3.4.1 DNA, genes and chromosomes. Flashcards
what’s the differences in structures of chromosomes/DNA in eukaryotes and prokaryotes?
eukaryotes:
- very long.
- linear.
- number of DNA per cell varies, but multiple.
- associated with histone proteins.
prokaryotes:
- short.
- circular.
- one per cell.
- not associated with proteins.
what is a gene?
a section of DNA (sequence of bases), which code for the amino acid sequence of a polypeptide/ protein (primary structure).
OR a functional RNA (like mRNA and tRNA).
what is the genome of a cell?
the complete set of genes in a cell.
what is the proteome?
the full range of proteins that a cell is able to produce.
what are 3 bases in DNA?
triplet.
what are 3 bases in mRNA?
codon.
what are 3 bases in tRNA?
anticodon.
what are the three characteristics of the genetic code?
1) degenerate.
2) universal.
3) no overlapping.
what does degenerate mean?
more than one triplet codes for an amino acid.
what does universal mean?
triplets code for the same amino acids in all species.
what does non overlapping mean?
each base belongs to one triplet when the sequence is being read.
what is the name for the coding section of DNA?
exon.
what is the name for the non-coding section of DNA?
intron.
how are introns removed?
by a spliceosome, which splices out the introns producing an mRNA strand with only exons.
