karyotypes and visual representation. Flashcards
understand karyotypes.
what is a karyotype?
a karyotype is the number and visual appearance of the chromosomes in the cell nuclei of an organism.
a picture of a personβs genome.
what are chromosomes made up of?
chromatin.
what does chromatin consist of?
DNA and protein.
how does a chromatin form?
starts with DNA being wound around proteins called histones and forms nucleosomes.
what is a chromatid bound by?
when chromosomes are copied the new chromatid is bound by the centromere.
(not always in the centre).
what are karyotypes used for?
medical screenings, to check that all 46 chromosomes are present, as too much or too less can result in health issues.
when should karyotyping occur?
during metaphase.
why should karyotyping occur during metaphase?
because the chromosomes are stained and visible.
when should karyotyping not occur?
during anaphase or telophase because the chromosomes arenβt together or visible.
what type of pairs are they arranged in?
homologous pairs.
what is a homologous pair?
when the chromosomes are the same.
where is each chromosome from?
one from the mother and one from the father.
how many chromosomes are in a cell?
46 chromosomes
how many chromosome pairs are in a cell?
23 pairs
what is an autosome?
any chromosome that isnβt a sex chromosome.
usually related to hair colour, hair texture, eye colour and height.
how many sex chromosomes are there?
1 pair
what is a female sex chromosome?
XX
what is a male chromosome?
XY
how many autosomal chromosomes are there?
22 pairs, 44 chromosomes.
how many chromosomes are from the father?
23 chromosomes
how many chromosomes are from the mother?
23 chromosomes
what can an uneven amount of chromosomes result in?
genetic disorders, down syndrome (an extra chromosome), turners syndrome (only 1 sex chromosome).
what is a genome?
a full set of DNA, contains all genes that influence traits.
