Cell division (paper 2) TOPIC 1 & 6 Flashcards
.what do most cells in the human body contain
a nucleus
what does a nucleus contain
the genetic meterial of the cell
what is the genetic chemical in the nucleus called
DNA
what is DNA arranged into
structures call chromosomes
what is a chromosome
a coiled molecule of DNA carrying different genes
what is a the term for a body cell
somatic cell
how are chromosomes found in somatic cells
in pairs
why are chromosomes found in pairs
because each pair is inherited from the person’s mother and one from their father
how many chromosomes do humans contain
46 chromosomes in 23 pairs
what is the haploid number and what is it for a human
the number of pairs of chromosomes
23 pairs in a human
what is the diploid number and what is it for humans
the number of chromosoms in a cell
46 chromosomes
what are gametes
sex cells
what is the female sex cell
an ovum
what is the male sex cell
sperm
what is the word for the picture of chromosomes when removed from a nucleus and arranged in order
a karyogram or karyotype
what are karyograms/karyotypes used for
to determine the sex of an individual and diagnose genetic disorders
how can you tell if an individual is female
they will have 2 x chromosomes
how can you tell if an individual is male
they will have one x chromosome and one y chromosome
how are new cells made
by the proccess mitosis
define mitosis
the growth and repair of tissues
what is the cell cycle
the series of stages which somatic cells divide in
what happens in stage one of the cell cycle for mitosis (interphase)
- cell increases in size
- the DNA is replicated
- the number of organelles is doubled
what happens in the second stage of the cell cycle for mitosis (prophase)
- the chromosomes condense in the middle of the cell
- half the chromosomes are pulled to one pole of the cell
- two nuclei are formed
- cell is split to form 2 genetically identical daughter cells
what is the longest stage of mitosis
when the cell grows and replicated their DNA and increases the sub-cellular structures (the first stage)
what do genes do
they carry the instructions to control a characteristic
what is binary fission
the method of asexual reproduction which single-cell organisms use to create a copy of themselves
in binary fission are plasmids equally shared between the daughter cells? explain?
No - the plasmids are shared randomly, but one loop of DNA goes to one daughter cell and the other to the other daughter cell