2 Cells- Cell structure (prokaryotic)

Question 1

How do prokaryotic cells differ from eukaryotic cells?

Answer 1

-Their cytoplasm lacks membrane-bound organelles
-Smaller ribosomes
-No nucleus (have singular circular DNA molecule, float free in cytoplasm, no association with proteins)
-Cell wall has murein (glycoprotein)

Question 2

What organelles do some prokaryotes have?

Answer 2

-Plasmids, smaller loops of DNA, can be exchanged by bacteria
-Capsule, enables to attach to surfaces in its environment
-Flagella (1 or more), tail-like, for locomotion
-Pili ,exchanging genetic material during reproduction-conjugation
-Fimbriae, for attaching to host cell

Question 3

How do prokaryotes replicate?

Answer 3

Binary fission

Question 4

What is the process of binary fission?

Answer 4

-Replication of circular DNA and plasmids
-The two sets of genetic material migrate to opposite poles
-Cytoplasm begins to divide (so new cells can sustain life)
-Two daughter cells are formed, each have a single copy of the circular DNA and varying numbers of plasmids
They are genetically identical to each other and parent cells, apart from plasmid number

Question 5

What is the structure of viruses?

Answer 5

-Acellular, non-living
-Have genetic material, a capsid and attachment proteins
-Lipid envelope
-Made up of nucleic acids, surrounded by capsids
-Smaller than bacteria

Question 6

Why are viruses considered not living?

Answer 6

-Have no nucleus, plasma membrane, cytoplasm or ribosome
-Not made of cells
-Cannot reproduce independently

Question 7

How does a virus replicate?

Answer 7

-Invade and hijack the reproductive mechanism of a living cell
-This is now a host cell
-Viruses have attachment glycoproteins that bind to complementary receptors on host cells
-Then they inject their DNA or RNA into the host cell
-The host cell divides as normal and the virus is replicated