Biology- key stuff

Osmosis/ diffusion

Diffusion-  net movement of particles (low to high conc.), down conc. gradient.

 Osmosis- diffusion of water (dilute to more conc.), through partially permable membrane.

  • Hypertonic- shrivelled.
  • Isotonic- normal for animals
  • Hypotonic- bursting, normal for plants.


Active transport- movement of substances agaisnt conc. gradient, using energy (low conc. to high).



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Mitosis/ meiosis

Mitosis- 1 stage process:                          (Diploid)

  • a copy of each chromosome made
  • cell splits in two
  • produce 2 identical daughter cells

NO variation!!!

Meiosis- 2 stage process:                         (Haploid)

  • a copy of each chromosome is made
  • cell splits in two
  • cells split in two again
  • produce 4 gamete sex cells

There IS variation!!!!

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  • muscular- contract to bring movement
  • glandular- produce/ release enzymes + hormones
  • epithelial- covers body/ organs.                                                                                                     PLANT
  • epidermal- covers surface of plant
  • paliside mesophyll- chloroplast (photosynthasis)- top layer
  • spongy mesophyll- big air spaces + surface area- diffusion.
  • xylem- transports water
  • phloem- transports sucros                                                                                                               TUMOURS
  • Benign- single, not affect other tissues, can be life threatning.
  • Maligant- (cancer), spreads (blood streme).
  • Causes: carcinogens, ionising radiation, virus infections.
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Lipids, proteins, carbs

     Lipids:                                                     Lipase

  • fat- source of energy                                     -nuts
  • test- ethanol (milky white)                            -cream
  • Made from: glycerol + fatty acids                  -butter                 Proteins:                                                Protease
  • Hormones, enzymes, antibodies                   -meat
  • Enzymes denature (too hot, wrong pH)           -pulses
  • Test: biurets solution (cloudy white)              -cheese
  • Made from: amino acids                                               Carboydrates:                                           Carbohydrase 
  •  Long lasting energy                                      -banana
  • Test: iodine (black)                                        -sugar
  • Made from simple sugars                                -bread


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Postitve: forces air into lungs (to infalte), pressure stops to deflate.

Advantages: portable, used in operations, patients can move, simple.      

Disadvantages: tube inserted into trachea, need source of gas.

Negative:air pumped into chamber 2 cause vaccume. IRON LUNGS

Advantages: used to treat polio, patient can talk, patients can cough.

Disadvantages: patients cannot move about, not portable, hard to acess                                  patientss, can cause blood in abdomen

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Energy used for: growth/ repair; active transport, heat generation, making proteins.

Aerobic: release large amount of energy in cells in presence of oxygen

     glucose + oxygen -> carbon dioxide + water +energy

Anaerobic: release small amount of energy in cells in the absence of oxygen.

          glucose -> lactic acid + energy

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Blood Vessels

Artery: brings blood away from the heart.

  • High pressure and oxygen
  • Thick walls

Vein: brings blood back to the heart.

  • low pressure
  • Valves
  • Thin walls

Capillary: links arterys and veins.

  • low pressure
  • allows diffusion of sudstances
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Parts of the blood

Platelets: helps blood clot (fibrogen to fibrin)

Red blood cells: picks of oxygen from lungs and carries to the body (haemoglobin).

White blood cells: bodies defences systeem. (antibodies and antitoxins).

Plasma: waste stuff carried around body. (urea, CO , digestive system)

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Nervous System key words

Central nervous system: brain and spinal cord

Neurotransmitters: chemiicals that diffuse across the synapse.

Reflex: automatic response of nerous system to stimuli, uncontious. 

Synapse: gap between neurons where the transmition of info is chemical, not electrical.


Stimulus response pathway: stimulus ->  receptor -> sensory  neurons -> coordinator -> motor neurone -> effector ->  response

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The brain

Cerebral Cortex: concerend with consciosness, intelligence, memory, and language.

Cerebellum: concerned mainly with coordinating muscualr activity and balance.

Medulla: concerenced with unconscious activites: heartbeat, breathing, movement of gut.

Hypothalmus: regulation of body functions (thermoregulation)

Pituitary Gland: produces chemical messags(hormones) which control reactions in the body.

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Homeostasis key words

Homeostatis: maintence of constant internal body conditions.

Hormone: chemical producaed in glands to carry chemical messages.

Coordinators: brain, spinal cord, pancreas.

Liver: organ that produces bile

Kidney: filters blood- removes ures, excess salts and water.

Urea: waste product formed by breakdown of amino acids

Selective reabsorbtion: the kidneys selectively reabsorb only those molecules which the body needs back in the bloodstream.

Thermoregulatory: in brain controls/ monitors body temperature.

Diabetes: failing to regulate blood sugar levels.

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Type 1:pancreas not producing enough inculin                                              = high blood glucose levels

  • Genetics
  • Control: transplant, inject insulin

Type 2: body cells not responding to insulin.

  • age, obesity.
  • Control: loose weight, drugs, exersize


Insulin: hormone controlling sugar levels

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Treating disease

MMR vacination: measels, mumps, reubella.

Heard immunity: if most people are immune to a diease in a community then it cant spread, and it will die.

White blood cells:               

  • Ingest pathogen
  • Antibodies made for specific antigen on pathogen to destroy it.
  • Antitoxins counteract toxins from pathogens.

Anitbiotics: chemical compund killing bacteria.                        

Painkillers/ drugs: relieve symtoms but not killing pathogen.

Antiseptic: kills microoganisms in the enviroment.                                                                                              

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Growing baterica

Keeping it uncontaminated:

  • sterilize petri dish + agar
  • sterilize incoulating loop (flame)
  • tape the lid down
  • place it upside down (condesation)


  • 25 degrees (not hotter as harmfull bacteria may grow)
  • culture medium: nutrients, carbohydrates, minerals. (agar jelly)
  • dont tape lid all the way round (oxygen needs to get in)
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                carbon dioxide + water -> glucose + oxygen

                       6CO + 6H O -> C H O + 6O

Photosynthesis ingrediants:

  • Carbon dioxide
  • Light
  • Water
  • Chlorophyll.

Limiting Factors: light, temperature, carbon dioxide

Testing for starch: iodine goes blue/ black.

  • no starch in plant left in the dark as it has used it all up to convert to energy (glucose)
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Auxin: plant horone controlling plant responses.

  • Phototropism
  • Gravitropism
  • Negative
  • Positve

Plant shoots grow towards light, against the force of gravity.

Plant roots grow towards moisture, in the direction of gravity.

                                                                         Auxin spreads to the dark side

Shoot grows more on the side with the most auxin

Root grows more on the side with the least auxin.

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