Transcript 2.3 Carbon-Based Molecules

2.3 Carbon-Based Molecules
KEY CONCEPT
Carbon-based molecules are the basis of life.
2.3 Carbon-Based Molecules
• Carbon atoms are considered the building blocks of life
because they :
1. Are the basis of most molecules in living things
(Structure)
2. Carry out most processes that keep organisms alive
(Function)
.
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Molecules that contain carbon are called
Organic compounds.
There are over 2 million known organic
compounds
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Why is Carbon so special?
• Carbon has four valence electrons.
• It .can forms covalent bonds with up to four
other atoms
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Carbon Molecules
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• Structural formula
• Molecular Formula
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Carbon-based molecules have three general types of
structures
• straight chain
• branched chain
• ring
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• Many carbon-based molecules are made of many
small subunits bonded together.
– Smaller individual molecule are called Monomers
– Larger molecules made when monomers bond are
called Polymers.
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Dehydration Synthesis – is the reaction that causes
monomers to jin together to make polymers.
• Animation
Dehydration synthesis means – making by removing water
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Dehydration Synthesis
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Hydrolysis – Break apart a polymer to the smaller
monomers that joined to form it by adding water
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Molecules that contain CARBON atoms are
called organic compounds.
Four major groups of organic compounds
in living things:
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids
Where do we get these?
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Carbohydrates molecules are made of
Carbon (C), Hydrogen (H), and Oxygen (O) atoms
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Uses in Living Things
• 1. “Quick” Energy
• 2. Builds body structures
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1. Monosaccharide: one small single molecule
•
1. Glucose – made in photosynthesis; blood sugar
2. Galactose – Component of milk sugar
3. Fructose - fruit sugar
4. Deoxyribose and Ribose – in nucleic acids
glucose
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2. Disaccharide – 2 monosaccharides joined together
1. Sucrose – table sugar (glucose + fructose)
2. Lactose – milk sugar (glucose + galactose)
glucose
fructose
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3. Polysaccharides - many monosaccharides joined
together
1. Starch – glucose storage in plants (bread, taters)
2. Glycogen – glucose storage in animals
3. Cellulose – forms plant cell walls
4. Chitin – forms insect exoskeletons and
fungus cell walls
glucose
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
glucose
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Carbohydrate molecules may have the same
monomers but they are joined together differently
.
Polymer (starch)
Starch is a polymer of
glucose monomers that
often has a branched
structure.
Polymer (cellulose)
monomer
Cellulose is a polymer
of glucose monomers
that has a straight, rigid
structure
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Chitin (C8H13O5N) n
•
Monomer
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LIPIDS
• Types of Atoms: C, H, O
• Uses of Lipids in Living Things:
1. Source of usable energy
2. Provide warmth and insulation
3. Component of cell membranes
4. Makes hormones
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Lipids share only a few Common Features
• 1. Nonpolar molecule
• 2. Hydrophobic – Don’t dissolve in water
• 3. No specific monomer found in all lipids.
MANY DO contain fatty acid molecules
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Categories of Fatty Acids
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• Dangers of Saturated Fats
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• If the Fatty Acid molecules have :
•
–.
Single
–.
bonds between C atoms –
Saturated Fats
• Double bonds between C atoms –
Unsaturated Fats
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• Fats and oils have different types of fatty acids.
– saturated fatty acids
– unsaturated fatty acidsbad
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• Lipids have several different functions.
– broken down as a source of energy
– make up cell membranes
– used to make hormones
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• Phospholipids make up all cell membranes.
– Polar phosphate “head”
– Nonpolar fatty acid “tails”
Phospholipid
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Proteins
• Types of Atoms: C, H, O, Phosphorus, Sulfur
• Enzymes
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• Proteins are polymers of amino acid monomers.
– Twenty different amino acids are used to build
proteins in organisms.
– Amino acids differ in side groups, or R groups.
– Amino acids are linked together through
dehydration synthesis to form peptide bonds
Amine group
Carboxyl group
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• Proteins are polymers of amino acid monomers.
– Amino acids are linked by peptide bonds which
form between an amino group and carboxyl group.
.
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• Proteins differ in the number and order of amino acids.
– Amino acids interact to give a protein its shape.
Hemoglobin
hydrogen bond
– Incorrect amino acids change a protein’s
structure and function.
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• 1. Albumin – protein in egg white
• 2. Amylase – breaks apart starch to glucose through
hydrolysis. Enzyme found in your saliva
• 3. Keratin – protein in hair, feathers and nails
• 4. Hemoglobin – in red blood cells, oxygen attaches to it
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Nucleic Acids
• Types of Atoms: C, H, O, N, P,
• 1. DNA
• 2. Ribonucleic Acid – RNA
• 1. Stores hereditary information (DNA)
• 2. Helps to make protein molecules (RNA)
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• Nucleic acids are polymers of monomers called
nucleotides.
– Nucleotides are made of a sugar, phosphate
group, and a nitrogen base.
A phosphate group
deoxyribose (sugar)
nitrogen-containing molecule,
called a base
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DNA
• Nitrogen containing base
• Adenine A - Thymine T
• Guanine G – Cytosine C
•
RNA
• Nitrogen containing bases
• Adenine A – Uracil U
• Guanine G - Cytosine C
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• Nucleic acids are polymers of monomers called
nucleotides.
• 1000’s of nucleotides join together to make a nucleic acid.
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• Nucleic acids are polymers of monomers called
nucleotides
– Nucleotides are made of a sugar, phosphate
• . group, and a nitrogen base.
– DNA stores genetic DNA
information.
– RNA builds proteins. RNA
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Bell Ringer
• What special atom do all organic compounds contain?
• What makes this atom special
• What are the 4 major organic compound types in living
things
• What are bigger molecules called? What are the smaller
molecules that join together to make big molecules
called?
• What atoms must be removed from monomers to make
polymers? What is this process called?
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• What special atom do all organic compounds
contain?CARBON
• What makes this atom special
• Has 4 valence electrons and forms 4 strong covalent bonds
• What are the 4 major organic compound types in living
things
• Lipids, Nucleic Acids, Proteins, Carbohydrates
• What are bigger molecules called? What are the smaller
molecules that join together to make big molecules called?
Polymers –biggies Monomers – little-ies
• What atoms must be removed from monomers to make
polymers? What is this process called?
• 2 Hydrogens 1 Oxygen Dehydration Synthesis
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BellRinger Activity
• Using either your memory, your notes or your homework
to answer the following questions
• What is the difference between a monosaccharide, a
disaccharide and a polysaccharide?
• What is the molecular formula for glucose?
• When two glucose molecules join they form maltose.
The process of joining these two molecules is known as
______________ _______________.
* What is the molecular formula for maltose?
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Bell Ringer
• What are the major categories of lipids?
• What molecule is found in many types of lipids?
• What is the difference between a saturated and
unsaturated fat? Which is better in your diet?
• Give two important uses of lipids