Carboydrate Structure and Chemistry Flashcards
What is the function of glyceraldehyde?
An important intermediate in glycolysis and the pentose phosphate pathway
What is the function of Dihydroxyacetone?
Its phosphate ester is an intermediate in glycolysis
What is an important Tetrose monosaccharide?
Erythrose (aldose)
What is the function of erythrose?
A pentose phosphate pathway intermediate
What are the important pentose monosaccharides?
Aldose: D-ribose
Ketose: D-ribulose
What is the function of D-ribose?
In its furanose form, it contributes to the structure of RNA and nucleotide coenzymes
What is the function of D-ribulose?
Its phosphate ester, which is the most important ketopentose, is an intermediate in the pentose phosphate pathway
What are the important Hexose monosaccharides?
Aldose: D-glucose, D-galactose, D-mannose
Ketose: D-fructose
What is the function of D-glucose?
The most important aldohexose; it is the building block for glycogen, starch and cellulose. Free D-glucose is found in blood
What is the function of D-galactose?
A constituent of lactose. Found in glycolipids and glycoproteins, along with D-mannose
What is the function of D-fructose?
The most widely distributed ketohexose. It is a component of sucrose
What is an important Heptose monosaccharide?
Ketose: Sedoheptulose
What is the function of sedoheptulose?
An intermediate of the pentose phosphate pathway
What are the important Triose aldose and Triose Ketose monosaccharides?
Glyceraldehyde and Dihydroxyacetone
What is the structure of carbohydrates?
Cn (H2O) n
n = 3-9
What is the simplest form of a CH? Give examples
monosaccharides
Glucose, fructose, galactose, ribose
What form of CH consists of two monosaccharides? Give examples
disaccharides
Maltose, lactose, sucrosse
What form of CH consists of 3-10 monosaccharides? Give examples
oligosaccharides
Glycolipids and glycoproteins
What form of CH consists of greater than 10 monosaccharides? give examples
Polysaccharides
Glycogen, starch, cellulose
What are the names of 3C, 4C, 5C, 6C, and 7C monosaccharides respectively?
Triose, tetrose, pentose, hexose, heptose
Monosaccharide structure: if the carbonyl group is on the 2nd carbon it is a/an ______.
ketone
Monosaccharide structure: if the carbonyl group is on the 1st carbon it is a/an ______.
Aldehyde
What are stereoisomers?
same molecular formula and bond constituents but differ in spatial orientation of atoms attached to the asymmetric carbon
What determines a monosaccharide D or L form?
OH group on the a carbon farthest away from carbonyl group
What are epimers?
Diastereomers that differ in configuration of only on sterogenic (chiral) center
What forms an asymmetric center?
4 different groups
*creates the mirror image
Most sugars are in the __-series in human
D
What is anomer?
The cyclic monosaccharides or glycosides that are epimers
When -OH at C-1 is on the opposite side of the rign from the CH2OH it is a/an __ anomer
alpha
A five carbon monosaccharide ring is called _____.
Furanose
A six carbon monosaccharide ring is called _____.
pyranose
True or false: The Fischer projection structure of a monosaccharide is more stable
False, The ring structure is more stable
What modified monosaccharide is a major component of DNA?
Deoxyaldose
What modified monosaccharides are components of glycoproteins and glycolipids? What do they play a major role in?
Acetylated amino sugars
Role: cell signaling, cell adhesion, immune response
Acidic sugars are components of what?
Glycosaminoglycans and proteoglycans that are present in plasma membranes of cells and extracellular matrix
What modified monosaccharide is created when a monosaccharide is attached to a phosphate group or sulfate group?
Sugar esters
What modified monosaccharides constituted the gangliosides in oligodendrocyte of the nervous system and G6P is an example of this modified monosaccharide?
Sugar esters
What creates sugar alcohols?
Carbonyl group is reduced, forming a hydroxyl group
What are examples of sugar alcohols?
Glycerol, Xylitol, sorbitol
What are the uses of sugar alcohols?
Food additives, gains importance in uncontrolled diabetes leading to cataracts and peripheral neuropathy; used in synthesis of lipids
Carbohydrates are linked through what type of bond?
Either O or N - glycosidic bond
O is most common
What is the nutritional reservoir of CH in plants?
Starch
What is starch made of? what is the name of the branched and unbranched form of starch?
Glucose
Amylopectin
Amylose
What is the natural sweetener?
Sucrose: Glucose and fructose
What is the major dietary carb of animal origin?
Lactose: glucose and galactose
*Lactose intolerance: body can’t easily digest lactose
Starch amylose has what type of glycosidic bonds?
Alpha 1,4
Amylose with the addition of branch points creates amylopectin: what is the glycosidic bond that creates these branches?
Alpha 1,6
Cellulose is a major plant polysaccharide; what is the typical structure?
unbranched polymer of glucose residues joined by Beta 1,4 linkages.. Very long straight chains
Why does starch and glycogen have bent structures?
More suitable for storage
• Blood Glucose: regulated through the actions of hormones such as 1. _______ and _______. Normal fasting plasma glucose concentration range is 2. _________.; rarely exceeds 3. ________ after a meal. When blood glucose drops below 60 mg/dL (4._________) after a meal, 5. _____, _______, and ______ may be experienced. Below 40: 6. ____,____,_____, and _____. Fasting levels above ~130 and postprandial ~200 are diagnostic of 7________.
- Insulin and glucagon
- 70-100 mg/dL
- 140 mg/dL
- hypoglycemia
- hunger, sweating, and trembling
- convulsions, coma, brain damage, and death
- diabetes mellitus
Glycolysis: Process most cells generate energy. 6-C 1. ______ metabolized to 2 molecules of 3-C organic acid 2. ______. Net synthesis of 3. ____ ATP. Under aerobic conditions: pyruvate can be oxidized in 4. ______ to yield more energy (5. ___ ATP).
- glucose
- pyruvate
- 2
- mitochondria
- 36
What are the only means that cells obtain energy from glucose under anaerobic conditions?
Anaerobic conditions: glycolysis is the only means by which ATP can be generated from glucose. Cells that lack mitochondria rely only on glycolysis (RBCs).
What is Pasteur effect?
Pasteur effect: aerobic conditions in other cells tend to suppress glycolysis in this phenomenon due to allosteric inhibition of glycolytic enzymes by citrate and ATP
What is the Warburg effect
Warburg effect: many cancers exhibit high rates of glycolysis even in the presence of oxygen. This property is used in clinical detection of cancer by position emission tomography (PET)
Describe erythritol
Erythritol: 4-carbon sugar alcohol used as artificial sweetener. Little metabolized, releases little energy when consumed in food. Doesn’t promote tooth decay. Absorbed and excreted in urine = less flatulence than other sugar alcohols
Describe Xylitol
Xylitol: 5-C sugar alcohol used as natural sweetener. Low glycemic index. Doesn’t promote tooth decay. Lower energy content than sucrose but same sweetness. Does cause flatulence after excess
Describe mannitol
Mannitol: energy storage by some micro-organisms and plants. Used to treat head trauma and kidney failure, heart-lung machine primer, make the blood-brain barrier permeable to drugs. Inhaled solid: treatment of cystic fibrosis by osmotically liquefying mucus. Low glycemic index, tooth-friendly sweetener, half as sweet as sucrose, high dose causes flatulence
Describe sorbitol
Sorbitol: sweetener in chewing gum, tooth-paste, mouthwash and laxative
(Carbs/lipids/proteins)_______ are synthesized from Acetyl CoA?
Lipids
