eukaryotes

what are eukaryotes

are organisms whose cells contain a nucleus and are compartmentalised by numerous membrane-bound organelles

• They have a greater level of structural complexity and are believed to have evolved from prokaryotic cells via endosymbiosis

what kingdoms are eukaryotes classified into?

animals

plant

fungi

protist

genetic material in eukaryotes

is found within a double-membrane structure called the nucleus. The presence of a nucleus allows eukaryotes to separate the processes of transcription (nucleus) and translation (cytoplasm)

membrane bound organelles in eukaryotes

includes mitochondria, endoplasmic reticulum, golgi apparatus and vesicles

organelle found only in plant cells

chloroplasts (for photosynthesis) and have a large, fluid-filled vacuole surrounded by a tonoplast membrane

multicellular fungi form this

filamentous hyphae that are typically separated by internal walls called septa.

ribosomes

• are responsible for protein synthesis are comparatively larger in size (80S)

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transcription (nucleus)

is the process by which specific DNA instructions (genes) are converted into RNA transcripts (mRNA)

translation

involves the synthesis of polypeptide chains (proteins) from the RNA transcripts by ribosomes

why is separating the processes of transription and translation important?

it allows for the post-transcriptional modification of mRNA before it is translated by ribosomes

• These modifications help to stabilise the mRNA transcript (via capping and polyadenylation) and remove non-coding sequences (introns) via splicing

• This greatly improves the efficiency of protein synthesis and allows for tighter control of gene expression than is possible in prokaryotic cells

what is the advantage of having membrane bound oragnelles in the cyoplasm?

• This enables the organelles to maintain an internal chemistry that is different to the cytoplasm (and suitable to its specific function)

• It also allows for the concentration of key enzymes and metabolites needed to optimise the function of the organelle

what are the advantages of phagocytic vacuoles and lysosomes?

they provide evidence for the advantage of compartmentalising the cytoplasm into discrete sections-

• These organelles contain hydrolytic enzymes that are responsible for digesting cellular debris or engulfed pathogenic materials

• If these enzymes were not contained within a specific compartment, they would freely digest the contents of the cell (autophagy)