Tut 12 - Stem Cells (Students)

St Andrew’s Junior College The Cell and Biomolecules of Life / Stem Cells 2022 H1 Biology 1 Full Name: Civics group: 21S Index no.: Date: Core Idea 1: Cells and Biomolecules of Life Stem Cells Tutorial 12 MCQ 1 2 3 4 5 6 7 1 Which of the following shows the correct developmental potency of the following stem cells? Zygotic stem cells Embryonic stem cells Myeloid stem cells Neural stem cells A Pluripotent Totipotent Multipotent Unipotent B Totipotent Pluripotent Multipotent Unipotent C Pluripotent Totipotent Pluripotent Multipotent D Totipotent Pluripotent Multipotent Multipotent 2 Which of the following best illustrates totipotency? A A somatic cell isolated from a root tip develops into a normal adult plant. B Stem cells are able to divide indefinitely. C Mesenchymal stem cells can differentiate into an extensive range of cell types, including bone cells, cartilage cells, muscle cells and fat cells. D The replacement of the nucleus of an unfertilised egg with that of a pancreatic cell converts the egg into a pancreatic cell. 3 Which of the following statements is/are true regarding zygotic stem cells and cancer cells? 1 Both are able to move from one location to another. 2 Both are able to divide by mitotic division. 3 Both are specialised cells and capable to differentiate further. 4 Both are capable of indefinite replication. A 2 only B 1 and 3 only C 2 and 4 only D 1, 2 and 4 only

St Andrew’s Junior College The Cell and Biomolecules of Life / Stem Cells 2022 H1 Biology 2 4 What is the role of stem cells with regard to the function of adult tissues and organs? A Stem cells are fully differentiated cells that reside under the surface of epithelial tissue, in position to take over the function of the tissue when the overlying cells become damaged or worn out. B Stem cells are embryonic stem cells that persist in the adult, and can give rise to all of the cell types in the body. C Stem cells are differentiated cells that have yet to express the genes and produce proteins characteristic of their differentiated state, and do so when needed for repair of tissues and organs D Stem cells are undifferentiated cells that divide asymmetrically, giving rise to one daughter cell that remains a stem cell and one daughter tha t will differentiate to replace damaged and worn out cells in the adult tissue or organ. [9648/2013/01/38] 5 Stem cells are found in many tissues that require frequent cell replacement such as the skin, the intestine and the blood. However, within their own environments, a bone marrow cell cannot be induced to produce a skin cell and a skin cell cannot be induced to produce a blood cell. Which statement explains this? A Different stem cells have only the genes requ ired for their particular cell line. B Genes not required for the differentiation of a particular cell line are methylated. C Binding of repressor molecules prevents the expression of genes not required for a particular cell line. D Expression of genes not required for a particular cell line is controlled at translational level. 6 All the following statements about stem cells are true except A Cord blood stem cells will only give rise to blood cells. B Cord blood from the newborn is a source of adult stem cells. C Adult somatic cells can be reprogrammed to behave like embryonic stem cells. D Cord blood stem cells are pluripotent. 7 Which of the following is a valid ethical concern on the use of stem cells? A Use of adult stem cells could result in the formation of new organism. B Totipotent stem cells should be recommended as they are in huge abundance. C Skin stem cells usage should be prohibited as they are limited in quantities D Embryonic stem cells retrieval results in the destruction of human embryos.

St Andrew’s Junior College The Cell and Biomolecules of Life / Stem Cells 2022 H1 Biology 3 STRUCTURED QUESTIONS QUESTION 1 (a) Describe the features of myeloid and lymphoid stem cells and discuss their use in the treatment of leukemia. ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….[6] (b) Describe the differences between stem cells and cancer cells. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. ……………………………………………………………………………………………….[3] [TOTAL: 9]

St Andrew’s Junior College The Cell and Biomolecules of Life / Stem Cells 2022 H1 Biology 4 QUESTION 2 [Worked example – Ans at the back] Describe the features of zygotic and embryonic stem cells that distinguish them from each other. ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….[4] [TOTAL: 4] QUESTION 3 The response of the human body to tissue damage depends on the types of tissues involved. Epithelial tissue, liver tissue and cardiac muscle tissue each respond differently to damage. • Epithelial tissue in the lungs contain stem cells. • Liver tissue contains cells that can divide when stimulated. • Cardiac muscle tissue contains cells that cannot divide at all. Damage is permanent and is associated with scar tissue formation. Researchers hope to repair heart tissue damaged by heart attacks. Cellular therap y using stem cells offer ways to replace damaged cardiac muscle tissue. Some fully differentiated cells from the patient can be reprogrammed into stem cells in tissue culture as seen in Fig. 3.1. Such cells are called induced pluripotent stem cells (iPSCs). Fig. 3.1

St Andrew’s Junior College The Cell and Biomolecules of Life / Stem Cells 2022 H1 Biology 5 (a) Outline two advantages of using induced pluripotent stem cells (iPSCs) in a patient suffering from a heart attack, to generate cardiac muscle for treatment. ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….[2] In experiments with mice, it was discovered that the introduction of four specific genes that code for transcription factors would reprogramme fully differentiated cells to iPSCs. (b) Suggest how the insertion of genes coding for transcription factors can cause a differentiated cell to become pluripotent. ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… ……………………………………………………………………………………………….[2] There is evidence to suggest that the introduction of the four genes has caused an increase in the production of telomerase in the fully differentiated cells. (c) Explain how telomerase may contribute to the re -programming of mouse skin cells into stem cells. ……………………………………………………………………………………………….…. …………………………………………………………………………………….………….… …………………………