Gene Expression Word Stimulants Flashcards
Gene mutation
Sequence of bases incorrectly copied during DNA replication
Spontaneously in DNA replication
Insertion
Bases added
Deletion
Bases lost
Duplicated
Bases repeated
Invertion
Turned around
Substitution
Copied wrongly
Nucleotides replace each other
Translocation
Bases separated
Inserted into different chromosome
Point mutation
Single base pair involved
Frame shift
Amino acid sequence changed downstream of point mutation
Significantly effects structure/function of polypeptide
Deletion
Insertion
Silent mutation
Degenerate nature of genetic code
Amino acids have 1+ codons
While polypeptide not changed
Substitution
Mutagen
Increased mutation rate
Environmental factor
Ionising radiator (strips electrons from atoms in DNA molecule)
Chemicals (Alkylation agents - transfer methyl/ethyl group to dna molecules)
Totipotent
Cells giving rise to al cell types
Zygote-cells of first few motorists divisions
Pluripotent
Totipotent descendent
Produce most but not all cells of organism
Multipotent
Adult stem cells
Differentiate into limited number of cells
Unipotent
Adult
Differentiate into single type of cell
Derived from multipotent
Differentiate
Only some genes expressed - synthesise into different polypeptides (type of cell); determines development pattern
Specialised cell types - enable particular function
Stem cells
Differentiate into different cell types
Divide continually by mitosis > new generations of cells
Stem cell therapy
Pluripotent stem cells
Transplanted
Tissue damaged beyond self repair
Embryonic stem cell issues
Ethical
Oestrogen properties
Steroid hormone
Lipid soluble - pass across phospholipid bi layer of target cells
Not transcriptional factor itself
Oestrogen > complex
Binds to cells with protein receptor
Oestrogen-receptor complex (cytoplasm > nucleus)
Complex binds to specific chromosomal protein DNA sequence
Oestrogen transcription
mRNA transcribed (nucleus > cytoplasm)
Binds to ribosome
Translated to polypeptide
Alters function of target cell (new synthased polypeptide chain)
siRNA structure
Small interfering RNA
Short double stranded RNA
20 nucleotides long
siRNA purpose
Small interfering RNA
Help regulate which DNA is active / how active
Causes RNA interference - prevents mRNA translation (silences)