B2.2 Flashcards
Define a compartmentalised cell structure (3)
membranes isolate certain parts of cell from the rest
to form separate organelles
e.g mitchochondrion matrix separated from cytoplasm by membrane
Usages of compartmentalisation in a cell (3)
enzymes have different optimal pH –> must be differentiated within cells
isolating toxic/damaging substances from cytoplasm
ability to change number/position of organelles through isolation
Chromatin
fiber of nucleosomes
Nucleolus
produces RNA which is made into ribosomes (move out of nucleus to produce proteins)
Nuclear envelope (3)
has nuclear pores - allows relatively large molecules to pass through
dense spherical structure
surrounds nucleolus
Structure of nuclear envelope outer membrane (2)
outer membrane is connected to rough endoplasmic reticulum
outer membrane surface dotted with ribosomes
Structure of nuclear envelope inner membrane
contains nuclear lamina (fibrous protein) - provides structural support + prevents collapse from external forces
Function of nuclear envelope (2)
protects genetic material
regulates transport between nucleus + cytoplasm
Perinuclear space
space between inner + outer membranes of nuclear envelope
Structure of smooth Endoplasmic Reticulum
no ribosomes on outer surface
Function of Smooth Endoplasmic Reticulum (3)
synthesizes lipid-based molecules - phospholipids + cholesterol + steroid hormones
Enzymes in SER detoxify substances
stores Calcium ions in muscle cells + releases them in muscle contraction
How does the smooth endoplasmic reticulum detoxify substances (3)
enzymes oxidise hydrophobic toxins
SER adds polar molecules to oxidised toxins - increases water solubility
broken down further with enzymes - become less reactive
Nuclear pores (2)
channel proteins
regulate mRNA leaving nucleus for rough endoplasmic reticulum + free ribosomes
