Prokaryotic and Eukaryotic cells

Question 1

what are the main differences between prokaryotic and eukaryotic cells?

Answer 1

cell size
packaging of DNA genome
genome complexity
organelles
ribosomes
flagella
cell wall

Question 2

what is the difference in genome complexity between eukaryotic and prokaryotic cells?

Answer 2

eukaryotes - much larger genome (10-10 000 Mbp); 6 000-40 000 protein-coding genes

prokaryotes - small circular genome (2-10 Mbp); 1000-5000 protein-coding genes

Question 3

what is the difference between the organelles of eukaryotic and prokaryotic cells?

Answer 3

eukaryotes - mitochondria, plastids (plants, algae, some protists), nucleus, ER, Golgi, etc.

prokaryotes - no organelles; sometimes complex internal membrane structures exist

Question 4

explain the theory of endosymbiosis

Answer 4

Mitochondria and chloroplasts are thought to be descendants of free-living bacteria that formed an endosymbiosis with protoeukaryotes ~2bya and ~1bya, respectively. They have retained their own genetic system to some extent, with many prokaryotic characteristics.

Question 5

what is the difference between the ribosomes of eukaryotic and prokaryotic cells?

Answer 5

eukaryotes - 80S ribosomes and 70S ribosomes in organelles

prokaryotes - 70S ribosomes

Question 6

what does the ‘S’ unit mean when used in reference to ribosomes?

Answer 6

S stands for the Svedberg unit and is a measure of size and density

Question 7

what is the difference between the flagella structure of eukaryotic and prokaryotic cells?

Answer 7

eukaryotes - made of bundles of microtubules (in a 9+2 formation) surrounded by a membrane sheath; move in a wave function

prokaryotes - single filament made from flagellin; rotates

Question 8

what is the difference between the cell walls of eukaryotic and prokaryotic cells?

Answer 8

eukaryotes - cellulose (plants, algae), chitin (fungi)

prokaryotes - peptidoglycan (bacteria), various (archaea)