This document provides an overview of basic chemistry concepts and biological molecules important for cellular structure and function. It discusses the atomic nature of matter and how atoms bond via ionic and covalent bonds. The four main biomolecules - carbohydrates, lipids, proteins, and nucleic acids - are introduced along with their monomers, polymers, and roles. Key cellular structures like the plasma membrane and differences between prokaryotic and eukaryotic cells are also summarized.

1. Lecture 1b Basic Chemistry Biological Molecules Introduction to Cells

2. Basic Chemistry Atomic theory All matter is made of atoms Molecules are atoms bonded together Not all atoms can bind; depends on their nature Types of bonds Ionic - electrons ‘donated’, creating charge Covalent - electrons shared H bonds

3. Basic Chemistry Bonds can be strong or weak Chemicals form different shapes and the shape influences the activity of the chemical Chemical reactions are the basis for most life processes

4. Chemical bonds Ionic bond

5. Covalent Bond

6. WATER Water has polarity Leads to H bonds

7. Water Water is a solvent Dissolves ionic substances and other polar nonionic substances

8. Water Cohesion Water clings to itself Surface tension Adhesion Water clings to other stuff too How it gets in everywhere

9. Water High heat capacity T of water rises and falls slowly How organisms are able to live in a changing environment High heat of vaporization Has to be really hot to break H bonds and turn to steam

10. Water Ice is less dense than liquid water Allows aquatic organisms to live underneath ice because it is on the surface

11. Carbon Because C forms 4 bonds, it is very versatile C chains are the basis of organic molecules (molecules containing C and H) Organic molecules are divided into 4 groups: Carbohydrates, Lipids, Proteins, Nucleic Acids Most are made up of polymers of different types of monomers

12. Carbohydrates Polymers of saccharides (sugars) Energy use Glucose Energy storage Starch in plants; glycogen in animals Structure Cellulose in plants; chitin

13. Lipids NOT soluble in water Fatty acid tails (usually 3) keep from dissolving Fats and oils; primary energy storage Fatty acid tails come in three varieties: Unsaturated, saturated, and trans

14. Lipids Not all lipids are bad! Phospholipids Have polar heads (water soluble); but non-polar tails (not soluble) This makes them arrange themselves in a bilayer These create the membranes of cells

15. Proteins Important to structure and function of cells Support Metabolism Transport Defense Regulation Motion

16. Proteins Amino acids are the building blocks of proteins There are 20 amino acids- combine in different ways to form thousands of different proteins The ‘chain’ of amino acids determines its shape, and therefore its function

17. Proteins Function of protein is determined by its shape There are 4 levels of structure: Primary: the sequence of aa Secondary: alpha helix, pleated sheet- formed by H bonds between aa Tertiary: the globular shape Quaternary: more than one

18. Nucleic Acids DNA and RNA are the nucleic acids in cells Nucleotides are the monomers DNA stores genetic info RNA takes genetic info to site of protein synthesis

19. DNA Each nucleotide in DNA contains one of 4 different bases: adenine, guanine, cytosine, thymine G always bonds to C; A always bonds to T in double helix structure Very important to replication Every 3 bases stands for one amino acid So, if you know sequence of gene, you know sequence of protein

20. RNA RNA is single stranded The complementary pairs allow information to be passed to RNA from DNA; protein synthesis actually occurs from RNA

21. Nucleic Acids to Proteins Very small changes in a gene can potentially result in very large changes in protein Ex. Sickle cell: one aa difference

22. Cells! Why are cells small? Surface to volume ratio- gives adequate surface area for exchange of chemicals All cells have an outer plasma membrane , which encloses the cytoplasm

23. Cells Two main types of cells: prokaryotic and eukaryotic Prokaryotes do not have a membrane bound nucleus, eukaryotes do Bacteria are prokaryotes Extremely successful, widespread and necessary

24. Prokaryotic structure The membrane is surrounded by cell wall and sometimes capsule DNA of bacterium is in a region called the nucleoid Ribosomes produce proteins Appendages include flagella, fimbriae, and conjugation pilli

25. Bacteria Fun fact: bacteria can smell!