DNA, genes and chromosomes Flashcards
what does prokaryote mean
before the nucleus
prokaryotic DNA circular or linear
circular
what DNA do prokaryotes contain
a single, circular chromosomal DNA molecules
what is the single, circular chromosomal DNA in prokaryotes sometimes reffered to as
nucleoid
what are plasmids
very small circular DNA molecules
how many genes do plasmids contains
a few
why are plasmids used
more accessible for proteins requires for a gene expression and therefore contain genes that are requires often, quickly and in emergencies
where are genes for antibiotic resistance found
plasmids
prokaryotic DNA protein association
not associated with any proteins
eukaryotic DNA protein association
histone proteins
what are chromosomes (eukaryotic) made of
one long, condensed DNA molecules associated with histone proteins
role of histone proteins
organise and condense the DNA tightly to fit into the nucleus
what are the other proteins (not histone) used for in eukaryotic chromosomes
enzymes used in copying and repairing DNA
what is chromatin
tightly coiled combination of DNA and proteins
what are chromatids and chromosomes made of
chromatin
what happens during s phase of interphase
the DNA replicates to create two identical strands of DNA called chromatids joined together by a narrow region called the centromere
what are sister chromatids
two chromatids that make up the double structure of a chromosome
why is important sister chromatids are identical
key to cell division as one chromatid goes into one daughter cell and one to the other during mitosis ensuring daughter cells are genitally identical
what is a chromatid made of
a very long, condensed DNA molecules, which is made up of a series of genes
how are ends of the chromatids in the chromosome
sealed with protective structures called telomeres
what DNA is mitochondrial and chloroplast DNA most similar to
prokaryotic
what is mitochondria and chloroplast DNA like
short, circular and not associated with proteins
Mitochondria + chloroplast DNA
small circular pieces of DNA
what organelles contains their own DNA
mitochondria and chloroplast