Topic 3 DNA Flashcards
What is DNA made of?
DNA are polymers made up of lots of repeating units called nucleotides which consist of a sugar, a phosphate group and one base. The Sugland of phosphate groups in the nucleotides backbone to the DNA
What is the DNA molecule look like?
It has two strand coiledtogether in a shape of a double helix where each base links to a base on the opposite strand in the helix.
The bases are complementary to one and another and are joined together by weak hydrogen bonds .
A-T, C-G
How is DNA stored?
It is stored as chromosomes and contains genes. Chromosomes are long coiled molecules of DNA found in the nucleus of a eukaryotic cell.
a gene is a section of a DNA on a chromosome that codes for a particular protein.
all of an organisms DNA makes up its genome
DNA extraction practical
Mash up strawberries with a pestle and mortar, add detergent and salt and mix. (detergent will break down the cell membrane to release the DNA.) (will make the DNA stick together.)
Then filter the mixture to get the insoluble bits out.
Then add ice cold ethanol, then the DNA will start to come out as it’s not soluble in the ice cold ethanol which causes a stringy white precipitate to form
The function of an amino acid chain
It folds up to give each protein a different and specific shape which means that the proteins have a different function. This is why enzymes have active site with a specific shape and so only catalyse a specific reaction.
What is the non-coding region of a DNA for?
It’s what they don’t include for any amino acids but are involved in protein synthesis
How is mutation formed?
Is a rare and random change to an organisms DNA base sequence that can be inherited. If a mutation happens in a gene, It produces genetic variance code for different sequence of amino acids which changes the shape of the final protein so it activity.
It could end up changing characteristics, which is phenotype of an organism. Mutations can also happen in the non-coding region of DNA.
What happens in transcription?
RNA polymerase binds to a region of non-coding DNA in front of a gene.
Then the two DNA strands unzip and the RNA polymerase moves along one of the strands of the DNA.
It uses the coding DNA in the gene as a template to make the mRNA. Base pairing between the DNA and RNA ensures that the mRNA is complimentary to the gene.
Once made, the mRNA molecule moves out of the nucleus pore and joins with a ribosome.
mRNA uses uracil (U) instead of thymine (T) as a base.
What happens in translation?
Amino acids are brought to the ribosome by tRNA. The order in which the amino acids are brought to the ribosome matches the order of the base triplets in mRNA base triplets in mRNA are also known as codons. Parts of the tRNA structure is called an anticodon. It is complimentary to the codon for the amino acid. The pairing of the codon and anticodon makes sure that the amino acids are in the correct order. The acids are joined together at the ribosome which then folds up and forms a polypeptide chain.
How to non-coding DNA affects the binding of RNA polymerase
Before transcription RNA polymerase has to bind to a region of non-coding DNA in front of a gene. If imitation happens in this region, it can affect ability of the RNA to bind, it can make it more difficult easier to bind. How well the RNA polymerase binds to this region of DNA will affect how much of mRNA is transcribed and therefore how much of the protein is produced and can also affect the phenotype. genetic variant in non-coding regions can affect the phenotype.
