IB Biology HL D2.1 Cell and Nuclear Division Questions

Similarities: [6 max]

a. (in both plants and animals) produces two genetically identical daughter cells;

b. maintains the chromosome number/genome of cell / produces diploid/2n cells;

c. used for generation of new cells/cell replacement/tissue repair/growth;

d. in prophase the chromatin/chromosome condenses/formation of chromatids/supercoiling of chromosomes;

e. supercoiling of DNA around histones (to form nucleosomes);

f. microtubules/microtubule motors to move chromosomes/chromatids;

g. in metaphase chromosomes align in equator of cell;

h. in anaphase separation of chromatids;

i. in telophase two nuclei/cells form / nuclear membrane/envelope reforms

OR

cytokinesis is the division into two cells;

Differences:

j. in animal cell centrosomes/centrioles facilitates the organization of the mitotic spindle/ spindle poles/microtubules;

k. in plant cells spindle fibres attach to walls;

l. in animal cells, the plasma membrane is pulled inwards around the equator to form a cleavage furrow in cytokinesis

OR

in animal cells actin and myosin pinch cell membrane to split cytoplasm/cytokinesis;

m. in plant cells a cell plate forms (at the equator) to develop into the new cell wall to achieve cytokinesis

OR

in plant cell vesicles (containing pectin) assemble sections of membrane/cell wall (at/across the equator) to achieve splitting/cytokinesis;

Marking guidance:

a nuclear membrane breaks down/disappears (in prophase/at start of mitosis)
b nuclear membrane reforms around two new nuclei (in telophase/at end of mitosis)
c plasma membrane pulled inwards at equator / cleavage furrow formed
d membrane pinches apart to form two cells / cytoplasm divided / cytokinesis

growth/increase in cell size;
division of mitochondria/chloroplasts/production of more organelles/number of organelles doubled;
replication of DNA/amount of DNA is doubled;
transcription of genes/production of mRNA;
protein synthesis;
cell respiration/production of ATP;

cell cycle is (repeated) sequence of cytokinesis/cell division, (then) interphase (then) mitosis / cell cycle includes the sequence of interphase, mitosis and cytokinesis/cell division (to form new cells which repeat the cycle);
cyclins control/regulate this cycle / ensure the cell moves on to the next stage of the cycle when it is appropriate;
extra cells produced when they are needed;
tumour formation is the result of uncontrolled cell division/ cells growing and dividing endlessly;
repeated mitoses/high mitotic index;
due to mutations in oncogenes / oncogenes may become active and contribute to the development of a cancer cell;
carcinogens/radiation/mutagenic chemicals/mutagens/smoking cause mutations/tumours;