Biology B1 (Higher Tier) - Understanding Ourselves

A simple bullet point summary of what you need to know for the B1 higher tier Exam.

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  • Created by: heather
  • Created on: 09-05-11 20:11

Fitness and blood pressure

  • Being fit is not the same as being healthy.
  • Healthy - being free from any infections or diseases.
  • Fit -is a measure of how well you can perform physical tasks.


  • possible consequences of having high blood pressure (burst blood vessels, damage to brain, stroke, kidney damage) 
  • possible consequences of having low blood pressure (dizziness, fainting, poor circulation).

  •  blood is under pressure due to contractions of heart muscles - so it reaches all parts of the body.
  • blood pressure varies according to - age, lifestyle, diet, exercise, weight, alcohol, stress.

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Respiration 1

  • Respiration - when glucose reacts with Oxygen in cells to release energy.
  • During exercise - breathing + pulse rates increase to deliver Oxygen + Glucose to muscles quicker - to remove carbon dioxide from muscles quicker.
  •  There are two types of respiration - aerobic and anaerobic
  • Aerobic respiration
  • word equation for respiration with oxygen(aerobic respiration) - Glucose + Oxygen = Carbon dioxide + water (+energy)
  • the symbol equation for aerobic respiration:C6 H12 O6 + 6O2 = 6CO2 +6H2O + (energy)
  • Aerobic respiration is what happens when there's plenty of Oxygen available
  • this is the respiration you use most of the time
  • Explain fatigue in terms of lactic acid build up (oxygen debt) and how this is removed during recovery: hard exercise causes lack of oxygen in cells; incomplete breakdown of glucose; continued panting replaces oxygen allowing aerobic respiration; increased heart rate ensures blood carries lactic acid away to the liver.

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Respiration 2

  • Anaerobic respiration releases much less energy than aerobic respiration

Anaerobic Respiration

  • Anaerobic respiration - Glucose = lactic acid (+energy)
  • Anaerobic respiration is when you do vigorous exercise your body can't supply enough oxygen to your muscles for aerobic respiration - even though your heart rate and breathing rate increases as much as they can.
  • Anaerobic means without oxygen.
  • In Anaerobic respiration, the glucose is only partly broken down, and lactic acid is also produced.
  • The lactic acid builds up in the muscles, which gets painful and makes your muscles fatigued.
  • After resorting to anaerobic respiration, when you stop exercising you'll have an oxygen debt.
  • Basically your muscles are still short of oxygen because they haven't been getting enough for a while. You also need extra oxygen to break down all the lactic acid that's built up in your muscles.
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Eating Healthily

  • carbohydrates - provide energy
  • fats - provide energy, energy stores and insulation
  • proteins - needed for growth and repair of tissues
  • Vitamins - vitamin C - prevent scurvy
  • Minerals - iron - needed to make haemoglobin for healthy blood
  • water - replaces water loss from urinating, breathing and sweating
  • Fibre - stops constipation (keeps gut in working order)

Age - children/ teenagers need more protein for growth - older people need more calcium to fight against degenerative bone diseases like Osteoporosis.

Gender - Females need more iron to replace the iron lost in menstrual blood.

Physical activity - Active people need more protein for muscle development, and more carbohydrates for energy.

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diet problems

  • Obesity is a common eating disorder - it is defined as being 20 percent or more over the recomended body weight.
  • Obesity can increase the risk of diabetes, arthritis, high blood pressure, coronary heart disease (CHD) and even some forms of cancer.
  • Eating too little protein can cause a condition called Kwashiorkor - a common symptom is a swollen stomach.
  • Calculate the reccomended daily allowance (RDA) of protein using this formula: RDA (grams) = 0.75 times body mass (kg)
  • Some psychological disorders cause under - nutrition, e.g. anorexia nervosa and bulimia nervosa. Anorexia leads to self - starvation. Bulimia invloves binge eating, followed by self - induced vomiting.
  • there both usually caused by low self - esteem.
  • these disorders can also cause a lot of other illnesses e.g. liver failure, kidney failure, heart attacks, muscle wastage, low blood pressure and mineral deficiencies. Bulimia can lead to tooth decay ( the acid in vomit eats away at the tooth enamel ) - both orders can be fatal.
  • The body mass index (BMI) is used as a guide to help decide whether someone is underweight, normal, overweight or obese.
  • Its calculated from their height and weight.
  • BMI = body mass ÷ (height)²
  • BMI isn't always reliable - Athletes have alot of muscle, which weights more than fat, so they get a high BMI even though their not overweight.
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  • Carbohydrates are broken down by carbohydrase into simple sugars*.
  • Proteins are broken down by protease into Amino acids*.
  • Fats are broken down by lipase into fatty acids and glycerol*.
  • *these are produces of digestion and are small enough to pass through the walls of the small intestine and into the blood stream.

Chemical digestion

  • First our teeth physically break down the food
  • second - food gets coated in saliva - makes food slippy so easy to swollow - and adds enzymes
  • third - proteins, fats and carbohydrates are too large for our body to use
  • forth - we have to break them down into small soluble molecules - so they are able to be absorbed into our blood stream and be transported around the body.
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Infectious diseases

  • infectious diseases are caused by pathogens (diseases causing micro organisms such as fungi, bacteria, viruses and protozoa.
  • Fungi - athlete's foot
  • viruses - flu
  • bacteria - cholera
  • protozoa - dysentery
  • the human body is protected against pathogens by : the skin, blood clotting, mucous membranes in the respiratory system, and hydrochloric acids in the stomach.
  • Malaria is an example of an infectious disease caused by a protozoa.
  • Your immune system deals with pathogens
  • White blood cells travel around your body and patrol for micro - organisms.
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Infectious diseases 2

  • When they come across an invading micro - organism they have three lines of attack:
  • 1. consuming them - White blood cells can engulf foreign cells and digest them.
  • 2. Producing Antitoxins - antitoxins counter the effect of any poisons (toxins) produced by the invading bacteria.
  • 3. producing antibodies -
  • 1. every pathogen has unique molecules on the surface of its cells - no two species have the same ones. these molecules are called antigens.
  • 2. When your white blood cells come across a foreign antigen they'll start to produce proteins called antibodies, which lock on to other pathogens.
  • 3. Antibodies produced are specific to that pathogen - they won't lock on to other pathogens.
  • 4. If the person is infected with the same pathogen again the white blood cells will quickly produce the antibodies to kill it - the person is naturally immune to that pathogen and won't get ill.
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