Biology 12 Unit A The Chemistry of Life – Part 2

Macromolecules Made of organic molecules

Organic Molecules Always contain: Carbon (C) and Hydrogen (H) A carbon atom may share electrons with another carbon atom

Organic Molecules Always contain: Carbon (C) and Hydrogen (H) A carbon atom may share electrons with another carbon atom

Organic Molecules Many molecules of life are macromolecules. (macromolecules contain many molecules joined together)

Organic Molecules Many molecules of life are macromolecules. (macromolecules contain many molecules joined together) Monomers: Simple organic molecules that exist individually Polymers: Large organic molecules form by combining monomers

Organic Molecules

Organic Molecules A meal containing carbohydrates, lipids, and proteins.

Organic Molecules Cells have mechanisms of joining monomers to build polymers

Organic Molecules Cells have mechanisms of joining monomers to build polymers

Organic Molecules Cells have mechanisms of joining monomers to build polymers Dehydration Reaction: an -OH and -H are removed Hydrolysis Reaction: the components of water are added

Organic Molecules

Macromolecules = BIG molecules Carbohydrates CH2O Lipids CHO -don’t form true polymers, the number of unit molecules that join together is limited Proteins CHON Nucleic Acids CHONPS

Carbohydrates Some Functions: Quick fuel Short-term energy storage Structure of organisms Cell to cell recognition

Carbohydrates Simple Carbohydrates

Carbohydrates Simple Carbohydrates Monosaccharides are sugars with 3 - 7 carbon atoms

Carbohydrates Simple Carbohydrates Monosaccharides are sugars with 3 - 7 carbon atoms Pentose refers to a 5-carbon sugar Hexose refers to a 6-carbon sugar

Carbohydrates Three ways to represent the structure of glucose.

Carbohydrates Disaccharides contain two monosaccharides.

Carbohydrates Polysaccharides are long polymers that contain many glucose subunits.

Carbohydrates Polysaccharides are long polymers that contain many glucose subunits. Starch is the storage form of glucose in plants.

Carbohydrates Polysaccharides are long polymers that contain many glucose subunits. Starch is the storage form of glucose in plants. Glycogen is the storage form of glucose in animals.

Carbohydrates Polysaccharides are long polymers that contain many glucose subunits. Starch is the storage form of glucose in plants. Glycogen is the storage form of glucose in animals. Cellulose can be found in the cell walls of plants.

Carbohydrates: starch

Carbohydrates: cellulose

Carbohydrates: glycogen

A3 concept check-up questions What is the difference between dehydration synthesis and hydrolysis? Why do lipids not form true polymers? Water is a by-product of condensation reactions. Where does it come from? How does the use of glucose in a plant differ from its function in an animal?

Lipids

Lipids Some Functions: Energy Storage Found in the plasma membrane Component of steroid hormones Lipids do not dissolve in water

Lipids Some Functions: Energy Storage Found in the plasma membrane Component of steroid hormones Lipids do not dissolve in water Lipids are electrically neutral

Lipids Fats and Oils

Lipids Fats and Oils Fats Usually of animal origin Solid at room temperature

Lipids Fats and Oils Fats Usually of animal origin Solid at room temperature

Lipids Fats and Oils Oils Fats Usually of plant origin Usually of animal origin Solid at room temperature Oils Usually of plant origin Liquid at room temperature

Lipids Functions of Fats

Lipids Functions of Fats Long-term energy storage Insulation against heat loss Protection of major organs

Lipids Synthesis and degradation of a fat molecule

Lipids Emulsification

Lipids Saturated and Unsaturated Fatty Acids

Lipids Saturated and Unsaturated Fatty Acids Fatty acids are hydrocarbon chains that end with -COOH.

Lipids Saturated and Unsaturated Fatty Acids Fatty acids are hydrocarbon chains that end with -COOH. Saturated fatty acids: No double covalent bonds between carbon atoms Unsaturated fatty acids: Double bonds between carbon atoms

Lipids Saturated Fatty Acid Unsaturated Fatty Acid

Lipids Phospholipids

Lipids Phospholipids Comprised of 2 fatty acids + a phosphate group Primary components of cellular membranes

Lipids

Lipids Steroids

Lipids Steroids All steroids have four adjacent rings.

Lipids Steroids All steroids have four adjacent rings. Examples: Cholesterol Testosterone Estrogen

Lipids

A4 concept check up questions What is the defining characteristic of lipids? What differences exist between fatty acids from animal sources and fatty acids from plant tissues? List the ways glycerides can be different from each other. Name two types of lipids that do not contain glycerol.

Proteins Proteins have important functions in cells. Proteins such as keratin and collagen have structural roles. Proteins are also enzymes that speed up the chemical reactions of metabolism. Proteins such as hemoglobin are responsible for the transport of substances within the body. Proteins also transport substances across cell membranes.

Proteins Proteins have important functions in cells. Proteins form the antibodies of the immune system that defend the body from disease. Proteins such as insulin are hormones that regulate cellular function. Contractile proteins such as actin and myosin allow parts of cells to move and muscles to contract.

Proteins Proteins are comprised of amino acids.

Proteins Amino acids Amino group (-NH2) Acidic group (-COOH) R group (remainder)

Proteins

Proteins Peptides A polypeptide is a single chain of amino acids. A peptide bond joins two amino acids.

Proteins

Proteins Levels of Protein Organization The structure of a protein has three or four levels of organization. The final shape of a protein is very important to its function.

Proteins

Proteins

Proteins

A5 concept check-up questions Describe the common structure of amino acids. What type of bond is a peptide bond? Where can one be found? What are two types of secondary structure in proteins? What causes the formation of each? What types of bonds and what level of structure is destroyed when a protein is denatured?

Nucleic Acids DNA (deoxyribonucleic acid)

Nucleic Acids DNA (deoxyribonucleic acid) RNA (ribonucleic acid)

Nucleic Acids DNA stores genetic information in double helix. DNA codes for the order of amino acids in a protein. RNA is an intermediary in the sequencing of amino acids into a protein.

Nucleic Acids Components of a nucleotide Phosphate Pentose sugar (ribose or deoxyribose) Nitrogen-containing base may be 2-ring purine (A, G) or 1-ring pyrimidine (C, T, U)

Nucleic Acids DNA Structure

Nucleic Acids

Nucleic Acids ATP (Adenosine Triphosphate)

Nucleic Acids ATP (Adenosine Triphosphate) A high energy molecule ATP undergoes hydrolysis (enzyme ATPase) and energy is released ATP can be converted to ADP and “recharged” by phosphorylation when 3rd P group is added back on

Nucleic Acids

A6 concept check-up questions How do the components of a DNA nucleotide differ from those in an RNA nucleotide? What’s the difference between a purine and a pyrimidine? What two types of biochemicals make up chromosomes? Describe the bonds between the phosphates in ATP. What is their function?