C 24:The chemistry of life Biomolecules

Primary Organic Compounds You are expected to learn the structure and functions of these organic compounds: Carbohydrates Lipids Proteins Nucleic Acids

Polymers and Monomers Each of these types of molecules are polymers that are assembled from single units called monomers. Each type of biomolecule is a string of a different type of monomer.

Monomers Macromolecule Carbohydrates Lipids Proteins Nucleic acids Monosaccharide Not always polymers; Hydrocarbon chains Amino acids Nucleotides

Proteins Organic polymers are made up of repeating blocks called monomers. Proteins are made up of amino acid monomers – spider webs are examples of protein polymers, and so are your muscles.

Amino acid structure An amine + carboxyl acid

Peptide bonds

Take ¼ sheet of paper Draw 4 consecutive amino acids across the top evenly spaced. Cut the paper so you have a strip with the 4 amino acids. Curl the paper around so you have a helix – connect amino acids with peptide bonds - draw in peptide bonds. If you do not wish to keep your protein - denature your protein and place in the recycling bin

Proteins Peptide – 2 or more amino acids bonded together Polypeptide – 10 or more amino acids Protein – 50 or more amino acids bonded together Are long chains of amino acids that start to fold into 3-d shapes. Cooking causes DENATURATION – unfolding of the protein molecule

Functions of proteins Enzymes – are catalysts for cellular reactions. Transport proteins – hemoglobin is an example of this – it carries oxygen to all parts of your body. Structural proteins – collagen is an example of this – it make up skin, tendons, hair, and fingernails Hormones – Insulin is a protein that carries signals from one part of the body to another.

Enzymes A biological catalyst Substrate – bind to specific sites on enzyme molecules – Like a lock= where the key fits; and a key= enzyme. Active site – is the lock to which the enzyme binds, or the key fits.

Carbohydrates Carbohydrates are made of carbon, hydrogen, and oxygen atoms, always in a ratio of 1:2:1; functional groups of alcohols –OH, and -C=O are common. Carbohydrates are the key source of energy used by living things. The building blocks of carbohydrates are sugars, such as glucose and fructose.

How do two monosaccharides combine to make a polysaccharide? are called ‘simple Sugars’. Two monomers linked together are called Disaccharides

Polysaccharides – 12 or more monomer units

Functions of carbohydrates Glucose – a monosaccharide that is found in our blood : commonly referred to as “blood sugar” Sucrose –a disaccharide commonly called table sugar. This is too big to be taken into the bloodstream and is broken down in the small intestine. Polysaccharides – many monomers 12 or more monomer units strung together – pasta is an example of this. Starch, Glycogen and Cellulose are examples of polysaccharides.

Functional groups break!

Lipids Lipids ARE NOT Always POLYMERS. Lipids are large, are nonpolar, are hydrophobic (water/fear – they are insoluble in water) Lipids ARE NOT Always POLYMERS. Lipids are made up of Fatty acids – long-chained carboxylic acids. Fats are either saturated – have the maximum number of hydrogens Unsaturated – have double bonds, so they could add more hydrogens.

Types of lipids Fatty acids Triglycerides – used in making soap, cell membranes (called phospholipids) Waxes – contain fatty acids Steroids – have no fatty acid chains, have cyclic rings - are used as hormones which regulate metabolic processes.

Functions of lipids Store energy efficiently Make up most of the structure of the cell membrane

Nucleic Acids DNA & RNA

What are they ? The 4th type of macromolecules The chemical link between generations The source of genetic information in chromosomes

What do they do ? Dictate amino-acid sequence in proteins Give information to chromosomes, which is then passed from parent to offspring

What are they made of ? Simple units (monomers) called nucleotides, connected in long chains Nucleotides have 3 parts: 1- A phosphate group ( P ) 2- 5-Carbon sugar (pentose) 3- Nitrogen containing base (made of C, H and N) The P groups make the links that unite the sugars (hence a “sugar- phosphate backbone”

Two types of Nucleotides (depending on the sugar they contain) 1- Ribonucleic acids (RNA) The pentose sugar is Ribose (has a hydroxyl group in the 3rd carbon---OH) 2- Deoxyribonucleic acids (DNA) The pentose sugar is Deoxyribose (has just an hydrogen in the same place--- H) Deoxy = “minus oxygen”

DNA Nucleotides Composition (3 parts): 1- Deoxyribose sugar (no O in 3rd carbon) 2- Phosphate group 3- One of 4 types of bases (all containing nitrogen): - Adenine - Thymine (Only in DNA) - Cytosine - Guanine

RNA Nucleotides Composition ( 3 parts): 1- Ribose sugar (with O in 3rd carbon) 2- Phosphate group 3- One of 4 types of bases (all containing nitrogen): - Adenine - Uracyl (only in RNA) - Cytosine - Guanine

DNA vs RNA DNA 1- Deoxyribose sugar 2- Bases: Adenine, Thymine, Cytosine, Guanine 3- Double-stranded helix arrangement RNA 1- Ribose sugar 2- Bases: Adenine, Uracyl, Cytosine, Guanine 4- Single stranded

The Double Helix (DNA) Structural model: Model proposed by Watson & Crick, 1953 Two sugar-phosphate strands, next to each other, but running in opposite directions. Specific Hydrogen bonds occur among bases from one chain to the other: A---T , C---G Due to this specificity, a certain base on one strand indicates a certain base in the other. The 2 strands intertwine, forming a double- helix that winds around a central axis

Double Helix of DNA

Quick Check An ending of –yne means? An ending of –ene means? An ending of –ane means?

Metabolism vs anabolism METABOLISM: Changing complex molecules (nucleic acids, polysaccarides, proteins, triglycerides) into their building blocks (amino acids, fatty acids, nucleotides, monosaccharides) ANABOLISM: The reverse: linking the building blocks (amino acids, fatty acids, nucleotides, monosaccharides) to make a complex molecule (nucleic acids, polysaccarides, proteins, triglycerides)

Slime cross linking