Download Chapter 2 - Biochemistry

Biology 2121
Chapter 2
Biochemistry
 1. Introduction

Biochemistry
 2. Macromolecules contain carbon
 Valance = 4
 Bonds with oxygen, hydrogen and nitrogen
Carbohydrates
 1. General characteristics
 Soluble in water (decreases with size)
 Sizes – small single units to larger compounds
 2. Function (s)
 Energy – 4 kcal/g
 Cell membrane – cell to cell recognition
 3. Structure
 Monomer – monosaccharide
 Polymer – polysaccharide
Carbohydrates
 1. Monosaccharides
 C6H12O6 - isomers
 2. Disaccharides
 Formed by
dehydration
 Split-up by
hydrolysis
 3. Polysaccharides
 Starch, Glycogen
1. Glycogen – STORED IN THE LIVER
2. Starches – plants
3. Cellulose - roughage
Lipids
 1. General Characteristics
 Insoluble in water – soluble in other nonpolar
substances (alcohol)
 Non-polar structure
 2. Function(s)
 Energy – 9 kcal/g
 Cell membrane, steroids, fat-soluble vitamins
 3. Structure
 Most – fatty acid tail (H-C chain) that is non-polar
STRUCTURE OF A TRIGLYCERIDE
1. Formation – dehydration synthesis
2. Single bonding between carbons – ‘saturated’
•
Long FA chains – solid at room temperature
3. CH2 – fatty acid tails
 1. Unsaturated and Polyunsaturated Triglycerides
 Double bonding between the carbons
 Chains ‘bend’ or form kinks


Plant lipids; olive, corn, safflower oil
Chains are shorter than saturated fatty acid triglycerides
PHOSPHOLIPID
1. BILAYER OF A PLASMA MEMBRANE
2. Two FA tails; glycerol; phosphate (polar)
3. Amphipathic – polar and non-polar nature
CHOLESTEROL IS CLASSIFIED AS A STEROL – LIPID. MADE UP OF
‘FUSED’ CARBON RINGS AND SIDE CHAINS OF MOLECULES
A ‘PRECURSOR’ TO OTHER STEROIDS – TESTOSTERONE, VITAMIN D
Side-chains made each steroid different
Proteins
 1. General Characteristics


Basic structural component of the body
C, H, O and Nitrogen!
 2. Function(s)


Cell functions – transport of material across cell membrane;
hemoglobin; muscle contractile protein
Biological Catalysts - enzymes
 3. Structure


Monomer: amino acids
 Peptide bonding via dehydration
Polymer: Polypeptide
Formation of a protein
1. Primary Structure
• As amino acid form straight
chains via peptide bonding
• Occurs during ‘protein synthesis’
- ribosomes of the cell
2. Secondary Structure
• Twist or bends after primary
formation
• Hydrogen bonds stabilize
• Between NH and CO
3. Two forms
• Beta and alpha-helix
A polypeptide chain may
contain both secondary
structures!
Other Structures
1. Secondary structures fold up on themselves.
2. Adjacent amino acids interact or form covalent and hydrogen bond. Forms a
3-D Tertiary structure
• Enzymes
3. If two or more tertiary structures (polypeptides) interact – quaternary
structure
• Hemoglobin (blood) or myoglobin (muscles)
Proteins – Structural Types
 Fiberous – only secondary; insoluble and stable;
 collagen; keratin
 Globular – tertiary structure; soluble;
 enzymes, antibodies
Enzymes
 1. What are enzymes?
 Biological catalysts
 Specific tertiary structure
 2. Substrate and active sites
 3. Function(s)
 Drive chemical reactions in cells!
 4. How enzymes work (Lowering of energy activation)
 Activation Energy (animation)
1. “HOW ENZYMES WORK” –
ANIMATION (Chapter 12 –
Alternate)
2. Biochemical pathways
(enzyme mediated)
3. Feedback in Biochemical
Pathways
Enzyme Denaturation
1. When enzymes
(proteins) stop
working.
2. Why?
•
Temperature; pH
changes
•
Bonds and
interactions
between amino
acids fail – unravels
and loses 3D shape
Animation
1. Denaturation
Activation Energy and Enzymes
Nucleic Acids
 1.
General Characteristics
 C, H, O, N and Phosphorus
 2. Function(s)
 DNA – genes – heredity
 RNA – important in production of proteins
 3. Structure
 Monomer: nucleotide (phosphate - 5 carbon sugar –
nitrogen base
 Polymer: Deoxyribonucleic Acid and Ribonucleic Acid
Nucleotides and DNA
1. Phosphates bonded to 5–C deoxyribose sugar via covalent bonding
2. Sugar bonded to nitrogen base (green and yellow) via covalent bonding
3. Bases bonded via hydrogen bonding (weak; unzips)
4. Base pairing rules: A-T; G-C
• Hydrogen bonding
between bases
• Base pairing
• Sugar-Phosphate
backbone
• Double Helix
ATP – Adenosine Triphosphate
1. Glucose is the fuel that powers
the cell.
2. As glucose is oxidized (anabolic),
ATP is built up in the process of
cellular respiration –
mitochondria of the cell
3. Energy is stored in the bonds of
ATP
4. Contains ribose sugar (RNA) and
adenine base.
5. Three phosphates – two have
unstable bonds and negative
charges – repel
6. Bonds are broken – energy
released – drives cellular work