CHAPTER 5 THE STRUCTURE AND FUNCTION OF MACROMOLECULES Copyright © 2002 Pearson Education, Inc.,...

CHAPTER 5 THE STRUCTURE AND FUNCTION OF MACROMOLECULES

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Section A: Polymer principles

1. Most macromolecules are polymers

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

• Cells join smaller organic molecules together to form larger molecules.

• These larger molecules, _______________, may be composed of thousands of atoms.

• The four major classes of macromolecules are: _____________, ________, __________, and ____________________.

Introduction


• Three of the four classes of macromolecules are also known as _________.

• Polymers consist of many similar or identical building blocks linked by covalent bonds.

• The repeated units are small molecules called ____________.

• Some monomers have other functions of their own.

1. Most macromolecules are polymers


• Monomers are connected by covalent bonds via a ____________ or ____________ reaction.

• This results in the ___________of a ______ molecule.

• This process requires _________.


Fig. 5.2a

• The bonds connecting monomers in a polymer are broken down by __________.

• Due to the _________ of a water molecule.

• Hydrolysis reactions dominate the __________ process.


Fig. 5.2b

• Each cell has thousands of different macromolecules.

• This diversity comes from various ___________ 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 ________ of words.

• Biological molecules are even more diverse.

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


• The simplest carbohydrates are ____________ or simple sugars.

• ________________, double sugars, consist of two monosaccharides joined by a condensation reaction.

• _______________ are polymers of monosaccharides.

Carbohydrates


• Monosaccharides generally have molecular formulas that are some multiple of _________.

• For example, ________ has the formula _________.

• Most names for sugars end in -_______.

1. Sugars, the smallest carbohydrates serve as a source of fuel and carbon sources


• Monosaccharides, particularly glucose, are a major _______ for _____________.

• Two monosaccharides can join to form a dissaccharide via dehydration.

• Sucrose, table sugar, is formed by joining glucose and fructose and is the major transport form of sugars in plants.


Fig. 5.5a

• Polysaccharides are polymers of hundreds to thousands of monosaccharides

• One function of polysaccharides is as an energy storage macromolecule that is hydrolyzed as needed.

• _______ in plants; ________ in humans

• Other polysaccharides serve as building materials for the cell or whole organism.

• __________ in plants; ________ in animals and fungi

2. Polysaccharides, the polymers of sugars, have storage and structural roles


• _________ are an exception among macromolecules because they are ______________.

• The unifying feature of lipids is that they all have little or _____________ for water.

• Lipids are highly diverse in form and function.

Lipids


• Although fats are not strictly polymers, they are large molecules assembled from smaller molecules by dehydration reactions.

• A ______ is constructed from two kinds of smaller molecules, ___________ and ___________.

1. Fats store large amounts of energy



Fig. 5.10a

• Glycerol consists of a __________________ with a hydroxyl group attached to each.

• A fatty acid consists of a carboxyl group attached to a ______________________, often 16 to 18 carbons long.

• The many C-H bonds in the long hydrocarbon skeleton make fats _______________.

• In an animal fat, three fatty acids are joined to glycerol, creating a __________________.


Fig. 5.10b

• The three fatty acids in a fat can be the same or different.

• Fatty acids may vary in length (number of carbons) and in the number and locations of double bonds.

• If there are no carbon-carbon double bonds, then the molecule is a _____________ - a hydrogen at every possible position.


Fig. 5.11a

• If there are one or more carbon-carbon double bonds, then the molecule is an _____________________ - formed by the removal of hydrogen atoms from the carbon skeleton.

• Saturated fatty acids are straight chains, but unsaturated fatty acids have a ____ wherever there is a double bond.


• The major function of fats is ________________.

• Fat also functions to __________ vital organs.

• A layer of fats can also function as ____________.

• This subcutaneous layer is especially thick in whales, seals, and most other marine mammals


• ________________ have two fatty acids attached to glycerol and a phosphate group at the third position.

2. Phospholipids are major components of ______________


• The interaction of phospholipids with water is complex.

• The fatty acid tails are hydrophobic, but the phosphate group and its attachments form a hydrophilic head.

• Steroids are lipids with a carbon skeleton consisting of four ________________.

• Cholesterol, an important steroid, is a component in animal cell membranes.

• Cholesterol is also the ___________ from which all other steroids are synthesized.

• Many of these other steroids are hormones, including the vertebrate __________________

3. Steroids include cholesterol and certain hormones


Fig. 5.14

• Proteins are instrumental in about everything that an organism does.

• These functions include ______________, _______, ___________ of other substances, intercellular _________, ___________, and _________ against foreign substances.

• Proteins make up the ___________ in a cell and regulate metabolism by selectively accelerating chemical reactions.

• Humans have tens of thousands of different proteins, each with their own structure and function.

Proteins


• Proteins are the most structurally _________ molecules known.

• Each type of protein has a complex three-dimensional shape or conformation.

• All protein polymers are constructed from the same set of ____ monomers, called ____________.

• Amino acid chains are also known as ___________.

• A protein consists of one or more polypeptides _______ and ________ into a specific conformation.


• Amino acids consist of four components attached to a ____________.

• These components include a hydrogen atom, a carboxyl group, an amino group, and a _________________ (or side chain).

• Differences in R groups produce the 20 different amino acids.

1. A polypeptide is a polymer of amino acids connected in a specific sequence


• A functional protein consists of one or more polypeptides that have been precisely twisted, folded, and coiled into a unique shape.

• It is the _______ of amino acids that determines what the three-dimensional conformation will be.

2. A protein’s function depends on its specific conformation


Fig. 5.17

• A protein’s specific _____________ determines its _________.

• In almost every case, the function depends on its ability to recognize and bind to some other molecule.

• The folding of a protein from a chain of amino acids occurs ___________ and goes through up to _______ levels of structure


• The _____________ of a protein is its unique sequence of amino acids.

• The precise primary structure of a protein is determined by inherited _______________.

• Even a slight change in primary structure can affect a protein’s conformation and ability to function.

• In individuals with __________ disease, abnormal hemoglobins, oxygen-carrying proteins, develop because of a single amino acid substitution.


• The ____________________ of a protein results from R group interactions along the polypeptide

• Typical shapes that develop from secondary structure are coils (an ______ ________) or folds (_____________ _________).


Fig. 5.20


• _______________ is determined by a variety of interactions among R groups and between R groups and the polypeptide backbone.

Fig. 5.22

• ___________________ results from the combining of two or more polypeptide subunits.

• __________ is a fibrous protein of three polypeptides that are supercoiled like a rope.

•This provides the structural strength for their role in connective tissue.

• __________ is a globular protein with two copies of two kinds of polypeptides.


Fig. 5.23

• Alterations in ___, ______ concentration, ______________, or other factors can unravel or _________ a protein.

• These forces disrupt bonds that maintain the protein’s shape.


• ______ and ______ are polymers of _______________.

• DNA is passed by the mechanisms of inheritance.

Nucleic Acids


• There are two types of nucleic acids: _____________ (RNA) and _________________________ (DNA).

• DNA provides direction for its own replication.

• DNA also directs RNA synthesis and, through RNA, controls protein synthesis.

1. Nucleic acids store and transmit hereditary information


• Nucleic acids are polymers of monomers called __________.

• Each nucleotide consists of three parts: a __________, a _______ ______, and a ____________________.

2. A nucleic acid strand is a polymer of nucleotides


• The pentose joined to the nitrogen base is ________ in nucleotides of RNA and ______________ in DNA.

• An RNA molecule is a single polynucleotide chain.

• DNA molecules have two polynucleotide strands that spiral around an imaginary axis to form a ______________

• The double helix was first proposed as the structure of DNA in 1953 by James Watson and Francis Crick.

3. Inheritance is based on replication of the DNA double helix


CHAPTER 5 THE STRUCTURE AND FUNCTION OF MACROMOLECULES Copyright © 2002 Pearson Education, Inc.,...

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