Biology B3
- Created by: Alice Fisher
- Created on: 11-05-13 11:30
Osmosis
- Movement of water, same process as diffusion
- Across a partially permiable membrane
- Movement is random
- Requires no energy
- Water moves from a high concentration to an area of low concentration
- From dilute solutions to more concentrated solutions
Active Transport
- Absorbtion of substances, not same process as diffusion
- Across a partially permeable membrane
- Requires energy from respiration
- Absorbtion is done against a concentration gradient
- Transport proteins attract molecule from out side cell
- Transport protein rotates and releases it into cell
Sports Drinks Dilemma
- During exercise, glucose is used up
- When you sweat your body cells loose water, you become dehydrated
- Necessary to replace the water, glucose and mineral ions
- Sports drinks balance the concentration of body fluids
- If drink concentraion matches body fluids, solution is isotonic
Lungs
- Large surface area, thin walls, short diffusion path
- Surface area is increased by alveoli
- Alveoli have thin walls, large surface area, good blood supply
- Lungs are ventilated, maintains steep diffusion gradients
- Oxygen diffuses into blood through alveoli
- Carbon dioxide diffused out of blood, back into lungs, through alveoli
Ventilating the Lungs
- Lungs situated in thorax
- Breath in: -intercostal muscels contract
-ribcage up and out, diaphragm flattens
-volume of thorax increases
-pressure of thorax decreases, draws air in
- Breath out: -intercostal muscels relax
-ribcage down and in, diaphragm domed
-volume of thorax decreased
-pressure of thorax increased, air forced out
Reasons Why People Cant Get Enough Oxygen
- Alveoli are damaged, reducing surface area for gas exchange
- Tubes leading to lungs are narrow
- Person is paralysed, muscles will not move ridcage up and out
Artificial Breathing Aids
- 'Iron Lung'- vacuum effect creating negative pressure, when air was drawn out the persons chest moved out and they breathed in
- 'Oxygen Mask'- positive pressure as measured amounts of air are forced into the lungs
Exchange in the Gut
- Food, digested into soluable molecules
- Small intestine absorbes solutes into blood
- Villi line surface of small intestine and increase surface area, they are the exchanges surface for the absorption of food molecules
- Villi, have thin walls and lots of capillaries
- Soluable products are absorbed in Villi by diffusion or active transport
Exchange in Plants
- Gas diffuse in and out of leaves through stomata
- Size of stomata controlled by guard cells
- Oxygen and Carbon dioxide diffused into and out of cell through stomata
- Water vapour lost through stomata, due to evapouration in leaves
- Water and mineral ions absorbed by roots, root hair cells increase surface area=quicker absorption
- If more water is lost than absorbed, stomata close
- Wilting reduces water loss, by reducing surface area
Transpiration
- Movement of water through plant=transpirtaion stream
- Plants dehydrate if rate of evapouration in leaves is greater than water uptake
- Evapouration more rapid in: hot, dry, windy, bright conditions
Circulatory System (Heart)
- Right pump: - takes blood from body
- forces deoxygenated blood into lungs
- where it picks up oxygen, looses carbon dioxide
- new oxygenated blood returns to the heart (left pump)
- Left pump: - takes oxygenated blood from heart
- pumps it round the body
- left side of heart is more muscular, has to pump blood to whole of the body
- Heart has 4 chambers: left and right atria (at the top) and the left and right ventricles (at the bottom)
Circulatory System (Heart)
- Right pump: - takes blood from body
- forces deoxygenated blood into lungs
- where it picks up oxygen, looses carbon dioxide
- new oxygenated blood returns to the heart (left pump)
- Left pump: - takes oxygenated blood from heart
- pumps it round the body
- left side of heart is more muscular, has to pump blood to whole of the body
- Heart has 4 chambers: left and right atria (at the top) and the left and right ventricles (at the bottom)
Heart Chambers and Valves
- The Atria: - recieves blood from the Vena Cava on the right
- recieves blood from the Pulmonary Vein on the left
- The Atria contracts to force blood into the lower chambers, the Ventricles
- The Ventricles: - forces blood into the Pulmonary Artery on the right
- forces blood into the Aorta on the left
- The heart contains valves to stop blood from flowing the wrong way
Keeping the Blood Flowing
- Artery: - thick walls
- small lumen
- thick layer of muscle and elastic fibres
- Vein: - large lumen
- relatively thick walls
- often have valves
- Capillary: - thin vessels with narrow lumen
- walls are single cell thick
- If blood vessels are blocked, organs will be deprives of oxygen and nutrients
- Stents are fitted to stop this
- Leaky valves can be replaced by artificial ones or animal ones
Transport in the Blood
- Blood is a tissue made up of plasma
- Plasma has white blood cells, red blood cells and platelets in it
- Plasma transports: carbon dioxide, soluable productes of digestion, urea
- White Blood Cell: - has a nucleus
- part of defence system
- Red Blood Cells: - biconcave
- no nucleus
- contains haemoglobin
- uses haemoglobin which combines with oxygen in lungs, to form oxyhaemoglodin, oxyhaemoglobin splits when it gets to organs for form oxygen and haemoglobin
- Platelets: - no nucleus
- helps blood to clot at site of wound
Artificial or Real? - Blood
- Blood Doners: Advantages - less expensive
- carries more oxygen
- dosen't cause side effects
Disadvantages - needs to be refrigerated
- has to be separated into cells and plasma
- blood has to be matched
- Artificial Blood: Advantages - Perfluorocarbons (PFCs) doesn't need refrigerated
- does not need matching to blood
Disadvantages - doesnt carry as much oxygen
- expensive
- can cause side effects
- inslouable in water, doesnt mix well with blood
Artificial or Real? - Hearts
- Heart Transplants:
Advantages - new heart, new life
Disadvantages - need to take immunosuppressents
- could be rejected
- Artificial Hearts:
Advantages - dont need to match tissues
- no immunosupressents
Disadvantages - problems with blood clotting
- long stays in hospital
- expensive
Transport Systems in Plants
- 2 transport systems: - xylem transports water and mineral ions from root to stems to leaves
- phloem transports food/sugars from leaves to other parts of the plant
Controlling Internal Conditions
- Homeostasis
- Waste products must be removed from the body eg: carbon dioxide and urea.
- if there is too much water or ions, too much of them may move into or out of the cell, causing damage or destruction
The Kidney
- Filters the blood, getting rid of unwanted substances and keeping those the body needs
- A heathly Kidney produces urine by: - filtering the blood
- reabsorbing all the sugars
- selectively reabsorbing the ions needed
- selectively reabsorbing as much water as needed
- releasing urea, excess water and ions in the blood
- No protein should leave the blood when being filtered as it is too big
Dialysis
- Dialysis filters the blood outside of the body instead of the kidney
- Blood leaves the body and enters a chamber with partially permiable membranes
- Dialysis fluid flows outside the membranes
- It contains the same useful substances as the blood needs, so none of the useful substances are diffused out of the blood
- The fluid contains no urea, so all of the urea gets diffused out because of the steep concentration gradient
- Disadvantage: - it has to be done every few days nd takes 3 hours
Kidney Transplants
- Donor must be a good match, so its not rejected
- rejection means: the recipients antibodies attack the donor kidneys antigens, as they are seen as forgien
- To stop rejection, have to take immunosuppressents
- Disadvantage: - suppressing teh immune system can make the patients immune system vulnerable to common infections
Controlling Body Temperature
- Human body temperature must be kept at 37, otherwise enzymes stop working
- Monitored and controlled by the thermoregulatory centre in the brain
- It contains receptors which detect temperature of blood flwing through brain
- Receptors ins kin also send impulses to brain about skin temperature
- When temperature rises: - blood vessels near surface of skin dilate, more blood flow, more energy is transferred through radiation
- sweating makes water evapourate off skin surface, takes heat energy from skin surface so it cools
- When temperature falls: - blood vessels constrict, less heat energy is radiated
- shivering requires respirtaions and this small movement creates heat energy and warms the blood
Controlling Blood Glucose
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Controlling Blood Glucose
- The pancrease monitors the amount of glucose in the blood and releases insulin to contol it if it gets to high
- The hormone Insulin controlls the amount of glucose in the blood by causing the excess glucose to move from the blood back into the cell
- If there is too little insulin produced, the person has Type 1 Diabetes
- If the blood glucose level gets too low, pancrease releases another hormone called glucagen
- Glucagen causes glycogen to be converted back into glucose and released into th blood
- Doctors are trying to find more ways to treat diabetes: - pancreas transplant
- transplanting pancreas cells
- using embryonic stem cells to produce insulin secreting cells
Effects of Population Explosion
- Humans are using more resources and producing more pollutants:
- Land and water pollution: - sewage must be treated to remove gut parasites that may get into the land or water ways
- landfills can leak toxic chemicals
- herbicideds and pesticides can get into the soil or run off the land into water ways
- Air pollution: - burning fossil fuels can produce sulfur dioxide which causes acid rain
- acid rain kills organisms eg: habitats, it chages the pH of the soil so damages roots, stops enzymes working as they are sensitive to changes of pH
Deforestation and Peat Destruction
- Deforestation leads to: - reduction of biodiversity (Biodiversity means having as wide a range of different species as possible)
- increases the levels of carbon dioxide, as it is released in the burning if trees, and the destruction of peat bogs ect
- raising cattle or growing rice in the new land areas releases methane
Global Warming
- An increase in the earths atmosphere can: - change the earths climate
- rise sea levels
- reduce biodiversity
- cause changes in migration patterns
- cause a change in the distribution of species
Biofuels
- Biofules are made from ethanol-bases
- Produced by anaerobic fermentation and distilation
- Microorganisms respire anaerobically to produce ethanol using sugars from crops
- glucose is produced using a carbohydrase, ethanol is then extracted from the glucose by distillation
- carbon neutral, only the amount of carbon dioxide used for photosynthesis by the plants is released
Biogas
- Mainly methane
- Produced during anearobic fermentation by bacteria
- Made in a Large container, the dung from animals goes in, ferments, methane is made and released and any excess materials is turn into slurry and used as a fertiliser on crops
Efficient Food Production
- Short food chains make food production more efficient
- It can be controlled by: - preventing the animals from moving, as this stops energy being wasted through movement
- keeping the animals in warm sheds, to stop them from using energy for heat
- Fish stocks can be maintained by controlling fishing quotas amd net size
- Fungus Fusarium is grown to produce mycoprotein, grown aerobically on cheap sugar syrup made from waste starch, little energy is used
- Industrial fermenters have: - an air supply of oxygen for respiration
- stirrers to keep microorganisms spread out
- water-cooled jacket on outside, to stop the energy made by respirtation heating the contents
- sensors to monitor pH and temperature
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