💜3.4.1 DNA, Genes And Chromosomes Flashcards
(14 cards)
Describe the DNA in prokaryotic cells
DNA molecules are short, circular and not associated with proteins
Describe DNA molecules in eukaryotic cells
In eukaryotic cells, DNA molecules are very long, linear and associated with proteins, called histone.
What is the word to describe a DNA molecule and its associated protein together ?
A chromosome
What are two other organelles in eukaryotic cells that contain DNA?
Mitochondria and chloroplast
What is the DNA like in mitochondria and chloroplast ?
It is like the DNA of prokaryotes. It is short, circular and not associated with proteins
What is a gene ?
A base sequence of DNA that codes for ;
- the amino acid sequence of a polypeptide
- a functional RNA ( including ribosomal RNA and tRNA’S )
What is a locus ?
A gene that occupies a fixed position on a particular DNA molecule.
Compare the DNA of eukaryotic and prokaryotic cells .
-In eukaryotic cells DNA is linear whereas in prokaryotic cells DNA is circular
-In eukaryotic cells DNA is associated with histone proteins where as in prokaryotic cells DNA isn’t associated with histone protein
-In eukaryotic cells DNA there are introns (non coding regions) where as in prokaryotic cells there are no introns
-In eukaryotic cells DNA is large whereas in prokaryotic cells it is short
The DNA code is universal. What does this mean ?
In all organisms, the same triplets ( codons in RNA ) code for the same amino acid
The DNA code is non overlapping. What does this mean?
Each base forms part of only one triplet
The DNA code is degenerate. What does this mean ?
More than one triplet (codons in RNA) can code for the same amino acids (this limits the damage mutations can do)
What does gene expression mean ?
The formation of proteins based on the genes genetic code.
There are two stages of of gene expression. What are they ?
- transcription
- translation
What is an exon ?
The coding regions of the gene
