1. Which of the following are roles of stem cells in living organ.o7km 8(.8vyw6 zkxooa6mz rrisms?
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 de*cs/-: d 1hxfvby6 utllsh91 ascribe the differentiated cells in an individual plant such as the fht/h sys c*b1l- vlxa1ud96:golden barrel cactusbarrel (Echinocactus grusonii) shown in the image?

  3. What are essential properties xxjf7k q dq( a-s*3pi ko(p/0uof stem cells?

  4. What is the cause of stem cells differentiating along dfnblx,0xczvp 4z r o) 57tkb37ifferent pathways to produce a kz p)7,b ztxo fc54nlxv730rb variety of differentiated cells?

a. Use the graph to estimate the volume of a liver cez16 o maw)e4xxll.

b. The image is of ca9anoi1 (z qj7j m:vq4trdiac muscle.

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 specia1w 1svv-b95ck1tk7en*n oc dzlized to have a large volume.

d. Estimate the mean length of a cell with a volume of 1009klnd+ :qps2e+(bwb o0 µm3 using the trend linbbq(l 9pke+:swo2 + nde on the graph.

e. The horizontal error bars represent standard deviation. Suggest what tzg q0ux,s**fs he standard devix* ,*guf0zss qation signifies.

f. Simplified models are commonly used to investigate scientific phenom,0(+p bq ;cyc7vq wneaq4cs+jena.
Outline the limitations in the use of a sphere to model surface area to volume ratio in cells.

6. Using examples frq3 )7cp ad7sa;+g;c:r 5eiqfl dcwdo5om human tissues, distinguish between pluripotent, totipotent and multipoter;pdg:dd f3 qal7a qo;7w sicec+)c5 5nt stem cells.

7. Explain the role of-o9*a1 yyaxvw stem cells in a multicellular organism.

(a) Explain why a large surface arqko:r-z ,v h4iea to volume ratio can increase cell efficiencyr-k4z ,oh: qiv.

(b) Describe, using two specific exam*o4q(p,ohy0 nnh7p vgples, how cell adaptation can increase surfa0 oq4gpvp*n hn 7h,o(yce area to volume ratio in a specialised cell.

(c) Many tissues found in plants are compobg6lyq, .k(u ln9q u1ound tissues, such as phloem tissue shown in the image. Phloem tissue transports organic nutruykbl q,.l9n gq(6o1u ients from their site of production (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