A2 Unit 5 Genetic Control of Protein Structure and Function Structure of Ribonucleic Acid.

DNA – 30 seconds go!

DNA

RNA ? What is the difference

Single mononucleotide chain Ribose sugar (not deoxyribose as in DNA) Thymine replaced with Uracil

Why?

Another Form tRNA (transfer RNA)

The Genetic Code: Gene encodes instruction for making a protein ( a polymer of amino acids in a certain sequence) Each amino acid is encoded by a triplet of three nucleotides. Degenerate, this means that most amino acids have more than one triplet code Leucine has six different codons UUA, UUG, CUU, CUC, CUA, CUG Non overlapping Each base is only read once ie) six bases 123456 are read as 123 456 and not 123 234 345 456 Universal the codon codes for the same amino acid in any organism.

http://www.youtube.com/watch?v=5MfSYnItYvg

Transcription

Translation

Translation http://www.youtube.com/watch?v=5bLEDd-PSTQ

ACTCGCGCGAATTCGTTGGCCACCGAGTAG This is the coding strand of a gene: ACTCGCGCGAATTCGTTGGCCACCGAGTAG Can you TRANSLATE it into a protein. http://www.youtube.com/watch?v=5ldkJxCzXak

Gene Mutation

THE CAT SAT ON THE MAT THE CAT SAT ON THE HAT Now insert the letter H after the S.

CANCER

Protooncogenes

Tumour Suppressor

Regulation of Transcription and Translation How does Oestrogen control gene expression. Small interfering RNA

Key words / phrases to think about. Transcription Gene Expression Lipid soluble DNA binding site DNA Protein complex Inhibitor protein Receptor site Conformational Change in shape

“small interferring RNA” Alternatively regulate gene exression through targeted degradation of mRNA A process of : Post Transcriptional Gene Silencing Si RNA “small interferring RNA”

http://www.nature.com/nrg/multimedia/rnai/animation/index.html

Totipotency and cell specialisation. Stem cells are found in multicellular organisms they have the ability to divide many times and remain undifferentiated. The have the potencial to develop into any other cell type. Fundamentally important in both natural development and future therapies.

STEM CELLS

Totipotent, Pluripotent, Multipotent Totipotent cells can form all the cell types in a body, plus the extra embryonic, or placental, cells. Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent. Pluripotent cells can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent. Multipotent are undifferentiated cells found in differentiated tissues and organs, these cells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells are considered multipotent

Embryonic stem cell therapy is cheaper than harvesting stem cells from adults Harvesting adult stem cells is dangerous to the healthy adult. Embryonic stem cells are more undifferentiated , allowing them to treat a wider range of diseases. Research into embryonic stem cell therapy may lead the way for more controversial research such as human cloning. Approximately 18% of fertilised eggs do not implant after conception. Thus far more embryos are lost due to chance than are proposed to be used for embryonic stem cell research or treatments. An embryo is actually a human; it should be valued as highly as a human life. Embryonic stem cells should be abandoned in favour of alternatives, such as those involving adult stem cells. Embryos are a cluster of human cells that have not differentiated into distinct organ tissue; making cells of the inner cell mass no more "human" than a skin cell Scientists have long promised spectacular results from embryonic stem cell research, and this has not yet occurred. In vitro fertilization (IVF) generates large numbers of unused embryos. Many of these thousands of IVF embryos are selected for destruction. Another concern with embryonic stem cell treatments is a tendency of stem cells from embryos to create cancer tumors. Embryos, while of value, are not equivalent to human life while they are still incapable of existing outside the womb The use of embryonic stem cell in therapies may not work, as the therapeutic cells may be rejected by the patient. Embryonic stem cells divide more rapidly than adult stem cells, potentially making it easier to generate large numbers of cells for therapeutic means. In contrast, adult stem cell might not divide fast enough to offer immediate treatment Umbilical cord blood has consistently produced more promising results than the use of embryonic stem cells. Furthermore, adult stem cell research may be able to make greater advances if less money and resources were channeled into embryonic stem cell research. Adult stem cells from the patient's own body might not be effective in treatment of genetic disorders, as these stem cells will also have the genetic disorder.

Embryonic stem cell therapy is cheaper than harvesting stem cells from adults Harvesting adult stem cells is dangerous to the healthy adult. Embryonic stem cells are more undifferentiated , allowing them to treat a wider range of diseases. Diamond nine. Approximately 18% of fertilised eggs do not implant after conception. Thus far more embryos are lost due to chance than are proposed to be used for embryonic stem cell research or treatments. Embryos are a cluster of human cells that have not differentiated into distinct organ tissue; making cells of the inner cell mass no more "human" than a skin cell In vitro fertilization (IVF) generates large numbers of unused embryos. Many of these thousands of IVF embryos are selected for destruction. Embryos, while of value, are not equivalent to human life while they are still incapable of existing outside the womb Embryonic stem cells divide more rapidly than adult stem cells, potentially making it easier to generate large numbers of cells for therapeutic means. In contrast, adult stem cell might not divide fast enough to offer immediate treatment Adult stem cells from the patient's own body might not be effective in treatment of genetic disorders, as these stem cells will also have the genetic disorder.