A2
Origins of cells
conditions of early Earth
hot
covered in single global ocean
methane and ammonia from volcanoes
high CO2
water and compounds brought by asteroids
no ozone layer
liquid inner core → high radiation
conditions to be “living”
Homeostasis
Metabolism
Movement
Reproduction
Growth
Response to stimuli
Excretion
Nutrition
why are viruses considered not living?
they are parasites relying on their host to survive
Miller-Urey experiment
water to represent ocean
gas inlet for CH4, NH3, H2
sparks for electrical storms
A2 1
, repeatedly vaporised and condensed water → “primordial soup” → found
monomers spontaneously created including amino acids
what is LUCA?
last universal common ancestor
large autotrophic anaerobic microbe
lived in hydrothermal vents in the ocean 2.5-3.5 million years ago
outcompeted other life forms leading to their extinction
Cell structure
types of microscopy
light → beam of light, lower resolution, can’t see subcellular structures
electron → beam of electrons, black and white dead structures only, high
resolution
freeze fracture microscopy
cryogenic electron microscopy
Endosymbiotic theory
theory that primordial cells were engulfed by other cells for their mutual
benefit, leading to the 1st eukaryotic cells
evidence → mitochondria + chloroplasts have 70s ribosomes, double
membranes from being engulfed, divide by binary fission
features of an animal cell
nucleus
80s ribosomes
mitochondria
rough ER
smooth ER
vesicles
A2 2
Origins of cells
conditions of early Earth
hot
covered in single global ocean
methane and ammonia from volcanoes
high CO2
water and compounds brought by asteroids
no ozone layer
liquid inner core → high radiation
conditions to be “living”
Homeostasis
Metabolism
Movement
Reproduction
Growth
Response to stimuli
Excretion
Nutrition
why are viruses considered not living?
they are parasites relying on their host to survive
Miller-Urey experiment
water to represent ocean
gas inlet for CH4, NH3, H2
sparks for electrical storms
A2 1
, repeatedly vaporised and condensed water → “primordial soup” → found
monomers spontaneously created including amino acids
what is LUCA?
last universal common ancestor
large autotrophic anaerobic microbe
lived in hydrothermal vents in the ocean 2.5-3.5 million years ago
outcompeted other life forms leading to their extinction
Cell structure
types of microscopy
light → beam of light, lower resolution, can’t see subcellular structures
electron → beam of electrons, black and white dead structures only, high
resolution
freeze fracture microscopy
cryogenic electron microscopy
Endosymbiotic theory
theory that primordial cells were engulfed by other cells for their mutual
benefit, leading to the 1st eukaryotic cells
evidence → mitochondria + chloroplasts have 70s ribosomes, double
membranes from being engulfed, divide by binary fission
features of an animal cell
nucleus
80s ribosomes
mitochondria
rough ER
smooth ER
vesicles
A2 2
