CARBOHYDRATES - Chapter 9 pgs 440-469

Carbohydrates

Hydrates of carbon - C, H, O - hexose, aldose, ketose - ose ending

(1) Carbon chain
(2) Alcohol group ROH
                                  H
(3) Aldehyde group RC=O
             or
                                R
(4) Ketone group - R-C=O

Monosaccharides or simple sugars
General Formula CnH2nOn;C3H6O3;C4H O;C5H O; and C6H O

Simpliest Sugars are 3 carbons in length.

 

 

glyceraldehyde             glycerol                     dihydroxyacetone                 acetone

 

Structures

L and D Designations

This is determined by the second carbon from the bottom - penultimate carbon. If it is on the left, it is L. If it is on the right, it is R.

     H-C=0                                                         H-C=O
          |                                                                    |
   HO-C-H                                                        H-C-OH
          |                                                                    |
    H-C-OH                                                       H-C-OH
        H                                                                   H

L-glyceraldehyde                                         D-glyceraldehyde

Most of the sugars found in nature are D.

Open chained structures also called Fisher projections
Ring structures are Haworth projections - important because structurally the sugars need to >fit= in the enzymes.

 

 

            D- glucose                         L- glucose
                            Fisher glucose ----->                                             Haworth

Anomers - When the Fisher formula goes into a ring structure, another place for an isomer occurs.

α is when the OH group is down from the carbon
β is when the OH group is up from the carbon

α glucose                                                                 β glucose

 

 

Pentoses

  H

            

     H

  C=O

     C=O

H-C-OH

 H-C-H

H-C-OH

 H-C-OH

H-C-OH

 H-C-OH

H-C-OH

 H-C-OH

    H 

      H

ribose

 deoxyribose

Hexoses

H                             H                                              H
C=O                       C=O                                     H-C-OH
C-                           C-                                             C=O
-C                           -C                                            -C
C-                           -C                                             C-
C-                            C-                                            C-
CH2OH                   CH2OH                                   CH2OH
glucose                 galactose                                 fructose

Review

Sugars CnH2nOn formula - alcohol group

D and L + - ose endings

aldehydes or ketones
List from the preceeding pages whether the sugars are

Aldose                                                                                  Ketose

 

 

Disaccharides

2 monosaccharides joined together
Maltose = glucose + glucose α 1->4 linkage
Lactose = galactose + glucose β 1->4 linkage
Sucrose = glucose + fructose α 1->2 linkage

Lactose intolerance means they can=t break the β bond

 

Recaps

Maltose = _______________ linkages of _____________ + _______________

Lactose = _______________ linkages of _____________ + _______________

Sucrose = _______________ linkages of _____________ + _______________

Polysaccharides

Many monosaccharides joined together

A. Starch - vegetable storage of glucose -

1. Amylose (20%)                 α 1-4 linkages of glucose            

                                                                                                                        (60-300 units)

 

                            glucose                                 glucose                                         glucose

 

2. Amylopectin (80%) branched α 1 - 4 and α 1-6

                                                                                                                        (300-600 units)

 

B. Glycogen - animal storage of glucose

α 1-4 and α 1-6 like anylopectin with shorter branching

C. Cellulose - plant β 1-4 linkages

 

                β-D-glucose                     β -D-glucose                                 β- D-glucose

Recap

Polysaccharides

Plants

1. ______________________

a. ______________________ with _________________________ linkages

b. ______________________ with _________________________ linkages

2. ______________________

Animals

1. __________________________ with _________________________ linkages

Hydrolyze

starch _________________________ monosaccharides

glycogen _________________________ monosaccharides

cellulose _________________________ monosaccharides

Glucose

Blood sugar 60-100 mg % normal level
                         150 mg % found in urine

Glucose tolerance Curve

 

 

Insulin lowers blood sugar by helping it get into cells
                (beta cells of pancreas)

Glucagon - raises glucose level in blood (alpha cells of pancreas)
5% glucose solution is isotonic with blood.
    How much sugar is in 100 ml of a 5% solution?
    How much sugar is in 1 liter of a 5% solution?

Approximately 4 Kcal/g of sugar - how many Kcal does a 1 liter bottle of a hospital 5% solution provide?

 

Galactose

Comes from Lactose - lactating - milk

Galactoseminia genetic defect whereby galactose cannot be metabolized. It accummulates and mental retardation occurs. What would be a possible treatment galactosemia?

Fructose

1/2 of sucrose - 70% sweeter than sucrose used in diets - too much get diarrhea
1/2 life is 20 min. 45 for glucose

Starch

Mixture of amylose and amylopectin
Not soluble in H2O because of size of polymers and water molecules attach around the OH's and make a colloid.

Other Important Carbohydrates

GLYCOPROTEINS Proteins with sugar groups attached.

BLOOD GROUPS

Blood groups antibodies are formed in response to foreign compounds p 459. These sugar polysaccharides are attached to proteins

sugar residues

Group     O         N-acetyl-glucosamine + Galactose + Fucose
               A         N-acetyl-glucosamine + Galactose + Fucose + N-acetyl-galactosamine
               B         N- acetyl-glucosamine + Galactose + Fucose + Galactose

O = universal donor doesn=t have the sugars present - no antibodies will be formed against given blood

A = has the A antigen, so if O or B received it, antibodies against the A antigens would be made

B = has the B antigen, so if O or A received it, antibodies against the B antigens would be made

AB = universal receiver has both A & B antigens, so it doesn=t see anything as foreign to it

Group O most prevalent about 50%
Group AB least prevalent

Rh factor 15% Rh negative

OTHER Chondroitin sulfate and glucosamine keeps healthy joints


Wednesday, March 21, 2007 01:28:02 PM