I. Chapter 5 Summary

A. Simple Sugars (CH2O)n:

1. One C contains a carbonyl (C=O) rest contain -OH

2. Classification by functional group: aldoses & ketoses

3. Classification by number of C's: trioses, pentoses, hexoses

4. Stereochemistry: all sugars have D conformation

5. Cyclic structure: -OH bonds to carbonyl carbon ==> 5- or 6-member ring

B. Disaccharides: 2 simple sugars joined by "glycosidic" bond between -OH of one and carbonyl of another

1. Table sugar 2 . M a l t o s e 3. Lactose

C. Polysaccharides

1. Food Storage: starch and glycogen are polymers of glucose

2. Structural: cellulose is polymer of glucose

3. Differ in conformation of carbonyl C where sugars are joined

II. Nucleotides & Nucleic Acids

A. Nucleotides: Base-sugar-phosphate

B. Nucleic Acids

1. Nucleotide polymer connected by phosphodiester bonds

2. RNA (RiboNucleic Acid)-nucleotides contain ribose sugar

3. DNA (DeoxyriboNucleic Acid)-nucleotides contain 2!-deoxy-ribose sugar

III. Lipids

A. Glycerides

1. Triglycerides: 3 fatty acids bonded to 3 -OH's of glycerol by ester bonds

2. Phospholipids: Diglycerides and Amphipathic (have polar and nonpolar groups)

3. Phospholipid bilayer

B. Cholesterol-sterol lipid

Figure 4-02

In 1953 Stanley Miller simulated what were thought to be environmental conditions in the prebiotic earth.

Water vapor

“Atmosphere”

Electrode

Condenser

Cold water

Cooled water

containing organic

molecules

Sample for chemical analysis

H2O “sea”

EXPERIMENT

CH4

Fig. 4-2: He created Building Block Molecules

Simple compounds: Formaldehyde & Hydrogen Cyanide More Complex Molecules: Amino Acids & Hydrocarbons

Fig. 5.2a: Common Features of Macromolecules (a) Dehydration reaction: synthesizing a polymer

Short polymer Unlinked monomer

Dehydration removes a water molecule, forming a new bond.

Longer polymer

1 2 3 4

1 2 3

(b) Hydrolysis: breaking down a polymer

1 2 3 4

1 2 3

Fig. 5.2b: Common Features of Macromolecules

Monomer Simple Polymer Complex Polymer (Macromolecule)

Monosaccharide (Simple Sugar)

Oligosaccharide Polysaccharide

(Complex Carbohydrate)

Nucleotide Oligonucleotide Nucleic Acid

Amino Acid Peptide Polypeptide

Protein

Chapter 5: Biological Building Block Molecules are the units (Monomers) of Macromolecules

What do Macromolecules Do?

Common Features of Macromolecules - Shape

Common Features of Macromolecules

Fig. 2.18: Important Concept The Function of a macromolecule is determined by its

Molecular Shape (conformation) & Composition

Macromolecules such as proteins work by interacting with other molecules. These interactions depend on the molecules having complementary shapes that fit together (like a lock and key)

Monomer Simple Polymer Complex Polymer (Macromolecule)

Monosaccharide (Simple Sugar)

Oligosaccharide Polysaccharide

(Complex Carbohydrate )

Nucleotide Oligonucleotide Nucleic Acid

Amino Acid Peptide Polypeptide

Protein

Chapter 5: Biological Building Block Molecules are the units (Monomers) of Macromolecules

Number of Carbon atoms:

3 C’s Triose

4 C’s Tetrose

5 C’s Pentose

6 C’s Hexose

Note: suffix …ose indicates a sugar

R-C-R

O

R-C-H

O

Aldose (Aldehyde Sugar) Ketose (Ketone Sugar)

D - Glyceraldehyde

Trioses: 3-carbon sugars (C3H6O3)

Dihydroxyacetone

Fig. 5.3a: Trioses

Chiral Carbon

D- because –OH is on the right

L-Glyceraldehyde D-Glyceraldehyde

–OH is on the right D

–OH is on the left L

4 Chiral Carbons

3 Chiral Carbons

3 Chiral Carbons

Linear and ring forms

Pentoses and Hexoses form ring structures in water when one of the –OH groups forms a bond to the carbonyl group

Fig. 5.4a: Linear and ring forms of glucose

OH

CH2OH

O

OH OH

OH

OH

CH2OH

O

OH OH

OH

OH

OH-CH2

OH

OH

CH2OH

O

OH

OH-CH2

OH

OH O Assume C’s at vertices and H’s at ends of lines

α-D-Glucose β-D-Glucose β-D-Fructose β-D-Ribose

Maltose Glucose Glucose

1–4 glycosidic

linkage

Figure 5.5a: Disaccharides

Table Sugar Glucose-Fructose

Milk Sugar Galactose-Glucose

Malt Sugar Glucose-Glucose

OH

CH2OH

O

OH OH

O OH

OH-CH2

OH

CH2OH

O

OH

CH2OH

O HO

OH

OH

CH2OH

O

OH OH

O O

OH

CH2OH

O

OH OH

OH

CH2OH

O

OH OH

O

O

(a) α and β glucose ring structures

α Glucose β Glucose

(b) Starch: 1–4 linkage of α glucose monomers (b) Cellulose: 1–4 linkage of β glucose monomers

Figure 5.7: Polysaccharides – Starch & Cellulose

Fig. 5.6: Starch & Glycogen – Food Storage Polysaccharides.

(a) Starch: a plant polysaccharide

(b) Glycogen: an animal polysaccharide

Chloroplast Starch granules

Mitochondria Glycogen granules

Amylopectin

Amylose

Glycogen

1 µm

0.5 µm

LE 5-8

Cellulose molecules

Cellulose microfibrils in a plant cell wall

Cell walls Microfibril

Plant cells

0.5 µm

β Glucose monomer

Fig. 5.8: Structural Polysaccharides - Cellulose

Chitin forms the hard exterior exoskeleton of insects

It is also used to make biodegradable surgical threads

β (14) Glycosidic Bond – similar to cellulose

Structural Polysaccharides - Chitin

Lipids

Lipids are a diverse group of molecules that are primarily water-insoluble and include:

Fats Oils

Waxes Phospholipids

Steroids Carotenoids

Triglycerides

Biological Membranes

Fatty Acids

Acyl chain (16 – 18 carbons)

Straight conformation Bent (kinked)

conformation

Fig 5.10: Triglycerides

Triglycerides consist of 3 fatty acids bonded to the three hydroxyl (-O-H) groups of a molecule of glycerol (ester bonds)

Dehydration (condensation) Reaction

Acyl chains can be saturated or unsaturated

Structural formula of a saturated fat

molecule

Stearic acid, a saturated fatty acid

(a) Saturated fat

Structural formula of an unsaturated

fat molecule

Oleic acid, an unsaturated

fatty acid

(b) Unsaturated fat

cis double bond causes

bending

Fig 5.12: Triglycerides

Fig 5.12: Phospholipids

Hydrophobic tails

Hydrophilic head

Fatty acids

Choline

Phosphate

Glycerol

Hyd

roph

obic

tails

H

ydro

phili

c he

ad

Fig 5.13 / 7.2: Phospholipids Assemble to Form Membrane Bilayers

Fig 7.2

Phospholipid bilayers form impermeable membranes

that enclose and compartmentalize cells

Fig 5.14: Steroids are lipid molecules (water insoluble) based on a hydrocarbon structure with four fused rings

The Polar -OH group makes this molecule amphipathic

Monomer Simple Polymer Complex Polymer (Macromolecule)

Monosaccharide (Simple Sugar)

Oligosaccharide Polysaccharide

(Complex Carbohydrate)

Nucleotide Oligonucleotide Nucleic Acid

Amino Acid Peptid e Polypeptide

Protein

Adenine

Phosphate

Adenosine 5’-monophosphate (AMP)

N-Glycosidic Bond

Phosphoester Bond

RNA RiboNucleic Acid

DNA DeoxyriboNucleic Acid

Sugar-phosphate backbone 5′ end

5′C

3′C

5′C

3′C

3′ end

(a) Polynucleotide, or nucleic acid

(b) Nucleotide

Phosphate group Sugar

(pentose)

Nucleoside

Nitrogenous base

5′C

3′C

1′C

Nitrogenous bases

Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA)

Adenine (A) Guanine (G)

Sugars

Deoxyribose (in DNA) Ribose (in RNA)

(c) Nucleoside components

Pyrimidines

Purines

Fig. 5.26: The components of Nucleic Acids

Phosphodiester Bond

Fig. 5.28: The DNA double helix and its replication.

Sugar-phosphate backbone

3′ end 5′ end

Base pair (joined by hydrogen bonding)

Old strands

Nucleotide about to be added to a new strand

5′ end

New strands

3′ end

5′ end 3′ end

5′ end