1.1 Flashcards
what is a somatic cell
any cell in the body other than the cells involved in reproduction
are somatic celle diploid or haploid
diploid
how do somatic cells divide
mitosis
are the same number of chromosomes passed onto the daughter cell
(mitosis)
yes
steps of mitosis
- chromosomes duplicate
- chromosomes line up along the equator
- chromatids are pulled apart to separate poles by spindlefibres
- cell divides into 2 daughter cells with 4 chromosomes
what is meiosis
a type of cell devision that results in half the number of chromosomes as the parent cell
where does meiosis take place
the testis and the ovaries
what are germline cells
they are gametes and the stem cells that divide to form gametes
how do germline cells divide
the nucleus of germaines cells divide my mitosis to form 2 identical daughter cells
these daughter germline cells then divide by meiosis to from four haploid gametes
what does germline division by mitosis produce
germline stem cells
what does division by meiosis produce
haploid gametes
what is cellular differentiation
the process by which a cell expresses certain genes to produce proteins characteristic for that cell type
why does differentiation allow the cell to carry out
specialised functions
what are stem cells
unspecialised cells that can self renew or differentiate into specialised cells
what are the two types of stem cells
embryonic and tissue
where are embryonic and tissue stem cells found
- very early embryo
- particular tissues and organs throughout the body
are embryonic stem cells multi or pluripotent
what does that mean
pluripotent
means they have all their genes switched on so they can differentiate into all the cell types
are tissue stem cells multi or pluripotent
what does this mean
multi-potent
only have some genes switched on and so can only differentiate into particular tissues
what are stem cells used as model cells for
-providing info on cell processes such as cell growth, differentiation and gene regulation work
- study how diseases and disorders develop
- test the response of cells to new drugs
what are examples of therapeutic uses of stem cells and explain the processes
- stem cell skin grafts
• culture skin stem cells and spray onto damaged skin to repair it - corneal repair
• culture corneal stem cells and place over damaged cornea to regenerate it
what are the ethical issues of stem cells
it destroys the embryo and people view it as destroying a human life
what causes a tumour to grow
cancer cells stop responding to regulatory signals that control cell division and divide excessively to form a mass of abnormal cells
what are benign tumours
tumours that remain in one place and don’t spread throughout the body
e.g warts and moles
what causes malignant tumours
when cells within a benign tumour fail to attach to each other and spread throughout the body through the bloodstream forming secondary tumours
