Genes and The Genetic Code Flashcards Preview

Biology-8-DNA, Genes and Protein Synthesis > Genes and The Genetic Code > Flashcards

Flashcards in Genes and The Genetic Code Deck (17):

What is a gene

A section of dna that contains the coded information for making polypeptides and functional rna.


What is the coded information in the form of

A specific sequence of bases along the dna molecule


What determines the nature and development of all organisms

Genes, along with environmental factors


How are genes responsible for an organisms development and activities

Polypeptides make up proteins so genes determine the proteins of an organism. Enzymes are proteins. As enzymes control chemical reactions they are responsible for an organisms development and activities


What’s the locus

The position of a gene on a chromosome / dna molecule


The gene is a base sequence of DNA that codes for what?

The amino acid sequence of a polypeptide

Or a functional rna, including ribosomal rna and transfer rna’s


How many bases code for an amino acid



How many amino acids regularly occur in proteins



Why are some amino acids coded for by more than one triplet

As there are 64 possible triplets and only 20 amino acids


Why is the code known as degenerate code

Because most amino acids are coded for by more then one triplet


What are stop codes

3 triplets don’t code for any amino acid. They mark the end of the polypeptide chain


Which triplet is always at the start

That code for the amino acid methionine


What does it mean by the code is non overlapping

Each base sequence is only read once


What makes the code universal

Each triplet codes for the same amino acid in all organisms


what are introns

sections of a gene that dont code for amino acids


What’s an exon

All the bits of a gene that do code for amino acids


Explain how a change in one base along a dna molecule may result in an enzyme becoming non functional

A different base might code for a different amino acid. The sequence of amino acids in the polypeptide produced will be different. This change to the primary structure of the protein might result in a different shaped tertiary structure. The enzyme shape will be different and may not fit the substrate. The enzyme substrate complex cannot be formed and so the enzyme is non functional