1. Which of the following a ost+) h ir69b.e(yxpnre roles of stem cells in living organisms?
I. Growth of new organs.
II. Replacement of damaged cells.
III. Production of cells which could differentiate.
IV. Produce new stem cells by mitosis.

  2. Which of the following y/flc+k8z ox9eh8d y0correctly describe the differentiated cells in an individual plant such as the golden byelc89+ h y x8ok0d/zfarrel cactusbarrel (Echinocactus grusonii) shown in the image?

  3. What are essential properties of stem 5+ t- ,zj.bo1oxriwuj cells?

  4. What is the cause of stem cells differentiating along different p xmyq(:p8 7dk*v:*qtz xbsn a3n1,soxathways to produce a variety of differentia qs7n yk,x381pzo*qvx(d:s m*xb :ntated cells?

a. Use the graph to estimate the volume of a liverhgqg ks); 7 a6xh-pp-d cell.

b. The image is of cardiac muscle.k9wl0qb, : 1vobzw:ls

Cardiac muscle cells have a mean length of 100 µm and an estimated volume of 8000 µm3.
Explain why the cell length and volume ratios are not constant for all cell types.

c. Suggest one reason why a human ovum has specialized to havevo4qjkq2/ s8 w a large volume.

d. Estimate the mean length of a cell with a volume of 1000 µm3 using the tre0 8(/oa bzs fqehni*,lnd line on the graph z/h a8*i(e,o0 qbflns.

e. The horizontal error bars represent standard deviation. Suggest what the sniv1kp7ejvlk4 6qa 58ws um2, ljdh-)tand 58w,hpsv12q 7dian-ull)jmk46jek v ard deviation signifies.

f. Simplified models x) mdpr;ql +)vare commonly used to investigate scientific phenomena.
Outline the limitations in the use of a sphere to model surface area to volume ratio in cells.

6. Using examples from human tissues, distinguish between pluripotedk(rgu+ 3xw8j y)bjj2nt, totipotent and multipotent stedj 8w (r j32ybjxk+u)gm cells.

7. Explain the role of stem cells in a multicellular organism. lpz7a, wg:zb7 m rof7b8c:zs-

(a) Explain why a large surface area to volume ratio can increase iw 5 do8)yu3.n tovm4icell efficiency.y3wo54tom8)niv iud .

(b) Describe, using two specific examples, how cell adaptae woplj l4kxko.v7 03)tion can increase surface area to volume ratio in 04)v73kpxkwlojo e.l a specialised cell.

(c) Many tissues found in plants are compound tissues,al kdlh7 qx71v(p3x u.b sx9-r such as phloem tissue shown in the image. Phloem tissue transports organic nutrients from their site of production (often, thelqdrk hv79 xl1p-.(a s7x xbu3 leaf) to sites of storage or metabolism (often flowers or roots)

Compound tissues consist of several different cell types, simple tissues of only one cell type.
Outline why many tissues in multicellular organisms have more than one cell type in the tissue