakdown of fatty acids
53
What are the typical symptoms for diabetic ketoacidosis?
Blood acidosis, high ketones, elevated glucose levels, fruity/sweet smelling urine
54
Which diabetes type is prone to diabetic ketoacidosis?
Type 1
55
What is unique about CNS tissues with respect to glucose?
Nervous system cannot store glucose and relies heavily on the intake of glucose. It uses a very large amount of the glucose we take in daily.
56
What does out of control type 2 diabetes lead to?
HHS
57
How can gestational diabetes affect the baby both before birth and after birth?
Can cause hypoglycemia in babies due to extra insulin made during pregnancy. They can be more at risk for diabetes later in life.
58
What are some causes of hypoglycemia in adults?
Too much insulin administration
Not eating enough food
Excessive ethanol intake
Hepatic failure
Addison's disease
Insulinomas
Septicemia
59
What are some causes of hypoglycemia in neonates?
Premature birth
Maternal toxemia
Maternal diabetes
Gestational diabetes
60
What does a glycosylated hemoglobin value tell us about most patients’ glycemic control? What time frame does this represent?
The glycosylated hemoglobin test shows what a person's average blood glucose level was for the 2 to 3 months before the test. This can help determine how well a person's diabetes is being controlled over time.
61
What laboratory methodologies for glucose are most specific? Why don't we use it as often?
Hexokinase; it is expensive
62
saturated vs monounsaturated vs polyunsaturated fats
saturated fats have no C=C
monounsaturated fats have 1 C=C
polyunsaturated fats have many C=C
63
What is a normal response to an oral glucose tolerance test?
Increase in blood glucose to 120, dips back to normal after 2 hours. (Two hour PG <140 mg/dL)
64
What two main factors affect the glycosylated hemoglobin level?
Average glucose concentration and RBC lifespan
65
What is the most common glycosylated hemoglobin formed?
Hemoglobin A1C
66
What test may be offered in some cases as an alternative to A1c? What patients might this benefit?
Fructosamine; might benefit patients with abnormal hemoglobins or anemia for a more accurate result.
67
What is the criteria for the diagnosis of diabetes?
Fasting plasma glucose >126 mg/dL
2 hour plasma glucose >200 mg/dL during OGTT
A1C >6.5%
Random plasma glucose >200 mg/dL
68
Major contributors to serum osmolality are:
Glucose
Sodium
Urea nitrogen
Chloride
69
What tests might be used to evaluate long-term glucose management/control?
Fructosamine, Glycosylated hemoglobin, Urinary protein/urinary microalbumin, kidney function
70
How does management of acute versus chronic hyperglycemia differ?
Acute management utilizes glucose measurements, ABG, electrolyes, ketones, lactate, and osmolality measurements. Chronic management is more in depth tests.
71
Function of lipids
Store energy, composed in cell membranes
72
What are the basic differences between cis and trans fatty acids?
Cis hydrogens on same side of double bond
Trans hydrogens on opposite side of double bond
73
Basic structure of a triglyceride
Three fatty acid molecules attached to one glycerol by ester bonds - no charged or polar groups (hydrophobic)
74
Basic structure of a phospholipid
Two fatty acid molecules and a phospholipid head group attached to glycerol
75
Basic structure of cholesterol
Unsaturated steroid alcohol containing 4 rings and a single C-H side chain tail similar to fatty acid
76
What compound is used as the precursor for the steroid hormones and vitamin D3?
Cholesterol
77
What is cholesteryl ester?
esterified form of cholesterol; delivers cholesterol and fatty acids to organs
78
What are the three ketone bodies?
Beta-hydroxybutyrate, Acetone, Acetoacetate
79
Which lipoproteins contain the most lipids? The most protein?
Most lipids and least protein: Chylomicrons
Most proteins and least lipids: HDLs
80
Describe the structure of a typical lipoprotein molecule.
Contains lipids and proteins; size of lipoprotein correlates with lipid content
81
Function of lipoproteins
Transports lipids to the peripheral cells
82
Chylomicrons; where is it produced? size? rich in _____? primary role?
Largest/least dense; produced by intestine; rich in triglycerides; delivers dietary lipids to the liver
83
How are exogenous triglycerides transported in plasma?
Chylomicrons
84
How are endogenous triglycerides transported in plasma?
LDLs
85
What are the four lipoproteins?
Chylomicrons, VLDLs, HDLs, LDLs
86
VLDLs; where are they produced? What are they rich in? What is the major function?
Produced by the liver; Rich in triglycerides; Major carriers of endogenous triglycerides
87
LDLs; what is the function?
Major carrier of cholesterol to peripheral cells
88
What is the major carrier of endogenous triglycerides?
VLDL
89
What is the major carrier of cholesterol to peripheral cells?
LDLs
90
HDLs; produced where? function? size?
Smallest and most dense; Synthesized by liver and intestine; ability to remove excess cholesterol from peripheral cells
91
Do women or men have a higher HDL content? Why?
Women, due to production of estrogen (uses cholesterol)
92
Tangier disease
Genetic condition associated with low HDL levels; significant risk factor involved with increased risk of cardiovascular disease
93
What is the Friedewald equation?
Used to calculate LDL
LDL = Cholesterol - HDL - (Triglycerides/5)
94
What are the two major problems associated with the Friedewald equation?
1. Using measurements of 3 things so more room for error
2. If triglycerides >400, cannot use this equation
95
What are the types of hypolipidemia?
Tangier disease (Low HDL)
Abetalipoproteinemia (Low LDL)
Hypobetalipoproteinemia (Low LDL)
96
What are the typical lipid panel components?
Cholesterol
HDL
Calculated LDL
Triglycerides
Cholesterol/HDL Ratio
97
Normal reference range for total cholesterol
<200
98
Normal reference range for HDL
>40
99
Normal reference range for LDL
<100
100
Normal reference range for triglycerides
<150
101
What causes lipemia in blood specimens in the lab?
Non-fasting patients; high levels of fat in the blood
