Section 2 Molecules of Life
Pg. 55
Carbohydrates
Organic compounds composed of carbon, hydrogen, and oxygen in a ratio of 1:2:1
Carbohydrates can exist as 1) monosaccharides (simple sugar) 2) disaccharides (double sugar) 3) polysaccharides (“many” sugars)
Glucose is a very important sugar to living things.Glucose,
hence carbohydrates, are the most important source of energy for our
cells.
Monosaccharides- simple sugarsGlucoseFructoseGalactose
They can be combined to form a disaccharide by a ? reaction.
CONDENSATION
Isomers- same formula but slightly different structure
glucose
C6H12O6
Polysaccharides & examplesComposed of three or more
monosaccharides especially glucose 1) glycogen 2) starch
Animals store glucose as glycogen.
Plants store glucose as starch.
Another large polysaccharide is cellulose
ProteinsCompounds made of carbon, hydrogen,
oxygen, and nitrogen
Proteins make up hair, skin, muscles, enzymes, and horns
Amino acids- the building block or subunit of proteinsThere are 20 amino acids and they are linked
together by peptide bonds to form proteins.
A ? reaction is the process that links them together.
CONDENSATION
A peptide bond forms between 2 amino acids…
The peptide bond forms between the C, H, N, O.
Happy Halloween!!!!
Amino acids are linked together to form a protein chain alanine arginine asparagine aspartic acid cysteine glutamic acid glutamine glycine histidine hydroxyproline isoleucine leucine lysine methionine phenylalanine proline serine threonine tryptophan tyrosine valine
Almost all of them end in ‘ine’
The chain then folds into various shapes.
The Structure of One Amino AcidEach amino acid has
a different “R” group. The “R” group gives different proteins different shapes and therefore different functions.
Enzymes are ProteinEnzymes are molecules that catalyze
reactions in living systems
They make reactions go faster by reducing activation energy
They lower activation energy by linking to a substrate and weakening the bonds within that substrate
Induced Fit Model (shows how enzymes work)
There are 3 basic steps of enzyme action:1) A substrate attaches to the active
site of an enzyme.2) The enzyme changes shape
weakening the bonds of the substrate.
3) The substrate turns into something different (products) and is released from the enzyme.
About enzymesThey may not work if the temperature or the pH is not right.
Enzymes are very specific for the reactions they control.
Without enzymes, reactions would go too slowly to support life processes.