Grade 12 Biology (SBI4U) Macromolecules
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Transcript of Grade 12 Biology (SBI4U) Macromolecules
GRADE 12 BIOLOGY (SBI4U)MACROMOLECULES
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Macromolecules:What you need to know!1. Structure of the basic unit (carbohydrates, lipids,
proteins, nucleic acids)
2. How they react to form larger molecules
3. How the larger molecules are broken down into basic units
4. Functions of the molecules in living organisms
What is a …
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Polyester
Polygamy
Polygons
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Greek poly =
many, mer =
parts
Polymers
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• long molecules • have many similar or identical repeating
building blocks (structural units, monomers, small molecules)
• connected by chemical bonds (covalent bonds)
Monomers
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• The smallest repeating unit of a polymer• Can exist individually
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• Organic molecules constructed of smaller units called polymers – these polymers are subdivided into their basic units called monomers
Macromolecules
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• a macromolecule is also called
… biological macromolecule… biomolecule… organic molecule… large carbon-carbon molecule
to name a few…
Macromolecules
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• fall into 4 major categories – can you name them?
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Macromolecules
Hint: 3 of the 4 can be found in foods!
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Macromolecules:4 major categories
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Macromolecules:Question: Which one isn’t
considered a polymer and why?
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• Start with water, add lots of small carbon-containing
molecules and …….
• Macromolecules are the molecules of life!
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Macromolecules:Why do we care?
• How do you build a cell?
use these four major classes of macromolecules
Macromolecules
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• All living things are made of cells • Cells are:
~72% H2O ~3% salts (Na, Cl, K…)~25% carbon compounds (macromolecules)
Macromolecules
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Ions, small molecules (4%)Lipids (2%)Nucleic Acids (DNAand RNA (1% + 6%)
Proteins (15%)
Carbohydrates (2%)
Making and Breaking of Polymers
MAKE BREAKor
“Condensation” or “Dehydration” Synthesis (aka polymerization)
why synthesis? – a polymer grows in length (a new bond is made)
why dehydration (or condensation) – formation of a water molecule
MAKE
“Addition” polymerization
monomer molecules added to a growing polymer chain
NO molecules are eliminated in the process
monomer is unsaturated (e.g., had a double bond)
after an addition reaction it becomes saturated
MAKECan we add a monomer to a polymerwithout losing a water molecule?
Hydrolysis (Cleavage)
hydrolysis (hydro = water, lysis = break) – reverses the process of dehydration by breaking down the polymer with the addition of water molecules
BREAK
Carbohydrates (sugar/starch)• Monosaccharide (b/w 3-7 carbon atoms)
- Contain multiple hydroxyl groups and a carbonyl group
– the simplest sugars glucose
fructose, galactose
ribose deoxyribose
- Contains C, H, O in ratio of 1:2:1
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IsomersIsomers – one of two or more molecules with the same number and type of atoms, but different structural arrangements
e.g. glucose, fructose, galactose
- Also differ in chemical and physical properties
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Carbohydrates• Disaccharides – 2 simple sugars (sucrose, lactose = glucose + galactose, maltose = glucose + glucose)- Bond linking monosaccarides together = glycosidic linkage
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Carbohydrates
• Polysaccharides (‘complex’)
– many sugars (e.g. starch, cellulose, glycogen, chitin)– energy storage– structural materials
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glycogen
cellulose
Note the linking of simple repeating units25
Carbohydrates (polysaccharides)
Carbohydrates (polysaccharides)
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Lipids• hydrocarbons• comprised of fatty acids• hydrophobic• reservoirs of energy• structural materials
– cell membrane• 4 forms of lipids
– neutral fats, phospholipids, sterols, waxes
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fatty acids
Lipids – Neutral fats• neutral fats
– three fatty acids and a glycerol– body’s most abundant lipid
• functions– energy reservoir– insulation
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Fats
glycerol + 3 fatty acid fat (triglyceride)
Ester linkage
Fats
Animal vs. Plant Fats
Animal Fats Plant Fats
- Triglycerols containing mostly saturated fatty acids
-triglycerols are unsaturated and polyunsaturated FA
- Straight hydrocarbon chains allowing for van der Waal attractions
-Hydrocarbon chains have double bonds and many kinks, ↓ van der Waal attractions
- Solid at room temperature - Liquid at room temperature
Fatty Acids
saturated fat unsaturated fattrans-unsaturated
fat
• Can be used for insulation
adipose tissue
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Lipids – Neutral fats
Lipids - Phospholipids• form double-layered cell membranes
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Phospholipids
Glycerol backbone + 2 fatty acids + phosphate phospholipid
Phospholipids
Phospholipids have:1. a hydrophobic head2. a hydrophobic tail
Due to the dual chemical nature of the molecule, it is said to be amphipathic.
Phospholipids
Phospholipids
Phospholipid Bilayer
Sterols also known as steroids
ProteinsProteins are used for:
structure metabolism (enzymes) immunological protection molecular transport
Proteins are made of subunits of amino acids.
Proteins are the most diverse class of macromolecules due to 20 available amino acids.
Amino Acids
Amino Acids in Aqueous Solutions
• Amino acids contain a basic amine group, which can act as a proton acceptor, and an acidic carboxylic acid group, which can act as a proton donor
Amino Acids
Essential vs. Non-essential Amino AcidsEssential Amino Acids: Cannot be produced by the body,
therefore must be consumed in ones diet 8 essential Amino Acids
Non-essential Amino Acids: Can be produced by the body 13 Non-essential Amino Acids
Peptides
amide bond
Protein Organization
Four layers of protein organization:1. primary (1°) structure2. secondary (2°) structure3. tertiary (3°) structure4. quaternary (4°) structure
Primary (1°) Structure sequence of amino acids polypeptide chain
Second (2°) Structure
H-bond between peptide bonds
1. a-helix
2. b-pleated sheets
not necessarily in all proteins
Second (2°) Structure
Tertiary (3°) Structure provides protein a final 3-D structure four major bond types between R groups of
amino acids
1. H-bonding2. ionic bonding3. hydrophobic interactions4. covalent bond (disulfide bridge)
Tertiary (3°) Structure
General Protein Shapes
Globular Proteins (Hemoglobin) Fibrous Proteins
(Tropomyosin & Keratin)
Quaternary (4°) Structure
fully functional protein requires all subunits present
not all proteins have quaternary structure
Protein PropertiesProteins have optimal conditions at which they
function.When exposed to extreme conditions, proteins
begin to unfold – denature.If denaturation occurs moderately over time,
returning to the original conditions may result in renaturation.
Protein Folding
Proper folding in the cell is completed by chaperonin molecules.
Utilizes ATP to help proteins fold properly.
Nucleic AcidsNucleic acids are used for:
maintaining genetic continuity delivering information for protein synthesis energy molecule (ATP – adenosine triphosphate)
Two major nucleic acid polymers:1. DNA – deoxyribonucleic acid2. RNA – ribonucleic acid
Nucleic Acids
DNA RNA
located in the nucleus
double-stranded, double helix structure
stable molecule
mainly found in cytoplasm
single-stranded structure
unstable molecule
NucleotidesThe basic subunit of nucleic acids is a
nucleotide.
Three components:1. phosphate2. pentose sugar3. nitrogenous base
Pentose Sugar
Nitrogenous Bases
purines
pyrimidines
Nucleic Acid
reaction between 1. pentose sugar OH
group of one nucleotide
2. phosphate group of another nucleotide
forms phosphodiester bond
In Conclusion
The building blocks (monomers) of macromolecules are amino acids, nucleotides, simple sugars, and fatty acids
In Conclusion
• Name the two main chemical reactions shown making and breaking organic molecules
In Conclusion
Carbohydrates are use for energy storage and as structural materials
Lipids are used as energy storage and structural components
Proteins are made of amino acids which form structures, enzymes, transport, movement, and are part of the immune system
Nucleic acids are the basis of inheritance and reproduction
In Conclusion
The versatility of carbon makes possible the great diversity of organic molecules
Variation at the molecular level lies at the foundation of all biological diversity
Macromolecule Example(s) of subunits
Main functions Examples of macromolecules
carbohydrates sugars (such as glucose) and polymers of glucose
energy storage sugars, starches, and glycogen
lipids glycerol and three fatty acids or glycerol and two fatty acids
energy storage and cell membranes
fats, oils, and phospholipids
proteins polymers of amino acids transport, blood clotting, support, immunity, catalysis, and muscle action
hemoglobin, fibrin, collagen, antibodies, enzymes, actin, and myosin
nucleic acids polymers of nucleotides transfer and expression of genetic information
DNA and RNA
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Answers to post-presentation activity #1 – the activity could be use alone as a pre-assessment (what should be known from Grade 11 SBI3U)
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Day 2
• In building large macromolecules carbon usually combines with other carbons
… AND with one or more functional groups
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Why study Functional Groups?• These are the building blocks for organic
molecules (or macromolecules – large organic molecules)
the components of organic molecules most commonly involved in chemical reactions
the number and arrangement of functional groups give each organic molecule unique properties
Why study Functional Groups?
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Types of functional groups
• 6 functional groups most important to chemistry of life:
hydroxyl amino carbonyl sulfhydryl carboxyl phosphate
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Functional groups
• they affect reactivity (e.g., hydrophilic, increase solubility in water)
Hydroxyl
organic compounds with OH = alcohols alcohols, carbohydrates, nucleic acids,
some acids, and steroids highly polar (makes molecules more soluble) e.g., ethanol
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Carbonyl if C=O at end molecule = aldelhyde if C=O in middle of molecule = ketone react with molecules (H-R2) to form H-
R2-C-OH a ketone and an aldehyde may be
structural isomers with different properties, e.g., acetone and propanal
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Carboxyl
compounds with COOH = acids fatty acids, amino acids acidic – tends to lose a proton (COO-) involved in peptide bonds e.g., acetic acid - gives vinegar its sour
taste
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Amino compounds with NH2 = amines amino acids, nucleic acids NH2 acts as base - can pick up a proton
(H+) from the surrounding solution (ionized)
glycine (has amine and carboxyl groups) – replace an H with an R group to get an amino acid
under cellular conditions
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Sulfhydryl
compounds with SH = thiols 2 sulfhydryl groups can interact to help
stabilize protein structure (S-S, disulfide bonds)
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Phosphate • compounds called organic phosphates• Acidic – up to 2 negative charges when H+
dissociates• Links nucleotides in nucleic acids• Energy-carrier group in ATP
Review
Review
Review
2003-200483
Do the functional groups make that much
difference? identical basic structure of male & female hormones
attachment of different functional groups interact with different targets in the body
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A Bit of Honey: Bee keeping was used in Crete over 4000 years ago to allow for the collection of honey, a highly prized food having great value in ancient civilizations Field bees gather the
nectar, a sweet secretion in plant blossoms that contains fructose, glucose and sucrose
Some worker bees secrete beeswax - Hexacosanoic acid, C26H52O2, and triacontanol, C30H62O