9.1. The Cell as a Factory Flashcards
Carbohydrates act as a source of stored energy in cells…
(Types of ______saccharide)…
Monosaccharides: single, simple sugars, such as hexoses and pentoses.
Disaccharides: two simple sugars joined together by strong glycosidic bonds.
Oligosaccharides: three to 20 simple sugars often covalently bonded to proteins and lipids on cell surfaces and act as recognition signals (importance in specificity of blood groups).
Polysaccharides: hundreds and thousands of monosaccharides.
Examples of polysaccharides…
Starch: glucose storage in plants.
Glycogen: glucose storage in animals.
Cellulose: structural component of plant cell walls.
Glucose…
All cells use glucose as an energy source.
Can exist as a straight chain or a ring.
Most commonly a ring due to its increased stability.
This can exist as alpha or beta glucose.
Lipids…
Non-polar, hydrocarbon chains.
Van der Waals occur when chains come close together.
Triglycerides (fatty acid + glycerol) are a store of energy:
- Phospholipids: amphipathic compound with a structural role in the cell membrane.
- Steroids and modified fatty acids: hormone control and production and presence of vitamins in cells.
Carotenoids and chlorophylls capture light energy in plants.
Can be saturated or unsaturated (elaborate).
ATP…
A nucleotide that captures and releases free energy.
ATP can phosphorylate other compounds (provide them with energy) and can be itself phosphorylated (as it is synthesised from ADP).
The phosphorylation of ATP releases a large amount of energy when hydrolysed (with the delta G between -7.3 and -14). It is exergonic.
Bioluminescence…
An endergonic reaction driven by ATP hydrolysis.
Luciferin + O2 + ATP –> oxyluciferin + ADP + Pi + light.
Oxidation of glucose releases free energy…
C6H12O6 + 6O2 –> 6CO2 + 6H2O + free energy.
Energy is released in very small packets so it can be controlled.
In eukaryotes, this process is compartmentalised into organelles to improve efficiency and control.
Metabolic pathways are similar in all organisms and each reaction is catalysed by a specific enzyme.
