4.1. DNA, Genes and Protein synthesis Flashcards
what are the three components of nucleotides?
- a pentose sugar
- a phosphate group
- an organic base
describe the role of DNA
carries genetic info and determines our inherited characteristics
describe the structure of RNA
- made up of ribose sugar
- a phosphate group
- and one of the four organic bases (A.C.G.U)
- single stranded
- short polynucleotide chain
describe the role of RNA
transfers genetic info from DNA to ribosomes for protein synthesis
(A,C,G,U)
which bases are purine and which are pyrimidine?
- purine (double ring)= A + G
- pyrimidine (single ring)= C + T + U
how is DNA in eukaryotic cells different from in prokaryotic cells?
- eukaryotic= found in nucleus, long and linear. Associated with histone proteins to form chromosomes. Mitochondria and chloroplasts contain prokaryotic-like DNA
- Prokaryotic= short n circular, no association with proteins
what is the genetic code?
the order of bases on DNA that consists a triplet of bases (codon)
there are 3
what are the features of the genetic code
-non overlapping=each triplet is only read once
- degenerate= more than one triplet codes for the same amino acid (64 possible triplets for 20 amino acids)
- universal= same bases and sequences used by all species
what is a gene?
a sequence of bases on a DNA molecule that codes for a specific sequence of amino acids to make a polypeptide
position
what is a locus
the fixed position on a DNA molecule occupied by a gene
what is an allele?
different versions of the same gene, found at the same locus on a chromosome
what are exons and introns? and where are introns found?
-exons= regions of DNA that code for amino acid sequences. Separated by one or more introns
-introns= regions of DNA that do not code for anything -> found between exons and within genes
what is the genome?
the complete set of genetic info contained in the cells of an organism
