Biochemistry Notes
*Describe the structure and function of the major
organic molecules found in living systems.*
- Carbohydrates – Contain carbon, hydrogen, and
oxygen in a ratio of 2 to 1 hydrogen
to oxygen
Supply quick energy
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A. Monosaccharides – simple sugars
Examples glucose, fructose, &
galactose
Glucose C6H12O6
Isomers – same molecular
formula, different structural
formula
B.Disaccharides – Double sugars, compound sugars
Examples: sucrose, maltose, lactose
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Formed by dehydration synthesis
Polymers their monomers are monosaccharides
C. Polysaccharides – Complex sugars
Formed by dehydration synthesis
Broken down by hydrolysis
Examples: cellulose, glycogen
Polymers their monomers are monosaccharides
- Proteins – Contain carbon,
hydrogen,
oxygen, nitrogen
Compounds of growth and
repair
Polymers their monomers amino acids
Parts of an Amino Acid
I. amine group
II. carboxyl group
III. hydrogen
IV. carbon
V. radical
The radical makes one amino acid different from another
Proteins are formed by dehydration synthesis
OH is removed from the carboxyl group of one
amino acid and a
H is removed from the
amine group of another
amino acid
Amino acids are joined by peptide bonds
Enzymes– protein catalysts
They speed up chemical reactions but are not destroyed by the
reaction
- Lipids – contain carbon,
hydrogen,
oxygen
The hydrogen and oxygen are not in a
2 to 1 ratio.
Provide stored energy and help form
plasma membranes
Building blocks (monomers) are fatty acids
and glycerol
Examples: fats,
oils,
waxes,
- nucleic acids – Contain carbon,
hydrogen, oxygen,
nitrogen
Direct cell activities
Transfer information
Polymers their monomers are
nucleotides
Components of a Nucleotide
I. sugar
II. phosphate
III. nitrogen base
Two Types of Nucleic Acids
A. DNA– Deoxyribonucleic acid
The genetic material.
It composes chromosomes
B. RNA– Ribonucleic acid
Aids DNA in protein synthesis
Three Types of RNA
a. messenger RNA (mRNA) – Carries the directions for
making proteins
to the ribosomes
b. transfer RNA (tRNA) – Brings the amino acids
coded by mRNA
to the ribosomes
c. ribosomal RNA – Double checks the mRNA code
*Describe the relationship between an enzyme and its substrate molecules.*
enzymes are substrate specific.
They only act on one substance.
The enzyme and the substrate join at the active site of the enzyme.
Two Enzyme Models
- lock & key – substrate fits into the
active site of the enzyme without
modification
2. induced fit – The active site
must be modified for the
substrate to fit.
The products of one enzyme may be the substrates of other enzymes. Enzymes may combine substances or
break them apart. Enzymes reduce activation energy (energy needed to start a reaction) and lower the temperature at which reactions occur, thus protecting the cell.
*Investigate the properties and importance
of water and its significance for life:*
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Water is the universal solvent.
Most organic compounds in organisms are broken down by hydrolysis.
Water is a polar molecule. It has a relative charge across the molecule. One side is more negative and one side of the molecule is more positive. The overall charge of a water molecule is neutral.
Polarity causes water to have the property of adhesion, water will stick to other substances. You can pick up a glass slide with another slide if there is a film of water between the two slides. Polarity causes water to have the property of cohesion. Water molecules stick together. Smaller droplets coming in contact will join together to make larger droplets.
The properties of adhesion and cohesion allow for capillarity; the movement of liquid up a tube. Capillarity allows for the movement of water and minerals upward in plants. It also helps blood to flow back to the heart.
The properties of water also produce surface tension.
Because of surface tension, various small insects are able to skate across the surface of a pond, objects of greater density than water can be made to float and molten lead forms shot when dropped into cool water.
Water helps to maintain pH because pH is controlled by the ratio of hydrogen (H+) ions to hydroxide (OH-) ions. Water can supply both of these ions and help to produce the proper pH for various body functions.
*Explain the role of energy in chemical reactions of living systems.*
Activation energy is the energy needed to start a chemical reaction.
Exergonic reactions give off more energy than they require.
Example: respiration
Endergonic reactions require more energy than they release.
Example: photosynthesis
Is the following equation exergonic or endergonic? endergonicWhat is the following equation?photosynthesis
6CO2 + 6H2O + sunlight C6H12O6 + 6O2
carbon water energy glucose oxygen
dioxide
Is the following equation exergonic or endergonic? exergonic
What is the following equation? respiration
C6H12O6 + 6O2 6CO2 + 6H2O + ATP
glucose oxygen carbon water energy
dioxide
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