Chapter 7 - Mass Transport Flashcards
What is haemoglobin
- A quarter art structure protein
- Found in red bloods cells
- That transport oxygen, as oxygen associates with haemoglobin to cause oxyhaemoglobin
Explain the oxyhaemoglobin dissociation curve
- Oxygen loads on to haemoglobin at a high partial pressure
- Haemoglobin becomes saturated with oxygen
- Oxygen disassociates at cells for respiration, so partial pressure falls
Draw the oxyhaemoglobin dissociation curve
Snapchat memories 15 nov
Describe and draw a graph showing the Bohr effect
Dissociation curve shift to the right
This means that at the same partial pressure, the saturation of haemoglobin with oxygen is lower
Explain why the Bohr effect may occur
- When an organism requires a lot of oxygen there is more CO2 in blood
- This increase blood acidity and therefore reduces haemoglobin affinity for oxygen (grip)
- Oxygen unloads more easily at respiring cells
- This means haemoglobin is less oxygen saturated
What happens to the curve for mammals in an environment with a high oxygen concentration and explain why
- Curve shifts right
- Haemoglobin has lower affinity for oxygen
- Releases more oxygen at cells
What mammals find a shift to the right useful
Animals with a high SA:VOL
Because this means they need a high rate of respiration due to heat loss per gram of body
What happens to the curve for mammals in an environment with a low oxygen concentration
- Curve shifts left
- Haemoglobin has a higher definition for oxygen
- There is a lower partial pressure in lungs
- Thus haemoglobin is able to load oxygen at a lower partial pressure of oxygen
Adaptations of arteries
- Elastic tissue
- Thick muscular walls
- Folded endothelium inside
- Narrow lumen
What are arteries
Blood vessels that carry blood away from the heart
What is the purpose of the adaptations of arteries
- They carry blood at high pressure due to the pump of the heart and narrow lumen
- Elastic tissue and folded and endothelium can stretch or relax to maintain constant pressure
- Thick muscles can contract to change flow of blood
What is it called when arteries contract and relax
Contract - Vascoconstriction
Relax - Vasodilation
What are veins
Blood vessels that carry blood to the heart
What are same adaptations of veins
Wide lumen
Thin muscles
Smooth endothelium
Valves
Why do veins have a wide lumen and a smooth endothelium
To reduce friction and thus create easier flow of blood
Why do veins have thin muscles
They don’t contract
Why do veins have valves
To prevent backflow of blood as blood is at a lower pressure
What are capillaries
Blood vessels that surround all cells to exchange gas and nutrients
Adaptations of capillaries
- Thin endothelium (1 cell thick)
- High surface area (due to number of them)
Both increase rate of diffusion
Draw and label the heart (10 labels)
Snap memories 15 nov
What is the aorta and what does it do
Biggest artery
Carries oxygenated blood around the body
What does the pulmonary vein do
Carry oxygenated blood from lungs to heart
What is the vena cava and what does it do
Largest vein
Returns de-oxygenated blood to heart
What does pulmonary artery do
Carry deoxygenated blood to lungs
What do the right and left atria (atrium) do
Pump blood into ventricles
What does the left ventricle do and how is adapted for this
Pumps oxygenated blood around the body
Has a thick muscle to do this
What does the right ventricle do
Pumps deoxygenated blood to lungs
What do atrioventricular valves do
- open when pressure is higher in atria than in ventricle (known as atrio-systole )
- They are uni-directional (one direction flow)
What is atrial systole
When muscles around atrium contract in order to pump blood into ventricles
What is atrial diastole
Where muscles around atria are relaxing and so atria are filling with blood
What do semi-lunar valves do
Open when there is a higher pressure in ventricles than in blood vessels
Explain how the heart beats
- Atria contract (systole) because pressure is higher in atria than in ventricle
- AV valves open and SL valves close
- Ventricles contract because pressure is higher in ventricles than in blood vessels
- AV valves close and SL valves open
- Atrial diastole occurs at the same time (atria begin filling up)
- Ventricle diastole then happens
Cardiac cycle graphs
Watch tt video to understand, make notes, make flashcards
What are the blood vessels that serve the heart called
Right and left coronary arteries
What are the blood vessels that connect to the heart and kidneys called
Renal artery and renal vein
What are 3 types of cardiovascular disease
Atheroma
Thrombosis
Aneurysm
What is atheroma
A build up of fatty plaque in arteries
What is thrombosis
A blood clot in arteries
What is an aneurysm
When the stretchy endothelium balloons out through the muscle of an artery because it is weakened
This can lead to internal bleeding if it ruptures
What can atheroma cause
Thrombosis or an aneurysm
What can thrombosis lead to
- Blocked arteries
- If coronary arteries are blocked
- Reduced blood flow and thus oxygen and glucose to heart
- Leads to myocardial infarction (heart attack)
- Heart can’t pump so cells can’t respire
What is a myocardial infarction
Heart attack
What is an arteriole
A small branch of an artery leading to capillaries
What is tissue fluid and it’s purpose
The fluid that bathes cells as it sits in intercellular spaces, and is the means by which materials are exchanged between blood and cells
It supplies cells with glucose, amino acids, fatty acids, ions and oxygen, and receives CO2 and other waste materials from cells
Explain the formation of tissue fluid
Use tt notes and textbook to research this properly
What is transpiration
The evaporation of water from the leaves, through stomata
What is meant by cohesion
The ability of water molecules to stick together as they are polar
What are xylem
Hollow tubes in plants made of dead cells so there are no cells walls between cells
What do xylem do
Transport water and minerals in an upward direction only
What minerals are transported by xylem
Inorganic only (not containing carbon, so not glucose or amino acids for example)
Explain cohesion tension theory in xylem
Water molecules are pulled up xylem
- Transpiration of water through stomata (plant is photosynthesising)
- Reduces water pressure at the top of xylem
- Water in the xylem is pulled upwards creating tension, due to cohesion
- Pulled up to leaves
Why does transpiration only occur when the plant is photosynthesising
Stomata are open
What are 4 factors that affect the rate of transpiration
Temperature
Light intensity
Humidity
Wind
How does temperature affect the rate of transpiration
Higher temperatures increase it due to more evaporation
How does light intensity effect the rate of transpiration
- More stomata are open when light intensity is higher
- Due to maximising gas exchange for photosynthesis
- So that CO2 is not limiting factor
- Increase rage of transpiration
How do humidity and wind affect the rate of transpiration
- Change water vapour gradient
- If the gradient is steeper (dry or windy), the rate will be faster
What is a potometer used for
Measuring rate of transpiration
Research this and how it happens etc
What are phloem made of
Living cells:
- Sieve tube elements
- Companion cells
What are companion cells
Cells that support drive tube cells, and provide ATP
What is meant by sieve elements
Sieve plates and sieve tube cells
What are sieve tube cells
Hollow living cells that have few organelles to allow this
Eg has little cytoplasm
What are sieve plates
Thin pores between sieve tube cells
What is meant by mass flow/translocation
The movement of solutes from the source to the sink
Why do companion cells need to provide ATP
Seive tube cells have no mitochondria
What is meant by a source
The site of production of molecules
Often the leaves
What are examples of solutes that are moved during translocation
- Glucose
- Amino acids
- Inorganic ions
Explain the mass flow theory in phloem
- High concentrates of solutes at source
- Active transport of solutes (using ATP against concentration gradient) from companion cells into sieve tube cell in phloem
- Creates a more negative water potential in sieve tube cells
- Water moves into phloem via osmosis, out of the xylem and companion cells
- Creating a high hydrostatic pressure in phloem
- Which forces water down to sink (carrying solutes)
- Sink then uses, breaks down, stores or concerts the solutes into something else
- This creates a low concentration of solutes at the sink
- Therefore it’s water potential is increased
- Water moves out of the phloem by osmosis, decreasing the hydrostatic pressure in phloem
What evidence is there for mass flow/translocation
- Radioactive isotope labelling
- Ringing experiments
What is meant by radioactive isotope labelling as evidence for mass flow/translocation
- Using C14 label
- Grow plants in C14 atmosphere
- Measure C14 as it moves down trunks/stem
What is meant by ringing experiments as evidence for mass flow/translocation
- Remove bark in a ring from the tree trunk (contains phloem not xylem)
- Solutes can’t move up and down
- Bulge forms above the ring
- Fluid above the ring has more solutes than below
- Suggesting that solutes are moving down
What do I need to be aware of in terms of evidence for mass flow/translocation
The evidence is not fully understood and therefore may not be true
(Correlation not causation)
What is meant by a sink
The places where molecules are used directly or stored for future use
What do phloem do
The process of translocation/mass flow
