Chapter+2

toc =Pg 29 Working with data:=

Question 1.
percentage calculations volume of primary oocyte = volume of secondary oocyte plus polar body = 0.6163 mm3 + 0.0015 mm3 = 0.6178 mm3 Polar body % of Primary Oocyte: (volume polar body/ volume primary oocyte) multiplied by 100 (0.0015 mm3/0.6178 mm3) x 100 = 0.24 %

Secondary Oocyte = (volume secondary oocyte/ volume primary oocyte) multiplied by 100 (0.6163 mm3/ 0.6178 mm3) x 100 = 99.76 %

Question2.
Total cell plasma membrane area for two cell zygote 2 x 2.22 mm2 = 4.44mm2

% Increase in plasma membrane area =(Area for two cell zygote / Area of one cell zygote) multiplied by 100 (4.44 / 3.52) x 100 = 126.13 %

=Dbq p30:Patch clamp analysis=

Question 1.
(a) 0 pA (b) Pico = 10-12 1 x 1012 picoamps in an Amp

Question 2.
(a) Gap length=2mm, Scale bar 1mm = 20ms, time open 2 x 20ms 40m (b) – 4 pA

Question 3
(a) The motor neuron synapse

Question 4.
(a) The Ach binds to the receptor opening the ion channel. Higher concentrations of Ach remain in the receptor region and open the channel again and again. (b) ACh opens the channel in an ‘all or none ‘ response. The period of time the channel is open is dicated by another mechanism The concentration of Ach required to open the channel is at a set level. There are not degrees of ‘opening’ of the channel this is an ‘all open’ or ‘all closed’ mechanism. Therefore the excess concentrations of Ach remain within the region of the channel opening it again.

Question 5.
(a) · When both channels are closed the current flow is 0pA · When the channel is open the current flowing is greater at a maximum of -12pA · The open channel shows variation in the current flowing when it is open. · Channels remain open for longer (b) (i) The membranes contain different types of channel (ii) Membrane receptors are different in for Ach and glycine. (iii)The spinal neuron channel response is stronger response to glycine than the muscle is to Ach.

=DBQ P 31 Albumin in blood=

Question 1
(a)The control has most blood plasma albumin concentration which is around 37% With marasmus the blood albumin plasma levels drop to approx 28% In kwashiorkor shows the blood plasma albumin is lower still at 15%. (b) Less albumin (protein) is absorbed into the blood stream when a person has a poor protein diet as is the case with marasmus and kwashiorkor. The latter is a specific lack of dietary protein which therefore results in less albumin (protein) being absorbed into the blood.

Question 2.
Albumin is a soluble molecule which has an electrostatic attraction for water molecules. These water molecules bond to the albumin thereby creating a region of effectively lower water concentration. Water will tend to move towards this region of lower water concentration (blood plasma) from regions of higher water concentration (gut).

Question 3.
The children most at risk are those with the lowest blood plasma albumin levels. Children with Kwashiorkor have the lowest albumin levels (15%) and therefore the lowest re-absorption of blood into the plasma. These children will develop oedema since the fluids will remain within the tissues.

=Dbq P 32 Osmosis in plant cells=

Question 1
(a) Water moved into the tissues (all show increases in mass due to water uptake). (b) Water moved into the pine kernel ( mass increase) but moved out of the other three tissues that all show a decrease in mass.

Question 2
Cactus; When bathed in a solution with only 0.1 mol dm-3 salt it starts to loose mass. So the solute concentration of cactus must be lower than that.

Question 3.
(a) Cactus is adapted to arid conditions (xerophytes) and has stored water in its tissues resulting in a low solute potential. The Butter squash and Sweet potato show intermediate mass changes suggesting they are mesophytes with higher solute potential in their tissues. The Pine kernel has a high solute potential in its tissue as an adaption to allow maximum water uptake in brief periods of exposure to water or due to the accumulation of solute in the cytoplasm to lower freezing points.

Question 4
Different tissues may have different densities. The initial mass of tissue used in the experiment maybe different.

=Dbq p33 Phosphate absorption=



Question 1.
Below 21% to 2.1 % O2 there is a slight reduction in phosphate absorption There is a significant reduction in phosphate absorption below 0.9 umol g-1 h-1

Question 2
Root cells generate an electronegative charge through the secretion of H+. Root cell accumulate phosphates ions within the cytoplasm of the root cells. Phosphates need to be absorbed against and electronegative concentration gradient. Phosphate is absorbed by active transport.

Question 3
Phosphate is mainly absorbed by active transport. The graph shows a reduction in phosphate active membrane transport as the concentration of DNP is increased up to 6 umol g-1 h-1. As the concentration of DNP increases there is a reduction in ATP synthesis. With no or reduced ATP available the active transport mechanism in the membrane stop functioning. There is some phosphate absorption even above 6 umol g-1 h-1 which will be due to the uptake of minerals in the mass flow of water through the apoplastic pathway.

Question 4
=**Dbq page 34. Autoradiography**=

1. a. In the rough endoplasmic reticulum (86.3 %) b. The amino acids are processed in the rER

2. After synthesis in the rER, vesicles transport the proteins to the Golgi apparatus. This can be derived from the data, which shows that the highest percentage of autoradiographic grains after 7 minutes is in the vesicles and after that in the Golgi apparatus.

3. Most proteins are synthesized within 7 minutes and then moved to the large storage vesicles within 117 minutes. < >

4. The proteins are not released in large quantities (?)

=Dbq. page 35. Diffusion of proteins in membranes=

1. a. membrane proteins move around at body temperature; the movement is indifferent of species b. The movement of membrane proteins is is passive, it doesn't requite ATP/energy c. The mixing is not caused by the breaking down and reassembly of the markers, since this was made impossible

2. a. The movement of markers increases with temperature, because the molecules move faster with higher temperatures. Then it levels off. b. At lower temperatures the membrane proteins hardly move, therefore the markers are hardly mixed.

3. A rise in marker movement can be expected at lower incubation temperatures. Since these animals are adapted to a colder environment.