IB Biology HL B2.2.3 Advantages of Compartmentalization Topic Practice

a. (membranes divide the cell into) organelles;

b. nucleus/chloroplast/mitochondrion is double membraned/has inner and outer membrane;

c. enzymes/substrates can be concentrated (in the small volume);

d. different/incompatible functions/processes in different organelles (so harm prevented);

e. hydrolytic/digestive enzymes held inside lysosomes/phagocytic vacuoles;

f. pH/conditions can be for optimized for (each) function/process;

g. small spaces/volumes for proton gradient/concentration gradient (to develop quickly);

h. (post- transcriptional) modification of mRNA in nucleus (before it reaches the ribosome);

i. vesicles for transport/transfers;

j. nuclear membrane/envelope protects DNA/chromosomes (from the cytoplasm);

Marking guidance:

Do not award marks
describing the functions of the plasma membrane.

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