4- human genome Flashcards
what is your phenotype?
what you look like
what is your genotype?
your genetics
what is precision medicine?
when you look at someone’s specific genetic make-up to see what medicine will be effect for people (different treatment for different genetic make-up)
describe DNA structure
-sugarphosphate bcakbone
-antiparallel strands
-base pairs A&T and G&C
-from 5’ to 3’ end
-complex molecule
what do chromosomes look like within nucleus?
it looks like a ball of string, stained fluorescent
how do you recognise chromosomes?
by size and where stripe is
how many bases in human genome?
3 billion bases
how many genes in human genome?
20 000-30 000
how many copies of gene per cell?
2 copies
what % of bases encode for genes?
2%
what stage in cell cycle is replication?
S phase
what is short description of mitosis?
one diploid parent cell becomes 4 haploid daughter cells (meiosis I and meiosis II) with crossing over, chiasmata
what is promoter sequence?
part of gene before bit to be encoded, it has TATA box and is bit where transcription factor binds
what is pre mRNA?
DNA is transribed to pre mRNA ( has intorns & exons) and then pre mRNA spliced to mRNA
what does DNA strands associate with?
proteins (including histones)
what can be caused by chemical crosslinking?
xeroderma pigmentosa
what are examples of DNA damage?
-DNA strand breaks
-UV or chemical crosslinking
-mismatched base
what is a result of mismatched base?
hereditary colorectal cancer
what is amount of protein produced determined by?
=Rate of transcription (manufacture of Pre-mRNA)
=Rate of splicing to mRNA
=Half life of mRNA
=Rate of processing of polypeptide
what are sequence changes that occur in DNA between genes?
- Single Nucleotide polymorphisms (SNPs)
- Larger deletions or duplications
what are sequence variations within genes?
- Changes in the promotor sequence
- Changes in the exon sequence
- Ones that change an amino acid
- Sequence changes that do not
what are polymorphisms?
Any variation in the human genome that has a population frequency of greater than 1%
or
Any variation in the human genome that does not cause a disease in its own right. It may however, predispose to a common disease
(changes in genome that are just like the differences between us - not disease causing)
what lead to variation in meiosis?
the random crossing over of genes that mean everyone has new genetic variants that their parents don’t
what is symptomatic testing?
testing for disease on person who has symptoms
what is pre-symptomatic pregnancy?
patient has relative with known disease and wants to know if they have it
what does recombination in meiosis ensure?
that genetic variants on same chromosome segregate independently (irrespective of maternal/paternal origin)
