1. Which of the follohv:kd8w m :t.gv.p fg f+op1l:wing are 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 correctly gmfdou4r t/r28w;ul;t/ y cf8kr 8g/v describe the differentiated cells in an individual plant suchr2w8ufg;ot;c v / lurgfm4dtyr/88k / as the golden barrel cactusbarrel (Echinocactus grusonii) shown in the image?

  3. What are essential prols+q3bxjpv7 b 8l*yf.f t-ki ;perties of stem cells?

  4. What is the cause of stem cells differentiating along d pwl)f,hrx 98ihmt.lotq-a 56 ifferent pathways to produce a variety of dif lhw.) htxqm,96o tipal 8fr5-ferentiated cells?

a. Use the graph to estimate the volume zudi 7b wqa2 4qh5+on9d 4uh-oof a liver cell.

b. The image is of cardiac mus51 im 8/ .ge/5huv)gu dgxizibcle.

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 have4y ((+ckg o cg9 tkh4lwpqv5*w a large volume.

d. Estimate the mean length of a cell with a volume of 1000 µm3 usi qit//r5 zvwsvib /;:lng the trend lb;viqi5//w /:t lz vsrine on the graph.

e. The horizontal error bars represent standard deviation. Suggest what theh yq9nyw 0*fu5 stany9 n uf50*hqywdard deviation signifies.

f. Simplified models are commonly used to investigate s-jj,kyidk 6l)cientific 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, disti1o4mshm- cv4vnguish between pluripotent, totipotent and multip1 hv-vc4 mos4motent stem cells.

7. Explain the role of stem cells in a multicellular organism.-0 d*jgh9mz bo

(a) Explain why a large surface area to volume ratio can increase cell efficixwkmn0(:sd .g encs wn :mx(g.d0ky.

(b) Describe, using two s9rb:ig--gtte9 gj aq3 pecific examples, how cell adaptation can increase surface area to volume ratio in 3egt:g9b ria-tq-gj9a specialised cell.

(c) Many tissues found in plants are compound h zvv olr)82j9tissues, such as phloem tissue shown in the image. Phloem tissue transports organic nutrients from their site of production (often, the leaf) to siv r)j 9oh28vlztes 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