VCAA Biology What is the role of nucleic acids and proteins in maintaining life?

Exons are sequences of coding DNA, which is transcribed into mRNA and then translated into proteins.
Introns are sequences of non-coding DNA and have a variety of other functions. They are spliced out of the mRNA prior to translation.

Telomeres protect the ends of chromosomes from being degraded, prolonging their life.

Helicase unwinds the double helix and separates the strands.
Polymerase adds nucleotides to the new strand.

The weak nature of hydrogen bonds makes it easy for helicase to separate strands.
Complementary base pairing allows DNA polymerase to be guided by the template strand.

Mutations occur when DNA polymerase makes an error by inserting, removing or adding an incorrect nucleotide. Substitution reactions involve A, T, C or G being swapped for a different nucleotide, and result in point mutations. Because of the way that codons work, these mutations will only affect one amino acid. Additions or deletions cause frameshift mutations, where all codons after the mutation will be affected.

DNA contains genetic information. mRNA is produced from DNA, and the genetic information or code is transferred to mRNA using complementary base pairing. The conversion of DNA to mRNA is called transcription.

The mRNA molecule transfers the genetic information from the nucleus to the cytoplasm, where the mRNA forms a complex with ribosomes. tRNA carries amino acids to the ribosome, ensuring the correct amino acid is added to the growing protein chain. One end of the tRNA molecule carries a specific amino acid, while the other end of the tRNA molecule, the anticodon, binds with the complementary mRNA codon. The amino acid on the tRNA is transferred to the protein chain, and different tRNAs add different amino acids. The conversion of mRNA to a protein is called translation.

Early life forms were a type of bacteria that consisted of single cells. They were prokaryotes and anaerobic, dating back 3.5 billion years.

The fossil record provides preserved remains of organisms that show the morphological characteristics of organisms. From this, we can obtain evidence of their age from the type and location of the rock.

Comparative genomics involves the comparison of genomes of different species. This is done by collecting DNA from a broad range of organisms to identify conserved sequences of the genome. These conserved sequences are used to determine the genetic characteristics of early life forms and construct a phylogenetic tree. The tree is used to identify early life forms or close relatives, assuming that early life forms have similar characteristics to their closest living relatives.