organisms exchange substances with their environment Flashcards
How does an increase in volume effect Surface Area:Volume ratio?
Larger volume means smaller SA:V ratio
Name the process by which prokaryotes exchange gasses?
Diffusion, due to the small diffusion pathway
Name three components of the tracheal system in insects?
Spiracles, Trachea, Tracheoles
Name two components of the gas exchange system in gills of a fish?
Gill filaments, Lamellae
By what principle do fish exchange gasses in their gills
Counter current mechanism
Define dicotyledonous?
A plant in which the seed has two embryonic leaves
Name two components of the leaves of dicotyledonous plants involved in gas exchange
Stomata, Guard Cells, mesophyll cells
How do xerophytic plants limit water loss?
Waxy cuticle, hairy leaves, curled shape, sunken stomata, reduced SA: ration of leaves
How do insects balance the need for gas exchange with the need to limit water loss
In dry conditions spiracles close to limit water loss
Name three components of the lungs involved in gas exchange?
Trachea, Bronchioles, Alveoli
Over which membranes in the lungs do gasses have to pass?
Alveolar epithelium, capillary epithelium
What features of the surface over which gasses pass in the lungs have to enable efficient gas exchange?
Thin, flattened cells so short diffusion pathway
Name the method of interaction between internal and external intercostal muscles
Antagonistic
Outline the movement of the diaphragm muscle in a) inhalation and b) exhalation
a) the diaphragm muscle contracts, causing it to flatten, increasing volume of thorax
b) the diaphragm muscle relaxes, arching upwards, reducing the volume of the thorax
What cavity is involved in gas exchange in the lungs?
Thorax/thoric Cavity
State the equation for PVR (pulmonary ventilation rate)
PVR = Tidal Volume x Breathing Rate
What builds up in the lungs as a result of cystic fibrosis?
Mucous
What elements of lung function are affected by cystic fibrosis
The shorter diffusion pathway is made larger
How do sufferers of fibrosis adjust to compensate for the change in their lung function
Increase ventilation (breathing) rate
What forms in the lungs of TB sufferers
Scar tissue
What disease does TB eventually lead to?
Cystic Fibrosis
How does reducing the quantity of oxygen available affect the cells of the body
Reduces the rate of respiration
What reaction occurs in which larger molecules are broken into smaller ones
hydrolysis
Why must molecules be made smaller to allow digestion
To allow them to pass through cell membranes
What two enzymes break down carbohydrates
Amylase and membrane-bound dissacharidases
Which enzyme breaks down lipids
Lipases
Explain how bile salts aid with the digestion of lipids
Bile salts emulsify lipids into micelles. This increases the SA for lipase to act upon
Which three enzymes break down proteins
Endopepitdases, Exopeptidases, Depeptidases
Briefly outline how the following enzymes carry out their function
a) Endopeptidases
b) Exopeptidases
c) Dipeptidases
Endopeptidases attack anywhere along polypeptide chain, except ends. Exopeptidases attack ends of polypeptide chain. Dipeptidases break down dipeptides into single amino acids
Where in mammals does absorption occur
Ileum
What mechanism permits absorption of amino acids and monosaccharides
Co-transport
State the equation for cardiac output (CO)
CO=heart rate x Stroke volume
What is the role of Haemoglobin
To transport 02 around the body
Do all organisms have the same type of haemoglobin
No
What is haemoglobin made out of
3-4 Protein with the prosthetic group Fe
Which metal ion is at the centre of the haemoglobin molecule
Fe
In what cells is haemoglobin located
Red Blood cell
How does one oxygen molecule binding to haemoglobin affect the binding of other molecules
It makes it easier
Outline the Bohr effect
As ppCO2 increases, oxygen affinity decreases
How do high altitude animals adapt to the low oxygen environment
They produce haemoglobin that has a higher affinity for oxygen
What is the function of the kidneys
To filter the blood
How do valves aid in heart function
Prevent back flow of blood and help maintain pressure
What connects the valves to the walls of the heart
Chords (valve tendons)
Describe the structure of the Arterioles and how it relates to the function
Thicker muscle than arteries.
Able to control movement of blood into capillaries.
Lower blood pressure than arteries so thinner elastic layer
Describe the structure of the Veins and how it relates to the function
Thin muscle as not controlling blood flow to tissues.
Thin elastic as low blood pressure. thin wall as low blood pressure. Valves prevent backflow
What feature of capillaries, relating to red blood cells, is important for their role as exchange surfaces
They are smaller. this pushes red blood cells right up against the capillary wall to shortest diffusion pathway
Why is fluid forced out of the capillaries at the start of the capillary bed
Large hydrostatic pressure in capillary
Were is hydrostatic press lower, the venue end or the arteriole end
Venule end
How does the water potential of the blood change across the capillary bed
It gets lower
What system is responsible for draining the excess fluid away from the tissues and back into the circulatory system
Lymphatic system
What dead tissue in plants transports water
Xylem
Outline the 4 steps fo the cohesion tension theory, starting at the leaves
1) Water evaporates from leaves
2) Tension created so water pulled into leaves from xylem
3) Cohesive water molecules pulled up xylem
4) Water enters xylem through roots
Which living tissue transports organic substances
Phloem
Does translocation require energy
yes
Where do solutes move from and to in translocation
Source to Sink
How do enzymes maintain a concentration gradient in translocation
They use up solutes at the sink, converting them to a different product to maintain a diffusion gradient
What is the name of the best supported theory for how translocation occurs
Mass Flow
How does ringing allow scientists to investigate transport in plants
Remove a ring of bark from a stem. Accumulation of sugars above the ring causes the bark to bulge, which indicates it is the phloem in the bark which is responsible for transporting sugars
Name the blood vessels entering and leaving the heart?
Leaving - aorta — renal artery (left ventricle to kidneys)
Leaving - Pulmonary artery (Right ventricle to lungs)
Entering - Renal vein — Vena Cava (kidneys tho right atrium)
Entering - Pulmonary vein (lungs to left atrium)
