I was going through the Biology Study design and came across this dotpoint
- the nature of evidence that supports or refutes a hypothesis, model or theory
Could someone please explain what this means.
Could someone also give me a definition for fossil record? What would we need to include
This is what Bio ninja said The totality of fossils, both discovered and undiscovered but google said
Britannica said the history of life as documented by fossils, the remains or imprints of the organisms from earlier geological periods preserved in sedimentary rock
Thanks
Pretty sure that study design dot point is just saying that if the results show what you predicted they'd show then that supports your hypothesis.
The fossil record is just fossils of species that have been preserved. Both of those definitions say pretty much the same thing, the Britannica one is just in more detail. Really doubt you'll be asked to define it.
Can someone plz summarise the cell-mediated response? Is this correct: APC's present antigens to helper t-cells, helper t-cells release cytokines, stimulate the clonal expansion of t-cells. More helper t-cells, t-memory cells and cytotoxic t-cells specific to the antigen are produced?
You don't need to talk about T helper cells that much.
Here's what I had in my notes about it:
-Naive Tc cells are always travelling throughout the body, attempting to bind to peptide fragments presented on MHC1 markers.
-When they find one that they can bind to, the Tc cell is ‘selected’
-The Tc cell will release granzymes (including perforin) which cause the cell to undergo apoptosis.
-The Tc cell continues to travel throughout the body and kill cells presenting the same peptide, but it will not divide or differentiate until cytokines are present.
-When cytokines have been released from the Th cells (this could happen before or after the Tc cell is selected), the Tc cell will divide (proliferate) and differentiate into Tc memory cells and Tc effector cells.
-The Tc memory cells will remain in the body to fight off subsequent infection by the same pathogen.
-The effector Tc cells will travel throughout the body, inducing apoptosis in cells presenting the same peptide fragment as the original cell.