1. Chemistry of Cells
Section 2-3

2. Carbon Compounds are found in Living Things
Most matter in your body that is not water is organic compounds.
Organic compounds contain carbon – carbon atoms are covalently bonded to H, O and C.
Four Principle Classes of Organic Compounds
Carbohydrates
Lipids
Proteins
Nucleic acids

3. Carbohydrates
Organic compounds composed of C, H, and O in the ratio of 1:2:1.
Key source of energy
Found in most foods – fruits, vegetables, grains
Building blocks of Carbohydrates – sugars
Single sugars = monosaccharides
Ex.: glucose, fructose
Glucose – major source of energy

6. Ex.: sucrose – common table sugar –
Disaccharides – double sugars formed when two monosaccharides are joined
Ex.: sucrose – common table sugar –
combination of glucose and fructose
Polysaccharides – chains of three or more monosaccharides joined (Ex. Starch; Figure 2-8)
Polysaccharides are examples of macromolecules
In organisms, polysaccharides function as storehouses of energy contained in sugar
Starch and glycogen – glucose molecules
Cellulose – polysaccharides providing structural support for plants

10. Lipids Nonpolar molecules that ARE NOT soluble in water
Four types – fats, phospholipids, steroids, & waxes
Important part of structure & functioning of cell membranes
Phospholipids – make up the lipid bilayer of cell membrane
Steroids – (cholesterol) in animal cell membranes
Pigments – chlorophyll – light absorbing compounds

13. Fats Lipids that store energy (Figure 2-9)
Typical fat – contains 3 fatty acids bonded to a glycerol molecule
Glycerol – alcohol with 3 C atoms
Fatty acid – long chain of C with H bonded to them. Either one or two H to each C.
Saturated Fatty Acid
All C to 2 H atoms (end has 3 H) – all single bonds
Straight molecules
Most animal fats – solid at room temperature

14. Unsaturated Fatty Acid
Some C atoms linked to only one H atom – double bonds present – these produce kinks in molecules
Most plant and fish oils
Generally liquid at room temperature
Hydrogenated vegetable oil – contains naturally unsaturated fatty acids that have been artificially saturated – solid at room temperature – margarine & shortening

17. Proteins Chain of amino acids
Amino acids – building blocks for proteins – 20 different found in proteins
Each amino acid – different chemical structure
Some polar
Some nonpolar
Some charged
Some uncharged
Proteins fold into compact shapes determined by how amino acids in the “arms” of protein interact with water and one another

18. Enzymes – promote chemical reactions
Some proteins – structural – collagen – skin, ligaments, tendons, bone, hair, muscles, blood clots
Antibodies – help body defend against infection
Specialized proteins in body – ex. Proteins to make muscles contract
Blood – hemoglobin – carries O2 from lungs to body tissues

21. Nucleic Acids Contained in ALL cells
Nucleic acid – long chain of smaller molecules called nucleotides
Nucleotide – made of sugar, nitrogenous base, and a phosphate
Two types of Nucleic Acids
DNA – deoxyribonucleic acid
RNA – ribonucleic acid

22. DNA – Deoxyribonucleic Acid
Made of 2 strands of nucleotides that spiral around each other
Held together by hydrogen bonds between bases
Chromosomes made of DNA
Carries hereditary information

24. RNA – Ribonucleic Acid Single strand of nucleotides
Plays several roles in cell function
ex. Manufacturing of proteins

25. ATP Adenosine Triphosphate Carries energy in cells
Single nucleotide with two extra phosphate groups
MAIN ENERGY CURRENCY
When food molecules are broken down inside cells, some energy temporarily stored in ATP
Cells need steady supply of ATP to function