1. Biological Molecules & Bonding

2. Learning Outcomes Spec Ref: 2.1.2 (b) the concept of monomers and polymers and the importance of condensation and hydrolysis reactions in a range of biological molecules (c) the chemical elements that make up biological molecules ALL: Identify the major molecules that make up the human body and the elements they are made from. MOST: Describe the types of bonding that occur and how elements are structure for this to occur SOME: Use key terminology to describe the types of bonding that occur within the major molecules found in the human body.

3. What are we made from?

4. In your group, discuss the following… Covalent bonds Single/double bonds Hydrogen bonds Chemical bonds What do you know?

5. Covalent bond A strong bond, formed when electrons are shared between non-metal atoms. Hydrogen bond A chemical bond that involves the electrostatic attraction between oppositely charged ions. One atom donates an electron to the other forming the positive and negative ions. Ionic bond A weak interaction that can occur wherever molecules contain a slightly negatively charged atom bonded to a slightly positively charged atom. Monomer A small molecule which binds to many other identical molecules to form a polymer. Polymer A large molecule made from many smaller molecules called monomers. Element A group of ions with a positive charge that migrate to areas of negative charge. Compound A group of ions that have gained electrons and have become negatively charged. Ion An atom or molecule with an overall electric charge because the total number of electrons is not equal to the number of protons Cation A substance made up of 2 or more elements chemically bonded together. Anion A type of an atom

6. Covalent bond A strong bond, formed when electrons are shared between non-metal atoms. Hydrogen bond A weak interaction that can occur wherever molecules contain a slightly negatively charged atom bonded to a slightly positively charged atom. Ionic bond A chemical bond that involves the electrostatic attraction between oppositely charged ions. One atom donates an electron to the other forming the positive and negative ions. Monomer A small molecule which binds to many other identical molecules to form a polymer. Polymer A large molecule made from many smaller molecules called monomers. Element A type of an atom Compound A substance made up of 2 or more elements chemically bonded together. Ion An atom or molecule with an overall electric charge because the total number of electrons is not equal to the number of protons Cation A group of ions with a positive charge that migrate to areas of negative charge. Anion A group of ions that have gained electrons and have become negatively charged. Answers

7. Recap… What type of bond would occur between carbon and hydrogen? A molecule made up of repeating monomer units is a…. Another name for a positive ion How does an ionic bond form?

8. Covalent Bonds Sharing of electrons Strong bond Example: –Atoms are most stable when have 8 electrons in outer shell. –Carbon has 4 –Carbon gains stability by sharing 4 electrons with other atoms.

9. Electron Shell Diagrams Atomic Number6 Number of protons6 Number of neutrons6 Number of electrons6 Mass number12

10. Your turn… Draw the electron shell diagrams for: –Hydrogen –Oxygen –Nitrogen

11. Hydrogen Atomic Number1 Number of protons1 Number of neutrons0 Number of electrons1 Mass number1

12. Oxygen Atomic Number8 Number of protons8 Number of neutrons8 Number of electrons8 Mass number16

13. Nitrogen Atomic Number7 Number of protons7 Number of neutrons7 Number of electrons7 Mass number14

14. Single/double bonds One shared pair of electrons = 1 single bond Two shared pairs of electrons = 1 double bond

15. Can you complete the table below? Biological MoleculeElements Carbohydrates Lipids Proteins Nucleic acids C, H and O C, H, O, N and S C, H, O, N and P carbon hydrogen oxygen sulphur phosphorus nitrogen

16. Hydrogen bonds Form when a slightly negatively charged part of a molecules comes close to a slightly positively charged hydrogen atom in the same (or another) molecule. Not strong, often described as interactions. Gives large molecules a particular shape which can be important for its function.

17. Condensation Reaction Molecule of water is removed when joined together.

19. Hydrolysis Water is added to break a bond.

21. Can you show the bonding in a water molecule? H O H

22. Can you show the bonding in methane? CH 4

23. Learning Outcomes Spec Ref: 2.1.2 (b) the concept of monomers and polymers and the importance of condensation and hydrolysis reactions in a range of biological molecules (c) the chemical elements that make up biological molecules ALL: Identify the major molecules that make up the human body and the elements they are made from. MOST: Describe the types of bonding that occur and how elements are structure for this to occur SOME: Use key terminology to describe the types of bonding that occur within the major molecules found in the human body.