1. Which of the following are roles of stem cells in livingw+ q5t5r0 tjpupy(r 1,thcc8h eu,* ja 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 descr-ybppp somy -qgu+8sap, r 626ibe the differentiated cells in an individual plant such as the golden barrel2y oupy+-rap6ps-s6 ,q g8bpm cactusbarrel (Echinocactus grusonii) shown in the image?

  3. What are essential properties of stem cells?tga+)i)gdwn 6

  4. What is the cause of stem cells differentiating along different pathwlfq ,jm r,8gu(99dva kays to produce a varietvf rdqa j(k99lm8g,, uy of differentiated cells?

a. Use the graph to estimate the volume of a l f+. cu9qx 2n2 -q/ mu+aru5qzcpckjp6iver cell.

b. The image is of cardiac muscle. l ae;a6 sf5ky ).qn,o j4gaw;af2qpq .

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 hhw*8v.r 6 wxc;d czv1xave a large volume.

d. Estimate the mean length of a cell with a volume of 1000 µm3 using the tri p554 z6a5nb(t*kf jayxmzth+l.w-q end line on the gryhq (l4 zj5-x w+zn56t5bip.m*atka faph.

e. The horizontal error bars represent standard deviation. Sugges 7 t4rpugui1g8t what the standard gu7 i4g1t8urp deviation signifies.

f. Simplified models are commonly used toig,nk r1).kzzv- j9hm 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 tissuesto)wxm:r+4 nn nn+wy+, distinguish between pluripotent, totipotent and multipotent stem+:y n n4xr)+wo+ wmtnn cells.

7. Explain the role of stem cemt8:j2fl hc3 7trh3ri lls in a multicellular organism.

(a) Explain why a large surql+39(n3lic9, o4bt a mkmnhnface area to volume ratio can increase cell efficienckqc(+o3 m n4tlan lhb,9m9in 3y.

(b) Describe, using two specific examples, how cell adaptation can in;u+rj5qaga g8 crease surfa8 g;uagajqr+5ce area to volume ratio in a specialised cell.

(c) Many tissues found in plants are compounm a 45t)vqw ewy cbv+(e7l7*epmkd +d8d tissues, such as phloem tissue shown in the image.8b)edw4 kmdy t7*++ec7vvl 5e(wpmqa Phloem tissue transports organic nutrients 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