CH 3 Molecules of Life

Biosynthesis/Anabolism Catabolism

structural formula for methane ball-and-stick modelspace-filling model Different ways to illustrate molecules

ball-and stick model for the linear structure of glucose

six-carbon ring structure of glucose that usually forms inside cells

Functional Groups: groups of atoms that give the molecules to which they are attached specific characteristics and functions.

Simple changes in molecular structure can have significant effects on function. Which functional groups have moved?

Most complex biological molecules are broken down BY CELLS during catabolic metabolism (catabolism) by way of hydrolysis reactions Reaction Catalyzed by an Enzyme During the evolution of molecular complexity, before the evolution of the first protocells, the appearance of the hydroxyl functional group allowed small molecules (monomers) to combine into larger molecules (polymers).

Most complex biological molecules are synthesized BY CELLS during anabolic metabolism (anabolism) by way of condensation reactions (i.e. dehydration synthesis) Reaction Catalyzed by an Enzyme

H OHH H H H 2 OH CH 2 OH H OH H H H O O HHO H Glucose, a monosaccharide Carbohydrates

O OHH H H 2 OH CH 2 OH OH CH 2 OH OH H H O H 2 OH HHO H Glucose and Fructose Which is an Aldehyde? Which is a Ketone? Carbohydrates H OHH H H H 2 OH CH 2 OH H OH H H H O O HHO H

a Structure of glucoseb Structure of fructose glucosefructose sucrose+ H 2 O O O O O O HOOH HO H HHO OHH H 2 OH CH 2 OH H OH H H H H H 2 OH O HHO OHH H H 2 OH CH 2 OH OH CH 2 OH HOH H H O O Condensation (dehydration synthesis) Reaction between the monosaccharides glucose and fructose to form the disaccharide Sucrose

Complex Carbohydrates (Polysaccharides)

Starch (Amylose) - how plants efficiently store glucose

Cellulose - how plants use glucose to provide themselves structure Hydrogen bonding holds cellulose chains together.

Glycogen - how animals efficiently store glucose

Keto-glucose amine (Chitin) - a polysaccharide modified for high strength and low mass Why is the monomer of chitin called “keto”- glucose “amine”?

Lipids: fats and oils

Types of Fatty Acids SaturatedMono-unsaturatedPoly-unsaturated Lipids

cis-fatty acid Trans-fatty acid cis-fats are good fats, trans-fats are bad fats

glycerol three fatty acids Triglyceride

Phospholipids two hydrophobic tails hydrophilic head Cell Membrane

Bee Wax Cholesterol Other Lipids

Amino Acids and the Proteins they Build

Proteins are long chains of amino acids

Fig. 3-15a, p.42 R

Amino Acids all have the same basic structure

Proteins are constructed by way of dehydration synthesis reactions, forming a peptide bond

A Dipeptide with a peptide bond

A Polypeptide with two peptide bonds and a third one on the way.

a primary structure b secondary structure The many levels of protein structure c tertiary structure d quaternary structure

Here, sucrase catalyzes a hydrolysis reaction and metabolizes sucrose to glucose and fructose.

Enzymes are a type of protein that acts as a catalyst, speeding up chemical reactions. Here, hexokinase attaches a phosphate to a glucose molecule, trapping it inside a cell.

Enzymes work by lowering the activation energy of a reaction, allowing it to proceed.

Enzymes have optimum temperatures and pH at which they work most efficiently.

DNA DNA (and RNA) are long chains of building blocks called nucleotides. Just like proteins and the polysaccharides of starch and cellulose, nucleic acids are polymers of nucleotide building blocks. Segments of DNA called genes provide the instructions for the building of specific proteins.

What happens when mistakes are made in the DNA of a gene?

Biosynthesis/Anabolism Catabolism

Amylase: Starch  Maltose Starch is a polysaccharide, a large molecule of long, branching chains of glucose molecules. Amylase is an enzyme produced in saliva that cuts starch into smaller units of two glucose molecules called maltose. Amylase is made in the salivary gland cells where the gene Amy-1 is active. How is this Evidence for Evolution?