Chapter 3: 3.9 Flashcards
DNA replication and the genetic code
What happens during Semi-conservative replication?
- Double helix structure unwinds into two strands
- H-bonds holding the complementary bases together must be broken
- Free DNA nucleotide pair with complimentary bases and H-bonds formed between strands
- New nucleotide join to the adjacent nucleotide with phosphodiester bonds
What are the roles of enzyme: DNA helicase?
DNA helicase unwinds and separated the two DNA strands: travels along DNA backbone, catalyses reactions that break H-bonds between complementary base pairs as it reaches them.
What causes Mutation?
- When sequences of bases that have not always matched exactly, or incorrect sequences in the newly coppied strand (These errors occur randomly and spontaneously)
Leading to a change in the base sequence .
What is the structure of protein?
Made up of a sequence of amino acids that fold into a complex structure
Structure is determined by the DNA (as the DNA codes the sequence of amino acid)
What is the structure of a triplet code like?
> Instructions that DNA carries are contained in sequence of bases along the nucleotide chains that make up the 2 strands of DNA (which is the base sequence)
> The sequence of the three base is what is known as a codon
> Codon codes or each amino acid
What is a gene?
A section of DNA that contains the complete sequence of bases to code for an entire protein.
What is the degenerate code?
As there are only 20 amino acids that regularly occur in biological proteins, there are a lot more codons than amino acids. Therefore, many amino acids can be coded for by more than 1 codon. Due to this, the code is known as degenerate.
What is the function of the enzyme: DNA polymerase?
DNA polymerase catalyses the formation of phosphodiester bonds between nucleotides.
Not a flashcard
Need to know about a degenerate code
Why are proteins important for life?
As they are the foundations of different physical and biochemical characteristics for living things
What is the structure of protein?
A sequence of amino acid that are folded
And the structure is determined by the genetic code
Why do cells divide?
In order to produce more cells needed for growth or repair of tissue.
What are the properties of daughter cells that are produced as a result of DNA replication?
They are identical to parent cell - as DNA they contain has a base sequence identical to parent
What happens during DNA replication?
Cell prepares to divide and the two strands of DNA separate and each strand serves as a template for the creation of a double-stranded DNA molecule
