AS Unit 1 Biology: Content

Lifestyle, Health and Risk
1. Transport and Circulation
  1. Water
    1. Solvent
      1. Molecule has an uneven charge, polar. Negative Oxygen, Positive Hydrogen
      2. Ionic substances can dissolve easily
        Glucose (-OH)
        Salt
        Amino Acids (-COOHJ) (-NH2)
    2. Hydrogen Bonds form between molecules
      1. Cohesion (important in the xylem)
      2. High Specific Heat Capacity. So temperature fluctuations can be managed and are small
        Sweating and transpiration cool the body down
  2. A Mass Transport System, using diffusion. Big organisms have smaller SA/V. Need to overcome inefficiency: need MTS
    1. Artery
    2. Vein
    3. Capillary
2. Cardiac Cycle and Heart Rate
  1. Systole
    1. Contraction of the muscle
  2. Diastole
    1. Relaxation of the muscle
  3. Valves
    1. Atrioventricular
    2. Semi-lunar
  4. Pressures within the heart cause valves to open and close. Elastic recoil lowers pressure in atria and ventricles
3. CVD
  1. Blood Clotting
    1. As a vital defence mechanism, it minimises blood loss, prevents entry of pathogens, provide framework for repairs.
    2. Can also block arteries: cell death
    3. Damage to blood vessel
      1. Exposes Collagen
        Platelets attach
        Platelets release thromboplastin
        Calcium and K catalyses thromboplastin to convert prothrombin to thrombin
        This converts soluble fibrinogen to insoluble fibrin.
        This makes a network of fibres to trap RBC and debris to make a clot.
  2. Atherosclerosis
    1. Damage to endothelial Lining
      1. Increased Risk of Blood Clotting
      2. Inflammatory Response: White Blood Cells move to artery wall
        Cholesterol builds up: ATHEROMA
        Build up of Calcium salts and fibres: PLAQUE FORMATION
        Narrowing of artery
        Increased Blood Pressure
        POSITIVE feedback
  3. Treatments
    1. Reduced Lifestyle Changes
    2. Anti-hypertensives
      1. Duiretics
        increased urine volume lowers bp and vol.
      2. Beta Blockers
        Block hormones= contractions less powerful
      3. ACE inhibitors
        blocks angiotensin which causes arterial constriction
    3. Aspirin/Clopidogrel
      1. Platelet Inhibitory drug: makes less sticky
    4. Anticoagulants
      1. Warfarin: reduce blood clots
    5. Statins
      1. Lower Cholesterol by blocking liver enzyme
4. Structure and function of Carbohydrates
  1. Monosaccharides
    1. Glucose
    2. Galactose
    3. Fructose
  2. Disaccharides
    1. Sucrose
    2. Lactose
    3. Maltose
  3. Polysaccharides
    1. INSOLUBLE
      1. Unbranched
        Amylose
        In Plants
        In Starch
        Alpha Glucose- tight spirals
        1,4
      2. Branched
        Amylopectin
        Lots of terminal ends, digested more rapidly than amylose
        In starch
        In Plants
        1,6
        Glycogen
        Animals, Bacteria Plants
        Storage
        Glucose
        Compact
  4. Bonding
    1. Glycosidic links
      1. Forming: Condensation: Loss of 1 H20
      2. Breaking: Hydrolysis: Addiction of 1 H20
      3. Catalysed by enzymes
5. Structure and Function of Lipids
  1. Insoluble in water
  2. Soluble in ethanol
  3. Triglycerides
    1. 3 fatty acids
    2. Glycerol
      1. CH2OH CHOH CH2OH
    3. Ester Bonds
      1. between fatty acids and Glycerol
    4. Fatty Acids vary
      1. Length
      2. Kinks/Double bonds
      3. combination of acids
    5. Saturated Fats
      1. Strong intermolecular bonds
      2. Solid
      3. Straight chain
    6. Unsaturated Fats
      1. Poly
        Weaker bonds
        Liquid
        many double bonds
      2. Mono
        Weak bonds
        Liquid
6. Reducing Risk
7. Population studies on Risk Factors
  1. Cohort studies
    1. Large number of people followed over long periods of time
    2. Monitored to see if diseases occurs
  2. Case-Control Studies
    1. Case compared to control
8. Risk Factors for CVD
  1. Genetic Factors
    1. HBP
    2. Poor Cholesterol Metabolism
  2. Age
    1. Elasticity/width in heart/arteries reduced
  3. Smoking
  4. High Blood Pressure
  5. Lifestyle
    1. Diet
      1. Obesity
    2. Exercise
  6. Mutations in Genes relative to HDL:LDL production
  7. Perceived Risk
  8. Actual Risk
  9. Gender
    1. Oestrogen gives women protection from CVDs before menopause
  10. Cholestrol
    1. Lipoproteins
      1. HDLs
        GOOD
        Formed from unsat fats
        Transport to Liver where broken down
        Reduces Cholestrol
      2. LDLs
        BAD
        Formed from sat fats
        Bind to cell surfaces receptors, become saturated, cant break down Cholestrol
        Reduce activity
  11. BMI= KG/M2
  12. Antioxidants
    1. Free Radicals: damage cells, need vitamin E/C to provide H to stabilise
    2. Reducing agents
9. Good Studies
  1. Valid
  2. Reliable
  3. non-Bias/controlled
  4. Large sample size
Genes and Health
1. Structure and Role of DNA and RNA
  1. Nucleotides
    1. Phosphate
    2. Organic Base
    3. Sugar
      1. Deoxy: DNA, Ribose:RNA
  2. Condensation reactions
  3. RNA
    1. Triplets=Amino
  4. DNA
    1. Double Helix, complementary Base pairing
    2. Purines
      1. Adenine
      2. Guanine
    3. Pyrimidines
      1. Thymine
      2. Cytosine
2. DNA replication and Protein synthesis
  1. DNA carries codes for Proteins
    1. Semi-Conservative theory
      1. Dispersive/Fragmentory
      2. Conservative
    2. 1. Hydrogen Bonds split
      1. 2. DNA nucleotides pair up with bases. DNA Polymerase links adjacent nucleotides
        3.Two identical daughter Strands created
  2. DNA Copied
    1. mRNA made in Transcription
      1. 1. DNA unwinds. Hydrogen bonds break.
        One strand used (antisense)
        2. Uracil pairs with Adenine. Ribonucleotides pair up complementory
        3. RNA Polymerase used
    2. Then Translation...
      1. mRNA to protein
        On Ribosome
        Transfer RNA translates base sequence
        Brings Amino Acid to bind
        Makes polypeptide
3. Genes, Mutation and CF
  1. Change in the base sequence of DNA
    1. Causing deformities within the protein being created
      1. Active sites etc.
  2. CF
    1. CFTR Protein
      1. Excess water:
        Na+ pumped across BASAL MEMBRANE
        Na+ diffuses through sodium channels
        Cl- follows down con gradient
        Water drawn out by osmosis due to high salt content in tissue fluid
      2. Not there, doesn't work.
  3. Effects of CF
    1. Gas Exchange
      1. In Lungs, Mucus: More infection, harbour pathogens.
      2. Block bronchioles/ reduces aveoli effectiveness
    2. Digestion
      1. Mucus blocks Pancreatic Duct: Digestive enzymes cant react small intestine. Tiredness, difficult gaining weight
      2. Damage insulin cells by fibrosed cysts, diabetes
    3. Reproduction
      1. Sperm cant leave/ Mucus blocks cervix
4. Genetic Inheritance
  1. Homozygous (same alleles)
  2. Phenotypes
  3. Genotypes
  4. Heterozygous
  5. Dominance
  6. Recessive
5. Gene Therapy and Genetic Screening
  1. Somatic Therapy
    1. Use a Vector: Liposome
    2. allele inserted into cell
  2. Germ-Line
  3. Amniocentesis
  4. CVS Sampling
  5. Ethics
    1. Rights
    2. Risk of Miscarriage
    3. Abortion
    4. Costs
    5. Mental and emotional issues
6. Cell Membranes
  1. Phospholipid Bilayer
    1. Hydrophobic tails inside the bilayer
    2. Phosphate, Glycerol, 2 fatty acids
  2. Proteins
    1. Channels
  3. Glycolipids/proteins
  4. Fluid Mosaic Model
    1. Phospholipids are triglycerides: Polar: Hydrophilic phosphate heads on the outside
      1. Polar molecules cannot easily pass through: lipid soluble can.
  5. Cholestrol
7. Enzyme Action and Rates of Reaction
  1. Enzymes: Catalysts
    1. Globular
    2. Lock and Key theory
    3. Active Sites
    4. Activation Energy
    5. Lowers Ea
      1. Creating suitable Ph
      2. assisting in breaking/making bonds as charged groups in active site interact and distort shape of substrate
8. Structure of Amino Acids and Proteins
  1. Carboxylic Group
  2. Amine Group
  3. Hydrogen and a Residual Group
  4. 4 Levels of Structures
    1. Primary
      1. Dipeptide
        Peptide bonds
        Condensation reactions
      2. Polypeptide
    2. Secondary
      1. Alpha Helix
      2. Beta Pleated
      3. The hydrogen bonding between amino acids
    3. Tertiary
      1. 3D shape
        Hydrophobic interactions
        Hydrophilic outside of protein
        disulphide bridges
        Hydrogen bonds
        Ionic bonds between R groups
        Covalent bonds
    4. Quaternary
      1. 2 or more polypeptide chains joining together: haemoglobin
  5. Globular
    1. enzymes
    2. Complicated tertiary
  6. Fibrous
    1. collagen/keratin
    2. little tertiary
9. Transport across Cell Membranes
  1. Diffusion
  2. Osmosis
  3. Facilitated Diffusion- protein channel
  4. Active Transport- ATP
    1. Carrier Proteins, up concentration gradient
  5. Exo and Endocytosis
10. Gas Exchange surfaces
  1. large area
  2. thinner diffusion distance
  3. Concentration gradient
Core Practicals
1. Daphnia
2. Vitamin C
  1. DCPIP- goes colourless when reduced (gaining e-)
    1. 1. Calibrate (known volume of conc. of Vit C)
      1. Add unknown solution, until colourless
        Errors:
        Systematic
        Burette/pipette error in volume
        Not measured at right place (meniscus)
        Random
        end point misjudged, drops may be too much/too little
3. Beetroot
  1. Cut equal sizes
    1. Rinse. Place in equal volumes of water (range of temperatures. Equal Time
      1. Remove, shake to disperse pigment
        Colourimeter

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