structure of prokaryotic cells Flashcards

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1
Q

what are prokaryotic cells?

A

+ smaller than eukaryotic cells
+ cytoplasm lacks membrane bound organelles
+ smaller ribosomes (70s compared to 80s in eukaryotes)
+ lack a nucleus
+ contain a cell wall made from murein, a form of glycoprotein ( and not cellulose)
+ e.g bacterial cells and cyanobacteria

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2
Q

what is the plasma membrane?

A

+ made mostly from lipids and proteins
+ controls movement of substances into and out of a cell

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3
Q

what is DNA (nucleoid) ?

A

+ free floating as a long coiled strand
+ has no proteins attached to it

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4
Q

what is a plasmid?

A

+ small circular DNA contains genes (for things like antibiotic resistance)
+ not always present but some can have more of them than other cells

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5
Q

what is the mesosome?

A

+ folded region of the membrane
+ provides a large SA
+ contains bound enzymes required for respiration

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6
Q

what is the capsule?

A

+ thick polysaccharide layer
+ used for…
sticking cells together
a food reserve,
protection against outside chemicals,
protection against phagocytosis

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7
Q

what is the cell wall?

A

+ formed from a polymer and murein
+ two kinds of cell wall that can be identified using a ‘Gram stain’
Gram+ : thick wall and stain purple
Gram- : thick wall with an outer lipid layer and stain pink

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8
Q

what are ribosomes?

A

+ site of protein synthesis
+ these are not attached to any membranes and they are also smaller (70s) than those in eukaryotic cells

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9
Q

what is the bacterial flagellum?

A

+ helical shaped tail for cell movement
+ embedded into the membrane and is driven by a proton (H+) gradient
+ clockwise rotation= move forward
+ anticlockwise= chaotic spin
+ not all prokaryotes have one and some may have more than one

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10
Q

what is binary fission?

A

+ bacterial reproduction
+ asexual process
+ no exchange of genes
+ in the right conditions bacteria will divide every 20 mins

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11
Q

what are viruses?

A

+ acellular ( not made up of discrete cells or cannot split into cells)
+ they are not cells - just a nucleic acid
surrounded by a protein
+ non-living
+ neither prokaryotic nor eukaryotic
+ part of a separate category called obligate
intracellular parasites
+ smaller than bacteria
+ all viruses will invade and reproduce within a host cell

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11
Q

what is a viral genome?

A

+ nucleic acid - core genetic material in a virus made of either DNA or RNA
+ viruses are classified based on this ( DNA - virus and RNA = retrovirus)

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12
Q

what is the nucleoplasmid?

A

+ protein coat that surrounds the core genetic material of the virus

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13
Q

what is the envelope protein?

A

+ AKA attachment proteins
+ allow the virus to cling to a suitable host

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14
Q

what is the envelope?

A

+ determines the virus ability to attach to and enter host cells

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