Cell Division Flashcards
Totipotent
A stem cell that is able to divide to form any of the specialised cells in the body
Differentiation
The development if a cell to become specialised for a particular function
What cells are totipotent
Any cells in a blastocyst
Stem cell
undifferentiated cells
capable of becoming specialised
to a number of cell types
Blastocyst
Tiny ball of cells formed by a ZYGOTE as it’s cells REPEATEDLY divide
What is the role of mitosis
Repairs damaged cells
Replaces old worn out cells
asexual reproduction
What can stem cells do dfferently from human cells
they are unspecialised
divide repeatedly to make new cells
differenntiate into specialsed cells
Another name for erythrocytes
REd blood cells
Describe the stages of the cell cycle
G1- intensive cellular synthesis, organelle production, cell mass increases
S- DNA replication, one chromosome made of 2 chromatids
G2- synthesis, centrioles replicated, cell mass increases
Mitosis- 4 stage nuclear division
Cytokinesisi- cytoplasm is distrubuted evenly betwen daughter cells
Definition of chromosome
A structure made from DNA and histones found in the nucleus of eukaryotic cells
Definition of chromatid
one of 2 IDENTICAL PARTS OF chromosomes
HELD BY A CENTROMERE
formed during interphase
what is chromatin
structure made of DNA where the chromsomes havent condensed
products of mitosis
Synthesis- DNA replication
G2- organelle production
2 genetically identical daughter cells
spindle fibres
factors that affect viral infection
Inherited
Mutations
cancerous growths
Explain why it’s important that eggs are haploid
Restore the haploid number at fertilisation
prevents doubling of chromosome number each generation
definition of homologous
chromosomes that have the same genes at the same loci
diploid organisms produced by sexual reproduction have HOMOLOGOUS PAIRS OF CHROMOSOMES- One member of each pair from the male and the other member from the female pparent
How are chromosomes checked for mutations
Proof reading enzymes, move along DNA strands and check copying has been done properly
What are the effects in the genes are not copied precisely
Mutations can occur, and the new cells may fail to function
What factors affect the rate of the cell cycle
Cell type
species
availability of nutrients
Why is mitosis for such a short amount of time
Chromosomes can’t perform their normal functions when SUPERCOILED in the prophase, so they have to spend as little time as possible in this stage
How many chromosomes are in a human red blood cell
None it has no nucleus
Why don’t bacteria do mitosis
They don;t have chromosomes, centrioles or spindles of eukaryotes
What’s the difference between plant cells and animal cells in mitosis
Any animal cell can do mitosis
only meristem plant cells can do mitosis
Plants don’t have centrioles, chromatids are pulled towards poles
cell wall formed at cytokinesis
Suggest why most plant cells except meristem cells dont do mitosis
The formation of the cell wall in plant cells stops them from being able to divide properly
Meristem cells have a very thin cell
3 ways in which differentiation can occur
Change in the number of cells
Change in the shape of cells
Change in the contents of cells
