Difference between eukaryotic and prokaryotic cells
ans in long

Eukaryotic cells are significantly larger(2-100um), often multicellular, cell wall absent or comprises of cellulose, a well-defined nucleus is present enclosed within a nuclear memebrane, DNA is linear and double-stranded, more than one chromosome, mitochondria, golgi apparatus and endoplasmic reticulum are present, reproduction is sexual, cell divides by process of mitosis, lysosomes and peroxisomes are present, organelles are membrane bound and are specific in function, replication has multiple origins. Prokaryotic cells are smaller (0.5-3um), single-celled, have a cell wall, have a circular, double-stranded DNA in the nucleoid, mitochondria, golgi apparatus and endoplasmic reticulum are absent, reproduction is asexual, cell divides by binary fission,  lysosomes and peroxisomes are absent, chloroplast is scattered in the cytoplasm, transcription and translation occurs together, organelles are not membrane bound, one chromosome a plasmid.

Explanation:

meteorologists would compare a new weather map with one 24 h old to see how fast a front is moving.

geologic time scale (for gradpoint) =)