Flashcards in Biology 3 Deck (118):
Name the four chambers of the heart
Why does the heart have valves?
To make sure the blood flows in the right direction.
Name the four main blood vessels leading into and out of the heart
How does blood flow through a heart?
1) Blood flows from the left and right atrium from the pulmonary vein and the vena cava.
2) The atria contract which pushes the blood into the ventricles.
3) The ventricles contract which forces blood into the pulmonary artery and the aorta.
4) Blood flows out of the heart, through the arteries and comes back through the veins.
They carry blood away from the heart. The heart pumps blood at high pressures so the walls of arteries are strong and elastic. So they can spring back, they are made out of elastic fibres. So they are strong, they have thick walls made out of muscle. They have a small lumen.
The walls are permeable so that substances can be exchanged with cells. The rate of diffusion is increased because the walls are very thin (about one cell thick). They are also narrow and have a large surface area to volume ratio so that diffusion can occur quickly.
What blood vessel has valves?
Which blood vessel has the smallest and largest lumen?
Artery has the smallest lumen.
Vein has the largest lumen.
Veins carry blood towards the heart. As the blood is at a low pressure the walls aren't as thick as they would be in an artery. Veins have a large lumen.
What is blood?
What is blood made out of?
Red blood cells
White blood cells
What are the components of the blood suspended in?
What do red blood cells do?
Transport oxygen around the body.
What shape do red blood cells have?
Why does a red blood cell have a biconcave shape?
Gives a larger surface area for absorbing oxygen. They contain haemoglobin which carries oxygen.
What makes red blood cells different from most cells?
It doesn't have a nucleus.
What happens to oxygen and haemoglobin in the lungs?
Oxygen diffuses into the blood and combines with haemoglobin to become oxyhaemoglobin.
What happens to oxygen and haemoglobin in the body tissues?
Oxyhaemoglobin becomes oxygen and haemoglobin.
What is the function of white blood cells?
To protect the body against microorganisms that cause disease.
How can white blood cells protect the body?
Engulf and digest microorganisms.
True or false.
White blood cells have a nucleus.
What are platelets?
Small fragments of cells.
What are the function of platelets?
They help blood to clot at the wound.
True or false.
Platelets have a nucleus.
What is plasma?
A liquid which carries everything in the blood.
What does the plasma carry?
Red blood cells
White blood cells
What are the advantages of artificial hearts?
Help a person live for longer.
Less likely to be rejected than donor hearts.
What are the disadvantages of artificial hearts?
Surgery can cause infections.
Electric motor could fail.
Can cause blood clots.
Have to take immunosuppressants.
Can be uncomfortable.
What are artificial heart valves?
Make sure blood flows in the right direction. It can cause blood clots and infections.
What are stents?
They are placed inside of arteries so that blood can pass through.
What are the advantages of stents?
Reduce the risk of a heart attack.
What are the disadvantages of stents?
They can irritate the artery.
Make scare tissue grow.
Blood clotting can occur.
What are the phloem tubes made of?
What are the xylem tubes made of?
What do phloem tubes transport?
What do the xylem tubes transport?
Water and mineral ions.
What is the transpiration stream?
The movement of water through a plant.
What are the stages of the transpiration stream?
1) Water from the leaf evaporates.
2) This creates a shortage of water so more is taken from the rest of the plant by the xylem.
3) Now more water is drawn up through the roots.
What is homeostasis?
The maintenance of a constant internal environment?
What two products have to be removed by the body?
What are the three roles of kidneys?
To remove urea.
Adjust ion content.
Adjust water content.
How is urine produced?
Blood from the renal artery enters the kidney.
A high pressure is built up the blood vessels so water, urea, ions and sugar is squeezed out of the blood and into a capsule at the start of the nephron.
The membranes between the blood vessel and the capsule don't allow big molecules to be squeezed out so they stay in the blood.
The liquid flows along the nephron and all useful substances such as all the glucose (by active transport), sufficient water and sufficient ions are reabsorbed.
3)Release of waste products-
The urea, excess ions and excess water go out of the nephron, into the ureter and into the bladder as urine.
How does kidney dialysis work?
Someone's blood flows along a partially permeable membrane. This allows smaller molecules to pass through. The dialysis fluid has the same concentrations of dissolved substances as normal blood which means that the useful substances are not lost. Instead waste products will diffuse across the membrane.
What are the disadvantages of dialysis?
Have to go to a hospital a lot.
Expensive to run the machines.
Can lead to infections.
Can cause blood clots.
Have to be careful about what they eat.
They have to be careful about how much fluid they consume.
What are the disadvantages of kidney transplants?
Long waiting list
Immunosuppressants can cause infections
How can the risk of rejection be reduced?
Get a donor with the same tissue type.
They person has to have immunosuppressants.
What part of the brain receives information about the body temperature from receptors?
Thermoregulatory centre in the brain.
What receptors are in the thermoregulatory centre in the brain?
Receptors which are sensitive to the temperature of the blood flowing through the brain.
What happens if you're too hot?
Hairs lie flat.
Sweat is produced- As it evaporates it removes heat.
Blood vessels dilate
What happens if you're too cold?
Hairs stand up
No sweat is produced
Shiver- Muscles contract which requires respiration. This releases energy and warms the body.
Blood vessels constrict
Where is insulin produced?
What happens if you have a meal?
1) Blood glucose level rises.
2) Pancreas responds by secreting insulin into the blood.
3) Insulin causes the cells to take in glucose. Cells in the liver and muscles convert it into glycogen.
4) The blood glucose level decreases.
What happens when a persons blood glucose level is too low?
1) Pancreas produces glucagon.
2) Glucagon causes glycogen to be converted back into glucose.
3) This causes the glucose level to rise.
How do you control type 1 diabetes?
Limit the intake of carbohydrates.
Artificial pancreas research.
Stem cell research.
How does waste affect water?
Chemicals can pollute water which harm the animals and plants which need the water for survival. Also, fertilisers get into rivers and cause pollution.
How does waste affect land?
Nuclear waste and household waste gets on landfill sites and it stays there for a long time. Also, toxic chemicals damage land as they are used in farming.
How does waste affect air?
Gases released into the air cause air pollution
How do humans use land?
Quarrying for metals
Why does deforestation occur?
For growing crops which can produce biofuels
What are the four main problems caused by deforestation?
1) Methane is added to the atmosphere-
Cattle release methane
Microorganisms produce methane, the more rice grown, the more methane produced as decomposers like warm and waterlogged conditions in which rice is grown in
2) A reduction in biodiversity
3) Carbon dioxide is released into the atmosphere
4) Less carbon dioxide is removed from the atmosphere-
Less photosynthesis occurs
What are bogs?
Areas of land which are acidic and waterlogged.
What happens when peat bogs are destroyed?
Carbon dioxide is released into the atmosphere.
How can people reduce the amount of carbon dioxide released into the atmosphere?
Buy peat free compost.
Name three natural stores of carbon dioxide.
Oceans and lakes
Green plants (it is stored as carbon compounds)
What is the greenhouse effect?
1) Energy from the sun is absorbed
2) This energy is then radiated back into the atmosphere
3) Carbon dioxide and methane then absorb the heat energy
4) Gases re-radiate the heat in all directions
What are the consequences of global warming?
Rising sea levels
Changes to migration patterns of animals
Changes to the distribution of organisms
How are biofuels made?
Fermentation of waste and natural products. Bacteria or yeast are used to break down sugars by anaerobic respiration.
What is the word equation for the ethanol?
Glucose (goes to) Ethanol + Carbon dioxide + Energy
What is biogas?
30% Carbon dioxide
Microorganisms ferment the plant material which contain carbohydrates.
How is biogas made?
It is made in a digester or a generator.
What does the standard generator consist of?
An inlet for waste materials to be put in.
An outlet for digested material to be removed.
An outlet for the biogas.
Name the four factors which need to be considered when designing a biogas generator.
What are the benefits of biogas?
The material is easily available.
The material needed is cheap.
Digested material is a good fertiliser.
It gets rid of waste.
It doesn't produce much sulphur dioxide or nitrate oxides.
It means methane is not released into the atmosphere.
Biofuels are carbon neutral.
How do you improve the efficiency of food production?
1) Decrease the amount if stages in the food chain.
2) Reduce the amount of energy lost at each stage through intensive farming where animals are kept in warm conditions where they are unable to move about. This is so they don't waste energy on movement and keeping warm.
How can you prevent overfishing?
Have fishing quotas.
Control net size.
What is mycoprotein?
The source is a fungus know as fusarium. Fungus is grown in fermenters using glucose syrup which is gathered from digesting maize starch with enzymes. There is oxygen present and nitrogen which is kept at the correct pH and temperature.
What are the advantages of intensive farming?
Increase efficiency of food production.
What are the disadvantages of intensive farming?
Cruel to animals.
Disease can easily spread.
Animals are given antibiotics which can cause resistance in humans.
To keep animals warm, fossil fuels would have been burnt.
There is less fish.
Spreading out of water molecules from an area of high to low concentration across a partially permeable membrane.
What do sports drinks contain?
Water- Replace it lost during sweat.
Ions- Replace those lost during sweat.
Sugar- Replace it used by the muscles during respiration.
What is tissue fluid?
Contains water, oxygen and glucose and surrounds all the cells in the body.
True or false.
Tissue fluid has the same concentrations of the fluid inside of cells.
Define active transport.
Movement of particles against a concentration gradient from an area of high concentration to an area of low concentration. It uses the energy released during respiration.
What is an exchange surface?
Allow dissolved substances to move.
How are exchange surfaces adapted?
Large surface area
In animals they have a lot of blood vessels
In animals they are ventilated
Why is exchanging substances harder in larger organisms?
The place where the substance is needed is a long way away from the exchange surface. As a result specialised organ systems are needed.
What are the adaptations of the alveoli?
Good blood supply
Large surface area
Increase surface area
Single layer of cells
Good blood supply to allow rapid absorption
Gas exchange in the lungs.
There is a higher concentration of oxygen in the air in the alveoli than in the blood so oxygen diffuses into the blood. Carbon dioxide works the other way round.
What is ventilation?
Movement of air in and out of the lungs.
What happens when you breath in?
Intercostal muscles contract
This moves the ribcage up and out
The diaphragm contracts
This makes it flatten
These increase the volume and decrease the pressure in the thorax which draws air into the lungs
What happens when you breath out?
The intercostal muscles relax
This moves the ribcage down and in
The diaphragm relaxes
This makes it bulge upwards
These decrease the volume and increase the pressure in the thorax which forces air out of the lungs
What is the top part of your body called?
When you breath what does the air move through?
What do the bronchioles lead to?
What does the trachea split into?
Air is pumped out of the case which causes the pressure to decrease so air is drawn into the lungs. Air is then pumped into the case which causes the pressure to increase so air is forced out of the lungs. They interfere with blood flow.
Air is pumped into the lungs causing the ribcage to move out and up. When it is not pumping the ribcage relaxes and air is forced out of the lungs. This can cause damage for example burst alveoli if the lungs are unable to cope with the air flow.
How is water lost through a plant?
What part of a leaf is an exchange surface?
What diffuses in and out of stomata?
Carbon dioxide diffuses in.
Oxygen and water vapour diffuse out.
How can the stomata be closed?
By guard cells.
What shape do stomata have?
Think inner walls and thin outer walls.
What happens when a plant is short of water?
The guard cells lose water and become flaccid. This causes the stomata to close.
What happens when a plant has a lot of water?
Guard cells fill with water and become turgid which makes the stomata open.
When is evaporation quickest?
Hot, dry and windy conditions.
Why is evaporation quickest in hot conditions?
Particles have more energy.
Why is evaporation quickest in windy conditions?
Rate of diffusion increases as there is a low concentration of water around the leaf.
Why is evaporation quickest in dry conditions?
Large difference in concentrations in the leaf compared to the air surrounding the leaf so the rate of diffusion increases.
True or false.
Root hair cells give a large surface area for absorbing minerals and water from the soil.
How does water move into a plant?
How do mineral ions move into a plant?
True or false.
Humans have a double circulatory system.
What does the first circuit in the double circulatory system do?
Pumps deoxygenated blood to the lungs to take in oxygen. The blood returns to the heart.
What does the second circuit in the double circulatory system do?
Pumps oxygenated blood around the organs (but not the lungs). It gives up its oxygen and becomes deoxygenated blood which returns to the heart, ready to be pumped out to the lungs.
What three things does the circulatory system contain?
What is the main function of the circulatory system?
To get food and oxygen to every cell in the body.