Topic 8 - Exchange and Transport in Animals Flashcards
What do organisms exchange substances with?
The environment
What do organisms exchange with the environment?
Substances
What substances do organisms need to exchange with the environment?
Oxygen
Water
Urea
Carbon Dioxide
What do organisms need oxygen for?
Aerobic respiration
How does oxygen move in organisms?
By diffusion
What does water have in it, in organisms?
Food molecules and mineral ions
What is water used for in organisms?
Provide structure to the blood
What happens to urea in organisms?
Diffuses from cells to the blood plasma for removal from the body by the kidneys
What does an organisms ability to exchange substances depend on?
It’s surface area to volume ratio
What is the surface area to volume ratio?
SA:V = Surface Area / Volume
What do substances diffuse over in single-celled organisms?
The cell membrane
Why don’t single-celled organisms need exchange surfaces?
Because they have a large SA:V so enough substances can be exchanged across the membrane to supply the volume of the cell
Multicellular organisms have a ______ surace area compared to their volume
Multicellular organisms have a smaller surace area compared to their volume
How have multicellular organisms evolved to exchange substances efficiency?
By having exchange surfaces/mass transport systems which allows enough substances to be exchanged to supply their entire volume across their outside surface alone
A bacterial cell can be represented by a 1 μm x 1 μm x 4 μm block.
Calculate the cell’s surface area to volume ratio
Give your ratio in its simplest whole number form
SA : V = Surface Area / Volume SA : V = (1x1)+(1x1)+4(4+1) / 1x1x4 SA : V = 18 / 4 SA : V = 18 : 4 SA : V = 9 : 2
What does the rate of diffusion depend on?
Distance
Concentration Difference
Surface Area
How does distance affect the rate of diffusion?
The further the distance, the slower the rate of diffusion
Why does distance affect the rate of diffusion?
The closer, the less distance the particles have to move
Why does concentration difference affect the rate of diffusion?
The more particles on one side, there more particles to get from one side to the other
Why does surface area affect the rate of diffusion?
The more area there is available for molecules to move across
What is the job of the lungs?
Transfer oxygen into the blood
Remove Carbon Dioxide from the blood
How are alveoli specialised?
Moist lining
Good blood supply
Very thin walls
Enormous surface area
What is fick’s law
Rate of Diffusion ∝ (Surface Area x Concentration Difference) / Thickness of membrane
If the surface area is doubled, what happens to the rate of diffusion?
The rate of diffusion doubles
If the thickness of membrane is halved, what happens to the rate of diffusion?
The rate of diffusion increases by double
Give one way in which the alveoli are adapted for gas exchange
Any one from: Moist lining Good blood supply Very thin walls Enormous surface area
What carrys blood?
Red blood cells (plasma aswell)
What are red blood cells also called?
Erythrocytes
How are red blood cells adapted?
Biconcave disc
No nucleus
Contain haemoglobin
What colour is haemoglobin?
Red
Compare the amount of red blood cells a regular human may have to a human who lives in high altitude conditions?
A high altitude living human will have more red blood cells so they can get more oxygen to the cells
What defends againt infection?
White blood cells
What cell undergoes phagocytosis?
Phagocytes
How do phagocytes defend against infection?
Undergoes phagocytosis which changes the shape of the cell to engulf microorganisms
How do lymphocytes defend against infection?
By producing and releasing antibodies and antitoxins
What is a potential sign of an infection?
High amounts of white blood cells in the blood
What helps the blood clot?
Platelets
What are platelets?
Small fragments of cells with no nucleus
What is the point of clotting?
Stops blood loss
Stops infection
What colour is plasma?
Straw-coloured liquid
What colour is plasma?
Straw-coloured liquid
What is carried in plasma?
Red, white blood cells and platelets Carbon Dioxide Hormones Urea Proteins Antibodies and antitoxins
Describe the purpose of platelets in blood?
Help the blood clot
Stopping infection and blood loss
Outline three ways in which red blood cells are adapted to carry oxygen?
No nucleus
Biconcave disc (large surface area)
Contain haemoglobin which combines with oxygen
What are arteries?
Vessels that carry blood from the heart
What are capillaries?
Vessels that are involved in the exchange of materials at the tissues
What are veins?
Vessels that carry blood to the heart
What vessels take the blood to the heart?
Veins
What vessels take blood from the heart?
Arteries
Describe the arteries?
Strong, thick and elastic walls
The walls are surrounded by elastic fibres to allow them to stretch and spring back
High pressure
What do arteries branch into?
Capillaries
Why are capillaries very narrow?
So they can squeeze into gaps so they can get really close to the cell to increase the rate of diffusion
What type of walls do capillaries have?
Permeable walls
How thin are capillaries?
One cell thick
What do capillaries eventually join up to?
Veins
Describe the veins?
Low pressure
Thinner than arteries
Bigger lumen than arteries
Valves
Describe the type of walls in veins?
Elastic fibres and smooth muscle
What do veins have that arteries don’t?
Valves
Why do veins have valves?
To stop blood flowing backwards
Explain how veins are adapted to carry blood back to the heart?
Big lumen to help the blood flow despite the low pressure
Valves to keep the blood flowing in the right direction
Explain the advantage of capillary walls being only one cell thick?
It increases the rate of diffusion of substances across them between the blood and cells
What does a double circulatory system mean?
The heart pumps blood around the body in two circuits
Where does the right atrium recieve its blood from?
The body
What and where here does the blood from the body come through?
Deoxygenated blood
Vena Cava
Where and how does the blood from the left ventricle go to?
The rest of the body
Aorta
Which wall is thicker out of the two sides of the heart?
The left ventricle is much thicker
Why is the left ventricle thicker?
Because it pushes blood around the whole body at high pressure meaning it needs more muscles to maintain this pressure
Why does the heart have valves?
To prevent the backflow of blood in the heart
What is the formula for cardiac output?
CO = HR x SV
Cardiac Output = Heart Rate x Stroke Volume
cm³/min = b/min x cm³
What is the heart rate?
The number of beats per minute
What is the stroke volume?
The volume of blood pumped by one ventricle each time it contracts
What is the cardiac output?
The total volume of blood pumped by a ventricle every minute
What is the heart rate of a person with an average stroke volume of 72 cm³ and a cardiac output of 5420 cm³/min?
CO = HR x SV HR = CO / SV HR = 5420 / 72 HR = 75 bpm
Calculate the stroke volume for a heart rate of 67 bpm and a cardiac output of 4221 cm³/min?
CO = HR x SV CO = 67 x 4221 CO = 4221 / 67 CO = 63 cm³
What does cellular respiration release?
Energy
What is respiration?
The process of transferring energy from the breakdown of organic compounds (glucose)
What type of reaction is respiration?
Exothermic
Give the two types of respiration?
Aerobic
Anaerobic
What is the energy released by respiration used for?
Metabolic processes
Contracting muscles
Maintaining a steady body temperature
What does aerobic respiration need?
Oxygen
What is the aerobic respiration equation?
Glucose + Oxygen -> Carbon Dioxide + Water
C6H1206 + 602 -> 6C02 + 6H20
When does the body do anaerobic respiration the most?
During vigorous exercise as the body won’t be able to supply enough oxygen to the muscles
Compare the energy of aerobic respiration to anaerobic respiration?
Aerobic respiration releases much more energy than anaerobic
What happens to the lactic acid in the body?
It builds up in the muscles and gets painful as it leads to cramp
What is the equation for anaerobic respiration?
Glucose -> Lactic Acid
What do plants produce during anaerobic respiration?
Ethanol + Carbon Dioxide
Other than plants, what organisms have different products when anaerobically respiring?
Fungi (eg. Yeast)
After five minutes of intense sprinting, a student got cramp in his leg
Explain what caused this
The leg muscles didn’t get enough oxygen during the sprint, so began to use anaerobic respiration
This would cause the production of lactic acid
The build up of lactic acid leads to cramp
What apparatus do you use to measure the rate of respiration?
Respirometer
How could you measure the rate of respiration?
Measure the oxygen consumed by organisms in a given time
When investigating respiration, why are soda lime granules added?
To absorb the carbon dioxide produced so there will be a gas change
When investigating respiration, what is the control?
Glass beads of the same mass as the woodlice are used in the control tube
When investigating respiration, what temperature is set?
15*C
When investigating respiration, what will happen to the volume of gas in the tube?
It will decrease as the oxygen is being used up by the woodlice whilst the carbon dioxide produced is absorbed by the soda lime granules
When investigating respiration, what is the independent variable?
The temperature of the water bath
When investigating respiration, what is the dependent variable?
The rate of respiration
What are the problems associated with using live animals in experiments?
Ethics
A student is carrying out an experiment to measure the effect of temperature
What could the student use as her control?
A test tube with an object that doesn’t respire with equal mass to the peas
A student is carrying out an experiment to measure the effect of temperature
What could she use to keep the beans at different temperatures?
A series of water baths
Name three substances that animals have to exchange with their environment
Water
Oxygen
Carbon Dioxide
Why do multicellular organisms need mass transport systems
Because their SA:V is too small to efficiently match the substances that the cells require fast enough to survive
Why do multicellular organisms need specialised exchange surfaces?
Because most cells are too deep for the required particles to diffuse into
Where does gas exchange take place within the lungs?
The alveoli
Explain the movement of oxygen between the alveoli and the blood
Higher concentration in the alveoli than the blood, meaning the oxygen goes down the gradient causing the oxygen to diffuse into the blood
Describe the shape of an erythrocyte
Biconcave
What is the name of the red pigment in red blood cells?
Haemoglobin
What is the function of lymphocytes?
To fight infection
What would happen to the body if there was no platelet?
Massive loss of blood
Massive amounts of infection
List four different substances that can be carried in the plasma
Any four from: Red, white blood cells and platelets Carbon Dioxide Hormones Urea Proteins Antibodies and antitoxins
How are arteries adapted for carrrying blood at high pressure?
Elastic fibres and smooth muscle allow it to stretch to endure the high pressure
The lumen is narrow to increase the blood pressure
Write the name of the blood vessel that carries blood into the right atrium
Vena Cava
Write the name of the blood vessel that carries blood into the lungs
Pulmonary Artery
Write the name of the blood vessel that carries blood into the left atrium
Pulmonary vein
Name the valves located in the heart
Tricuspid
Bicuspid
Semi-lunar
What is the equation for heart rate?
HR = B / T
What is the equation for cardiac output?
CO = SV x HR
How would you calculate the heart rate, given you have the cardiac output and stroke volume?
HR = CO / SV
What is the purpose of respiration?
Release of energy to be used on life processes
