unit 1.1: division and differentiation of human cells Flashcards
what are somatic cells?
non-sex cells
diploid (23 pairs of homologous chromosomes)
give an example of somatic cells
(name a body tissue)
(connective cells)
epithelial cells covering the bodies surfaces and inner cavities
how do somatic cells divide and why?
mitosis
to replenish old cells (growth and repair)
to maintain diploid chromosome complement and ensure no genetic information is lost
what are germline cells
sex cells
diploid
how do germline cells divide and why
mitosis:
to create more diploid germline cells ensuring no genetic information is lost
meiosis:
to create gametes (sperm and eggs)
what is the process of meiosis
homologous chromosomes separate
chromatids separate
what is produced from mitosis
2 genetically identical daughter cells
what is produced from meiosis
4 genetically varied daughter cells (haploid)
what is haploid
23 single chromosomes
what is diploid
23 pairs of homologous chromosomes
what is cellular differentiation
the process in cells expressing (turning on) genes to perform specialised functions
what are the 2 types of stem cells
embryonic
tissue
what are embryonic stem cells
pluripotent
what are tissue stem cells
multi-potent
what is pluripotent
can give rise to all cell types as all of the genes are switched on
what is multi-potent
give only give rise to a limited type of cells found in a particular tissue as some genes are switched on
what cells can bone marrow tissue give rise to
platelets
red blood cells
white blood cells
give an example of a cell that performs a specialised function
red blood cells, the gene for producing the protein haemoglobin is switched on whilst is switched off in all other cells, this allows red blood cells to carry oxygen
what is stem cell research used for
drug testing
discovering how diseases develop
what is used in stem cell research
stem cells used as model cells
what are the therapeutic uses of stem cells
bone marrow transplants
corneal repair in the eyes
regeneration of damaged skin by skin grafts
repair of damaged or diseased organs
ethical issues of stem cell use
embryonic cells result in the death of an embryo, resulted in regulation around their use
how do cancer cells divide
by mitosis in an excessive or abnormal way
why do cancer cells divide abnormally
they do not respond to regulatory signals
