University Biology Question Thread

[cosine]

Hey guys, the main reason behind my achievements in VCE Biology was due to the wonderful help on the Biology thread. I learnt that asking questions is never a bad thing, and it is a vital way of learning new concepts and information. So instead of just posting irrelevant Biology questions on the VCE thread, I decided to make this one here for any University Biology questions.

[cosine]

The attached image comes from my bio textbook, and it says that prokaryotes, such as bacteria, have single outer membranes. However, do not bacteria have a cell wall plus a plasma membrane?

[TheAspiringDoc]

The attached image comes from my bio textbook, and it says that prokaryotes, such as bacteria, have single outer membranes. However, do not bacteria have a cell wall plus a plasma membrane?

Well current bacteria have a plasma membrane, a cell wall (usually petidoglycan) and also a slime layer or capsid. I'm not sure about your textbook , but perhaps it's saying that bacteria only had a cell membrane and no wAll or slime/capsid layer.. 

[Redoxify]

The attached image comes from my bio textbook, and it says that prokaryotes, such as bacteria, have single outer membranes. However, do not bacteria have a cell wall plus a plasma membrane?

They are referring to the first bacterias that habited our planet. I guess the cell wall developed after the introduction of anti-biotics?

[TheAspiringDoc]

They are referring to the first bacterias that habited our planet. I guess the cell wall developed after the introduction of anti-biotics?

no it certainly did NOT. Structures in an organism do not "devolope" as that means to acquire during one's lifetime. Rather, structures and characteristics are selected for over generations, due to differential reproductive success (which in turn is due to survival, which allows for more opportunities to reproduce, and also sexual selection, which in turn is due to factors such as the ability to have sex with another member of the same species (e.g., even a greyhound and a sausage dog are of the same species, they probs coulnd't fit their ... Equipment together), and also whether other organisms of the same species choose to mate with it.). And still, bacteria definately did not evolve (that's the correct word) a cell wall since the introduction of penicillin and the associated drugs. Some functions of the cell wall in bacteria include protection and maintain emcee of turgor pressure.

And finally, penicillin actually inhibit the formation of the cell wall, so it isn't exactly logical in hind site to think that anti-biopics preceded the cell wall when in fact one of the first antibiotics actually targeted the very cell wall of bacteria.

Sorry for crash course on evo. 

[cosine]

Think it is just an error in the textbook xD

[cosine]

1. For the attached image, it says that cell walls of most bacterial cells are composed of peptidogglycan, an amino sugar polymer. What exactly are amino sugar subunits, that make the polymer?

2. So most prokaryotic cells have a cell wall. Do all bacterial cells have a cell wall? (Assuming that the 'most' part refers to some Archaea lacking a cell wall)

Thank you.