cell division - exam questions Flashcards
stem cells can specialise to form a variety of cell types.
what other feature is shown by stem cells but not by specialised cells?
the ability to continue dividing
suggest why the use of fluorescent dyes in flow cytometry is inappropriate when analysing red blood cells
red blood cells have no nucleus and therefore no DNA
explain how the organisation of homologous chromosomes during metaphase 1 increases genetic variation
- homologous chromosomes line up across centre of the cell on the equator
- each chromosome of homologous pair can end up facing either pole in either daughter cell
- leads to independent assortment
- each chromosome of homologous pair is genetically different
- so increases genetic variation
explain why a plant leaf is described as an organ
- it is a group of tissues combined to form a specific function
- plant leaves have epidermis, phloem/xylems/palisade mesophyll/vascular tissues
- to carry out photosynthesis and gaseous exchange
what happens if DNA damage is discovered at the G2 checkpoint?
the cell cycle is halted and the cell tries to repair the DNA
what explains the significance of mitosis in the development of whole organisms?
mitosis can be controlled at certain points in development which will change body plans
what correctly describes one specialisation of a sperm cell?
acrosome contains enzymes to digest outer portion of egg
mitosis occupies only a small part of the cell cycle.
outline the events that take place in the rest of the cell cycle.
- cytokenesis occurs
- DNA replication occurs and being checked
- cell growth and increase in no. of cell organelles
- can also talk about g1/s/g2
from the start of mitosis, describe the events that have taken place in this cell to enable it to reach stage shown (anaphase)
- chromosomes supercoil / condense
- nuclear envelope disintegrates
- nucleolus no longer visible / disappears
- centrioles move to opposite poles
- chromosomes attach to spindle fibres at centromere
- chromosomes align at the equator
- chromosomes move to opposite poles of the cell
- spindle fibres change length/shorten
