Download The Significance of Carbon - Ms. Mosby`s Science Class

The Significance of Carbon Advanced
Douglas Wilkin, Ph.D.
Jean Brainard, Ph.D.
Say Thanks to the Authors
Click http://www.ck12.org/saythanks
(No sign in required)
To access a customizable version of this book, as well as other
interactive content, visit www.ck12.org
CK-12 Foundation is a non-profit organization with a mission to
reduce the cost of textbook materials for the K-12 market both in
the U.S. and worldwide. Using an open-source, collaborative, and
web-based compilation model, CK-12 pioneers and promotes the
creation and distribution of high-quality, adaptive online textbooks
that can be mixed, modified and printed (i.e., the FlexBook®
textbooks).
Copyright © 2016 CK-12 Foundation, www.ck12.org
The names “CK-12” and “CK12” and associated logos and the
terms “FlexBook®” and “FlexBook Platform®” (collectively
“CK-12 Marks”) are trademarks and service marks of CK-12
Foundation and are protected by federal, state, and international
laws.
Any form of reproduction of this book in any format or medium,
in whole or in sections must include the referral attribution link
http://www.ck12.org/saythanks (placed in a visible location) in
addition to the following terms.
Except as otherwise noted, all CK-12 Content (including CK-12
Curriculum Material) is made available to Users in accordance
with the Creative Commons Attribution-Non-Commercial 3.0
Unported (CC BY-NC 3.0) License (http://creativecommons.org/
licenses/by-nc/3.0/), as amended and updated by Creative Commons from time to time (the “CC License”), which is incorporated
herein by this reference.
Complete terms can be found at http://www.ck12.org/about/
terms-of-use.
Printed: August 19, 2016
AUTHORS
Douglas Wilkin, Ph.D.
Jean Brainard, Ph.D.
www.ck12.org
C HAPTER
•
•
•
•
•
Chapter 1. The Significance of Carbon - Advanced
1
The Significance of Carbon
- Advanced
Explain why carbon is essential to life on Earth.
Give examples of carbohydrates, lipids, proteins, and nucleic acids.
List the functions of carbohydrates, lipids, proteins, and nucleic acids.
Name the monomers of the four classes of organic compounds.
Compare condensation to hydrolysis reactions.
Carbon. Element number six. Right in the middle of the first row of the Periodic Table.
Carbon is the most important element to life. Without this element, life as we know it would not exist. As you will
see, carbon is the central element in compounds necessary for life-organic compounds. These compounds include
carbohydrates, lipids, proteins and nucleic acids.
The Significance of Carbon
Why is carbon so important to organisms? The answer lies with carbon’s unique properties. Carbon has an
exceptional ability to bind with a wide variety of other elements. Carbon makes four electrons available to form
covalent chemical bonds, allowing carbon atoms to form multiple stable bonds with other small atoms, including
hydrogen, oxygen, and nitrogen. Carbon atoms can also form stable bonds with other carbon atoms. In fact, a carbon
atom may form single, double, or even triple bonds with other carbon atoms. This allows carbon atoms to form a
tremendous variety of very large and complex molecules.
Organic Compounds
Carbon has the ability to form very long chains of interconnecting C-C bonds. This property allows carbon to form
the backbone of organic compounds, carbon-containing compounds, which are the basis of all known organic life.
1
www.ck12.org
Nearly 10 million carbon-containing organic compounds are known. Types of carbon compounds in organisms
include carbohydrates, lipids, proteins, and nucleic acids. The elements found in each type are listed in the table
below. Elements other than carbon and hydrogen usually occur within organic compounds in smaller groups of
elements called functional groups. When organic compounds react with other compounds, generally just the
functional groups are involved. Therefore, functional groups generally determine the nature and functions of organic
compounds.
When combined with oxygen and hydrogen, carbon can form many groups of important biological compounds
including carbohydrates (sugars), lignans (important in plants), chitins (the main component of the cell walls of
fungi, the exoskeletons of arthropods), alcohols, lipids and fats (triglycerides), and carotenoids (plant pigment). With
nitrogen it forms alkaloids, and with the addition of sulfur in addition to the nitrogen, it forms amino acids which
bind together to form proteins, antibiotics, and rubber products. With the addition of phosphorus to these other
elements, carbon forms nucleotides which bond into nucleic acids (DNA and RNA), and adenosine triphosphate
(ATP), which is known as the energy currency of the cell. The properties of all these organic molecules is related to
the composition of the elements that compose the molecule. Certain carbohydrates, proteins and nucleic acids are
known as macromolecules, as they are very large polymers made of individual monomers.
MEDIA
Click image to the left or use the URL below.
URL: https://www.ck12.org/flx/render/embeddedobject/183291
A Comparison
TABLE 1.1: Organic Compounds
2
Type of Compound
Carbohydrates
Elements It Contains
carbon, hydrogen, oxygen
Examples
Glucose, Starch, Glycogen
Lipids
carbon, hydrogen, oxygen
Cholesterol, Triglycerides
(fats), Phospholipids
Proteins
carbon, hydrogen, oxygen, nitrogen, sulfur
Enzymes, Antibodies
Nucleic Acids
carbon, hydrogen, oxygen, nitrogen, phosphorus
Deoxyribonucleic
acid
(DNA),
Ribonucleic
acid (RNA), Adenosine
Triphosphate (ATP)
Functions
provides energy to cells,
stores energy, forms body
structures
stores energy, forms cell
membranes, carries messages
helps cells keep their
shape/structure,
makes
up muscles, catalyzes
chemical
reactions,
carries messages and
materials
contains instructions for
proteins, passes instructions from parents to offspring, helps make proteins
www.ck12.org
Chapter 1. The Significance of Carbon - Advanced
The Table 1.1 lists the four types of organic compounds, the elements they contain, and examples and functions of
each type of compound.
Condensation and Hydrolysis
Condensation reactions are the chemical processes by which large organic compounds are synthesized from their
monomeric units. Hydrolysis reactions are the reverse process. During condensation reactions, water is produced
from the two molecules being bonded together; an H from one monomer is joined to an -OH from another molecule,
producing H2 O.
TABLE 1.2: title
Polymer
carbohydrates
lipids
proteins
nucleic acids
Monomer
monosaccharides
fatty acid
amino acids
nucleotides
Bond
glycosidic
ester*
peptide
phosphodiester**
• The ester linkage is between a glycerol molecule and fatty acid chain.
Summary
• Carbon’s exceptional ability to form bonds with other elements and with itself allows it to form a huge number
of large, complex molecules called organic molecules. These molecules make up organisms and carry out life
processes.
Review
1.
2.
3.
4.
5.
Why is carbon essential to all known life on Earth?
What is an organic compound? Give an example.
List the four main classes of organic compounds. What are examples of each?
What is condensation of hydrolysis?
What is a phosphodiester bond?
3