2.2

Not organelles

• cell wall- extracellular structure

• Cytoskeleton - extends through cytoplasm and is not discrete

• Cytoplasm - diverse rather than specific function

Separation of nucleus and cytoplasm

• eukaryotes modify mRNA before translating it into polypeptides. Which happens inside the nucleus, where RNA is produced by transcription

• Nuclear membrane ensures that this post-transcriptional modification is completed before mRNA meets the ribosomes that will translate it in the cytoplasm

• in prokaryotes there is no nunclear membrane, so ribosome can translate mRNA as soon as it is produced and post transcriptional modification is not possible

Draw adaptation of mitochondrion for ATP production by aerobic respiration

• in notes

Draw adaptation of chloroplast for photosynthesis

• in notes

benefits of double membrane

• pores can be formed by joining the outer membrane to inner membrane, nuclear pores are needed for ribosome and mRNA to move from nuclues where they are produced to the cytoplasm where they are used

• nuclear membrane can easily break up into vesicles during mitosis and meiosis which releases the chromosomes so they can move within the cell. the vesicles move ot the pole of the cells where they are later used to construct nuclear membrane around daughter nuclei

Clathrin coated vesicles

• clathrin cage used to pull a patch of membrane inwards from plasma membrane until vesicle formed