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Carbohydrates
Carbohydrates
Simple
Monosaccharides
Contain a single sugar unit
Disaccharides
Contain two sugar units
Complex
Polysaccharides
Contain many sugar units
Glucose, Fructose Sucrose, LactoseStarch, Glycogen & Cellulose
The nucleotide monomer
SUGAR
PHOSPHATE
Nucleic acids contain C, H & O in addition to N & P
Proteins
3 groups: Amino group, Carboxyl group & R-group
When joined together they form peptide bonds
Aside from the C, H, O & N in the base molecule, the R group may also contain S & P
Protein structure• Primary structure
• The linear sequence of amino acids
• Secondary structure• The type of peptide bond determines how sections of the protein fold
– spiral helix / pleated sheet / random coils• Shape reinforced by additional H bonds
• Tertiary structure• Eventual 3D shape formed by folding• Shape reinforced by additional H bonds
• Quanternary structure• When a protein is formed by the interaction of 2 or more polypeptide
chains
Summary
Biomacromolecule Type of bonding ElementsCarbohydrates Glycosidic bond C, H, OLipids Ester bond C, H, O (less H2O)Nucleic acids Phosphodiester
bondC,H,O,P,N
Proteins Peptide bond C,H,O,N P,S
Elements of a plasma membrane
cholesterol
glycoprotein
protein channelphospholipid bilayer
glycolipid
carbohydrate chains
How does it regulate molecular transport?
• Passive Transport– Diffusion– Osmosis– Facilitated diffusion (channel, receptor & carrier
mediated)• Active Transport– Primary (uses chemical energy)– Secondary (uses electrochemical gradient)
• Isotonic: (iso - same) surrounding fluid and cells internal fluid are of equal concentration
• Hypotonic: (hypo - lower) surrounding solution has a lower concentration than the cells.
• Water will diffuse through the membrane into the cells
• Hypertonic: (hyper - higher) surrounding solution has a higher concentration than the cells
• Produces chemical energy in the form of adenosine triphosphate (ATP) through the process of cellular respiration
• Outer & inner membrane• The inner membrane contains many folds to provide a
larger surface area for energy production• ATP produced by reactions on inner membrane• Only in eukaryotes
• Energy supplying organelleMitochondrion
Enzyme Structure• Enzymes have an active site and a regulatory region• The active site (formed by folds in the protein) is where substrate binds to
the enzyme• The regulatory region is where cofactors coenzymes or enzyme inhibitors
can alter the function of an enzymeSubstrate
Active site
Regulatory region
Products
Enzyme inhibitor
Factors Affecting Enzyme Activity
pHTemperaturePressureEnzyme ConcentrationSubstrate concentrationCofactors / coenzymesInhibition
Inputs Outputs
Water H2O ATP
Electron e- NADPH
NADP+
ADP + POxygen (“waste”)
Light Dependent
Reaction
Light-dependent reaction
• Occurs in the grana• Light energy is used to split water in to two H+
ions and O2 gas
• The O2 is released as waste• With the power of the two free electrons– One H+ ion fuses ADP to Pi to form ATP– One H+ ion fuses to NADP to form NADPH
Light-independent stage• Occurs in Stroma• Does not need light, but NADPH and ATP
from previous stage• Needs CO2 and H+ ions • Sugar molecules are synthesised from CO2
CO2 = oxidised state (low E compound)
C(H2O)n = reduced state (high E compound)
• NADPH (carrier H+) is the reducing agent• ATP is the energy source
Putting Photosynthesis together
2 x PGAL = fructose
fructose = glucose
fructose + glucose = sucrose
glucose x ∞ = starch
Glycolysis
• Occurs in cytosol – uses enzymes and vitamins as coenzymes
• 1 glucose (6C) converted to 2 pyruvate (3C)
• Forms 2 ATP & 2 NADH
Krebs Cycle• Occurs in mitochondria• Pyruvate initially broken down in
to CO2 and Acetyl-coA• Joins with 4C molecule to form 6
C molecule• CO2 to form 5 C molecule, then
again to form 4 C molecule• Further oxidation takes place to
reform original 4C• Throughout cycle, constant
oxidation is fusing hydrogen to carrier molecules NAD → NADH and FAD → FADH2
Electron Transport• Occurs in inner membrane of
mitochondria• Produces 2-3 ATP per loaded
receptor• Electrons passed from one
cytochrome to next until accepted by O2- to form water
• Return of released protons through ATP synthase carrier provides energy to produce ATP from ADP & Pi (phosphorylation)
Anaerobic respiration (in humans)• Occurs in muscles where oxygen supply exceeds demand• The only stage that can occur is glycolysis• So 1 glucose produces 2 ATP• 2 NADH convert pyruvate to lactate (lactic acid)• Lactate build up causes pH to fall and pain & muscle fatigue• When activity returns to normal and oxygen becomes available,
lactate converted back to pyruvate to enter the Krebs Cycle.
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