cell division Flashcards
what are the advantages of being multicellular?
it allows an organism to become larger and more complex
it also allows different cells to take on different jobs
what is it called when being multicellular allows different cells to take on different jobs?
differentiation
what does an organism need to have to be multicellular?
allow communication between all cells in the body
supply all the cells with enough nutrients
control exchanges with environment such as heat and gas
what is mitosis?
the process that produces new cells for growth
what must take place before cells divide?
DNA replication
why should DNA replication occur?
so that each cell produced still has two copies of each chromosome
what mammals with two copies of each chromosome called?
diploid cells
what does DNA replication involve?
two strands of the DNA molecule unzipping to for single strands
new double strands forming by DNA bases lining up in complementary pairings
explain what happens when mitosis occurs?
the chromosomes line up along the centre of the cell and divide. The copies then move to opposite poles of the cell (ends)
what is meiosis?
the type of cell division that produces gametes
why are gametes haploid cells?
because they contain only one chromosome from each pair
what does this mean?
that the zygote gets one copy of a gene from one parent and another copy from the other parent. This produces genetic variation
how is the structure of a sperm cell adapted to its function?
many mitochondria to provide energy for swimming to the eggs
an acrosome that releases enzymes to digest the egg membrane
what is the first division in meiosis?
one chromosome from each pair moves to the opposite poles of the cell
what is the second division in meiosis?
the copies of each chromosome come apart and move to opposite poles of the cell
