Download Biological Macromolecules

Biological Macromolecules
The monomers of each
Common polymers
You read the following phrase in a research
article: “Individuals who exercise will lose weight
faster than individuals who do not exercise.” This
statement is an example of:
1.
2.
3.
4.
data collection
A theory
A hypothesis
A prediction
4 Biological Macromolecules
1. Carbohydrates
Monosaccharides, Disaccharides & Polysaccharides
2. Lipids (Fats)
Glycerides & Sterols
3. Proteins
Enzymes, structures, membrane proteins
4. Nucleic acids
DNA, RNA
Monomers -> Polymers
• Monomer: simple molecule
• Polymer: strings of similar,
simple monomers
• Recall:
– Dehydration synthesis
– Hydrolysis
Unity
• ALL polymers are made from very few
monomers
– All proteins from 20 Amino Acids
– Most polysaccharides from 3 monosaccharides
• ALL organisms build the same polymers
– We build and store the same glycogen molecules in
our muscles as do sharks
– Redwoods & sword ferns make same cellulose
Carbohydrates (sugar, starch &
fiber)
•
•
•
•
•
Monomers = Monosaccharides
Polymers = Polysaccharides
CH2O
Hydroxyl & carbonyl groups
Arrangement of atoms alters taste
Common food sugars
Carbohydrates
1. Mono and di-saccharides
• Simple Sugars
1. Polysaccharides
– Starches
•
•
Amylose; Amylopectin (starches)
Glycogen
– Structural polysaccharides
•
•
•
Cellulose; hemicellulose
Chitin
Peptidoglycan
Carbohydrates
• Polysaccharides
– Energy storage: Starch & Glycogen
– Structure: Cellulose, chitin & peptidoglycan
Lipids
• Glycerides
• Phospholipids
• Sterols
• Hydrophobic
Triglycerides
• Glycerol - an alcohol
• Fatty acids - carboxyl
group with hydrocarbon
chain
• Energy storage (9
kcal/gram), insulation,
padding
Saturated & Unsaturated
Phospholipid
• Both hydrophobic & hydrophilic
• Structural molecules (ALL cell membranes are
made of these)
Steroids
• Hydrophobic
• Signaling
– hormones
• Structural
– Stiffen cell membranes
Proteins
• Monomers = Amino
Acids (AA)
– AA = carboxyl group, R
(functional) group, amino
group
• Polymers = Proteins
– (3 - 100K) linked by
peptide bonds
• Most abundant
molecules of human body
(~ 2 million; 20% of body
weight)
Protein Function
• Support - Structural proteins in cell membranes
• Movement - Contractile proteins move muscles and cells
• Transport - Transport proteins bind insoluble compounds and
molecules to allow transport in bloodstream
• Buffering - Buffer against detrimental pH changes
• Metabolic regulation - Enzymes accelerate chemical reactions
• Coordination & Control - Hormones
• Defense - Antibodies, clotting proteins (globulin), keratin
Making a protein
• Join amino group to carboxyl group
• Peptide bond
– Any chain of two or more amino acids joined together are
peptides
• “R” side chain = functional group
Protein structure
1. Primary (covalent, peptide bond)
–
AA sequence
2. Secondary (H-bonding)
–
–
α-helices
β-pleated sheets
3. Tertiary (H- bonding)
4. Quaternary
–
Additions of other polypeptides
Primary structure
• Polypeptide chain: linear sequence of AA
Secondary structure
• Common macrostructures formed by
H-bonding between
functional groups of
AA.
• α-helices: common in
fibrous proteins
• pleated sheets:
common in globular
proteins
Tertiary Structure
Quaternary Structure
• Final, assembled &
functional protein
• Consist of:
– Multiple polypeptides
joined by hydrogen bonds
OR,
– Single functional
polypeptide
Various protein shapes
Concept Check
This lysozyme protein is found in tears & protects the eye from
bacterial infections. Which of the following best describes the
outside of the molecule?
1. The R-groups on the surface of the
molecule are mostly hydrophobic.
2. The R-groups on the surface of the
molecule are mostly hydrophilic.
3. The R-groups on the surface of the
molecule are mostly non-polar.
4. The R-groups on the surface of the
molecule are constantly changing
between non-polar and polar as the
protein chain bends and folds.
Example: Hemoglobin
• HbA, HbB, HbE
• Multiple Hb proteins exist; only two producenormal O2 binding to
RBC’s
Hemoglobin
• HbA, HbB, HbE
• Small changes in AA sequence
result in major functional
changes
– Less functional protein produced;
Fewer competent RBC’s are made;
HbE
– Defective protein is produced: RBC’s
sickle (collapse); HbS
• Each altered phenotype results
from a single AA change
Denaturation
• Loss of function due to shape change
– Caused by changes in pH or temperature
Nucleic Acids
• Polymers that serve as recipes for proteins
• DNA (deoxyribonucleic acid): double stranded
polymer; duplicate, read in reverse (think of this entire
molecule as a cookbook)
• RNA (ribonucleic acid): single stranded polymer;
usually, a short transcript (copy) of a tiny portion of a
single strand of DNA (recipe)
• Monomers = nucleotides
Nucleotides
• 5 nucleotides
– DNA: Adenine, Thymine,
Guanine, Cytosine
– RNA: Adenine, Uracil,
Guanine, Cytosine
• Consist of Phosphate,
Sugar, Nitrogenous base
– The base is variable
• Where are they joined? What
reaction joins them?
RNA
• Single polynucleotide
strand
• Repeated Sugar phosphate ladder
• Base protrudes from sugar
• Many varieties:
– mRNA, tRNA, rRNA
RNA
• Single polynucleotide
strand
• Repeated Sugar phosphate ladder
• Base protrudes from sugar
• Many varieties:
– mRNA, tRNA, rRNA
• 3-D shape also due to Hbonds
DNA
• Double stranded ladder
• Each base binds to one specific
counterpart
– A-T; C-G (base pairs)
• What type of bonds hold base pairs (bp)
together?
• thousands - millions of bp in length
– Codes for hundreds - thousands of
genes
Concept Check
When proteins are heated, they
denature. If moderate heat was
applied to this molecule of DNA what
part of the molecule would break
apart first? (Use your knowledge of
chemical bonds.)
1. The nucleotides along each side would
break apart.
2. The sugar-phosphate backbone would
separate from the nitrogen bases.
3. The nitrogen base pairs would separate
in the interior of the molecule.