IBHL- Genetics SL content

To be used with Bioninja

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid responsible for containing the genetic instructions for all cell activities

Messanger RNA

A single-stranded copy of a specific genetic sequence in DNA that is made via transcription

Central Dogma of Biology

Explains the flow of genetic material within a cell

Transcription

process by which mRNA is synthesized on a DNA template

Antisense strand (Template Strand)

Strand of genetic sequence that IS transcribed and complementary in sequence to the RNA

Sense strand (Coding Strand)

Strand of genetic sequence that is NOT transcribed and is identical in sequence to the RNA except RNA uses Uracil instead of Thymine

Genome

Totality of genetic information in a cell or organism

What are the functions of

1.Messenger RNA

2. Transfer RNA (tRNA)

3. Ribosomal RNA

1. Copies genetic sequence from DNA and transports it to the cytoplasm for protein synthesis

2. Transfers amino acids to ribosomes during translation

3. Provides the catalytic energy for translation

What is the function of the small subunit of the ribosome

Binds to the mRNA and decodes the genetic sequence, identifies the starting point for translation and ensures the correct tRNA matches their anticodon to the mRNA codon

What is the function of the large subunit of the ribosome

Binds to two tRNA molecules and mediates peptide bond formation

What two things are a ribosome composed of?

Ribosomal RNA and protein for structural stability

What is a codon and its purpose

A sequence of three nucleotides on mRNA that together code for a amino acid, the order determines polypeptide sequence.

What is a anticodon and its purpose

A complementary sequence to the codon possesed by a tRNA molecule, ensures the correct amino acid is paired to the correct codon

What specific codons signal the start and end of translation?

Start: AUG

Stop: UAA, UAG, UGA

MrCatApp Mnemonic

mRNA binds to the ribosome via small subunit, codons on mRNA are recognised by anticodons on tRNA, Amino acids are joined by peptide bonds to form polypeptides

Genetic code is universal

Every organism uses the same code that codes for the same codons and amino acids

Genetic code is degenerate

The same amino acid can be coded for by different codon combinations as there are 20 amino acids but 64 different codon combinations

Point Mutation (Silent, Missense, Nonsense)

- Swapping of single nucelotide

1. Amino acid produced is not changed due to genetic code degenracy

2. Results in a different amino acid produced

3. Produces a stop codon, cutting polypeptide short