Mendelian Inheritance Flashcards
Will 2 restriction target sites on the same DNA strand be compatible?
No
The eukaryotic metaphase chromosomes will consist of 2…
sister chromatids. This happens by 1 chromatid opening and being replicated to form an identical sister
Cohesin attaches to…
the 2 sister chromatids when the replica has been made. This is designed to keep things organised
The centromere is..
a part of the chromosome which is known as the primary constriction site where proteins bind to initially
A telomere is
The end parts of chromosomes. There are 2 on each one
DNA is 1 single molecule running from….
one telomere to another
Centromeres are where…
chromosomes attach, via the kinetochore, to the mitotic spindle during metaphase.
The centromere divides the chromosome…
into 2 arms. These are known as the p arm (shorter) and the q arm (longer)
DNA of each chromatid is packaged tightly with proteins to form….
chromatin
During interphase (s phase)
DNA is replicated
During metaphase…
DNA is condensed to form chromosomes
Cohesin holding sister chromatids must be broken at the centromere….
after the arms
Telomeres have 2 problems.. these are
free ends and telomere shortening
New DNA is synthesised in the…
5 prime to 3 prime direction.
The lagging strand is synthesised in…
short stretches
telomeric repeats are
a bit of DNA which is repeated. These are 6 nucleotides long but take up a reasonable amount of kb. These repeats are recognised by a protein called shelterin which aids in the folding of the strand.
Chromosomes 1-22 exist as
homologous chromsomes.
Females have a homologous pair of…
x chromosomes
Males have a non- homologous pair of
sex chromosomes
Issues with chromosome 21 (having an extra 1) can result in
Down’s syndrome
cri-du-chat syndrome is
related to the cry that the baby makes. This happens due to the partial deletion of 5p (part of chromosome 5)
Fragile X syndrome
results in defects from x chromosome genes. Occurs due to issues with the secondary constriction on part of the arm. Particular genes affected include the FMR1 gene
One of the benefits of telomeres forming is that…
it ensures that cells remain mortal, hence, it actually suppresses diseases such as cancer.
how do kinetochores know where centromeres are?
Centromeres have different histones which make up the chromatin there
Most of the eukaryotic genome is…
non- coding (i.e. they dont code for proteins or anything useful)
Our genome contains…
unique and repetitive sequences
Some genes are also…
present more than once in the genome
In eukaryotic gene expression…
transcription and translation can never be coupled
Each eukaryotic gene has its own transcription unit with a promoter at the
5’ end
each gene is transcribed on its own specifically in…
eukaryotes
Multiple transcription factors recognise specific DNA sequence elements within the…..
gene promoter
The TATA box is…
the sequence of DNA where the TBP exists and the Transcription factor binds
RNA polymerase is recruited by…
transcription factors in eukaryotes
In prokaryotes, RNA polymerase…
identifies the promoter on its own.
The steps of mRNA processing is
- capping - this is where mRNA’s have a 5 prime cap for ribosome binding
- slipicing - this is where the introns are spliced and the exons are brought together which maintains the open reading frame
- Polyadenylation - a polyA tail is added to the 3 prime end for stability
splicing occurs in the
spliceosome
The spliceosome recognises…
the boundary between the intron and exon nucleotide
Only pol II coding genes are
polyadenylated and capped
Duchenne Muscular dystrophy
is a progressive muscle degeneration, and it comes across due to defects in dystrophin gene, it is sex linked, there is a milder form known as BMD. Dystrophin protein sits in the membrane that surrounds muscle fibres, and protects the membrane. DMD occurs due to a deleted exon, which therefore results in the protein being non functional.
non coding genes could possibly have a function
It is possible that some of the non coding genome does work to make RNA however more investigation is needed. Also having non- coding genes are responsible for alternative splicing.
Dominant negative mutations….
is where the mutant allele product interfering with the function of the unaffected allele.
Haploinsufficiency is where …
the gene product is insufficient because of the mutant allele, and this prevents the normal phenotype.
Dominance is a property…
of the phenotype
loss of function allele is normally
recessive
co dominant alleles each produce
a phenotype
incomplete dominance arises when two alleles produce
an incomplete phenotype
Mammalian coat colour results from the interaction of atleast
5 separate genes
complex or multifactorial traits result from
participation in the same or overlapping pathways
genome wide association studies
exploits naturally occuring linkage disequilibrium
