Biology unit 1

Biology unit 1

Lungs
1. Many alveoli
  1. alveolar walls are folded to provide a large surface area
    1. Many alveoli provide a large surface area so fast diffusion
      1. Alveolar walls are thin so there's a short distance between the alveoli and blood/
        Ventilation Maintains a diffusion gradient so fast diffusion
Heart
1. AVN delays electrical impulses Allowing atria to empty before ventricles contract
2. Atrium has higher pressure than ventricles so Atrio-ventricular valve opens
3. higher pressure in aorta so semi lunar valve closes
4. ventricle has higher pressure than aorta so semi-lunar valve opens
5. ventricle has higher pressure than atrium so atrio-ventricular valves close
6. AVN sends wave of electrical impulses down Bundle of His and Purkyne fibres ventricular systole
  1. oxygen travels through alveolar epithelium Through capillary epithelium
7. SAN sends wave of electrical impulses across atria causing atrial contraction
immunity
1. how memory cells are important
  1. Memory cells remain from previous infections / when an individual comes in contact with the antigen again/ more antibodies produced to destroy the virus
    1. Vaccine has dead pathogens/ T cells activate B cells/ b cells divide and produce antibodies / memory cells are then produced for immunity
      1. A anti-gen is a protein that causes immune response
Cholera
1. Cholera bacteria produces a toxin which causes chloride ions to move into lumen of the intestine. Water potential of intestine falls / water moves by osmosis into intestine.
  1. Lowers water potential in lumen so water enters intestine leaves the cells by osmosis
    1. Does not have a nucleus/nuclear envelope/has loop of DNA//no mitochondria / no golgi/ no endoplasmic reticulum/Small Ribosomes/ Capsule/flagellum/plasmid / cell wall/
How science works
1. factors that increase risk of CHD
  1. Smoking/age/genes/high blood pressure/gender alcohol/lack of exercise/obesity/stress
    1. random selection avoids bias. / Control groups are To ensure that results are not due to some other substance./
      1. Denature at 30, active site is distorted, no more es complexes can form
      2. Allows comparison Idea that weights/Idea that cylinders have different starting masses
    2. high substrate concentration = higher ROR but will plateau
      1. Line of best fit is more reliable / point where line crosses axis is more reliable - (additional readings)
CELLS/Adaptations
1. Adaptions of epithelial cells
  1. carrier protein for sodium (ions) and glucose
    1. carrier proteins for facilitated diffusion
      1. Carrier proteins for active transport
        Many mitochondria provide energy for active transport
        Microvilli increase surface area
        Asthma narrows airways/ Air in alveoli is not replaced as efficiently / Difference in concentration of oxygen is lowered so rate of diffusion lower
Sugars
1. Glucose + glucose = maltose/ glucose + Galactose = lactose/ glucose + fructose = sucrose
  1. Hydrolysis is the opposite of condensation reaction ( adds h20)
Enzymes being specific
1. Enzymes Active site has a specific structure so it does not bind with other lipids, so it does not form enzyme-substrate complexes
  1. (induced fit) Active site is not complementary/the active site changes is flexible/Change in enzyme allows E-S complex to form
    1. Competitive inhibitorsHave similar structure so will compete to the complementary active site. This causes less enzyme substrate complexes to be formed
Homoginisation - releases organelles
1. Isotonic - Prevents osmosis So organelle named organelle is not damaged
  1. Ice Cold - Reduces enzyme activity
    1. Filtration - Removes cell debris
      1. Buffer solution maintains a constant Ph
Tem/sem
1. Cannot look at living cells /Tem is high resolution/ black n white/ large expensive/small objects can be seen
2. Thin sections do not need to be prepared/shows surface of specimen/can have 3-D images
cross a cell surface membrane
1. lipid-soluble molecules pass via phospholipid bilayer
  1. Water moves by osmosis from high water potential to low water potential
    1. Active transport is movement from low to high concentration against concentration gradient
      1. facilitated diffusion down the concentration gradient
Alveoli walls thicken/ Less surface area/ Loss of elastin so lungs cannot recoil/air not replenished so Less oxygen enters blood / less energy released (emphysema)
1. Bacteria transmitted in droplets /Bacteria ingested by phagocytes / then Bacteria is encased in nodule and is not replicating/ If immunosuppressed bacteria replicate and go to destroy the epithelial cells Leading to scar tissue Damage so there's less diffusion/damage allows bacteria to spread to other organs
  1. Phagocytes engulf pathogens/Enclosed in a phagosome/Lysosomes have enzymes that digest the pathogens

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	Created by theodryden about 9 years ago