Biology Questions and Answers
exoskeleton of arthropods); in plants,
the cell wall is made of cellulose too.
- Do membranes form only
the outer wrapping of cells?
Lipid memouter cover of cells. Cell branes do not form only thorganelles, e
such as the Golgi complex,
mitochothe endoplasmicndria, chl reticulaoroplasts, and the lysosom es,
nucleus, are delimited by membranes
too.
- Which type of cell came
first in evolution - the
eukaryotic cell or the
prokaryotic cell?
This is an interesting problem of
biological evhypothesis asserts that the olution. The most acceptemore simpled (^)
cell, the prokaryotic cell, appeared
earlier in evolution thacomplex eukaryotic cell. Thn the moree
endosymbiotic hypothesis, for example,
affirms that aerobic eukaryoticappeared from the mutualist ecological cells (^)
interaction between aerobic prokaryotes
and primitive anaerobic eukaryotes.
- Concerning the presence
of the nucleus what is the
difference between animal
and bacterial cells?
Animal cells (cells of living beings of the
kingdom Animalia) havmembrane that delimitse an interior a cell nucleus (^)
and thus they are eukaryotic cells; in
these cells thlocated within the genetic material ise nucleus. Bacterial (^)
cells (cells of living beings of the
kingdom Mocellular nuclei nera) do not have organizedand so they are
prokaryotic cells and their genetic
material is fcytosol. ound dispersed in the
- What are the three main
parts of a eukaryotic cell?
The eukaryotictwo main portions: th cell can e cell mbe divided intoembrane (^)
that sefrom thparates the outer space phe intracellular spaceysically
delimiting the cell; the cytoplasm, the
interior paqueous flortion uid inside the cell); and thefilled with cytosol (the (^)
nucleus, tinternal region that contains thhe membrane-delimitee geneticd (^)
material.
- What are the main
structures within the cell
nucleus?
Within the cell nstructures are: the nucleolus, anucleus the main (^)
opticallywhere there are concentrate dense region, spherical shaped,d ribosomal
RNA (rRNA) associated to proteins
(there may bein a nucleus); t more than one nucleolushe chromatin, made of
DNA molecules dispersed in the nuclear
matrix dukaryotecha, or nuclear ring the cell intmembrane, theerphase; the (^)
membrane that delimits the nucleus.
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