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types of microscopes (3)
light, confocal, electron
properties of light microscope (3)
relatively low resolution allow live cell imaging easier and cheaper
fluorophores in cell staining
added to antibodies which attach to specific cellular components for detection
immunostaining
bind to specific proteins so coupling with a fluorescent probe can be used to image a specific part of a cell
4 advantages and 3 disadvantages of confocal microscopes (7)
high sensitivity and resolution little sample is needed able to reconstruct 3D structure of cells allow live cell imaging slow scan speed limited penetration for thick samples expensive
properties of electron microscopes (3)
high sensitivity views dead and dehydrated cells - may lead to inaccurate imaging expensive
2 potential origins of life
lightning created HCN –> UV light drove conversion of HCN to simple sugars –> phosphate catalysed reactions forming RNA molecules pH and energy gradients in the sea caused a chemical gradient which led to formation of life
3 core functions of RNA
central intermediate between DNA and protein stores information and takes part in templated replication has catalytic activity
initialy proton motive force was thought to have formed through ___ it is a key to ___ in cells, only happens when ___
precipitation of salts in alkaline vents key to energy generation in cells - only happens when there is a pH gradient
universal features of cells (4)
store their hereditary information in DNA replicate DNA by templated polymerisation into the same intermediate form use proteins as catalysts enclosed in a plasma membrane across which nutrients and waste material must pass through
relationship between genome size and replication time
the larger the genome the longer it takes to replicate
why do prokaryotic cells reproduce faster than human eukaryotic cells
smaller size implies higher surface area to volume ratio, maximising the update of nutrients across the plasma membrane smaller genomes so fewer sequences to replicate
intragenic mutation
an existing gene is modified by changes in DNA through errors in replication
gene duplication
an existing gene is duplicated which creates and identical set of genes in a cell (may then diverge)
segment shuffling
two or more existing genes can be broken and rejoined to make a hybrid gene
horizontal transfer
a piece of DNA can be transferred from the genome of one cell to another
ortholog
genes in two separate species from the same ancestral gene in the last common ancestor
paralog
related genes resulting from gene replication within a single genome
homolog
genes related by descent in either way umbrella term of ortholog and paralog
2 types of prokaryotes
archea and bacteria
6 sub-cellular components of prokaryotes
plasma membrane (complex) cell wall cytoplasm DNA strand ribosomes flagellum
6 sub-cellular components of eukaryotes
(NO cell wall) nucleus (+nuclear envelope) plasma membrane ribosomes mitochondria lysosome Golgi apparatus
Golgi aparatus
transport and sorting of proteins and lipids
lysosomes
stores enzymes in eukaryotic cells