1. Which of the following u+ x-)wf0zwf7bk6k qz j3 ry5yare 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 descrwuiyr;a .;y z ag5sl2(ibe the differentiated cells in an individual plant such as the golden.as 5yygza 2;uwlr(;i barrel cactusbarrel (Echinocactus grusonii) shown in the image?

  3. What are essential propertiew/-:rd:n z rwh3lkb7gb,mve , s of stem cells?

  4. What is the cause of stem celu8ft v g )p.ogokwb7,/o05rvpls differentiating along different pathways to produce a variety of rg go85), ouvpp7 ./tbvkow0 fdifferentiated cells?

a. Use the graph to estimate the vo n)wiukv tlcne/(+j02lume of a liver cell.

b. The image is of cardiac mu nq8(t 0visx(escle.

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 wsy e;d s:1a;ow zbp*he6p;6au hy a human ovum has specialized to have a large volume.

d. Estimate the mean length of a cell with a volume of ykvbr b93+-48-au o vzhmibw;1000 µm3 using the trend line on tho9zbbvb ik-h+48w -r;v m uya3e graph.

e. The horizontal error bars represent standard deviation. tni/+ +bn (sinSuggest what the standard debin/n i(ns++t viation signifies.

f. Simplified models are commonly -ded+0b; s r;hf l,oalused 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 frcc 8pi .qe8p e.0ulv(nom human tissues, distinguish between pluripotent, totipotent and multipotent stem celli .p(08p8n uelv.ccq es.

7. Explain the role of stem cellsu0:wk emj:j: n in a multicellular organism.

(a) Explain why a large surface area to volume ratio can increase cell effi/gn8/9 6ysn5gnb,eni kis sbvsc83 5qcienc5g8s nbkg36/ ns/5sbvyq,9c inie8 sny.

(b) Describe, using two specific examples, how cell adaptation can increase s nsl im/.6twc*i1-x*jijj 0b lurface area l.ij icwt 0n**lm-j x bsij61/to volume ratio in a specialised cell.

(c) Many tissues found in plantsygr ri1 /5llf.nv(oq* are compound tissues, such as phloem tissue shown in the image. Phloem tissue transports organic nutrients from their site of product*yrl5qrv /i.gn (fo l1ion (often, the 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