Please enable JavaScript.
Coggle requires JavaScript to display documents.
Shit I Don't Know About Human Biology - Unit 1 - Coggle…
Shit I Don't Know About Human Biology - Unit 1
Differentiation is when a cell expresses certain genes to produce protein characteristic for that type of cell - differentiated cells have become specialised to carry out their various functions
Stem Cells
Adult stem cells are multipotent so they're capable of differentiating into a limited range of cells
Embryonic stems cells are pluripotent so they're capable of differentiating into any cell type
Stem cell research can provide information on gene regulation, cell growth and differentiation and drug testing
Stem cells can be used in corneal repair and the regeneration of damaged skin
Cancers
Tumour cells fail to attach to each other, spreading throughout the body, where they may form secondary tumours
A benign tumour doe snot invade neighbouring tissues
Protein examples: collagen and insulin
Replication of DNA:
DNA is unwound an unzipped to form two separate strands
DNA is unzipped by helicase
Deoxyribose at the 3' end and phosphate at the 5' end
To start adding nuclotides, DNA polymerase requires a primer
DNA polymerase adds nucleotides to the 3' end
The leading 3' strand is replicated continuously and the lagging strand is replicated in fragments - later joined by ligase
Needs DNA, enzymes, ATP and free nucleotides before it can begin
PCR:
Heating at 90-95, which DNA denatures and separates the strands
Annealing at 54, primers bind to complementary sequences, which are short DNA sequences
Extension at 72, nucleotides are added to 3' end of primers and extends into new strands
Continued cycles of heating and cooling cause DNA to be doubled
PCR cycles amplify target DNA
Types of RNA
tRNA folds due to complementary base pairing. Each tRNA molecule carries a specific amino acid to the ribosome
rRNA and proteins form the ribosome
mRNA carries copy of DNA code from nucleus to ribosome
Transcription
Weak hydrogen bonds break and unzip
Single stranded DNA acts as a template in the formation of mRNA - weak hydrogen bonds form between complementary base pairs and free nucleotides find complementary nucleotides
RNA polymerase cause strong chemical bonds to form between RNA nucleotides
Weak bonds between RNA and DNA break and mRNA strand separates from DNA template and mRNA moves out of nucleus and into the cytoplasm where translation occurs
Translation:
Peptide bonds join the amino acids together to form a polypeptide and tRNA leaves the ribosome
Different proteins can be expressed from one gene, as a result of alternative RNA splicing
Anticodons bond to codons by complementary base pairing, translating the genetic code into amino acids
tRNA translates mRNA into a polypeptide at the ribosome
Different mRNA transcript are produced from the same primary transcript depending on which exons are retained
Polypeptide chains form to form 3D shape of a protein, held together by hydrogen bonds and other interactions between amino acids
Phenotype is determined by proteins produced as a result of gene expression
Single-nucleotide substitution
Nonsense - change to DNA sequence results in a premature STOP codon
Splice-site - create or destroy codons for exon-intron splicing
Missense - one nucleotide is changed
The genome of an organism is its entire hereditary information encoded in the DNA
Bioinformatics uses computers and
Pharmacogenetics uses genome information in the choice of effective drug treatments
Muscle twitch fibres:
Slow-twitch - contract slowly for long periods of time, glycolysis & aerobic respiration, many mitochondria,high density of blood capillaries, lots of myoglobin, fats - long distance running
Fast-twitch - contract quickly for short periods of time, glycolysis, few mitochondria, glycogen - sprinting & weightlifting