Biology- B1

?
  • Created by: skylidge
  • Created on: 09-04-17 08:39

Heart Health

  • Circulatory System:
  • Carries Oxygen and Glucose in blood to cells
  • Cells release energy through Anerobic respiration 
  • Heart relaxes to fill with blood and contracts to squeeze it out 
  • Blood Pressure: -mmHg (milllimeters of mercury)- systolic/diastolic
  • Systolic- Pressure when heart contracts
  • Diastolic- Pressure when heart relaxes 
  • Normal blood pressure is 120/80 mmHg
  • High pressure can be reduced by regual aerobic excercise and a healthy diet 
  • High pressure can be cause by: Excess weight, Stress, Alcohol, Smoking (Nicotine increases heart rate and CO takes the place of O2 in the haemoglobin). Diet high in salt, sugar and saturated fat ( builds up cholesterol which forms plaques- increased risk of heart attack0 
  • High pressure can weaken blood vessels causing them to burst if this happens in the brain it can cause a stroke/ brain damage. 
  • Low pressure means some of the body doesnt get O2 or Glucose: organ failure, fainting, cold. 
  • Heat disease: too much salt, high pressure, smoking, high fat diet. Fat and Cholesterol block arteries this narrows them and can cause heart attacks and Thrombosis. 
1 of 19

Health and Fitness

Health vs Fitness

  • Healthy means being free from disease and infection 
  • Fit relates to how much physical activity you can do and how quickly you can recover
  • Aspects of fitness include: strength, stamina, agility, speed and flexibility. 

Cardiovascual Efficiency

  • How well your heart copes with aerobic exercise and how quickly it recovers after.
  • Fit person- heart rate will be lower during exercise and will return to normal faster after exercise compared to a less fit person. 
  • A combination of tests is the best way to measure someones fitness. 
2 of 19

Diet

Balanced Diet

  • Gives us energy and nutrients.
  • A balanced diet needs cabohydrates/fats for energy, protein for growth and repair. 
  • Carbs-simple sugars e.g. glucose (stored in liver or made into fat). Fats- fatty acids and glycerol (stored as adipose tissue). Proteins- amino acids (not stored)
  • To stay healthy you also need: Minerals(iron makes haemoglobin), Vitamins(C prevents scurvy), fibre (help with bowels) and water (remove waste). 
  • You may change the way you eat due to: Beliefs, religion, medical issues, age, sex and activity. 

BMI

  • You need to balance the amount of energy you take in with the amount you use up. 
  • BMI= Body mass index=  Mass(kg)/ Height(m)2
  • Below 18.5 means underweight, 18.5-24.9 ideal weight, 25-29.9 overweight, above 30 obease
  • If you eat more than you need you can become obease, this is a major health problem and can cause arthritis, heart disease, type 2 diabetes and breast cancer. 
3 of 19

Diet 2

Protein- Enable us to grow

  • Esential amino acids must be taken in by eating food, Non-essential can be made in your body
  • Proteins from animals are first class proteins becuase they contain all essential amino acids. Plant proteins are called second class. 
  • Protein dificiench can cause kwashiorkor. This is common in developing countires. 
  • EAR= estimated average daily requirment of protein= 0.6* Body mass (kg)
  • EAR can vary depending on age, pregnancy and lactation. 

Poor diets and eating disorders

  • Low self esteem, poor self image and desire for perfection can all cause poor diets.
  • This can be very damaging to the body as it doesnt get the right balance of energy and nutrients to function correctly.
  • Bone and reproductive damage can be caused
  • Eating disorders such as anorexia nervosa and bulimia nervosa may result.
4 of 19

Diseases

Non-infectious- Can't be caught as no pathogens are involved

  • Caused by: poor diet, organ malfunction, genetic inheritance and mutations.

Cancer- Mutated cells growing out of control

  • Ways to reduce the risk of it: Don't smoke, don't drink in excess, avoid getting sun burn, eat healthily. 
  • Cancer is caused by tumours. A tumour that grows in one place is called benign, but if cells break off and a tumour grows in a different part of the body then it is malignant. 
  • A persons chance of survival depends on which kind of cancer they have and how early it is caught, their age and the kind of tumour.

Infectious Diseases- Can be spread and are caused by pathogens

  • Caused by microorganisms: bacteria (Cholera), fungi (Athlete's foot), viruses (Flu) and protozoa (Malaria). 
5 of 19

Diseases 2

Malaria- Spread by vectors (mosquito) Can be fatal

  • Mosquito sucks blood from host, if there are malaria parasites in the host then they move to the vectors gut and then to its salivary glands. If the vector bites another perosn then it passes the maleria to them through the blood stream. The parasites move to the new hostsliver where they mature and reproduce. New parasites move to the blood and replicate in blood cells which burst open. 
  • By learning how the disease is spread we can contol it. Sleep under mosquito nets, use insect repellant amd use insecticides. 

Defence against pathogens

  • Ways to stop them getting in: Skin, Blood clots, mucus, strong stomach acid (Hydrochloric).
  • If they enter the body we start to develop symptoms as the pathogen damages cells with toxins. 
  • White blood cells deal with pathogens: White blood cells engulf pathogens in the blood stream. They also make anibodies which are made once they recognise antigen markers on the pathogen. Every pathogen has unique antigens so white blood cells have to make specific anti bodies for them. 
6 of 19

Immunity

Natural (Active immunity) 

  • Comes after being infected by a pathogen. The white blood cells create the specific anti body needed to destroy the infection. The prevents future infections from the same pathogen. 
  • Immunisation provides natural immunity wihtout being infected. The person is given a weak or dead strain of the pathogen which can't multiply and with this their body learns how to fight the pathogen if it is detected again. 
  • Benefits include: The extinction of a disease and it protects agaisnt very harmful diseases. 
  • Risks include: Bad reaction and its not 100% safe. 

Passive Immunity

  • This is when anti bodies are put into an individuals body rather than the body producing them.  This is needed if the person has a weak immune system. 
  • E.g. snake venom acts very fast so people need to be injected with anti bodies. This will not give them a long term resistance to the pathogen. 
7 of 19

Medical Drugs

Treatment

  • Fungi and Bacteria can be treated with antibiotics. Viruses can be treated with antivirals
  • If antibiotics are over-pescribed then bacteria can become resistant to the drug. 
  • MRSA is a superbug which has become resistant to most antibiotics. 

Testing new drugs

  • Drugs need to be tested to see if they are safe
  • This can be done by: computer models (predicts how it will affect cells based on known infomation) Animals ( how it affects living organisms, seen as cruel) Human tissue ( to see how it affects human celss, some believe this is unatural and wrong) 
  • Finally, the drug needs to be tested on volunteers both with the disease and without. Some are given the new drug and some are given a placebo so its effects can be recorded. Drug trials can never be 100% safe. 
  • Blind trials- voulnteers don't know whether they have the drug or placebo. (eliminates psychological factors and gives a fair comparison) 
  • Double blind trials- neither doctor or voulenteers know if they have the drug or placebo. Eliminates bias from the test as the doctors can't inffluence the voulenteer's response. 
8 of 19

The Nervous system

Nervous system 

  • Allows you to react with surroundings and coordinate your behaviour. 
  • CNS (central nevous system) and PNS (Peripheral nervous system) these contain neurones and receptors. 
  • Recoptors (specialised nerve endings) allows us to detect changes in our environment

Neurones 

  • Carry nerve impulses. Electrical messages are carried along the axon (long thin part of the cell)
  • The 3 types: Sensory (carry impulses from receptors to the brain) Realy (make connections between your brain and spinal cord) Motor ( carry nerve impuleses from the brain to muscles and glands) 
  • Neurones are adapted: elongated shape to make connections from one part of the body to another. Insulating sheath which speeds up impulse. Dendrites (branced ends) which allow one neurone to work on many muscle fibres.
9 of 19

Reflexs

Synapse- Gap between neurones

  • Impulse reaches the synpase, A transmitter substance diffuses across the synapse. Transmitter binds with receptor molecules on the next neurone causing an electrial impulse to be initiated and the signal to go on. 

Actions

  • Voluntary- under your conscious control, you decide how to react. 
  • Reflex- bypasses your brain to give a fast automatic response. 
  • Examples of Reflex : pupil controls light entering the eye, knee jerk, automatical moving your hand from a hot object to avoid being burnt. 
10 of 19

The Eye

Parts

  • Iris- contols the amount of light entering the eye 
  • Cornia- refracts rays of light 
  • Lens- focuses light onto the retina to produce a clear image
  • Retina- contains light receptors which detect light/ colour 
  • Optic nerve- takes sensory infomation from the retina to the brain
  • The lense is a clear, flexible bag of fluid, joined to ciliary muscles by suspensory ligaments
  • When object is near- muscles contract, ligaments relax, lens is short and fat
  • When object is far- muscles relax, ligaments contract, lense is long and thin

Defects

  • Colour blindness- caused by missing colour detecting cells in the retina
  • Long/ short sight- Eye ball of cornia is the wrong shape. Can be corrected with contacts and glasses: convex lenses for long sight and concave for short sight. It cal also be fixed by laser surgery, with this the cornia is rehsaped
11 of 19

Vision

Binocular

  • Eyes close together on the front of the head.
  • Each eye has a limited veiw feild
  • Can judge distance and speed accurately
  • Found on humans and preators
  • Judges distance by comparing the imgaes from each eye, the more similar the futher the object is. 

Monocular

  • Eyes on either side of the head
  • Each eye had a wide feild of veiw, can see behind and in front. 
  • Litlle overlap in the feild of veiw which makes it difficult to jusge distance and speed.
  • Found on prey
12 of 19

Drugs

Types

  • Stimulants- increase brain activity as more neurotransmitter crosses the synapse, gives feelings of alertness and heightened perception
  • Depressants- decrease brain activity as they bind to receptor molecules blocking neuro impulses. Can make you feel tired, slow reaction times, lathargic and forgetful 
  • Pain killers: reduce pain by blocking nerve impulses
  • Performance enhancing: increase muscle development.
  • Hallucionogens- distort what is seen and heard
  • Class A (cocaine, heroin) B (speed, barbiturates) C (steroids, tranquilisers)

Addiction

  • The 'need' for a drug. As an adicts body becomes tolerant to the drug they need more to feel the same effect. 
  • When an adict stops taking drugs they can get phycholgical problems and physical problems. 
  • Rehabilitation is the process by which an adict learns to live without a drug. 
13 of 19

Alcohol and Tobacco

Alcohol 

  • Short term effects: Lack of balance, blurred vision, slurred speech, poor judgement, vasodilation- heatloss, in extream cases death and unconciousness
  • Long term: Liver damage as the liver uses enzymes to break down the alochol but this produces products that are toxic to the liver. Brain damage due to dehydration. 
  • Legal blood alchol for driving is 80mg of alochol of every 100ml of blood. 

Tobacco

  • Problems caused by smoking: cancer, heart disease, emphysema and bronchitis. It damages the cilia which stops them from removing mucus, tar and dirt from the smokers lungs and causes 'smoker's cough'. 
  • They contain: Tar which contains chemicals that are irritants and carcinogens. Particulates in the smoke accumulate in living tissue and can cause cancer. Nicotine which is very addictive, carbon monoxide which takes the place of oxygen in the blood. 
14 of 19

Homeostasis- Temperature control

Homeostasis- Maintains a constant internal environment 

  • You body balances inputs and outputs: temperature, water, oxygen and carbon dioxide.

Body Temperature

  • Enzymes in your body work best at 37oC, heat produced through respiration is used to maintain this temperature.
  • Too hot- Vasodilation, the blood vessels widen so blood flows closer to the skin and heat is lost, sweat glands also release sweat which uses heat energy to evaporate thus cooling down the skin. If you get too hot you can become dehydrated as a result of sweating, get heat stroke and even die, hyperthermia
  • Too cold- Vasoconstriction, blood vessels get tighter so less energy is lost through the skin, muscles start making tiny shivers which release energy and keep you warm. If you get too cold you can get hypothermia which is when your core temerature is below 35oC. This can cause unconsciousness and even death. Puting on clothing and doing exercise can keep you warm.
  • Negative feedback- when the body automaticaly reverses its condition when the environmental condition changes. E.g. If you get too cold your brain switches on systems to warm its self and vica versa. 
15 of 19

Homeostasis-Hormones

Hormones - Chemical messages released by glands into the blood stream

  • They are slower than impulses as they travel at the speed of blood. 
  • Glands include: Pitrutary gland, thyroid, pancreas, adrenal, ovaries and testies

Diabetes

  • Insulin is a hormone used to control blood sugar levels, it converts excess glucose into glycogen in the liver. It allows sugars to eneter cells
  • Type 1 diabetes: is where the pancreas fails to produce insulin. This can cause bloodsugars to become fatally high and could resulat in coma or death. Blood sugar has to be controlled by insulin injections. Before eating the person must take a ***** test to check their blood sugar. If the food they are eating is high in sugar they need more insuline, if they intend to excercise then they need less as it will use up sugar.
  • Type 2: This affects cells which respond to insulin. Injecting insulin has no use as the cells are desesitised to it. This is usaly treated with diet. 
16 of 19

Plant growth

Plant Hormones - Contol the growth of shoots and roots as well as fruits

  • Auxins- move through the plant in solution, affect growth by responding to tropisms. E.g. Shoots have positive geotropism and negative phototropism and Roots have postive phototropism and negative geotropism. 
  • Auxin is made in the shoot tip. It causes plants to grow towards the sun. The auxins on the side the sun is shining on are denatured whereas the ones on the other side aren't so the side facing away from sunlight grows and causes the plant to bend towards the sun. 

Commercial uses

  • Rooting powder- encourages the growth of roots in stem cuttings
  • Fruit-ripening- causes fruit to ripen so we can accelerate or delay it if required
  • Control of domancy- hormones can be used to speed up or slow down plant and bud development 
  • Selective weedkillers- hormones which disrupt the weeds growth pattern and cause them to die but dont harm other plants, this is becuase the weeds absorb more weed killer as they have a larger surface area. 
17 of 19

Variation and Inheritance 1

Variation - Differences in the same species

  • Gentic- Individuals can inherit different combinations of genes: mutations, differences in gametes or just the random nature of fertilisation. E.g. Nose shape or Eye colour
  • Environmental- Individuals develop in different conditions which can change some characteristics. E.g. Language, scars
  • Scientists are still debating which has the biggest infulence in characteristics such as intelligence or health but they are unlikely to be just due to one. 
  • Alleles - The different versions of a gene 
  • 23 Chromosomes hold our genetic infomation. These code of characteristics or proteins called genes. 
  • Dominant alleles contol a characteristic even if only in one chromsome of the pair. Recessive only contol development if the dominant isn't present. B-dominant, b-resesive
  • Homozygous- a person containing the same allele of a gene in both chromosomes
  • Heterozygous- contain different alleles.  
  • When a charateristic is contoled by just 1 pair of alleles it is called monohybrid inheritance. 
  • Letters used to descibe a gene is the genotype, the expressed characteristic is the phenotype.
18 of 19

Variation and Inheritance 2

Sex

  • Gender is determined by sex chromosomes: **=female; XY= male
  • Eggs carry the X chromosome and half sperm carry X and half carry Y. 
  • There is an equal chance to have male offspring as female due to the 50:50 X:Y of sperm.

Diseases -  Caused by faulty genes

  • E.g. Sickle cell anaemia, colour blindness, cystic fibrosis. 
  • Mostly caused by recessive faulty alleles. Offspring only have to disorder if both genes are fauty. 
  • This means for something such as cystic fibrosis you can be a carrier for the disease but not have it as your dominant allele protects you. 
  • E.g. Two healthy parents with Cc Cc have 1 in 4 chance of having a child with cystic fibrosis. 
19 of 19

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Understanding Organisms resources »