Transcript AIM: What are Macromolecules?

AIM: WHAT ARE BIOMOLECULES?
DO NOW :
DEFINE WHAT A MOLECULE IS AND
GIVE AN EXAMPLE OF ONE.
• Cells are made of biomolecules which are
build from smaller organic molecules containing
3 main chemical elements: carbon, oxygen, and
hydrogen (plus lots of other elements)
• An organic molecule is any molecule
containing Carbon (C) and Hydrogen (H)
elements combined with any other chemical
elements.
Examples : Glucose (C6H12O6 ) is organic, H2O is
not organic , CO2 (carbon dioxide) is not
organic.
Chemical reactions inside cells join together
small organic molecules (monomers/building
blocks) to form large molecules
(polymers/macromolecules/biomolecules) by a
process called dehydration synthesis.
The 4 main macromolecules in cells are
Carbohydrates, Lipids, Proteins, and Nucleic
Acids.
Carbohydrates
• Are made from simple organic molecules called
sugars
• Scientific name for sugar is saccharide.
• Major source of energy . Most organisms break
down glucose to release chemical energy from
it.
• Can provide structural support for some
organisms. Cell walls of plants are made
cellulose (carbohydrate). Shells of crabs and
lobsters are made of chitin (carbohydrate)
• Cell recognition -In complex organisms cells
recognize neighboring cells by carbohydrate
molecules on the cell membranes.
• One sugar molecule is called
monosaccharide , two sugar molecules linked
together form a disaccharide molecule. Three
or more sugar molecules linked together form
polysaccharide.
• All carbohydrates consist of C, H, and O
combined in a very specific ratio : 1:2:1
(Means that for every atom of Carbon there
are twice as many Hydrogen atoms and the
same number of Oxygen atoms)
Common monosaccharide – glucose (made by plants
during photosynthesis process)
Common disaccharides – sucrose (table sugar) and
lactose ( milk sugar that some people have intolerance
to)
Common polysaccharides :
• Starch found in plants and consists of hundreds of
glucose molecules bonded together. We obtain starch
from the foods we eat and break it down during
digestion into glucose molecules.
• Glycogen found in animals . Extra glucose molecules
are assembled together for storage in a form of a
glycogen molecules.
Identify the following as mono-,di-, or polysaccharides:
1.
3.
2.
Lipids
• Group includes fats, waxes, steroids, and
phospholipids
• Main function is to store energy( can do it more
efficiently than carbohydrates) and control
water movement (repel water)
• Consist of long chains of carbon atoms bound
to hydrogen atoms
• Built from simpler molecules of fatty acids and
Glycerol
• Examples of lipids are oils, butter, cholesterol,
ear wax.
Lipids are insoluble in water. What does this
tell you about some properties of those
molecules ?
Proteins
• Provide structure and support, enable
movement, aid in transportation , and assist
in chemical reactions
• Made of amino acids ( building blocks)
• All amino acids have N atoms together with C,
O, and H.
• The body needs 20 amino acids to build all the
proteins it needs.
• Most of the amino acids we obtain from the
food we eat when we digest proteins.
• The amino acids are linked together by peptide bonds
This is why proteins can be called polypeptides (if
they have more then two peptide bonds) or
dipeptides ( if they contain two bonds)
• Examples of proteins :
• Keratin (found in hair and nails)
• Hemoglobin ( found in our blood , helps transport
oxygen molecules)
Enzymes
• Large group of molecules which belongs to the protein group
• Major function is to increase the rate of chemical reactions.
• Called Catalysts (speed up reactions)
• Hold molecules close together and in correct orientation
speeding up their possibility of a chemical reaction .
Chemical Reactions
A reactant – the substance that is changed
A product – a new substance that is formed
Every chemical reaction requires a minimum amount of kinetic
energy . This amount of energy is called Activation Energy.
Chemical reactions can occur only when the activation energy is
available and the correct atoms are aligned.
Name the reactants and the product in this reaction.