Module 1 Chromosomes Flashcards
Chromatin to DNA process (5)
Chromatin (through nuclear pore)
Solenoid Chromatin Fiber
Nucleosomes
Histones
DNA Helix
Parts of a condensed chromosome (3)
Telomere
Centromere
Arm
In Eukaryotic Chromosome structure;
Loose DNA is coiled around ___ to form ___, which look like beads on a string.
___ DNA can be seen extending from one ___ to the next. They coil to form a thicker ___ and it is organized tighter by protein scaffold to form the condensed chromosome characteristic of a ___ chromosome.
Histones
Nucleosomes
Linker, Nucleosome
Solenoid fiber (thin loop that is coiled)
Metaphase
The ___ refers to the nucleosome which is the first order of DNA ___ in the nucleus.
A nucleosome is a ___ composed of 2 copies of ___, ___, __, and ___.
Chromatin Primary Structure
Packaging
Histone octamer
H2A
H2B
H3
H4
Histones are proteins which are rich in ___ and ___ residues and are thus ____-charged. Which is the main reason that they can bind tightly to the ___-charged ___ in DNA.
lysine, arginine
positively-charged
negatively-charged
phosphates
Among the ___ kinds of histones that can be found in ___ chromosomes, ___, which is not included in the nucleosome, is not part for the binding histones.
Instead these are responsible for ___ the binding of the DNA for the histone octamer.
5
Eukaryotic
H1
Tightening
A nucleosome is composed of ___ base pairs of ___ DNA.
Between nucleosomes, the linker DNA is approx, ___ to ___ base pairs but varies.
146
superhelical DNA
20 to 90
In the ____ the formation of the secondary structure of chromatin is driven by ___, ___, and ___.
It is then stabilized by ___.
In ___, chromatin compacts into the maximally folded structure, comparable to the ___.
Chromatin Secondary Structure
salt
Intrinsic Nucleosome-Nucleosome
Nucleosome-DNA interactions
physiological salt
30 nm fiber
___ is the part of a chromosome that links sister ____. In mitotic chromosomes, they represent a constricted region where the previouslt mentioned are most closely in contact.
Centromere
Chromatids
During mitosis, spindle fibers attach to the centromere via the ___. The physical role of this segment is to act as its site of assembly.
Kinetochore
There are usually 2 arms in a chromosome:
The ___ arm which is the ___ one
and the ___ arm which is the ___ one.
p, short
q, long
p for petit
This is a region of repetitive nucleotide sequences. At each end of a ___ which protects the end of a chromosome from ___ or from ___.
Telomere
Chromatid
Deterioration
or fusion from neighbouring chromosomes.
When a telomere gets too short what happens?
The cell can no longer divide
it becomes inactive or dies.
This is attributed to aging, cancer, and a higher risk of death.
Types of chromosomes based on position of centromere (4)
Metacentric
Submetacentric
Acrocentric
Telocentric
The centromere is in the middle and chromosome arms are of equal length.
Appears v shaped.
Metacentric
