The variety of life (heam & starch) Flashcards
The oxygen dissociation curve of the fetus is to the left of that for its mother. Explain
the advantage of this for the fetus.
- Higher affinity for oxygen;
- At lhigh partial pressure
- Oxygen moves from mother/to fetus;
After birth, fetal haemoglobin is replaced with adult haemoglobin. Use the graph to
suggest the advantage of this to the baby
- Low affinity / oxygen dissociates;
- (Oxygen) to respiring
tissues/muscles/cells;
Explain the advantage to the lugworm of having haemoglobin with a dissociation curve in the position shown.
High(er) affinity for oxygen
At lower partial pressure
In humans, substances move out of the capillaries to form tissue fluid. Describe how this tissue fluid is returned to the circulatory system.
- pressure lower in capillary
- Water returns;
- By osmosis;
- Water potential lower in capillary
- Due to protein in blood;
- Returns via lymph system
Give features of starch and explain how they enable it to act as a storage substance.
- Helical/coiled; Compact - ‘tightly packed’
- Insoluble; does not affect water potential so prevents osmosis
- Large molecule; so Does not leave cell
Explain how the structure of cellulose is related to its role in plant cell walls.
Long unbranched chains (of glucose);
Joined by hydrogen bonds form fibrils
which provide structural support;
describe how haemoglobin loads and unloads oxygen in the body.
hb associates oxygen at high p.O 2
in lungs haemoglobin has a high affinity for oxygen;
dissociates oxygen at low p.O2
dissociation is due to higher carbon dioxide concentration;
Heat from respiration helps mammals to maintain a constant body temperature.
Explain the relationship between the SURFACE AREA to VOLUME ratio of mammals and the oxygen dissociation curves of their haemoglobins.
- Smaller mammals have greater SA:VOL
- So more heat lost
- Smaller mammal also has greater rate of metabolism;
- Oxygen is required for respiration;
- haemoglobin has a lower affinity in smaller mammels so oxygen is released more readily
Name the process in which cells become adapted for different functions.
differentiation
Describe and explain how an increase in respiration in the tissues of a mammal affects the oxygen dissociation curve of haemoglobin.
Increase in carbon dioxide
this reduces the pH
which moves the curve to the right
There is less oxygen at high altitudes, why is it an advantage for people who live there to have a lot of red blood cells
More haemoglobin;
So can load more oxygen
Explain the advantage to people living at high altitude of having the oxygen dissociation curve shifted to the right
Haemoglobin has lower affinity for oxygen
therefore more oxygen is released into the cells
Explain how cellulose gives plant cells strength
unbranched chains; lie side by side to form microfibrils; which form Hydrogen bonds between chains holding them together; this gives structural support
3
what is the monomer in cellulose?
beta glucose
Name the type of reaction that converts cellulose to its monomers
hydrolysis
Describe the function of the chlorplast
the site of Photosynthesis;
Uses light energy to produce carbohydrates
Explain what is meant by a quaternary structure.
A protein with more than 1 polypeptide chains
Explain why haemoglobin is 96 % saturated with oxygen when it leaves the lungs
PO2 is high in the lungs and there is a low concentration of CO2 in the lungs
Explain how carbon dioxide helps haemoglobin to release oxygen to rapidly respiring tissues.
Displaces dissociation curve to the right as Hb has a lower affinity for oxygen due to high concentration of CO2
Explain why there is a high concentration of carbon dioxide in rapidly respiring tissue.
Carbon dioxide is a product of respiration;
describe the test for starch
substance turns blue-black with iodine
What is meant by the term partial pressure?
It is a measure of the concentration of a gas
Explain how exercise can effect:
- the temperature
- the pH
- the PO2 and PCO2
- muscle contraction causes increased respiration; 2.increased CO2 production lowering blood pH;
- lactate released lowering blood pH;
- increased heat released therefore increased temperature;
- increased O2 consumption lowering tissue PO2
Explain why the oxygen dissociation graph is shifted to the right during exercise (Bohr effect)
haemoglobin has a lower affinity for oxygen; due to increased CO2 production so more O2 is released for respiration;
The oxygen dissociation curve for haemoglobin shifts to the right during vigorous
exercise. Explain the advantage of this shift.
- Lower affinity for oxygen therefore unloads more oxygen more readily;
- To muscles cells;
- For high respiration;
Explain how the body shape of an animalcould be adaptation to living in a cold environment.
small SA:VOL therefore reduced heat loss
How are cellulose and starch different
Starch 1. 1,4 and 1,6 bonds - branched 2. All monomers same way up 3. Helix,coiled,compact 4. Alpha glucose 5. No micro/macro fibrils Cellulose 1. 1,4 bonds but no 1,6 bonds - unbranched 2. Alternate monomers upside down; 3. Straight; 4. Beta glucose; 5. Has Micro/macro fibrils
How is the structure of cellulose linked to its function
- H-bonds / micro/macro fibrils /fibres;
2. Strength / rigidity / inelasticity;
What is the advantage to the organism if their Hb has a higher affinity for oxygen at low pO2?
- Hb will become more saturated with O2 even with low O2 concentration
- so can act as an oxygen store
Explain why fetal Hb has a higher affinity for O2 than adult Hb
- fetal Hb needs to load oxygen
- from maternal Hb
- across the placenta
Describe two adaptations that enable oxygen to be transported rapidly from maternal blood into
the fetal tissues
- reduction of tissue layers in placenta
2. increase in maternal blood supply to placenta giving larger exchange surface area;
Why is fetal haemoglobin unsuitable for use after birth?
- has greater affinity for oxygen than adult haemoglobin;
- higher oxygen tensions in atmosphere than placenta;
- thus in air would be unable to unload oxygen to tissues;
