Synoptic Revision Flashcards
Describe how organisms are grouped in a phylogenetic classification system.
A phylogenetic classification system attempts to arrange species into groups based on their evolutionary origins and relationships. It uses a hierarchy in which smaller groups are placed within larger groups, with no overlap between groups. Each group is called a taxon (plural taxa).
Suggest why the student soaked the root tips in hydrochloric acid in step 2.
To break up the tissues into individual cells.
For some patients, HSCT is an effective treatment for MDS.
Explain how.
It aims to stop the damage MS causes by wiping out and then regrowing your immune system, using your stem cells.
The control patients were treated with conventional drugs.
Give two reasons why.
- Effect of AZA can be compared;
- patents still need treating as they suffer from MDS
Suggest and explain how AZA can reduce the effects of MDS in some patients
- (AZA) reduces methylation
- (Tumour suppressor) gene is
transcribed - Prevents rapid/uncontrollable cell division
(d)
Use the figure above and the information provided to calculate the difference in the
number of patients surviving at 10 months after treatment with AZA compared with
conventional drugs.
360 1:1 so 180:180
AZA= 0.74 x180 =133.2
CVD= 0.58 x180= 104.4
133.3-104.4= 28.8%
Pressing the coverslip downwards enabled the student to observe the stages of
mitosis clearly.
Explain why.
it seperates the cell in the tissue into
individual cells In a single layer. Making it easier to see the chromosomes and identify the different stages of mitosis
Name the stage of mitosis shown in cell G. Explain the appearance of this cell
Anaphase
V-shaped sister chromqtuds are being pulled apart to opposite poles bu spindle fi res
what can u conclude about the uptake of oxygen over the entire body of the lugworm
partial pressure of o2 is low in the lugqorm. so haemoglobin has a high affinity for o2. o2 binds to haemoglobin by alterering the tertisry structure creating a new binding site so more o2 molecules can bind. o2 used up in aerobic respiration therefore a decrease in partial pressure in oxygen leaves the lugworm through the water.
what are two other control variables other than temp and pH when prePARING Liquid medium
-volume of bacteria
-concentration of nitrogen
What can u conclude about the uptake of oxygen over the entire body of the lugworm
ppO2 is low as there is a one-way flow system
This suggests that there is a gradient of concentration from the water to the lugworm’s blood.
Given that the blood has a partial pressure of less than 2.7 kPa and an oxygen intake of 8.8 kPa, it seems likely that the lugworm is absorbing oxygen along its entire length, The blood and water must flow in the opposite directions within the lugworm for concentration gradient to be maintained.
2 reasons why hardy weinburg differs
-no random mating
-Mutations
explain how a fetus is protected against the pathogens that infect its mother during pregnacy
The placenta forms a physical, selective barrier between the maternal and fetal circulations, preventing transfer of pathogens. The uterine mucosal lining, the endometrium, is transformed into the decidua during early pregnancy
how does vaccinating babies protect uk population against pathogens such as measles and tetanus
measles: viral diseases: could rapidly spread so more babies vaccinated means less spread and more babies immune to it. vaccinating is a form of herd immunity
tetanus: not contagious but is only occurs when immune system is really bad and vaccinating babies against other bad pathogens leads to strong immune sytem.
explain why giving children more than one tetanus vaccination develops good immunity against tetanus
-its a bacterial disease so its not contagious. so cant be prevented by herd immunity
-not a viral disease so b memory cells wont remember the pathogen on the second infection so have to repeatedly get it done so body can stay immune.
