module 2 - foundations in biology Flashcards
what are the 3 types of potencies for stem cells
totipotent
pluripotent
multipotent
what cells can totipotent stem cells differentiate into, and where are they from
can become any type of cell, and are from zygotes (first 8-16 divisions)
what can pluripotent stem cells differentiate into, and where are they from
can become any tissue type, but not a whole organism, and are from inside layer of blastocyst cells
what can multipotent stem cells differentiate into, and where are they from
can become any cell type within a tissue, and can be harvested from the adult body (bone marrow, skin, testes, intestine, cardiac cells, brain)
what are the two things stem cells can do
self renewal, where identical stem cells are made
differentiation, the making a specialised cell from a stem cell
what are the levels of organisation within an organism
cells are organised into tissues, then organs, then organ systems, then organism
e.g. neurons, nervous tissue, brain, CNS, badger
why are erythrocytes made in the bone marrow, and how
need to be made because they have no nucleus, so no mitosis
made via erythropoiesis (subform of haemopoiesis)
how does erythropoiesis work
multipotent cell form proerythrocytes
haemoglobin builds up in cytoplasm
nucleus is ejected
further changes make the cell a mature erythrocyte (biconcave shape etc)
what adaptations do erythrocytes have and why
biconcave shape - increase surface area
haemoglobin builds up - haemoglobin binds to oxygen
ejection of organelles - more room for haemoglobin
elastic membrane - allow cell to fit in capillaries
what main changes occur when stem cells differentiate into neutrophils
indentations in nucleus give it a lobed structure (squeeze in capillaries) granules accumulate (lysosomes that contain hydrolytic enzymes) flexible shape (allow it to phagocytose pathogens)
where does mitosis occur most in plants
meristematic tissue (roots and shoots) for growth
what are the xylem and phloem formed from
the cambium - meristematic tissue between the phloem and xylem in stems and roots
what stimulates cell differentiation
hormones/balance of different hormones
name all stem cell sources
inside layer of embryos, bone marrow, skin, liver, brain, intestines, umbilical cord blood, tips of roots and shoots
define a stem cell
a cell that can divide an unlimited number of times via mitosis, and can differentiate into other cells
what can stem cells be used for
repair of damaged tissues,
treatment for alzheimer’s, parkinson’s, type 1 diabetes, blood diseases and research into developmental biology
what are the controversies surrounding embryonic stem cells
could’ve potentially been a living person
usually wasted from ivf
what can be dangerous about tissue transplants
the immune system may consider it antigenic and attack it (esp blood type)
how many types of microscopes are there?
light (also called optical)
laser scanning confocal
scanning electron
transmission electron
what two key features of microscopes are needed for microscopy
high magnification (how many times bigger things can look than they are) high resolution (how close two things can be together while remaining visually distinct)