Genetics

Comprised of of base pairs of nucleotides bound together by hydrogen bonds to create a double helix

Adenine with thymine Guanine with cytosine

this is the process of making mRNA

step 1 - Beginning: Every gene contains a promoter that signals the start of the gene at the 5’ end. This is the starting place for the DNA’s separation.

Elongation - RNA polymerase uses one of the DNA strands as a template to create an RNA strand.

Termination - The RNA copy is finished and released from the RNA polymerase once the terminator DNA sequence is reached.

The phosphate group of the chain’s first nucleotide sticks out at the 5’ end. This is referred to as the 5’ end of the sugar ring because the phosphate group is connected to its 5’ carbon.

The hydroxyl of the final nucleotide added to the chain is visible at the other end, known as the 3’ end. This is referred to as the 3’ end of the sugar ring because the hydroxyl group is joined to the 3’ carbon.

Gene shows on double helix in sections you get larger and smaller which the first expressed gene forms a protein

mRNA is converted into proteins via translation

During translation groups of three mRNA nucleotides (a codon) equate to one amino acid.There are 64 possible codons and 20 possible amino acids.Three codons cause protein synthesis to stop

Can cause incorrect amino acids or premature termination of the polypeptide chain

As specified in the DNA code, proteins are polypeptides made of a chain of amino acids. The great majority of biological activities are performed by proteins, which fold into three-dimensional structures to perform specialised tasks.

Substitutions and Deletions and Insertion

Mutations in the DNA sequence are likely to result in a change in the protein output of a gene and are the root cause of genetic disease.

Missense mutations- Sickle cell anaemia Nonsense mutations- Many cancers

Insertion mutations- Fragile X syndrome Deletion mutations- Prader-Willi syndrome

Are coiled up portions of DNA. 22 pairs of autosomes 2 allowsomes (sex chromosome) XX female XY male

Produces two genetically identical daughter cells Accepted as being comprised of five stages Prophase Metaphase Anophase Telophase Cytokinesis

Three copies of chromosomes 21 (additional chromosmes) Non Invasive Prenatal Testing blood test can be done for when a woman receives a higher chance result forT21

Caused by an additional copy of chromosome 13 - but the copy is only present in some of the baby’s cells - mosaic in partial form Patau’s syndrome, the baby has only inherited part of an extra copy of chromosome 13 Incidence 1 in 10,000 live births.Average survival age 2 ½ days

disorder in which babies are born with 3 copies of chromosome 18 instead of 2.Rate of occurrence Less than 10% of live babies survive the first year, with 95% of them dying in utero.

condition that affects only females, results when one of the X chromosomes (sex chromosomes) is missing or partially missing. Turner syndrome can cause a variety of medical and developmental problems, including short height, failure of the ovaries to develop and heart defects.

Law of segregation Law of independent assortment Law of dominance