control of gene regulation Flashcards
what is a substitution mutation, does it effect the triplet code?
-a single nucleotide is replaced with another, due to its degenerate nature some amino acids are coded for by more than one triplet code.
what is a addition mutation, how does it effect the triplet code?
-one extra base is added to the sequence
- a frameshift occurs in which a new sequence of amino acids is coded for resulting in a non-functioning protein
what is a deletion mutation and how does it effect the triplet code?
- its the deletion of a base in a sequence
-this causes a frameshift, resulting in a different polypeptide chain resulting in a different amino acid
what is a inversion mutation and how does it effect the triplet code?
-a section of DNA is reversed within the gene, the sequence remains the same but the codon order is altered, affecting protein function
what is a translocation mutation, how does it affect the triplet sequence?
-a section if DNA moves to a different location either within the same chromosome or to another, this disrupts the gene regulation and can contribute to cancer
what is a duplication mutation and how does it affect the triplet sequence
- a section of the DNA is copied, which may increase the protein production or lead to a non-functional protein if frameshift is created
what are stem cells?
-undifferentiated cells that continually divide to become specialised cells
what are totipotent stem cells?
-stem cells that can divide into ANY TYPE OF CELL
-found in the early stages of the embryo
-they translate only part of their DNA resulting in specialised cells
what are pluripotent stem cells?
-found in the early stages of embryo
-found in inner blastocyst
-can be used to form any cell
how are pluripotent cells used?
-used in human research to treat human disorders
what are the issues on pluripotent stem cell research?
-they can divide uncontrollably to form tumours
-ethically, you have to create a zygote (clone of patient you want to treat), so embryo doesnt last long
therapeutic cloning
- potential for life
uses of pluripotent stem cells?
-can be used ot create damaged cells and tissues
e.g beta cells that are not creating insulin
where are multipotent and unipotent cells found?
both found in mature mammals and can divide into a limited number of cell types
where are multipotent cells found?
- found in the bone marrow and differentiate into a limited number of cells
what can unipotent cells differentiate into?
- differentiate into 1 cell type
sources of stem cells in mammals:
-embyros 16 days after fertilisation (pluripotent)
-umbilical cord blood (multipotent)
-placenta (multipotent)
-bone marrow (adult stem cells)
Induced pluripotent stem cells steps:
1) cells are altered back to the state of pluripotentcy
2) genes that were switched off are turned back on again via transcriptional factors
3) IPS have self-renewal properties so they can divide indefinitely
what is epigentics?
-the heritable change in gene function without changing the DNA base sequence
what does it mean if a gene is expressed?
-DNA is expressed/ a protein is created/ transcription/translation
what factors can add epigenetic, chemical tags to the DNA?
-diet
-stress
-toxins
what is the meaning of epigenome?
- single layer of chemical tags on the DNA
how is transcription inhibited by the epigenome?
- when DNA is tightly wound then the transcription factors cannot bind therefore the epigenome can inhibit transcription
what is METHYLATION?
- the addition of a methyl group to the DNA
what impact does increased methylation have on DNA?/ how?
- this results in transcription being inhibited
-as DNA is tightly coiled , transcription factors cant bind instead it attracts proteins that condense the DNA complex.
