Cell biology
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are somatic cells diploid or haploid?
diploid and contain two sets of homologous chromosomes
what are somatic cells?
they are all body cells which arent involved in reproduction
what are germline cells?
they are reproductive cells
what can germline cells divide by?
divide by meiosis (to produce haploid gametes e.g sperm/egg cell) or mitosis (to produce more germline cells)
what do somatic cells divide by?
mitosis
haploid cells have how many chromosomes (in a human?)
23 single chromosomes
what is cellular differentiation?
this is the process by which a cell expresses certain genes to produce protein characteristic for that type of cell, this allows a cell to carry out specialised functions
what are the two types of stem cells in mammals?
embryonic and tissue stem cells
what are stem cells?
they are unspecialised somatic cells that can divide to make copies of themselves (self-renew) and to make cells that differentiate into specialised cells of one or more types
what are the two stages of gene expression?
transcription translation
medical uses of PCR?
diagnosing disease estimate the risk of disease onset
forensic uses of PCR?
to amplify DNA samples from crime scenes
What is used to confirm a paternity dispute after PCR
gel electrophoresis can be used to confirm
what does PCR stand for?
polymerase chain reaction
steps of PCR?
DNA is heated between 92-98 degrees to separate the DNA strands it is then cooled to between 50-65 degrees to allow primers to bind target sequences it is then heated to between 70 and 80 degrees for heat tolerant DNA polymerase to replicate the region of DNA
what is gene expression?
is the process by which specific genes are activated to produce a required protein
are all the genes in a cell expressed?
only a fraction of genes in a cell are expressed
what are the 3 types of RNA needed in transcription and translation
mRNA tRNA and rRNA
what does mRNA do?
mRNA is also known as messenger RNA and is used to carry a copy of the DNA code from the nucleus to the ribosome. type of RNA that makes up ribosomes
function of mRNA?
mRNA is transcribed from DNA in the nucleus and translated into proteins by ribosomes in the cytoplasm
what is codon (mRNA)
each triplet of bases on the mRNA molecule is called a codon and codes for a specific amino acid
why does tRNA fold?
tRNA folds due to complimentary base pairing
DNA replication
process by which a cell makes an identical copy of its DNA
when does DNA replication happen?
at the start of cell division