Nucleic acids - basis of genetic code Flashcards
What carries the genetic code in DNA molecules?
A sequence of nitrogenous bases in the nucleotides
The nitrogenous bases include adenine, guanine, cytosine, and thymine.
What are the four nitrogenous bases found in DNA?
- Adenine
- Guanine
- Cytosine
- Thymine
What is the coding strand of DNA?
The strand that carries the base sequence read by enzymes
What determines the order of amino acids in proteins?
The sequence of bases that form genes on the coding strand
How is the genetic code read?
As a triplet of bases, called a codon
What does each codon code for?
One amino acid
How many different amino acids can be coded for?
20
What determines the shape and function of a protein?
The sequence of amino acids
What is the nature of the genetic code?
Universal
What does it mean that the genetic code is universal?
Almost every organism uses the same code
What is the significance of the universal genetic code?
Genetic information is transferable between species
What provides evidence for a universal common ancestor?
The universal nature of the genetic code
What leads to changes in base sequences over time?
Mutations
What do base sequences form in an organism?
The genome
What are coding sequences?
Regions that code for proteins
What are non-coding sequences?
Regions that do not code for proteins
What are conserved sequences?
Coding and non-coding sequences that remain unchanged in all organisms
Where are highly conserved sequences usually found?
In genes that code for proteins involved with transcription and translation, and histone proteins
What do histone proteins do?
Help to package DNA tightly into the nucleus
What do similarities in conserved sequences indicate?
Living organisms share a universal ancestry
