Please look at the picture before trying to answer the questions! In Figure 1 th
ID: 55776 • Letter: P
Question
Please look at the picture before trying to answer the questions!
In Figure 1 the LDL binding to normal cells is compared to LDL binding to cells from patients with hypercholesterolemia, Mr. F.H. and Mr. J.D..
What are the units for LDL bound?
Which is the independent and which is the dependent variable on the graph?
To what specific molecules in the cell membrane is the LDL binding?
Why does LDL binding by normal cells and by Mr. J.D.’s cells reach a plateau?
Which skin cells (normal, JD, or FH) bind the most LDL?
Suggest an explanation for why Mr. F.H.’s cells bind so little LDL.
Do Mr. J.D.’s cells have as many LDL receptors as normal cells? Justify your answer based on the data shown in Figure 1.
In Figure 2, LDL internalization – the transfer of LDL into the cell- by normal cells is compared to cells from patients FH and JD, both of whom have hypercholesterolemia.
What are the units for LDL internalized?
Which is the independent and which is the dependent variable on the graph?
Describe what happens when a large protein like LDL is internalized via receptor mediated endocytosis.
Which skin cells (normal, JD, or FH) internalize the most LDL?
Figure 1. LDL binding to skin cells at 4e C Figure 2. LDL internalization after warming to 37° C. normal -JD normal -OJD 0.2 0.15 0.1 0.05 1.2 0.8 0.6 0.4 0.2 0 20 40 60 80 100 120 0 20 40 6080 100 120 extracellular LDL (ug/ml) extracellular LDL (ug/ml) normal FH normal .+FH 1.2 0.2 0.15 0.1 0.05 0.8 0.6 0.4 0.2 0 20 40 60 80 100 120 0 20 40 6080 100 120 extracellular LDL (ug/ml) extracellular LDL (ug/ml)Explanation / Answer
The units of LDL bound is apo protein B ,phospho lipids and cholesterol . extracellular cholesterol is independent variable and dependent variable is LDL binding to its receptor . the LDL is binding to the lysosomes .
Why does LDL binding by normal cells and by Mr. J.D.’s cells reach a plateau?Which skin cells (normal, JD, or FH) bind the most LDL?Do Mr. J.D.’s cells have as many LDL receptors as normal cells?Suggest an explanation for why Mr. F.H.’s cells bind so little LDL.
Binding of LDL of normal cells and binding by JD cells reach plateau beacuse theer are limited number of receptors percell ,they get saturated at high levels of LDL .JD has few recptors on the cell ,but they have affinity to normal cells also .It is not essential they bind to cholesterol ,even at saturated levels ,FH cells has no LDL , it could be because they lack completely receptors or may be receptor is defective so that it s affinity for the LDL is drastically reduced o recpetors on the cells may not be expressed .
What are the units for LDL internalized?Which is the independent and which is the dependent variable on the graph?Describe what happens when a large protein like LDL is internalized via receptor mediated endocytosis.Which skin cells (normal, JD, or FH) internalize the most LDL?
The units which are inetrnalized is apo protein B which is degraded latter into aminoacids . dependent variable is the amount of cholesterol binding to recpetors ,independent variable is thenumber of receptors .LDL is made up of the monolayer of the phopsholipids and cholestrol ,it also contain large number of apolipoprotein B,whichis internalized and breakdown into aminoacids , later the cholesterol is released ,these are then carried to lysosomes which breaks down cholesterol to the esters and cholesterol .th e cholestrol is directly internalized and incoroperated onto the cell memberane . FH cells are more internalized