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IPS: Chemistry Review
Atom- basic unit of matter
Protons- positive charge, located in the nucleus
Neutrons- neutral, located in the nucleus
Electrons- negative charge, located outside the nucleus
IPS - Chemistry Review
Element- made of only one kind of atom. The number of protons determines what the element is called. In an atom, the number of protons and electrons are equal.
The same element will always have a set number of protons.
The number of neutrons may vary. These are called isotopes.
Electrons may also vary. These are called ions.
IPS - Chemistry Review
The ion is determined by the number of electrons in the outer shell or orbit. These are called valence electrons.
If an atom gains electrons, it becomes negatively charged.
If an atom loses electrons, it becomes positively charged.
IPS - Chemistry Review
Bonds- joining two or more atoms together
Ionic bond- formed by joining two ions together
Co-Valent bond-formed by the sharing of electrons
Example: NaCl
Example: C6H12O6
Macromolecules: Carbohydrates
S u g ar S ta rch C e llu lose
C arb oh yd ra tesm ad e o f C ,H ,O
The ratio of hydrogen to oxygen is 2:1
Carbohydrates
Sugar- manufactured in green plants. Provides the basic fuel for both plant and animal life.
Carbohydrates
M on osacch arid esM on o = on e
sacch arid e = su g ar
D isacch arid eD i = tw o
P o lysacch arid eP o ly = m an y
S u g ar
Carbohydrates
SugarMonosaccharides- simple sugars that may contain 5 or 6 carbon atoms. Examples: Glucose, Fructose, Galactose
These simple sugars are made in plant cells. They have the same empirical or molecular formula: C6 H12 O6.
Their structural formulas are different.
Monosaccharides
Monosaccharides
Glucose
Galactose
Fructose
MonosaccharidesStructural formulas allow you to visualize the molecule.
Notice, even though these molecules all have the same number of each atom, they look different.
Holt, Modern Biology
Disaccharides
Disaccharides Di = two
Two simple sugars form one molecule of a double sugar. One molecule of water is given off. This is called a dehydration synthesis reaction.
De = away
hydro = water
synthesis = put together
Disaccharides
Disaccharides
MaltoseSucrose Lactose
Disaccharides
Glucose + glucose maltose + water
C6H12O6 + C6H12O6 C12H22O11 + H2O
Dehydration synthesis- take away water to put a molecule together
Holt, Modern Biology
Disaccharides
Glucose + fructose sucrose + water
C6H12O6 + C6H12O6 C12H22O11 + H2O
Sucrose is common table sugar. It is found in sugar cane and sugar beets.
Dehydration synthesis- take away water to put a molecule together
Dehydration Synthesis
Prentice Hall, Biology
Disaccharides
Lactose is milk sugar, found in the milk of mammals.
C6H12O6 + C6H12O6 C12H22O11 + H2O
Glucose + galactose lactose + water
Dehydration synthesis- take away water to put a molecule together
Disaccharides
Can these reactions be reversed to break the disaccharide apart into two monosaccharides?
Yes. What must be added? What is the process called?
Water must be added. The process is called hydrolysis.
Hydro = water lysis = break apart or to break down
Disaccharides
This is an example of Hydrolysis. Water is added to maltose in order to break it down into two glucose molecules. Of course, enzymes would control this process.
Holt, Modern Biology
Hydrolysis
Prentice Hall, Biology
Polysaccharides
Polysaccharides are large molecules formed by joining monosaccharides.
Poly = many
Carbohydrates: Starch
Starch is a polysaccharide made up of glucose units in branched chains.
Each time a glucose molecule is added, one water molecule is removed (dehydration synthesis).
There may be 500 to many thousands of glucose molecules joined to form a starch molecule.
Examples: potatoes,corn, rice, wheat, and other grains.
Carbohydrates: Cellulose
Cellulose is a large polysaccharide made of chains of glucose molecules.
It may contain as many as 3,000 glucose molecules.
Cellulose forms a strong fibrous structure in plant cell walls. It gives the walls support.
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