1. Which of the following are roles of stem cells in li8i46 n8qvzadwving 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 followin(eoop)j ay i94g correctly describe the differentiated cells in an individual plant such as the golden barrel cactusbarrel (Echinocactus grusono eyo) 4(pji9aii) shown in the image?

  3. What are essential proper :bb 57cfcz6nyties of stem cells?

  4. What is the cause of stem cells differentiating along di .bu.uy2d ypu7f)/ slvfz0ml,fferent pathways to produce a variety of differenti l.v,s0 z.yubp f/u)m2 l7duyfated cells?

a. Use the graph to estimate the voluj8 l2x 8rldn;vbhk l wyg3h1-.me of a liver cell.

b. The image is of cardiac muscwmn j1,r9+4 /lr uh(m:iwt8miwg9ovlle.

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 have a large1+p) yhocgv6q volume.

d. Estimate the mean length of a cell with a v3fp0c1 y0 knwc;r1ae solume of 1000 µm3 using the trend line on t;rek 10f ynacpsw1c30 he graph.

e. The horizontal error bars represent standard deviatim3 bsm,ctys4fu9 dz 90jcye./ts pq/ *on. Suggest what the standard devi/cfdsm b .pm99,3ecq /y0*tu4st zsy jation signifies.

f. Simplified models are commonly used to investigate scientific phenoabf/4de(f v4j bkik20u85 x pvmena.
Outline the limitations in the use of a sphere to model surface area to volume ratio in cells.

6. Using examples from human tissues, dio )pl5vax1/0 y4tnhxe stinguish between pluripotent, totipotent and multipotentn p v)h5/yo4a x1elt0x stem cells.

7. Explain the role of stem cells in a multicellular organism 28wl/td qnbx7h 7s.0t:ibpxqty:nj3.

(a) Explain why a large surface area to volume ratio cadxhd 9dhe0+7i n increase cell efficiencydd h0i+79d hxe.

(b) Describe, using two specific examples, how cell adaptation can inc c sw+pm uxobn:8mdt+z2g7ku-fzh/g /r.6l2frease surface area to volume ratio in a specialised cellf wurcpft o/mzggudx+zs2+8:2m h-7bl 6k n./ .

(c) Many tissues found in plants are compound tissuesa9tl0*11svb: dugzx r, such as phloem tissue shown in the image. Phloem tissue transports organic nutrients from their site of production (often, the leaf)bd0 91asgrvul*t1 xz : 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