Zusammenfassung der Ressource
Biology - Unit 2 - Key area 1
- Part a
- Metabolic pathways
- Reversible and irreversible
- Steps can be skipped
- Only if there is
an alternative
route
- Membrane compartments
- Embedded in the
phospholipid bilayer
membrane
- Can be pumps, pores or enzymes
- Membrane compartments
- Increases surface area
- Increases the
reaction rate
- Key terms
- Metabolism
- Build up/breakdown
of reactions in cells
- controlled by
enzymes
- Anabolic pathways
- Build up/synthesis
reactions
- Use up energy
- glucose-1-phosphate ------> starch (GPS)
- Amino acids ------> Proteins
- Catabolic pathways
- Breakdown/degradation reaction
- Starch ---amylase---> Maltose (SAM)
- Part B (Control of
metabolic pathways)
- Enzyme activity
- Products
- Low affinity with
the active site
- Substrate
- Affinity for the
active site
- Induced fit
(like a surgical
glove)
- Active site
changes shape
to perfect fit the
molecule
- Activation energy
- Energy needed to
start a chemical
reaction
- Enzymes
lower the
activation
energy
- Each step in a metabolic
pathway is controlled by
a specific enzyme
- If an enzyme is missing
(caused by a mutation)
it will disrupt the
pathway causing the
reaction to stop
- Inhibited
- Slowed
down/held
back
- Competitive
inhibition
- Inhibiter molecule has
a similar shape to the
substrate molecule
- Inhibitor attaches
to the substrate
molecule to block it
- Non competitive inhibition
- The inhibitor
attaches somewhere
on the enzyme (not
on the active site)
- This changes the shape
- Substrate no longer fits the active site
- End product
inhibition/feedback
inhibition
- End product of a reaction
binds to the enzyme and
inhibits its reaction
- Substrate
- Intermediate 1
- Intermediate 2
- Intermediate 3
- Product
- Enzyme 4
- Enzyme 3
- Enzyme 2
- Enzyme 1
- If the environment has
enough of the product
then the organism
conserves energy
- So the inhibitor attaches to
an enzyme in the pathway
to stop the product being
produced
- If the product isn't in the
environment anymore the
inhibitor will detach to let the
process start again