BABS1201 Lecture Notes - Lecture 3: Olive Oil, Beta Sheet, Glycolipid
Macromolecules
99% of all living matter is made up of: H C O N (P S)
Inorganic molecules (H2O)
• Elements of life in the same ratio
Macromolecule:
A large molecule formed by joining smaller molecules, usually by a dehydration reaction.
Four main classes
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids
•
Macromolecules
• Chain-like molecules called polymers
• Polymers: consist of many similar or identical subunits joined by covalent bonds (i.e.
monomers)
Synthesis and Breakdown of polymers
• Synthesis: a water molecule is lost in "dehydration" to form a new covalent bond
• Hydrolysis: breaking down of a polymer, where a water molecule is added to break a
covalent bond
Carbohydrates
• Monosaccharides (monomer unit)
o E.g. glucose. CnH2nOn
o Their carbon skeleton ranges from three to seven carbon atoms
o Often drawn with linear carbon skeletons - in water, all monosaccharides with C>3
bend around to form ring structures
find more resources at oneclass.com
find more resources at oneclass.com
• Glucose - major nutrient, central to cellular metabolism.
▪ Broken down for energy in cellular respiration
▪ Used to build many other organic molecules, including amino acids and fatty
acids
• Glyceraldehyde
▪ Energy-storing molecule produced by photosynthesis
▪ Two of these from glucose
• Galactose - Combines with glucose to form lactose
• Fructose - Used to make sucrose
• Ribose - RNA and ATP
▪ A modified form is used in building DNA
• Disaccharides - two monosaccharides joined by a glycosidic bond
o E.g. Maltose
o
• Polysaccharides e.g. starch
Storage Polysacchrides
• Starch : stored by plants
o Amylose and amylopectin
o Stored energy can be accessed via hydrolysis
• Glycogen: stored by animals in liver and muscle cells.
o Hydrolysis of glycogen releases glucose when the demand for energy increases
(cannot sustain an animal for long periods of time
find more resources at oneclass.com
find more resources at oneclass.com
Structural polysaccharides
• Cellulose
o major component of plant cell walls - used as fibre for humans (we do not have the
enzyme to break down the cellulose)
• Chitin (polymer of glucose with N group)
o Found in the exoskeletons of arthropods (insects, spiders, crustaceans, etc)
• Amylose < amylopectin < glycogen (least to most branching)
• All polymer of glucose
• Difference: the number of side chains / branching present
Plant cells
• Chloroplast
• Starch
• Mitochondria
• Glycogen granules (lots of branching)
•
[Carbohydrates - chocolate (sugar, glucose syrup), Jelly (sugar)]
Lipids
• Hydrophobic (non-polar); mix poorly with water
• Have various forms and functions:
o Energy storage and transport - fats (triclyglycerols or TAGs)
o Structure - phospholipids (cell membranes), sterols
o Chemical messengers - steroids (cholesterol), glycolipids (carbohydrate portions)
o Photoreceptors - carotenoids (makes plants yellow - Vitamin A) photoreceptor -
vitamin A receives red light
▪ Protein that receives light
o Coverings - waxes
How to Make a Fat:
• Three fatty acid molecules to one glycerol
• Dehydration reaction to form an ester bond
• Forms a fat called a triacylglycerol (TAG) or triglyceride
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
99% of all living matter is made up of: h c o n (p s) Inorganic molecules (h2o: elements of life in the same ratio. A large molecule formed by joining smaller molecules, usually by a dehydration reaction. Macromolecules: chain-like molecules called polymers, polymers: consist of many similar or identical subunits joined by covalent bonds (i. e. monomers) Synthesis: a water molecule is lost in dehydration to form a new covalent bond: hydrolysis: breaking down of a polymer, where a water molecule is added to break a covalent bond. Starch: chloroplast, mitochondria, glycogen granules (lots of branching) [carbohydrates - chocolate (sugar, glucose syrup), jelly (sugar)] How to make a fat: three fatty acid molecules to one glycerol, dehydration reaction to form an ester bond. Forms a fat called a triacylglycerol (tag) or triglyceride: three fatty acids to glycerol (tricyglycerol) Similar structure of tag phosphate and choline replaces the third fatty acid.