Unit 1- Division & Differentiation Flashcards
What is a somatic cell?
Any cell in the body other than the cells involved in reproduction. They divide by mitosis to form more somatic cells.
What is a germline cell?
Germline cells are gametes (sperm and ova). Germline stem cells can divide by mitosis to produce more germline stem cells or by meiosis to produce germline cells.
Decribe the diploid chromosome complement during mitosis and meiosis.
The nucleus of a germline stem cell can divide by mitosis to maintain the 46 chromosomes. Or divide by meiosis to produce a haploid gamete with 23 chromosomes.
Describe the divisions in meiosis.
It undergoes two divisions, firstly separating homologous chromosomes, secondly separating chromatids.
Define cellular differentiation.
Cellular differentiation is the process by which a cell expresses certain genes to produce proteins characteristic to that cell type. Allowing a cell to carry out specials functions.
Describe the potential of differentiation for embryonic stem cells.
Embryonic stem cells can differentiate into all cell types and so pluripotent because all genes can switched on.
Describe the potential for differentiation of tissue stem cells.
Tissue stem cells can differentiate into all of the types of cells found in a particular tissue type and so are multipotent. Tissue stem cells are involved in growth and repair of cells found in that tissue.
Examples: blood stem cells are found in bone marrow and can produce red blood cells, platelets, phagocytes and lymphocytes.
What are Therapeutic uses of stem cells?
This involves the repair of damaged or diseased organs or tissues. For example corneal repair and skin grafts.
What is a Research use for stem cells?
Using stem cells as model cells to study how diseases develop or for drug testing.
How do cancer cells form?
Cancer cells do not respond to regulatory signals and divide excessively forming a mass of abnormal cells called a tumour.
Describe how secondary tumours can form.
Cells in the tumour may fail to attach to each other, spreading through the body, creating more cancer cells which divide uncontrollably, forming secondary tumours.
