Download CH 2 -CH 2 -CH 2 -CH 2

Biochemistry
SOL BIO 3 b,c
BIO 3 b, c
OBJECTIVE:
• TSW investigate and understand the
chemical and biochemical principles
essential for life.
Key concepts include• b) the structure and function of
macromolecules
• c) the nature of enzymes.
• Most life processes are a series of chemical
reactions influenced by environmental and
genetic factors.
Metabolism
• the sum of all biochemical
processes
2 Metabolic Processes
• Anabolism- the building up of
complex molecules
•Catabolism- the breaking down
of complex molecules
• Most cells function best within a
narrow range of temperature and pH.
•At very low temperatures,
reaction rates are too slow.
•High temperatures or extremes of
pH can irreversibly change the
structure of proteins and alter their
function.
–The main components
of a living cell are:
•Carbon
•Hydrogen
•Nitrogen
•Oxygen
-Phosphorus
-Sulfur
• Inside every cell is a concentrated mixture of
thousands of different macromolecules
forming a variety of specialized structures
that carry out cell functions, such as:
–
–
–
–
–
energy production
transport
waste disposal
synthesis (creation) of new molecules
storage of genetic material.
Organic Compounds
• Compounds that contain CARBON are called
organic.
• Macromolecules are large organic
molecules.
Carbon (C)
• Carbon has 4 electrons in outer shell
• Carbon can form covalent bonds with as
many as 4 other atoms (elements)
• Usually with H, O, N, or C
• Example: C6H12O6 (sugar)
Macromolecules
• Large organic molecules.
• Also called POLYMERS.
• Made up of smaller “building blocks” called
MONOMERS.
• Examples:
1. Carbohydrates
2. Lipids
3. Nucleic acids (DNA and RNA)
4. Proteins
1. Carbohydrates
• Small sugar molecules to large sugar
molecules.
• Examples:
A. monosaccharide
B. disaccharide
C. polysaccharide
1. Carbohydrates
A. monosaccharide: one sugar unit
• Examples:
glucose
glucose (C6H12O6 blood sugar)
deoxyribose
ribose
galactose (milk sugar)
fructose (honey)
B. disaccharide: two sugar unit
• Example: sucrose = glucose + fructose
glucose
fructose
C. polysaccharide: many sugar units
• Examples:
glucose
starch (bread, potatoes)
glycogen (beef muscle)
cellulose (lettuce, corn)
chitin (exoskeletons)
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
glucose
• The primary functions of carbohydrate
macromolecules are to:
– provide and store energy.
2. Lipids
• General term for compounds which are not
soluble in water.
• Lipids are soluble in hydrophobic
solvents.
• Remember: “stores the most energy”
2. Lipids
• Examples: 1.
2.
3.
4.
5.
6.
Fats
Phospholipids
Oils
Waxes
Steroid hormones
Triglycerides
• 5 functions of lipids:
1. Long term energy storage (fat)
2. Protection against heat loss
(insulation)
3. Protection against water loss & germs
(oils & waxes)
4. Chemical messengers
(hormones & steroids)
5. Major component of membranes
(phospholipids)
• Triglycerides: composed of 1 glycerol
and 3 fatty acids.
H
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
fatty acids
H-C----O C-CH -CH -CH -CH
2
2
2
H
glycerol
• There are two kinds of fatty acids you may see
on food labels:
1. Saturated fatty acids: no double bonds (bad)
2. Unsaturated fatty acids: double bonds (good)
saturated
O
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
unsaturated
O
C-CH2-CH2-CH2-CH
3. Nucleic acids
• Nucleic acids (DNA and RNA) control cell
activities by controlling protein synthesis
3. Nucleic acids
• Two types:
1. deoxyribonucleic acid (DNA-double
helix)
2. ribonucleic acid (RNA-single strand)
• Nucleic acids
are composed of long chains of
nucleotides
3. Nucleic acids
• Nucleotides:
Backbone:
phosphate group
sugar (5-carbon)
nitrogenous bases:
adenine (A)
thymine (T) - uracil (U)
RNA
cytosine (C)
guanine (G)
Nitrogenous Base pairs:
• DNA: A-T
G-C
RNA: A-U
G-C
Phosphate
Group
O
O=P-O
O
Nucleotide
5
CH2
O
N
C1
C4
Sugar
(deoxyribose)
C3
C2
Nitrogenous base
(A, G, C, or T)
5
O
DNA - double helix
3
3
P
5
O 5
O
C
G
1
P
3
2
4
4
2
3
P
1
5
O
T
3
P
3
A
O
P
5
O
5
P
4. Proteins (Polypeptides)
• Amino acids (the building blocks of
protein)
• 2 kinds of amino acids
- essential & non-essential amino acids
- Essential amino acids cannot be
synthesized by our body & need to be
obtained through our diet
• 7 functions of proteins:
1.
2.
3.
4.
5.
6.
7.
Storage:
Transport:
Regulatory:
Movement:
Structural:
Enzymes:
Defense:
albumin (egg white)
hemoglobin
hormones
muscles
membranes, hair, nails
cellular reactions
antibodies
• A protein’s structure depends on its
specific job
• The sequence of amino acids and
the shape of the chain are a
consequence of attractions between
the chain’s parts.
• Four levels of protein structure:
A. Primary Structure (1°)
B. Secondary Structure (2°)
C. Tertiary Structure (3°)
D. Quaternary Structure (4°)
A. Primary Structure (1°)
• Amino acids bonded together by
peptide bonds.
Amino Acids (aa)
aa1
aa2
aa3
Peptide Bonds
aa4
aa5
aa6
B. Secondary Structure (2°)
• 3-dimensional folding arrangement of a
primary structure into coils and pleats
held together by hydrogen bonds.
B. Secondary Structure (2°)
Two examples:
Alpha Helix
Beta Pleated Sheet
Hydrogen Bonds
Alpha Helix
Beta Pleated
Sheets
C. Tertiary Structure (3°)
• Secondary structures bend and fold into a
more complex 3-D arrangement.
• Called a “subunit”.
C. Tertiary Structure (3°)
Alpha Helix
Beta Pleated Sheet
D. Quaternary Structure (4°)
• Composed of 2 or more “subunits”.
• Example: enzymes (hemoglobin)
3° subunits
Subunits
Enzymes: Special Proteins