01 Flashcards
cell division stages:
interphase
early prophase
late prophase
metaphase
anaphase
telophase
interphase
types of cell division
mitosis and meiosis
only splits into two
mitosis
splits into four
meiosis
mitosis process:
prophase
prometaphase
metaphase
anaphase
telophase
meiosis process:
prophase 1
metaphase 1
anaphase 1
telophase 1
prophase 2
metaphase 2
anaphase 2
telophase 2
result either from errors
in DNA replication or from the
damaging effects of mutagens,
such as chemicals and radiation,
which react with DNA and change
the structures of individual
nucleotides
mutations
is the highly condensed form of
DNA
chromosome
when does chromosome shape into its familiar shape X?
metaphase
humans have how many autosomal pairs?
22
how many pairs of sex chromosomes do humans have?
1
Study of chromosomes and chromosomal abnormalities
cytogenetics
picture of an individual’s chromosomes in Metaphase, spread out on a slide
study karyotypes
– More condensed
– Silenced genes (methylated)
– Gene poor (high AT content)
– Stains darker
heterochromatin
– Less condensed
– Gene expressing
– Gene rich (higher GC content)
– Stains lighter
euchromatin
– chromosome tips
– Repeats
– Act as sort of biological clock
– Being whittled down at each Mitosis
telomeres
– middle
– Highly condensed
– Also repetitive sequence
– Region where spindle fibers attach
– Pulling chromatids apart during Mitosis
centromeres
the smaller of the two arms
– p stands for petite
p arm
the longer of the two arms
q arm
chromosome parts:
heterochromatin
euchromatin
telomeres
centromeres
p arm
q arm
4 types of chromosomes:
- Telocentric
- Acrocentric
- Submetacentric
- Metacentric
no p arm; centromere is on end
telocentric
no p arm; centromere is on end
acrocentric
p arm just a little smaller than q arm;
centromere in middle
submetacentric
p and q arms are exactly the same length; centromere in exact middle of chromosome
metacentric
what chromosomes are not identical
and can have different alleles of genes
homologous
what are identical
– Form as cells go through S phase (replication)
– Attached to each other by centromere
– Until Anaphase of Mitosis
– Once separated each is again referred to as a chromosome
sister chromatids
– Two q arms of two different chromosomes come together
– Two p arms are lost entirely
robertsonian translocation
– Two different chromosomes exchange parts
– Since all parts are still present – often normal
reciprocal translocation
types of translocations:
robertsonian and reciprocal
one chromosome absent is called?
monosomy
one chromosome extra is called?
trisomy
When nondisjunction occurs in both themother and the father’s gametes
Causing two copies of one chromosome to come only from one parent
uniparental disomy
