L8 : cells communication, interaction, differentiation, cell death

Question 1

Stem cells

Answer 1

• Can become specialised cells

- Can be used to replace damaged tissues

Question 2

How to get stem cells (2)

Answer 2

Adult stem cells
- obtained from the body tissue of an adult

Embryonic stem cells

• fertilised egg formed outside the body (ZYGOTE)
• 4/5 days later embryo cells extracted from embryo
• embryo then is destroyed
• controversial

Question 3

Different types of stem cells

Answer 3

Totipotent : can from all cell types of the body plus extraembryonic & placental cells

Pluripotent : can only form cells of the embryo proper - juts placental cells

Multi potent ; can only form cells within a particular germ layer derivative

Question 4

chemical signals can control differentiation potential

e.g. of signalling include (revision)

Answer 4

autocrine, paracrine, neural, endocrine

Question 5

examples of specialised cell junctions

Answer 5

what ; provide contact between neighbouring cells or cells and extra cellular matrix

eg.
gap junctions; directly contact cytoplasm of 2 cells
allows passage of small soluble ions and molecules

dermosomes; provide strong adhesion between cells

tight junctions; seals neighbouring cells in epithelial sheets to prevent leakage of molecules

Question 6

ECM ?
contains
function

Answer 6

Extra cellular matrix

• contains extra cellular molecules inserted by cells
• provides structural & biochemical support

Question 7

how quikly a stem cell can divide depends on its environment

Answer 7

look back at slides

Question 8

apoptosis
what is it`?
process?

Answer 8

what; programmed cell death

process;
Normal cell – shrinkage of cell; collision of cytoskeleton –changes in cell membrane ; membrane blebbing – collapsion of nucleus & DNA fragmentation, – apoptic body formation — engulfed by macrophages (large white blood cells )