CHAPTER 5 THE STRUCTURE AND FUNCTION OF MACROMOLECULES

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CHAPTER 5 THE STRUCTURE AND FUNCTION OF
MACROMOLECULES
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Chapter 5 Objectives

• After reading this chapter, completing the study
  guide, and participating in class, you should be
  able to
• List the levels of biological organization from
  subatomic particles through macromolecules
• Describe the distinguishing characteristics of
  carbohydrates and explain their classification

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1. Describe the important biological functions of
   polysaccharides
2. Explain what distinguishes lipids from other
   classes of biological macromolecules
3. Describe the unique properties, building blocks
   and biological roles of fats, phospholipids and
   steroids
4. Distinguish proteins from the other classes of
   macromolecules and list the biological functions
   which members of this class perform
5. List and be able to recognize the four major
   components of a typical amino acid and explain
   how amino acids may be grouped according to the
   nature of their side chain

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1. Identify a peptide bond and describe how it is
   formed
2. Explain what determines protein conformation and
   why it is important
3. Name the four levels of protein structure and
   briefly describe from what aspect of protein
   structure each is derived
4. Define denaturation and explain how proteins may
   be denatured

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1. Describe the characteristics that distinguish
   nucleic acids from the other classes of
   macromolecules
2. Summarize the functions of nucleic acids
3. Juggle three flaming batons...just checking that
   you're still paying attention (smile!)
4. List the major components of a nucleotide and
   describe how these monomers are linked together
   to form a nucleic acid

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• 16. Distinguish between a pyrimidine and a purine
  and name those which occur in nucleic acids.
• Describe at least one function of nucleotides
  other than their inclusion in nucleic acids 
• Briefly describe the three-dimensional structure
  of DNA
•  

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Introduction

• Cells join smaller organic molecules together to
  form larger molecules.
• These larger molecules, macromolecules, may be
  composed of thousands of atoms and weigh over
  100,000 daltons.
• The four major classes of macromolecules are
  carbohydrates, lipids, proteins, and nucleic
  acids.

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Polymer Key Principles

• 1. Most macromolecules are polymers
• An immense variety of polymers can be built from
  a small set of monomers
• Pgs. 58-60

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1. Most macromolecules are polymers

• Three of the four classes of macromolecules form
  chainlike molecules called polymers (greek poly
  many, mer parts).
• Polymers consist of many similar or identical
  building blocks linked by covalent bonds.
• The repeated units are small molecules called
  monomers (mono one).
• Some monomers have other functions of their own.

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Making or Breaking Polymers

• The chemical mechanisms that cells use to make
  and break polymers are similar for all classes of
  macromolecules.
• See figure 5.2, pg 59

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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.

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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.

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2. An immense variety of polymers can be built
from a small set of monomers

• Each cell has thousands of different
  macromolecules.
• These molecules vary among cells of the same
  individual, even more among unrelated individuals
  of a species, and are even greater between
  species.
• This diversity comes from various combinations of
  the 40-50 common monomers and other rarer ones.
• These monomers can be connected in various
  combinations like the 26 letters in the alphabet
  can be used to create a great diversity of words.
• Biological molecules are even more diverse.

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Objective 1

• List the levels of biological organization from
  subatomic particles through macromolecules