UNIT 1 TEST Flashcards
What is differentiation?
process that cells become specialised for a particular function and can’t change into different cell types
What are embryonic stem cells involved in
growth repair and renewal of cells found in the tissue
Germline cells
If mutation occurs then mutation is PASSED onto the offspring
Somatic cells
If mutation occurs its NOT PASSED onto the offspring
Therapeutic use of stem cells
bone marrow transplant
skin grafts
what is cancer
uncontrolled growth of cells
why do cancer cells divide uncontrollably
- dont respond to the usual regulatory signals and chemical messengers inside and outside the cell to produce a mass of abnormal cells
- if cancer cells fail to attach to each other, they can spread throughout the body to form secondary tumours.
what is a tumour
abnormal cells produced by uncontrollable cell division
what forms DNA nucleotides
- phosphate
- deoxyribose sugar
- base
whats the backbone called
sugar phosphate backbone
prevent tangling in dna
molecules of the DNA are tightly coiled around proteins
what does DNA polymerase do
adds complementary DNA nucleotides to the 3’ end
what does ligase do
enzyme that joins DNA fragments together
what is the structure of RNA
- phosphate
- ribose sugar
- base
differences between DNA and RNA
- rna is single stranded and DNA is double stranded
- RNA contains uracil and DNA contains Thymine
- RNA contains ribose sugar and DNA contains deoxyribose sugar
Transcription
mRNA carries a copy of the DNA code out the nucleus to the ribosome
tRNA
bring specific amino acids to the ribosome where the mRNA and the genetic information is translated into a protein
what enzyme is responsible for transcription
RNA polymerase
what is a mutation
change to the genetic structure of an organism
missense mutation
altered codon for amino acid still makes sense but not the original sense.
Nonsense mutation
a codon used to code for an amino acid is exchanged for one that acts as a premature stop codon. it causes protein synthesis to be halted prematurely and results in a polypeptide chain shorter than normal and unable to function
splice site mutation
if one or more introns have been retained by modified mRNA, they may in turn be translated into an altered protein that doesn’t function properly
frameshift
every codon after the site of mutation to be altered. altered protein will not be able to function
PCR
1- dna strands separate
2-primers bind to the DNA strands
3- DNA polymerase builds nucleotides into the DNA strands
