ch 2 notes

16
Ch 2 Notes

Upload: hova

Post on 24-Feb-2016

45 views

Category:

Documents


0 download

DESCRIPTION

Ch 2 Notes. Molecules of Life. Four categories of molecules are unique to cells (called macromolecules ) Carbohydrates Lipids Proteins Nucleic acids Synthesis of macromolecules involves a dehydration reaction Breakdown of macromolecules involves a hydrolysis reaction. Carbohydrates. - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Ch 2 Notes

Ch 2 Notes

Page 2: Ch 2 Notes

Molecules of Life

• Four categories of molecules are unique to cells (called macromolecules)– Carbohydrates– Lipids– Proteins– Nucleic acids

• Synthesis of macromolecules involves a dehydration reaction

• Breakdown of macromolecules involves a hydrolysis reaction

Page 3: Ch 2 Notes

Carbohydrates

• The ratio of hydrogen (H) atoms to oxygen (O) atoms is approximately 2:1

• Function for quick, short-term cellular energy

Page 4: Ch 2 Notes

Carbohydrates

• Simple carbohydrates– Low number of carbon atoms (3-7)– Monosaccharides• Glucose • Fructose – found in fruits• Galactose – found in milk

– Disaccharides• Two monosaccharides joined together• Sucrose (table sugar) – formed when glucose joins with

fructose• Lactose – formed when glucose joins with galactose

Page 5: Ch 2 Notes

Carbohydrates

• Complex carbohydrates– Contain many glucose (monosaccharide) units– Starch – storage form of glucose in plants– Glycogen – storage form of glucose in animals– Cellulose• Found in plant cell walls• Humans are unable to digest (passes through digestive

tract as fiber)

Page 6: Ch 2 Notes

Lipids

• Contain more energy per gram than other biological molecules

• Some function as long-term energy storage in organisms

• Do not dissolve in water • Consist mostly of carbon and hydrogen atoms;

contain few oxygen atoms

Page 7: Ch 2 Notes

Lipids

• Fats and Oils– Formed when one glycerol molecule reacts with

three fatty acid molecules– Fats• Usually of animal origin• Solid at room temperature• Used for long-term energy storage, insulation, and

cushioning– Oils• Usually of plant origin• Liquid at room temperature

Page 8: Ch 2 Notes

Lipids– Emulsification – cause fats to mix with water– Saturated and Unsaturated Fatty Acids• Fatty acid (carbon-hydrogen chain ending with an acidic

group –COOH• Saturated fatty acids have only single covalent bonds;

lard and butter are examples• Unsaturated fatty acids have double bonds between

carbon atoms wherever fewer than two hydrogens are bonded to a carbon atom; vegetable oils

Page 9: Ch 2 Notes

Lipids

• Steroids– Structure consists of four fused carbon rings with

attached functional groups– Cholesterol• Structural component of animal cell membrane• Precursor of several other steroids

Page 10: Ch 2 Notes
Page 11: Ch 2 Notes

Proteins

• Function of proteins– Fibrous structural proteins– Hormones– Muscle contraction– Transport– Protection– Enzymes

Page 12: Ch 2 Notes

Proteins

• Structure of proteins– Made of amino acid subunits• Amino group• Acid group• R (Remainder) group – differentiates amino acids

– Dipeptide – two amino acids joined together– Polypeptide – three or more amino acids joined

together

Page 13: Ch 2 Notes
Page 14: Ch 2 Notes

Nucleic Acids

• Huge macromolecules composed of nucleotides

• Nucleotides composed of 3 subunit molecules:– A phosphate– A pentose sugar– A nitrogen-containing base

• Two classes of nucleic acids– DNA– RNA

Page 15: Ch 2 Notes

Nucleic Acids

• Two classes of nucleic acids– DNA• Make up genes• Contain pentose sugar deoxyribose• Nitrogen-containing bases

– Adenine (A)– Thymine (T)– Guanine (G)– Cytosine (C)

• Usually double stranded

Page 16: Ch 2 Notes

Nucleic Acids

– RNA• Intermediary in process of protein synthesis• Contain pentose sugar ribose• The nitrogen-containing base uracil (U) replaces

thymine• Usually single stranded