CARBOHYDRATES AND LIPIDS

Carbohydrate

Hydrogen

Oxygen

• three elements of carbohydrates

C_x(H₂O)_y

• general formula of carbohydrates

Carbohydrates

• hydrates of carbon

False (water-soluble)

T or F

Carbohydrates are water-insoluble.

True

False (not)

T or F

Most of the sugars of carbohydrates are reducing.

Sucrose is a reducing sugar.

Carbohydrates

• major component of human diet, important source of body energy

• found as part of the cell membrane

Carbohydrates

• storage form of energy

• component of cell membranes

Ribose

• carbohydrate of RNA

Deoxyribose

• carbohydrate of DNA

Fructose

• levulose

• fruit sugar

Lactose

• millk sugar

• found in dairy products

Sucrose

• common table sugar

• obtained from beets and sugar cane

Maltose

• found in cereals, wheat, and malt products

Glycogen

• storage form of glucose in the body

• stored in the liver and skeletal muscle

a. Glucose

b. Galactose

c. Fructose

• monosaccharides

1. Sucrose (fructose + glucose)

2. Maltose (glucose + glucose)

3. Lactose (galactose + glucose)

• disaccharides

1. Glucosans

   a. Starch

   b. Glycogen

2. Fructosans

   a. Inulin

3. Cellulose

4. Chitin

• polysaccharides

Glucose (Dextrose)

• principal and almost exclusive carbohydrate circulating in the blood

Glucose (Dextrose)

• central, pivotal point of carbohydrate metabolism

Brain

• most important glucose consumer

CNS

• consumes about 50% of glucose used by the body

1. Diet

2. Body Stores like Glycogen

3. Endogenous Synthesis (from proteins or glycerol of trig)

• glucose can be derived from _____

1. Carbohydrate Digestion

2. Carbohydrate Metabolism in the Blood

• two steps of carbohydrate metabolism

1. CHO from diet enter the body through mouth.

2. Salivary amylase (ptyalin) in the mouth (partial digestion)

3. Partially digested CHO go from esophagus to stomach.

4. No CHO digestion in stomach.

5. CHO go to small intestines.

6. Alk. pancreatic secretion increases pH of intestines.

7. Pancreatic amylase (amylopsin) in intestines

8. Maltase, Sucrase, Lactase hydrolyzes disaccharides to form monosaccharides (Glucose, Galactose, Fructose)

9. Monosaccharides and absorbed from the duodenum and ileum into blood.

• how are carbohydrates digested

False (starts in the mouth, no CHO digestion in stomach)

T or F

Carbohydrate digestion starts in the stomach.

Acidic pH

• why does no carbohydrate digest in the stomach

Alkaline Pancreatic Secretions

• increases the pH of the intestines, enabling carbohydrate digestion

Pancreatic Amylase (Amylopsin)

• digestive enzyme in the intestines

Maltase

Sucrase

Lactase

• these enzymes hydrolyzes disaccharides to form monosaccharides

1. Energy production (CO2 to Water)

2. Glycogen in the liver

3. Triglycerides in the adipose tissues

4. Conversion to ketoacids, amino acids, or proteins

• what does metabolism of hexoses lead to?

Embden-Meyerhof Pathway

metabolic pathway that uses glycolysis

Glucose → Pyruvate

Pyruvate → ATP + NADH

summary of EMP

Glucose Oxidation → NADPH + Ribose-5-Phosphate

principle of HMP

Glycolysis

• metabolism of glucose molecule to pyruvate or lactate to energy

Glycolysis

• decreases blood glucose since glucose in consumed to produce lactata/pyruvate

Gluconeogenesis

• formation of G6P from non-carbohydrate sources

Gluconeogenesis

• increases blood glucose, new glucoses are formed from other sources

Glycogenolysis

• breakdown of glycogen to glucose for use as energy

Glycogenolysis

• increases glucose since glycogen is degraded into glucose molecules

Glycogenesis

• conversion of glucose to glycogen for storage

Glycogenesis

• decreases glucose since excess glucoses in the body is stored in the liver and skeletal muscle as glycogen

Lipogenesis

• conversion of carbohydrates to FA

Lipogenesis

• decreases glucose since carbohydrates are converted into FA and stored as fats

Lipolysis

• breakdown of fats

• increases glucose because fats are converted into consumable glucose

1. Gluconeogenesis

2. Glycogenolysis

3. Lipolysis

• what carbohydrate metabolism processes increase blood glucose

1. Glycolysis

2. Glycogenesis

3. Lipogenesis

• what carbohydrate metabolism processes decreases blood glucose

1. Glucagon

2. ACTH

3. Growth Hormone

4. Cortisol

5. H

6. Epinephrine

7. Thyroxine

• hormones that increase blood glucose

Insulin

• what hormones decrease blood glucose

Somatostatin

• regulator hormone

• inhibits release of GH, insulin, and glucagon

1. GH

2. Insulin

3. Glucagon

• what hormones does somatostatin inhibit

Insulin

• produced by beta cells of pancreas as proinsulin

Insulin

• only counterregulatory hormone of glucose

Removal of C-peptide

• how is proinsulin converted into insulin

Alpha and Beta Chains

C Peptide

Signal Peptide

components of preproinsulin

Alpha and Beta Chains

C Peptide

components of proinsulin

Alpha and Beta Chain

components of insulin

C Peptide

determines insulin amount

Inc. in plasma glucose

• stimulus of insulin increase

1. Glucose Entry into Cells

2. Glycogenesis

3. Lipogenesis

4. Glycolysis

5. Amino Acid Synthesis from Pyruvate

• action of insulin

Glucagon

• produced the the alpha cells of pancreas

Liver

target of glucagon

Decrease in plasma glucose

• stimulus of glucagon increase1

1. Glycogenolysis

2. Gluconeogenesis

• action of glucagon

Cortisol

• hormone that increases gluconeogenesis

• decreases glucose uptake and utilization by extrahepatic tissues

Catecholamines

• hormone that stimulates glycogenolysis

Thyroid Hormone

• hormone that increases glucose absorption in the small intestines

Somatostatin

• hormone that inhibits glucose and insulin secretion

delta cells

cells of the pancreas that produces somatostatin

Growth Hormone

• hormone that increases liver gluconeogenesis

• inhibits glycolysis and glucose transport

Somatostatin

Insulin

Glucagon

• these are regulatory hormones in carbohydrate metabolism

Venous Plasma Glucose

• standard clinical specimen for glucose determination

8-10 hours (non-diabetics)

6-10 hours (diabetics)

• fasting hours of glucose determination

1. Arterial Blood

2. Capillary Blood

3. Venous Blood

• ranking of high to low values of blood glucose on different blood vessels

10-15% lower

• Whole blood gives ______ glucose levels than serum or plasma.

1.15

• you multiply this to convert whole blood glucose into serum or plasma level

30-60 minutes

• A serum specimen is appropriate for glucose analysis if serum is separated from the cells within _______

7/mg/dL/hr (0.4 mmol/L/hr)

• Rate of glucose metabolism at RT

2 mg/dL/hr

• glucose metabolism at 4C

Gray Top

• color of top tube for plasma glucose collection

Sodium Fluoride (anti-glycolytic)

Potassium Oxalate (anticoag)

• additives of gray top

• 2 mg

Sodium Fluoride

• antiglycolytic agent that prevents glycolysis for 48-72 hours

• binds with magnesium

Enolase

• enzyme that sodium fluoride inhibits

48-72 hours

• 2 mg of sodium fluoride per mL of whole blood prevents glycolysis for _______________-

Fluoride

• binds magnesium which causes inhibition of the enzyme enolase

Potassium Oxalate

• anticoagulant of gray top

60-70% that of plasma concentrations

• CSF glucose concentration

1-2 hours

• when should blood glucose be obtained before the spinal tap

True

T or F

CSF for glucose analysis should be performed immediately.

Centrifuge then store at 4C or at -20C

• what must CSF specimen undergo if delay in glucose analysis is unavoidable

1. Copper Reduction

2. Ferricyanide Method (Ferric Reduction)

3. Condensation Method (o-toluidine method/Dubowski Method)

• non-enzymatic methods or chemical methods for glucose analysis

1. Glucose Oxidase

2. Hexokinase with G6P Dehydrogenase

3. Glucose Dehydrogenase

• enzymatic methods for glucose analysis

True

False (directly proportional)

T or F

Most CHO are reducing sugars and are capable of decreasing the oxidation state of copper, from the cupric (Cu³⁺ ) form into cuprous form (Cu²⁺)

Cuprous ions formed in the copper reduction test are inversely proportional to the amount of reducing sugar present.

Copper Reduction

• not specific for glucose since other carbohydrates such as fructose and galactose are also reducing sugars

Sucrose

• not detected by copper reduction methods since it is a non-reducing sugar

1. Folin Wu

2. Nelson-Somogyi

3. Neocuproine Method

• methods of copper reduction

Reagent: Phosphomolybdate

(+) Result: Phosphomolybdenum Blue

• reagent and positive results in Folin Wu method of copper reduction

Reagent: Arsenomolybdate

(+) Result: Arsenomolybdenum Blue

• reagent and positive result in Nelson-Somogyi method of copper reduction

Reagent: Neocuproine

(+) Result: Orange-Red (Yellow to Orange) Color

• rgt and positive result of Neocuproine method of copper reduction

Ferricyanide Method (Ferric Reduction)

• also known as Hagedorn Jensen Method

Negative or Inverse Colorimetry

• principle of Ferricyanide Method