Nucleoid/ nucleosomeNucleoid/ nucleosome
Scaffold proteinScaffold protein
Histone/ non histoneHistone/ non histone
Highly dependent on the type of org.Highly dependent on the type of org.
Prokaryotic vs Eukaryotic org.Prokaryotic vs Eukaryotic org.
Different technique used to visualise.Different technique used to visualise.
Such a compact space. Question arises on how key activities inSuch a compact space. Question arises on how key activities in
protein synthesis can take place within this limited space.protein synthesis can take place within this limited space.
Chromosome discovered by W. Waldeyer.
Euchromatin –Fibers less packed, disperse–Fibers less packed, disperse
appearance occupying most of the nuclearappearance occupying most of the nuclear
Heterochromatin- More dense area, found atMore dense area, found at
Diff. org = diff. no.
Man 23 pairs =Total 46.
22 pairs of autosomes
2 sex chromosomes.
Cht. size shape + pattern,
Numbered in order of size.
Different cell diff number eg.
Liver cells 92.
Varies among species.Varies among species.
Unrelated to the size or biological complexityUnrelated to the size or biological complexity
of an org.of an org.
An asian deer = 3.An asian deer = 3.
Diploid – 2 of the chromosome in a set.Diploid – 2 of the chromosome in a set.
Tetraploid – 4 of each chr.Tetraploid – 4 of each chr.
Octaploid – 8 of each chr.Octaploid – 8 of each chr.
Certain Tx/ staining techniques (Eg. Giemsa)Certain Tx/ staining techniques (Eg. Giemsa)
will allow chromosomes to have striations.will allow chromosomes to have striations.
Large structures containing approx 10Large structures containing approx 1077
bp DNAbp DNA
chromosomes can be id by cht. bandingchromosomes can be id by cht. banding
pattern- Used for karyotyping –pattern- Used for karyotyping –
Translocations can be id. by comparing to theTranslocations can be id. by comparing to the
original diploid set.original diploid set.
Chromosomes and genes..
The dark lines
bears a particular set
of genes, these genes
are arranged in a
Typical metaphase chromosome
i.i. Contains a DNA replication origin
ii. A centromere to attach the DNA to the mitotic
iii. A telomere located at the end.
DNA needs to be condensed.
Chromosomes with AT/ GC base pair specific dyes. When
Mitotic chromosomes have a banded structure
. ? Methaphase and not other stages?
Basic units of a chromosome
i. i. DNA (2.2m = Massive folding + coiling)
ii. Proteins (Histones, scaffold p, polymerase)
iii.Small amounts of RNA.
Complex between histones + DNA = chromatin.
Nucleosome = basic structure of chromatin (beaded appearance)
Scaffold protein = non-histone p. Nucleosome coils aound it.
Polymerases = enzymes involved with
a)transcription of the gen. information during protein synthesis
b)replication of the DNA prior to the division of chromosomes.
Contains 200 bp DNA.Contains 200 bp DNA.
Subunit of chromatinSubunit of chromatin
composed of short DNAcomposed of short DNA
wrapped around histonewrapped around histone
8 histone molecules =8 histone molecules =
Nucleosome fibre is tightlyNucleosome fibre is tightly
coiled and looped aroundcoiled and looped around
non-histone proteinsnon-histone proteins
Nucleosomes are packedNucleosomes are packed
together = compact.together = compact.
Placement of genes
Gene = A region of DNA Gene = A region of DNA
that that controls hereditary
info specifiying the
sequence of a particular
Carries biological info Carries biological info
that must be copied and that must be copied and
transmitted to its transmitted to its
Can be as short/long.Can be as short/long.
2001: 30,00/40,000 2001: 30,00/40,000
Color BlindnessColor Blindness
Muscular DystrophyMuscular Dystrophy
Fragile X syndromeFragile X syndrome