L19 Neoplasia I Flashcards
Three P’s of Neoplasia
Progressive, purposeless, parasitic
Two substances that control cell division
cyclin
cyclin dependent kinases
join together to form active compound
Example of cycle inhibitor
p27 protein
Where are the three cell checkpoints in the cycle and what do they check
G1: checks cell size, nutrients, growth factors
G2: cell size and DNA replication
M checkpoint: chromosome spindle attachment
Two genes involved in neoplasm formation
proto-oncogenes
tumor-suppressor gene
What does a proto-oncogene do in normal cell and how does it contribute to neoplasm
regulates normal growth
can become ONCOGENE from mutation or increased expression - one allele needs to have mutation
will cause cells that are supposed to apoptose to proliferate instead
What does a tumor suppressor gene do in normal cell and how does it contribute to neoplasm
applies breaks to proliferation
mutations need to happen in both alleles to have effect
mutation causes inactivation = increased mutation rate
p53
tumor suppressor gene
plays role in apoptosis
inactivation = uncontrolled mutant cells dividing
Two types of genetic mutations
acquired: only some cells, occurs during life/damage
inherited: present in germ cells and therefore all cells in body, passes from generation to generation
5 types of mutation
point, missense, nonsense, frameshift, block
What is a point mutation?
where one base is switched with another
What is a missense mutation?
when one base pair has be switched for another
What is a nonsense mutation?
stop codon is inserted accidentally
What is a frameshift mutation?
removal or insertion of codon which affects reading of whole DNA sequence following
What is a block mutation?
change in chromosome
eg. deletion, substitution, translocation
