1. Chemistry of Cells

5. Objectives
Describe the distinguishing characteristics of carbohydrates
Describe the important biological functions of polysaccharides
Explain what distinguishes lipids from other classes of biological macromolecules
Describe the unique properties, building blocks and biological roles of fats, phospholipids and steroids
Distinguish proteins from the other classes of macromolecules

6. Objectives Cont. List the biological functions which proteins perform
Explain what determines protein conformation and why it is important
Define denaturation and explain how proteins may be denatured
Describe the characteristics that distinguish nucleic acids from the other classes of macromolecules
Summarize the functions of nucleic acids

7. Objectives Cont.
Briefly describe the three-dimensional structure of DNA
Evaluate the importance of energy to living things
Relate energy and chemical reactions
Describe the role of enzymes in chemical reactions
Identify the effect of enzymes on food molecules

8. MacroMolecules Macro = large
Molecules = 2 or more atoms covalently bonded
Usually referred to as polymers
Like a chain
Made from several repeating subunits
The repeated subunits are called monomers
Like links in a chain
3 of the 4 macromolecules are polymers of monomers

9. Making or Breaking Polymers
The chemical mechanisms that cells use to make and break polymers are similar for all classes of macromolecules.

10. Making Polymers
Monomers are connected by covalent bonds via a condensation reaction or dehydration reaction.
One monomer provides
a hydroxyl group and
the other provides a
hydrogen and together
these form water.
This process requires
energy and is aided
by enzymes.

11. Breaking Down Polymers
The covalent bonds connecting monomers in a polymer are disassembled by hydrolysis.
In hydrolysis as the covalent bond is broken a hydrogen atom and hydroxyl group from a split water molecule attaches where the covalent bond used to be.
Hydrolysis reactions
dominate the
digestive process,
guided by specific
enzymes.

12. There are four of them.
Carbohydrates
Lipids
Proteins
Nucleic acids
☺ For each of these you will be expected to identify, describe, and differentiate between all four macromolecules.
☺You will also be expected to describe the biological importance of each macromolecule

13. Function of Carbohydrates
Sugars, the smallest carbohydrates, serve as fuel and carbon sources
Polysaccharides, the polymers of sugars, have storage and structural roles

14. Structure of Carbohydrates
Monosaccharides generally have molecular formulas containing C,H and O in a 1:2:1 ratio.
For example, glucose has the formula C6H12O6.
Most names for sugars end in -ose.
Monosaccharides are also classified by the number of carbons in the backbone.

15. Monosaccharides, particularly glucose, are a major fuel for cellular work.
They are also building blocks for of other monomers, including those of amino acids (protein) and fatty acids (lipids).
While often drawn as a linear skeleton, in aqueous solutions monosaccharides form rings.

22. 2. Polysaccharides, the polymers of
sugars, have storage and structural roles
Polysaccharides are polymers of hundreds to thousands of monosaccharides joined together (What is a polymer?)
One function of polysaccharides is energy storage
it is hydrolyzed as needed.
Other polysaccharides serve as building materials for the cell or whole organism.

23. Starch is a storage polysaccharide composed entirely of glucose monomers
Great big chain of glucose molecules
What would this look like? (Draw it.)

25. Biological Uses of Polysaccharides
Plants store starch within plastids, including chloroplasts.
Plants can store surplus glucose in starch and withdraw it when needed for energy or carbon.
Animals that feed on plants, especially parts rich in starch, can also access this starch to support their own metabolism.
Hey, this sounds like an objective!