Unit 1: Normal Differentiation and Abnormal Division Flashcards
what is benign tumour?
usually do not cause serious problems and can be removed by surgery
what is a malignant tumour?
cancer - may undergo metastasis - enter the circulation
what is the loss of control of cell division and excessive cell growth due to?
mutations in the genes which regulate cell division
what are proliferation genes/proto-oncogenes?
The encode proteins that promote cell division only when an external signal is received
what are oncogenes?
They are found in many cancers
How many alleles does the mutation need to occur in for proliferation genes and why?
Only one of the pair as it is a dominant allele
What are Antiproliferation genes?
The code for proteins which restrict cell division at checkpoints.
what are anti proliferation genes also known as and why?
tumour suppressing genes because they normally prevent excessive cell division
How many alleles does the mutation need to occur in for anti proliferation genes
both copies as it is recessive
Drugs that interfere with the cell’s ability to make microtubules have been used in chemotherapy to treat cancer, how would this treatment work and why should it not be used longterm?
spindle fibres are microtubules. during mitosis spindle fibres guide the chromosomes and pull them apart to opposite ends of the cell. if chemotherapy interfered with the cell’s ability to make microtubules then spindle fibres cannot be formed. chromatids cannot be separated into daughter cells. the cycle stops are the M checkpoint and the daughter cells cannot enter the next G1 phase. Cell stop dividing and prevents the tumour formation. Cannot be used for a long time because it is not specific so it interferes with all cell division. Cell division is important in normal cell growth and repair
what do we call the process of cells becoming specialised to perform specific functions?
differentiation
how is differentiation brought about in cells?
by the switching off of unnecessary genes and leaving essential and cell specific genes switched on
what is a division of labour in multicellular organisms?
They have cells that are specialised, have different structures for particular functions
What is tissue made up of?
differentiated cells which has the same function
what are organs made up of?
tissues grouped together
what are meristems?
The growing points of plants that are capable of cell division
what does totipotent mean?
they can differentiate into any other type of cell
All cells in an organism has the same set of genes except from?
red blood cells and sex cells
Why do red blood cells not have genes?
They don’t have a nucleus
What are essential genes?
necessary for all cells to survive
what are cell specific genes?
necessary for the function of that cell
what are unnecessary genes?
those not needed by the cell
what cells have the ability to differentiate into any type of cell
embryonic stem cells
what is beta galactosidase?
an enzyme that is involved in the breakdown of lactulose into glucose and galactose
what is the role of the regulator gene?
codes for the repressor molecule
what is the role of the repressor molecule?
binds to the operator gene to switch it off
what is the role of the operator gene?
switches on the structural gene
what is the role of the structural gene?
codes for the production of the enzyme
together the operator gene and the structural gene are called?
operon
Describe the steps of jacob monod theory when lactulose is absent
Regulator gene is always on and causes the repressor molecule to be produced.
The repressor molecule binds to and switches off the operator gene.
operator gene is unable to function therefore the structural gene remains switched off.
The enzyme is not produced.
Describe the steps of jacob monod theory when lactulose is present
Regulator gene is always on causing the repressor molecule to be produced.
Repressor molecule combines with lactulose.
Repressor-lactulose complex is unable to switch off the operator gene.
Operator gene switches on the structural gene.
The enzyme is produced and breaks down the lactulose.
When all of the lactulose is broken down, the repressor molecule is again free to switch off the operator gene and enzyme production is stopped.
In the jacob monod theory, what is the inducer molecule?
lactulose
what do genes code for?
the production of proteins
why are genes switched on and off when not required?
for conservation of energy and resources