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Where is most eukaryotic DNA found
in the nucleus
where is the minority of eukaryotic DNA found
in the mitochondria and chloroplasts
define chromatin
DNA tightly coiled around histone proteins
define chromosomes
chromatin in linear lengths
Define centromere
The narrow region joining chromatids
What are chromosomes made of
One very long, condensed DNA molecule associated with proteins
What is the role of histone proteins
To organise and condense the DNA so it fits in the nucleus
what do chromosomes contain
A series of genes
Describe a telomere
A protective structure that seals the end of the chromatid
what is the name of the protein involved in eukaryotic DNA
histone proteins
what do genes code for
a polypeptide or a functional RNA molecule
Name the two functional RNA molecules
tRNA or rRNA
define intron
a non-coding region of a gene
What is the name of the process of removing introns
Splicing
what occurs during protein synthesis
the introns are removed leaving mRNA as exons
what does the presence of introns in genes mean
that most of the DNA is non coding
describe structure of prokaryotic DNA
circular, with no introns or histone proteins
give two examples of DNA which is ‘prokaryotic in nature’
mitochondria, chloroplasts
Define a plasmid
Small circular DNA molecules containing a few genes
What specific genes are found in plasmids
Genes for antibiotic resistance
When may plasmids be used and why
When genes are required quickly or in an emergency, as they are more accessible
define genome
all the genes present in a cell or organismefid
define proteome
all the polypeptides a cell is able to produce
what three things is the genetic code described as
universal, degenerate, non-overlapping
define universal
same in all living organisms
define degenerate
many amino acids coded for by more than one triplet codon
define non-overlapping
each nucleotide is only used in one codon
define a codon
3 bases
What is DNA in mitochondria and chloroplasts similar to
DNA of a prokaryote
Define a gene
A base sequence of DNA that codes for the amino acid sequence of a polypeptide or functional RNA molecule
Describe the purpose of mRNA
To code for the polypeptide chain
Describe the purpose of tRNA
To collect the corresponding amino acid
Describe the purpose of rRNA
To form part of the ribosomes structure
Define a locus
The position of a gene on a chromosome
What difference do alleles of genes have
Different nucleotide sequences with the same loci
Describe differences between DNA and mRNA
DNA is longer, ribose/deoxyribose sugar, single/double stranded, uracil/thymine
