16
+ Chapters 2-4 Organic Molecules and Enzymes

+ Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

Embed Size (px)

Citation preview

Page 1: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+

Chapters 2-4

Organic Molecules and Enzymes

Page 2: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 2

2.3: Chemical Constituents of CellsOrganic v. Inorganic Molecules

Organic molecules • Contain C and H• Usually larger than inorganic molecules• Dissolve in water and organic liquids• Carbohydrates, proteins, lipids, and nucleic acids

Inorganic molecules • Generally do not contain C and H• Usually smaller than organic molecules• Usually dissociate in water, forming ions • Water, oxygen, carbon dioxide, and inorganic salts

Page 3: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 3

Inorganic Substances

Water • Most abundant compound in living material• Two-thirds of the weight of an adult human• Major component of all body fluids• Medium for most metabolic reactions• Important role in transporting chemicals in the body• Absorbs and transports heat

Oxygen (O2) • Used by organelles to release energy from nutrients in

order to drive cell’s metabolic activities• Necessary for survival

Page 4: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 4

Inorganic Substances

Carbon dioxide (CO2)• Waste product released during metabolic reactions• Must be removed from the body

Inorganic salts• Abundant in body fluids• Sources of necessary ions (Na+, Cl-, K+, Ca2+, etc.)• Play important roles in metabolism

Page 5: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 5

Organic SubstancesCarbohydrates

• Provide energy to cells

• Supply materials to build cell structures

• Water-soluble

• Contain C, H, and O

• Ratio of H to O close to 2:1 (C6H12O6)

• Monosaccharides – glucose, fructose• Disaccharides – sucrose, lactose• Polysaccharides – glycogen, cellulose

Page 6: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 6

Organic SubstancesCarbohydrates

O

(a) Monosaccharide

O O

O

(b) Disaccharide

O

O

O

(c) Polysaccharide

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 7: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 7

Organic SubstancesLipids• Soluble in organic solvents; insoluble in water• Fats (triglycerides)

• Used primarily for energy; most common lipid in the body

• Contain C, H, and O but less O than carbohydrates (C57H110O6)

• Building blocks are 1 glycerol and 3 fatty acids per molecule

• Saturated and unsaturated

Glycerolportion

Fatty acidportions

C

O

OH C C

H

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

C

O

OH C C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

C

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

C

O

OH C C

H

HH

C

H

H

C

H

H

C

H

H

C

H H

H

C

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 8: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+Neutral Fats

Triglycerides are formed from a fatty acid and glycerol (a sugar).

They are the most plentiful source of stored energy to our bodies. Two types:

Saturated- contain only single bonds Unsaturated- contains one(mono) or more(poly) double

bonds

Short, unsaturated fats are liquids (oils) and come from plants.

Long, saturated fats are solid (butter and meat fat) and come from animals.

Page 9: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 9

Organic SubstancesLipids

• Phospholipids

• Building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per molecule

• Hydrophilic and hydrophobic

• Major component of cell membranes

C

H

C

OH

CH

H

Glycerol portion

(a) A fat molecule

O

O

Fatty acid

Fatty acid

Fatty acid

H

C

H H

HH

C

H

H

N

O

O

Fatty acid

Fatty acid

O

POCH

O–

Phosphate portion

(b) A phospholipid molecule(the unshaded portion may vary)

H

CH

C

H

H

O

(c) Schematic representationof a phospholipid molecule

Water-insoluble (hydrophobic) “tail”

Water-soluble(hydrophilic)“head”

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 10: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 10

Organic Substances Lipids• Steroids

• Four connected rings of carbon• Widely distributed in the body, various

functions• Component of cell membrane• Used to synthesize hormones• Cholesterol

(a) General structure of a steroid

CC

CH2C

H2C C

H

(b) Cholesterol

C

CH CH2

CH2

CH

CH3

CH2

HC

HC

H2

H2

CH2 CHCH2

CH3

CH3

CH2

CH

CH3

HO C

CH3

CH2

CHC

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 11: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ Organic SubstancesProteins• Structural material• Energy source• Hormones• Receptors• Enzymes• Antibodies

• Protein building blocks are amino acids

• Amino acids held together with peptide bonds

11

H N

H

C

H

C

O

OH

S

C

H

HH

H N

H

C

H

C

O

OH

C

C

C

H

H

C H

C H

H

CH

CH

H N

H

C

H

C

O

OH

R

Page 12: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 12

Organic SubstancesNucleic Acids

• Carry genes• Encode amino acid sequences of proteins

• Building blocks are nucleotides

• DNA (deoxyribonucleic acid) – double polynucleotide• RNA (ribonucleic acid) – single polynucleotide

S

P B

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 13: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 13

4.3: Control of Metabolic Reactions• Enzymes

• Control rates of metabolic reactions

• Lower activation energy needed to start reactions

• Most are globular proteins with specific shapes

• Not consumed in chemical reactions

• Substrate specific

• Shape of active site determines substrate

Product molecule

Active site

(a) (b) (c)

Substrate molecules

Unalteredenzymemolecule

Enzyme-substratecomplex

Enzymemolecule

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 14: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 14

Enzyme Action

• Metabolic pathways• Series of enzyme-controlled reactions leading to

formation of a product• Each new substrate is the product of the

previous reaction

• Enzyme names commonly:• Reflect the substrate• Have the suffix – ase• Examples: sucrase, lactase, protease,

lipase

Substrate1

Enzyme A Substrate2

Enzyme B Substrate3

Enzyme C Substrate4

Enzyme DProduct

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 15: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 15

Factors That Alter Enzymes

• Factors that alter enzymes:• Heat• Radiation• Electricity• Chemicals• Changes in pH

Page 16: + Chapters 2-4 Organic Molecules and Enzymes. + 2 2.3: Chemical Constituents of Cells Organic v. Inorganic Molecules Organic molecules Contain C and H

+ 16Regulation of Metabolic Pathways

• Limited number of regulatory enzymes

• Negative feedback

Inhibition

Substrate1

Substrate2

Enzyme B Substrate3

Enzyme C Substrate4

Enzyme DProduct

Rate-limitingEnzyme A

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.