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Chapter 11 The Chemistry of Living Things

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Section 1 Elements in Living Things

Section 2 Compounds of Living Things

Concept Map


Section 1 Elements in Living ThingsChapter 11

Bellringer

Make a list of materials that contain carbon.

Write your list in your Science Journal.



What You Will Learn

• Carbon is a unique element because it can form long chains as well as bond with other elements.

• Living organisms are made of molecules that consist largely of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.



The Bonding of Carbon Atoms

• Carbon has a central role in the chemistry of living organisms because it can form long chains with other carbon atoms and because it can bond with atoms of other elements to form many different compounds.

• Each carbon atom has four valence electrons. So, each carbon atom can make a total of four bonds.



The Bonding of Carbon Atoms, continued

• Carbon-based molecules can come in many different shapes, or backbones.

• Three kinds of carbon backbones are the straight chain, the branched chain, and the ring.


The Chemistry of Living ThingsChapter 11




• A covalently bonded compound that contains carbon is called an organic compound.

• Atoms of carbon most often form four separate single bonds with other atoms.




• A single bond is a covalent bond made up of one pair of shared electrons.

• Carbon atoms can also form two covalent bonds, called a double bond, and three bonds, called a triple bond.



Organic Compound



Other Elements in Living Organisms

• Living organisms are made of compounds that are composed mostly of the elements carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.

• Today, many kinds of organic compounds are manufactured, such as vitamins, hormones, and other supplements.


Section 2 Compounds of Living ThingsChapter 11

Bellringer

Make a list of foods that contain carbohydrates. Then, use your list to describe what carbohydrates are made of.

Write your responses in your Science Journal.



What You Will Learn

• Living organisms depend on large compounds, such as carbohydrates, lipids, proteins, and nucleic acids.

• Living organisms depend on many smaller compounds such as water and salt.



Carbohydrates

• Biochemicals are large organic compounds that living things make and use.

• Biochemicals that are composed of sugar molecules bonded together are called carbohydrates.



Carbohydrates, continued

• A complex carbohydrate can be a long-chain polymer. A polymer is a chain of repeating units.

• Complex carbohydrates may be made up of a chain of thousands of simple sugars.

• Living things use carbohydrates mostly as a source of energy.



Lipids

• Lipids are biochemicals that do not dissolve in water. Fats, oils, and waxes are lipids.

• Lipids usually have very long chains of carbon atoms.

• Lipids store energy and make up cell membranes.



Types of Lipids



Proteins

• Proteins are biochemicals that are made of much smaller molecules called amino acids. Most proteins are made of very long chains of amino acids.

• There are 20 different amino acids that can combine in any order to form proteins in living things.



Proteins, continued

• Protein is needed to build and repair body structures and to regulate processes in the body.

• Hemoglobin is an important protein found in red blood cells that helps carry oxygen to all of the cells of the body.



Proteins



Nucleic Acids

• The largest molecules made by living organisms are nucleic acids. Nucleic acids are biochemicals made up of nucleotides.

• Nucleic acids are sometimes called the blueprints of life because they carry all of the information needed for a cell to make all of its proteins.



Nucleic Acids, continued

• There are two kinds of nucleic acids: DNA and RNA.

• DNA is the genetic material of a cell.

• The four kinds of nucleotides found in DNA are Adenine, Thymine, Guanine, and Cytosine.



Other Important Compounds

• No living thing on Earth can survive without water. Water regulates temperature, helps transport substances, and provides lubrication.

• Salt plays an important role in nerve cells by helping conduct signals throughout the body.


Chapter 11 The Chemistry of Living Things

Use the terms below to complete the concept map on the next slide.

organic compounds

carbohydrates

lipids

proteins

nucleic acids

Concept Map



Concept Map

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