Flashcards in Control of Gene Expression Deck (62)
a change to the nucleotide sequence of DNA
what does a Mutogenic Agent do?
increases the rate of mutation
What is a Base Analogue?
a chemical that can substitute for a normal nucleotide base ----> substition mutation
what does radiation cause?
change to the structur of DNA eg) UV
one base swapped for another one
describe addition, and what it causes
one base added this causes frame shift
one base is removed
decribe inversion and what it can cause
sequence of bases are reversed, can cause no change (degenerate) ,change a few, doesn’t cause frame shift
one or more bases are repeated
DNA is moved from one part of a genome to another part of a genome
what could be the impact of the alteration of one AA?
changes primary structure, changing H bonds, changing tertiary structure (could have negligable change)
what does change to many AA cause?
frame shift= change to primary/H bonds ---> tertiary
describe stem cells
capable of diffferentiating into specialised cells, can divide for the organisms lifetime (no apoptosis)
what is a totipotent stem cell?
can differentiate into any specialised cell, found in early mammalian embryos
describe a pluripotent cell
can differentiate into many types of cells, but cannot make placental cells
describe a multipotent stem cell
can differentiate into a few types of specialised cells
describe a unipotent stem cell
stem cells that can differentiate into one type of cell
what happens when a cell becomes specialised?
conditions inside the cell control which genes are expressed (eg) transcription factors) cells become irreversibly specialised
How can we obtain induced pluripotent stem cells (iPS)
use a modified virus as a vector, virus inserts transcription factors from pluripotent ----> unipotent, transcription factors are expressed
how can we obtain embryonic stem cells?
IVF embryos, pluripotent stem cells are removed after a few days, pluripotent cells can differentiate into all types of body cell
how can we obtain Adult Stem Cells?
taken by consenting adults in an operation (eg) bone marrow) Adult stem cells are multipotent
how can bone marrow be used in medicine?
contain multipotent stem cells, can differentiate into WBCs and RBCs, donor bone marrow can be used to treat leukemia
how can stem cell grown organs be used in medicine?
no donor required, use iPS cells, no rejection
what are the advantages of stem cells in medicine?
improve quality of life, prevent suffering, save lives
what are the disadvantages of stem cells in medicine? (how can some of these be combatted)
embryos could develop into a foetus, fertalised ---> right to life ( use an unfertalised egg that has been triggered to multiply, or develop iPS cells)
define transcription factor
proteins that control the rate of transcription by switching genes on and off
define promotor region
short sequence of DNA at the start of the gene that the ribosome attaches to
decribe the process of a transcription factor
TF moves from the cytoplasm to the nucleus, binds to the promotor region, activate/ repress transcription by helping/ preventing RNA ploymerase binding to DNA
describe using the example of oestrogen how transcription factors can be controlled
steriod hormone, binds to receptor, foring oestrogen - oestrogen receptor complex, alters shape to make transcription factor