Stem Cells

Stem cells can undergo mitosis to form genetically identical cells with the same differentiation potential.

• False

• True

Answer explanation

Further Explanation:

This is called the symmetric mode of division.

Stem cells can also undergo asymmetric mode of division to form one stem cell with the same differentiation potential and one progenitor cell with a limited differentiation potential.

Stem cells achieve differential gene expression by silencing genes using repressor proteins.

• False

• True

Answer explanation

Correct ans:

Long term silencing of genes in stem cells happens via DNA methylation.

 

Silencing of genes using repressor proteins applies to silencing of genes on a shorter term.

Stem cells and cancer cells have an activated telomere gene giving them limitless replicative potential.

• False

• True

Answer explanation

Correct ans:

Stem cells have an activated telomerase gene which codes for telomerase enzyme (involved in process that replenish the ends of chromosomes with new telomeres).

Zygotic stem cells can divide and differentiate to form a whole organism

• False

• True

Answer explanation

Further explanation:

Zygotic stem cells can form both extra-embryonic tissue and all other cells of the embryo (extra-embryonic tissues)

Totipotent stem cells can differentiate into all cell types including extra-cellular tissues.

• False

• True

Answer explanation

Correct ans:

Totipotent stem cells can differentiate into all cell types including extra-embryonic tissues.

Zygotic stem cells are totipotent, embryonic stem cells are pluripotent, while myeloid and lymphoid stem cell are multipotent in nature.

• False

• True

Answer explanation

Further explanation:

Blood stem cells a.k.a haemotopoietic stem cells (which are pluripotent) present in the bone marrow further divide to form myeloid and lymphoid stem cells (which are multipotent).

Myeloid stem cells differentiate to form red blood cells, macrophages, and NK cells where lymphoid stem cells differentiate to form B-lymphocytes and T-lymphocytes.

• False

• True

Answer explanation

Correct ans:

 

Myeloid stem cells differentiate to form red blood cells, macrophages whereas lymphoid stem cells differentiate to form B-lymphocytes, T-lymphocytes and NK cells.

iPS cells can be formed by reprogramming adult stem cells into embryonic stem cells using transcription factors.

• False

• True

Answer explanation

Correct ans:

iPS cells can be formed by reprogramming somatic cells into pluripotent stem cells using transcription factors.

Stem cell research is controversial as it involves the invasive extraction of zygotes from women to obtain zygotic stem cells.

• False

• True

Answer explanation

Correct ans:

extraction of oocytes to fertilise them in-vitro to form zygotes, then blastocysts to extract embryonic stem cells.

Due to advanced research, all future implications of stem cell transplant in a patient are fully known, making the treatment safe and effective.

• False

• True

Answer explanation

Correct ans:

one of the ethical concerns: not all are known, may have unknown safety implications.