Biology SL Unit 1 Flashcards
What is the principles of cell theory?
All living things are composed of cells
Cells are the smallest unit of life
Cells arise from pre-existing cells
Define a cell
A cell is a basic standard, functional and biological unit of all known organisms
What are the characteristics of a cell?
Cell membrane
Genetic material
Cytoplasm
Own energy release system (respiration)
One nucleus for each cell
State the caveats to the cell theory
Giant Algae (large)
Striated Muscles cells (autonomous)
Aseptate fungal hyphae (continuous cytoplasm , septa, discrete cells)
What is the role of cell division in surface area to volume ratio of a cell?
Cells often get too large and cannot support themselves anymore. This is because the internal volume grows at a faster rate than the membrane which leads to cell death. Cell division ensure that 2 new cells with a stable s.a to volume ratio are created replacing the cells that died
How do cells get to tissue stage?
Cell differentiation-
specific genes turned on in DNA signaling for that cell to carry out a specific function
Define a stem cell
Does not have a specific function and can turn into multiple type of specialized cell// precursor
How are genes packaged?
Active genes in expanded form called - euchromatin
Inactive genes packed in condense form called heterochromatin
How are stem cells used to replace damaged or dead ones?
Biochemical solutions to trigger differentiation
Surgical implantation of cells into patients tissue
Suppression of host immune system to prevent rejection of cells
Careful monitoring of new cells to ensure they don’t become cancerous
How is Stargardts Disease caused?
By gene mutation that impairs (damages) energy transport in retinal photoreceptor cells, causing them to degenerate
How is Parkinson’s caused
Death of dopamine secreting cells in the mid brain
State cells and their disease
Bone marrow-leukemia
Nerve cells-Parkinson
Skin cells-burn victims
Islet cells-Diabetes
Myocardium-Heart disease
Where can stem cells be derived from?
Embryos
Umbilical cords
Adult tissues
State the ethical concerns that come with these stem cells derivations
Multipotent adult tissues limits types of cells
Umbilical cord needs to be preserved at a high cost, raise a concern towards access
Pluripotent stem cells come from embryos which requires destruction of potential living organism
Define prokaryotes
Organisms whose cell lack a nucleus
