1. Biology: Life on Earth (Audesirk)
Chapter 2
Biology: Life on Earth (Audesirk)
Biological Molecules
Biological MoleculesChapter 3

4. Copyright Pearson Prentice Hall
Macromolecules
Macromolecule
molecule that is synthesized by living organisms, formed by building blocks named Monomers
Macromolecule = Polymer = Many Monomers
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5. Many macromolecules consist of polymers
A polymer is a large molecule built up from smaller building block molecules
Monomers (a.k.a., subunits) are the building block molecules
Polymers / Monomers

6. Carbohydrates 1st of 4 Classes
Carbohydrates serve as quick energy and short-term energy storage.
They play a structural role in plants, bacteria, and insects.
Monomers of carbohydrates are the monosaccharides:
glucose
fructose
galactose
Carbohydrates also play a role in cell-to-cell recognition. Carbohydrates have the atomic grouping H-C-OH, in which the ratio of H to O atoms is close to 2:1.

7. Memorize this structure
Ring Forms (Glucose)
Memorize this structure

8. carbon and energy (glucose) storage molecules
Larger polysaccharides are made from linking many glucose molecules together through condensation synthesis.
Examples of polysaccharides:
Starch
glycogen
cellulose
carbon and energy (glucose) storage molecules
Starch and glycogen are the storage forms of glucose in plants and animals, respectively. Cellulose is found in plant cell walls. In cellulose, the glucose chains are joined differently than in glycogen or starch; human digestive enzymes cannot break these linkages in cellulose (thus humans derive no energy from eating cellulose).
These are all Glucose
These are all Glucose

9. Biology: Life on Earth (Audesirk)
Cellulose
Chapter 3 OH O
CH2OH HO OH O
CH2OH HO
Note that the bonds connecting the glucoses in cellulose are alternating up and down, unlike in starch. The chains are crosslinked with hydrogen bonds. OH O
CH2OH HO O
CH2OH OH O
CH2OH HO O
CH2OH OH O
CH2OH
Biological MoleculesChapter 3

10. Cellulose is a Structural polysaccharide

11. Biology: Life on Earth (Audesirk)
Chitin
Like cellulose, but with nitrogen
Arthropods’ exoskeletons
Strong, very resistant to digestion
The hard outer covering of arthropods, like beetles, is composed mostly of chitin. It is very resistant to degradation and digestion. Only a few animals can digest chitin, among them, some insectivorous birds.
Biological MoleculesChapter 3

12. Lipids

13. Lipids
Lipids serve as long-term energy stores in cells, form membranes, and serve as hormones and insulation.
Lipids do not dissolve in water.
Fats and oils are formed from a glycerol molecule and three fatty acid molecules.

14. In animals such as ourselves, fats are stored in adipose cells
Fats are also important as cushions for body organs and as an insulating layer beneath skin
Fat Functions

15. Fats function in biological systems as energy storage molecules, particular for organisms or stages of life cycles in which mobility and energy storage are simultaneously necessary, e.g., nuts, seeds, and animals
Fat versus Oil
Fat
Fully saturated
Solid at room temp.
> high-temp. stability
Oil
Unsaturated
Liquid at room temp.
> low-temp. fluidity

16. Beef Fat & Linseed Oil
Triglycerides!!!

17. Phospholipids
Polar group!!!!

18. Phospholipid Bilayer

19. Steroids
Cholesterol
Estradiol
Testosterone

20. Proteins - 3rd of 4 Classes
Biology: Life on Earth (Audesirk)
Proteins - 3rd of 4 Classes
Proteins are amino acid polymers
Many roles in cell
Enzyme speeds up reactions
Hormone
Structure
Composed of many amino acid units.
A polymer of amino acids.
"Polymer" is a generic term for a large molecule consisting of many repeating units connected together.
Other examples of polymers are cellulose and starch, both of which are glucose polymers.
Many roles in cell.
Enzymes.
Biological catalysts that control all the biochemical reactions in metabolism.
Hormones.
Chemicals that are released into the blood by one cell and are designed to influence another cell some distance away.
Structure.
The framework of many subcellular structures are based on a protein grid work.
Biological MoleculesChapter 3

21. Same Materials, Many Products
20 amino acids are the building blocks used to build a great variety of proteins

22. Generic Amino Acid: 20 Different “R” Groups
Biology: Life on Earth (Audesirk)
Generic Amino Acid: 20 Different “R” Groups
Chapter 3
Amine Group    
Carboxylic Acid Group R
See p 34
“Alpha” Carbon
The “R” Group Placeholder
Biological MoleculesChapter 3

23. Structural Proteins
Chapter 3
Hair
Horn
Spiderweb

24. Hair Chapter 3 Straight Hair Naturally Curly Hair Permanent Wave
| S | S |
Straight Hair
Naturally Curly Hair
Permanent Wave
| S | S |
Fiber type protein

25. Curling of Hair Straight Hair Naturally Curly Hair Permanent Wave
Chapter 3
Straight Hair
| S | S |
Naturally Curly Hair
| S | S |
Permanent Wave
| S | S |
| S | S |
| S | S |

26. Nucleic Acids: 4th of 4 Classes
Biology: Life on Earth (Audesirk)
Nucleic Acids: 4th of 4 Classes
Nucleic acids are nucleotide polymers
Genetics & cell control
DNA: Genes
RNA: Manages protein synthesis
ATP : ENERGY CARRIERS
Nucleotide polymers.
Nucleotide subunits connected end to end.
Genetics & cell control.
Sequence of nucleotides determines genetic information.
Also determines the nature of proteins produced when gene is expressed.
DNA: Genes.
RNA: Manages synthesis.
DNA contains genetic information.
RNA carries out instructions in genes.
Biological MoleculesChapter 3

28. Nucleotide Structure: 3 Parts
Biology: Life on Earth (Audesirk)
Nucleotide Structure: 3 Parts
Phosphate Group
This is a model of the molecule described on the previous slide.
See p37.
Nitrogenous Base (1 of 5)
Pentose Sugar
Biological MoleculesChapter 3

29. Copyright Pearson Prentice Hall
2–3
Large carbohydrate molecules such as starch are known as
lipids.
monosaccharides.
proteins.
polysaccharides.
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30. Copyright Pearson Prentice Hall
2–3
Many lipids are formed from glycerol and
fatty acids.
monosaccharides.
amino acids.
nucleic acids.
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31. Copyright Pearson Prentice Hall
2–3
Proteins are among the most diverse macromolecules because
they contain both amino groups and carboxyl groups.
they can twist and fold into many different and complex structures.
they contain nitrogen as well as carbon, hydrogen, and oxygen.
their R groups can be either acidic or basic.
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32. Copyright Pearson Prentice Hall
2–3
Which of the following statements about cellulose is true?
Animals make it and use it to store energy.
Plants make it and use it to store energy.
Animals make it and use it as part of the skeleton.
Plants make it and use it to give structural support to cells.
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33. Copyright Pearson Prentice Hall
2–3
A major difference between polysaccharides and proteins is that
plants make polysaccharides, while animals make proteins.
proteins are made of monomers, while polysaccharides are not.
polysaccharides are made of monosaccharides, while proteins are made of amino acids.
proteins carry genetic information, while polysaccharides do not.
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