Chapter 7 Introduction to Carbohydrates Flashcards
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Overview
- another term for saccharides ?
- can serve as components that mediate intercellular communication
- A full set of carbohydrates produced by an organism ?
- function of carbohydrates
- carbohydrates
- carbohydrates
- glycome
- energy, cell communication and structure
Classification and Structure
- simple sugars classified according to the number of carbon atoms ?
- carbohydrate with aldehyde as their carbonyl group ?
- carbohydrate with keto as their carbonyl group ?
- carbohydrates that have a free carbonyl group has suffix of ?
- Ketoses have an additional “ ul” in their suffix such as ?
- what type of carbohydrate contains two units of monosaccharides ?
- how about THREE units of monosaccharides ?
- how about three or more than 10 ?
- monosacharrides
- Aldoses
- Ketoses
- “ose”
- xylulose
- Disacharrides
- Oligosaccharides
- Polysaccharides
Isomers and Epimers
- they have the same chemical formula but with different structures ?
- examples of isomers of each other ?
- what is the chemical formula of all of number 2. ?
- Carbohydrate isomers that differ only in ONE specific carbon atom?
- C-4 epimers ?
- C-2 epimers ?
- Galactose and Mannose differ in the position of -OH, therefore they are called ?
- Isomers
- Glucose, Mannose, Fructose and Galactose
- C6H12O6
- Epimers
- Glucose and Galactose
- Glucose and Mannose
- isomers rather than epimers
Enantiomers D and L forms
- structures that are mirror images of each other ?
- The two members of the paired mirror images are called ?
- what configuration do humans have as the vast majority ?
- Most enzymes are very specific in recognizing enantiomers either if it is
- Enzymes that are capable of interconverting D and L are called ?
- enantiomers
- D and L configurations
- D- configuration ( carbonyl carbon is on the RIGHT)
- D or L
- Isomerases
Mososaccharide Cyclization
- how much percentage of monosaccharides exist in open chain form; (acyclic) in solution ?
- What is an ANOMER ?
- example of anomers ?
- Not referred to as mirror images but referred to as diasteriomers ?
- Glycogen is formed from Alpha or Beta (- D Glucopyranose)?
- what is mutarotation ?
- rare ! less than 1 percent !
- Alpha and Beta forms
- Alpha- D- glucopyranose and Beta-D- glucopyranose
- Alpha and Beta forms
- Alpha
- spontaneous forming equilibrium mixture alpha and beta
Reducing Sugars
- a ring of sugar not linked to another compound by glycogen bond ?
- This sugar acts as what ?
- examples of reducing sugars ?
- what type of monosaccharide can be isomerized into an aldose ?
- What type of monosaccharide is Fructose ?
- it means the ring can open. ( the hydroxyl group on the anomeric carbon is not linked to another compound)
- Reducing sugar
- All monosaccharides but not all disaccharides
- Fructose
- Ketose
Glycosidic Bonds
- Bonds that l_ink sugar molecules_ are called ?
- glycosidic bonds are formed by enzymes called ?
- These enzymes “glycosyltransferases” use activated sugars as substrates ?
- example of activated sugar ?
- Activated sugars are used by glycosyl transferase enzymes as ?
- Glycosidic bonds
- Glycosyl-TRANSFERASES
- nucleotide sugars
- uridine diphosphate
- Substrates
what is involved in the linkage of Lactose ?
glycosidic bond between:
carbon 1 of B-galactose and carbon 4 of glucose
If lactose** is linked by **C1 B-galactose and C4 glucose; then what kind of glycosidic bond does it present ?
the linkage is a Beta 1-4 Glycosidic bond
- Lactose is a disaccharide made by ?
- is lactose a reducing or non-reducing sugar ?
- what is the reason for lactose being a reducing sugar ? (explain your answer.
- glucose and galactose
- lactose is a reducing sugar
- because the anomeric carbon of glucose is not involved in glycosidic linkage.
Carbohydrate Linkage to Noncarbohydrates
- examples of noncarbohydrate molecules that can be linked carbohydrates ?
- purine
- pyrimidine (nucleic acids)
- aromatic rings ( steroids, bilirubin)
- proteins (glycoproteins and proteoglycans)
- lipids (glycolipids)
noncarbohydrate group linked to carbohydrates :
O type or N type Glycosidic Linkage
- If the sugar is attached to an -NH2 what is the bond called ?
- if the sugar is attached to an - OH then what is the bond called ?
- All _sugar to sugar l_inkage ?
- the bond is called N-glycosidc linkage
- O glycosidic linkage
- are O- glycosidic linkage
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Dietary Carbohydrate Digestion
- where are the principle sites of digestion found ?
- digestion is catalyzed by enzymes called ?
- glycosidases (digestive enzymes) hydrolyze what ?
- endoglycosidases breakdown (hydrolyze) complex sugars like ?
- DISACCHARIDASES breakdown what ?
- mouth and intestinal lumen
- glycosidases (digetive enzymes)
- glycosidic bonds
- polysaccharides, oligosaccharides and DISACCHARIDASES
- tri- disaccharides into reducing sugars
Salivary Alpha Amylase
- what are examples of dietary polysaccharides ?
- what is starch composed of ?
- what do alpha amylase hydrolize breifly in mastification ?
- what type of sugar is not able to be digested by humans ?
- cellulose contains what type of bond
- branched amylopectin anf glycogen contain what bonds ?
- Are disaccharides resistant to alpha amylase ?
- why is carbohydrate digestion halted temporarily in the stomach ?
- starch
- amylose and amylopectin (plant) glycogen (animal)
- both alpha and beta (1-4) bonds
- cellulose
- Beta 1-4 Glycosidic bonds between glucose residues
- alpha 1-6 bonds
- yes
- because of high acidity in the stomach
Pancreatic Amylase
when the acidic content from the stomach reaches the small intestine how are they neutralized ?
by bicarbonate released by the pancreas
Intestinal Disaccharides
- where does the final dogestive process happen primarily; at which part of the mucosal lining ?
- what bond does isomaltase cleave (break) ?
- what bond does maltase break (cleave) ?
- Sucrase breaks alpha (1-2) in Sucrose producing what ?
- what bonds do Sucrase break (cleave)?
- what bonds do Lactase break (cleave) ?
- when lactase breaks beta 1-4 bonds of lactose what does it produce?
- duodenum and upper jujenum
- alpha 1-6 bond in isomaltose
- alpha 1-4** in **maltose and maltriose
- glucose and fructose
- alpha 1-2 bonds in sucrose
- Beta 1-4 bonds in lactose
- glucose and galactose
Trehalose
- is trehalose a monosaccharide or a disaccharide ?
- This disaccharide of glucose are found in where ?
- how are these fungi disaccharides broken down ?
- trehalase transmembrane proteins found where ?
- disaccharide
- in MUSHROOMS and other fungi
- they are broken down by trehalase
- brush border on the luminal (apical) surface of enterocytes
Intestinal Absorption of Monosaccharides
- what part of the intestine absorbs the bulk of monosaccharide digestion ?
- how are sugars absobed ?
- how are galactose and glucose absorbed ?
- what does secondary active transport require ?
- what does the transport protein require in this mechanism ?
- How is sugar transport driven ?
- the upper jujenum
- each sugar is absorbed differently uniquely per type
- taken to enterocytes by active SECONDARY active transport
- current uptake (symport) of Sodium ions Na+
- (SGLT-1) Sodium dependent glucose cotransporter 1
- Driven by Na+ gradient created by Na/K ATPase
Fructose Absorption
- fructose absorption makes use of an energy and ?
- how are all three monosaccharides transported from the enterocytes to portal circulation ?
- Glucose and Galactose ?
- Fructose ?
- Frcutose, Glucose and Galactose to circulation ?
- Na+ independent monosaccharide transporter (GLUT-5)
- transported by GLUT-2
- SGLT-1
- GLUT-5
- GLUT-2
Polysaccharides
- what are linear polysaccharides ?
- what are branched polysaccharides ?
- amylose
- glycogen