All Notes Needed For OCR As Biology (F212 exam)

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  • Created by: Amy
  • Created on: 03-06-12 16:36

Biological Molecules

Water

  • High Specific Heat Capacity – organisms survive in deeper warmer water; layer of ice prevents further heat loss.

  • Hydrogen Bonds – creates surface tension; some small organisms can move across the surface of the water.

  • Solvent – polar substances dissolve in water due to charges.

  • Transport Medium – flows; blood plasma is mainly water.

  • Involved in Metabolic Reactions – photosynthesis and respiration.

Proteins

Primary Structure – a sequence of amino acids.

Secondary Structure – twisting of the primary structure into alpha helix and beta pleated sheets.

Tertiary Structure – Hydrogen Bonds, Ionic Bonds, Disulfide Bridges, Hydrophobic Interactions.

Quaternary Structure – addition of prosthetic groups, carbohydrates, etc.

Haemoglobin

  • Globular Protein
  • Chain of amino acids
  • Alpha helical secondary structure
  • Hydrogen, ionic, disulfide, hydrophobic bonds in tertiary structure
  • 4 polypeptide chains (2 alpha, 2 beta)
  • 1 haem group per polypeptide
  • Fe2+ ion in haem

Collagen

  • Fibrous Protein
  • High proportion of glycine
  • 3 polypeptide chains
  • Chains form a tight coil held by hydrogen bonds
  • Ends of parallel molecules are staggered
  • Covalent bonds form between adjacent molecules
  • Prevents lines of weakness

Carbohydrates

Alpha Glucose – OH is below carbon 1

Beta Glucose – OH is above carbon 1

Amylose

  • Energy Store (Plants)
  • Polysaccharide
  • Alpha Glucose
  • 1,4 glycosidic links
  • Non-branched
  • Compact

Amylopectin

  • Energy Store (Plants)
  • Polysaccharide
  • Alpha Glucose
  • 1,6 glycosidic links
  • Branched
  • Insoluble to not affect water potential
  • Easily hydrolysed

Cellulose

  • Plant Cell Walls
  • Beta Glucose
  • 1,4 glycosidic links
  • Each glucose molecule is rotated 180 to its neighbour
  • Straight chains
  • Adjacent chains held by hydrogen bonds

Glycogen

  • Energy Store (Animals)
  • Polysaccharide
  • Alpha Glucose
  • 1,4 glycosidic links and 1,6 glycosidic links
  • Branched and Compact
  • Insoluble to not affect water potential

Lipids

Triglyceride

  • 1 Glycerol Molecule

  • 3 Fatty Acids

  • Ester Bonds

Phospholipid

  • 1 Glycerol Molecule

  • 2 Fatty Acids

  • 1 Phosphate

Cholesterol

  • 4 carbon rings

  • Hydrophobic

  • Hormones & Vitamin D

  • Cause gallstones and atherosclerosis

Protein

  • Biuret A and Biuret B
  • Blue to Lilac

Reducing Sugar

  • Benedicts
  • Warm
  • Blue to Brick Red

Non-Reducing Sugar

  • Hcl
  • NaOH
  • Benedicts
  • Warm
  • Blue to Brick Red

Starch

  • Iodine
  • Brown to Black

Lipids

  • Alcohol
  • Water
  • White Emulsion

Glucose Colorimetry

  • Add Benedicts Solution

  • Solution turns brick red

  • Remove red precipitate

  • Use colorimeter

  • Calibrate using water

  • use a red filter

  • record readings of absorbance

  • less absorbance = more glucose

  • using known concentrations, set up calibration curve

  • read concentrations off the graph

Enzymes

  • Globular proteins.

  • Soluble in water.

  • Specific 3D shape.

  • Catalyse chemical reactions inside and outside cells.

Enzymes are Specific to the Substrate they act on

  • Tertiary structure form the active site.

Lock and Key Theory

  • Active site has a specific shape that is complementary to the substrate.

Induced Fit Theory

  • Enzyme changes shape slightly as the substrate binds with the active site.

  • Makes active site fit more closely around the substrate.

  • Change in shape put stress on bonds in substrate so reaction occurs more easily.

Factors Affecting Enzyme Controlled Reactions

Enzymes Concentration – Increases rate of reaction.

  • More active sites available.

  • More chance of substrate colliding with active site.

  • More product produced.

Comments

Rachael Ogundunmade

very helpful :)

neelam

thank uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu

Kat

Thanks for this! Left my bio text book at home... life saver!

Zayn Carlson

Awesome 

Arya Ahmed

Great notes :)

Bethany Cunningham

Well done, these are awesome. Thank you, they are great to consolidate knowledge.

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