Carbohydrates

Question 1

what are the four classifications for carbohydrates?

Answer 1

1. size of the carbon chain
2. location of C=O functional group
3. number of sugar units
4. stereochemistry

Question 2

what are examples of monosaccharides, disaccharides, and polysaccharides?

Answer 2

mono: glucose, fructose, and galactose

di: maltose, lactose, and sucrose

poly: starch (plant-based glucose molecules) and glycogen (animal-based glucose molecules)

Question 3

Carbohydrates are ________ substances. To do this, they must contain either what two things? What are examples of such carbohydrates?

Answer 3

They are reducing substances (while they themselves are oxidized). They have to contain either an active ketone or aldehyde group.

small sugars such as glucose or lactose are capable of reduction

Question 4

what is the one nonreducing sugar?

Answer 4

sucrose

Question 5

most ingested carbs are digested in the form of _______. What breaks then down? What happens to them from there?

Answer 5

most carbs are ingested as polymers, such as starch and glycogen

salivary and pancreatic amylase break them down into disaccharides, and then maltase breaks those down into monosaccharides (glucose), which are absorbed by the GI and transported to the liver

Question 6

what is the only carb that can be used directly for energy, and what is a result from this?

Answer 6

glucose is the only carb that can be used directly for energy, so all other carbs have to be converted to glucose for use

Question 7

what is the first step of glucose metabolism, and what is used to accomplish this?

Answer 7

glucose turned into G6P using ATP via the enzyme hexokinase

Question 8

what are the three glucose metabolism pathways?

Answer 8

Eden-Meyerhof

Hexose monophosphate shunt

Glucose to glycogen (glycogenesis)

Question 9

What is the process of the Eden-Meyerhof pathway?

Answer 9

where glucose is turned into G6P and then broken down into 2 3-carbon molecules of pyruvic acid/pyruvate (aerobic glycolysis) or lactic acid (anaerobic glycolysis)

the aerobic pathway leads to the Kreb’s cycle

Question 10

what is the hexose monophosphate shunt (pentose-p) pathway?

Answer 10

it’s the oxidative glycolysis pathway branching off from G6P that yields 2 NADPH and nucleotides
- pentose and ribose can enter the glycolytic pathway

Question 11

what are the definitions of the following:
- glycogenesis
- glycogenolysis
- glycolysis
- gluconeogenesis
- lipogenesis

Answer 11

• glycogenesis: the storage/conversion of glucose to/as glycogen
• glycogenolysis: breakdown of glycogen to glucose to use as energy
• glycolysis: the actual usage of glucose (conversion of it to pyruvate/lactate)
• gluconeogenesis: creation of G6P from noncarb sources
• lipogenesis: carbs turned to fatty acids

Question 12

what three things (body parts) regulate carbohydrate levels?

Answer 12

liver, pancreas, and endocrine glands

Question 13

what are the two hormones from the pancreas that directly control glucose blood levels and how do they work?

Answer 13

insulin from the beta pancreatic cells of islets of langerhans: lets glucose into the cell to reduce blood glucose levels
- when beta cells see increased glucose they release insulin
- secreted with C-peptide from pancreas

glucagon from the alpha pancreatic cells of islets of langerhans: works against insulin to increase blood glucose levels
- released when blood glucose levels are decreased in order to turn glycogen to glucose (glycogenolysis)

Question 14

what are four other hormones that work to increase plasma glucose?

Answer 14

epinephrine, cortisol, somatostatin, and GH

Question 15

how do epinephrine and cortisol work to increase plasma glucose?

Answer 15

epinephrine (during stress): inhibits insulin secretion

cortisol (also during stress): decreases intestinal entry of plasma glucose into the cell and increasing gluconeogenesis/lipolysis and decreases glycogenesis

Question 16

how does somatostatin and GH increase plasma glucose?

Answer 16

somatostatin from delta cells in pancreas (has two forms: 14,28 amino acids) inhibits insulin, glucagon, and GH

GH: decreases entry of glucose into cells

Question 17

durning non-fasting states, plasma glusoe levels of _____ are normal

Answer 17

less than or equal to 140 mg/dL

Question 18

type 1 DM is cause by what?

Answer 18

rapid t-cells mediated autoimmune destruction of beta cells of the pancreas, which causes an absolute deficiency of insulin secretion
- initiated by environmental factor, (viral) infection, or genetic disposition

Question 19

T1DM makes up what percentage of all DM, and when does it most commonly occur in life?

Answer 19

makes up 5 - 10% of all DM and most commonly occurs in childhood and adolescence

Question 20

what are the signs and symptoms of T1DM? What are some complications?

Answer 20

the three p’s: polydipsia, polyphagia, and polyuria; rapid weight loss, hyperventilation, metal confusion, and possible loss of consciousness

complications: ketoacidosis microvascular nephropathy/neuropathy/mental confusion; increased incidence of heart disease

Question 21

T2DM is the most _______ form of diabetes mellitus, and it is due to what? what is the main complication of T2DM?

Answer 21

most common form of diabetes, and is due to a person’s resistance to insulin, combined with a secretory insulin defect
- progressive loss of beta cells
- relative loss of beta cells
- increased body body fat distribution

main complication: hyperosmolar coma

Question 22

gestational DM is a degree of glucose intolerance with onset when during pregnancy? What is the name of the test for gestational DM?

Answer 22

onset during second or third trimester of pregnancy

oral glucose tolerance test

Question 23

what are infants are risk of developing is their mother has gestational diabetes? What happens to the baby birth due to the gestational diabetes?

Answer 23

increased risk of respiratory distress, hypocalcemia, and hyperbilirubinemia

fetal insulin stimulated in neonate in response to gestational diabetes, which leads to hypoglycemia in the baby at birth

Question 24

What happens when the body doesn’t have enough insulin (other than increased glucagon) that is a complication of DM type 1?

Answer 24

ketoacidosis: the body burns fatty acids which produce ketone bodies. There’s an increase in glucose, decrease in pH, and ketoacids in the urine

Question 25

what are signs and symptoms of ketoacidosis? what are some (lab) findings?

Answer 25

S&S: abdominal pain, vomiting, hyperventilation, fruity breath, weakness and confusion

findings: dehydration, electrolyte disturbance, and high osmo

Question 26

what is hyperosmolar coma? what are signs and symptoms of it? what is the glucose level for a serious case of it?

Answer 26

complication of untreated T2DM where increased blood sugar too high for too long leads to dehydration and confusion

• weakness, cramps, vision problems, altered consciousness, seizures, DIC, artery occlusion
• glucose over 1000 mg/dL

Question 27

what is the typical age for testing for diabetes? what else is used alongside glucose for testing?

Answer 27

45 years old

hemoglobin A1c

Question 28

what are the parameters to diagnose diabetes?

Answer 28

• HbA1c over 6.5%
• fasting glucose > or = to 126 mg/dL
• OGTT 1 and 2 hrs over 200 mg/dL

Question 29

hypoglycemia can affect the ______, leading to seizures, coma, impaired judgement, ect. What can be used to see if natural or injected insulin is the problem?

Answer 29

affects the brain

C-peptide test used to see if natural or injected insulin is the problem

Question 30

what is the rr for hypoglycemia, and when it drops to ______ mg/dL, symptoms first begin where in the body? What are two of the first hormones to respond to this decrease in glucose?

Answer 30

glycogen released around 65-70 mg/dL, and when it gets serious (50 - 55 mg/dL), epinephrine and glucagon are the first to respond

Question 31

what is the name of an autosomal recessive severe hypoglycemia with metabolic acidosis?

Answer 31

G6PD deficiency (glycogen storage disease) = Von Gierke’s disease

Question 32

what are the rr for serum, plasma, whole blood, CSF, and urine glucose

Answer 32

serum glucose / fasting plasma glucose: 74 - 100 mg/dL

whole blood glucose: 11% less than FPG

CSF glucose: 50 - 80 mg/dL

urine glucose: 15 mg/dL or less or none

Question 33

what are three ways to self-monitor glucose levels? HbA1c is _________ __________, or, a glucose level over what time period?

Answer 33

fingerstick, POCT, glucometer

HbA1c: glycosylated Hbg (glucose over the past 3 months)

Question 34

Diabetes mellitus changes the _____, so a sign of early ______ disease is more _______ in urine

Answer 34

DM changes the kidneys, so an early kidney disease sign is more albumin in the urine

Question 35

oxygen consumption measurement of glucose is called _______ ________, where there is a monitoring of oxygen disappearance or _______ consumption. What two things will lead to a false decrease with this method and why?

Answer 35

glucose oxidase method measures oxygen disappearance or peroxidase consumption, and is affected by ascorbic acid and uric acid because those oppose the oxidation of the chromogen that is measured spectrophotometrically

Question 36

hexokinase glucose measurement uses what two enzymes for its reaction? what is a type of POCT way to measure glucose? When would you use glycosylated protein for measurement?

Answer 36

G6PD and NADPH

POCT test = glucose dehydrogenase

use glycosylated protein to test for glycemic when HbA1c isn’t possible or results are insufficient