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 CH 2 O • 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

• Fats and Oils Lipids

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 – Fats • Usually of animal origin • Solid at room temperature – Oils • Usually of plant origin • Liquid at room temperature

• Functions of Fats Lipids

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

• Phospholipids Lipids

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

Lipids

• Steroids Lipids

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 structural roles.

and collagen have – Proteins are also enzymes that speed up the chemical reactions of metabolism.

– Proteins such as for the transport of substances within the body.

hemoglobin are responsible – 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 regulate cellular function.

are hormones that – 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 (-NH 2 ) – 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 3 rd group is added back on P

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?