2.1 a Metabolism and Survival Flashcards
What is metabolism?
Metabolism is the sum total of all the chemical reactions in a living cell
What is a metabolic pathway?
A series of stepwise chemical reactions controlled by enzymes
What is an anabolic pathway?
Anabolic pathway synthesises new complex molecules from simple molecules using ATP
example of an anabolic pathway?
Synthesis of protein molecules from amino acids
What is a catabolic pathway?
Breakdown of large complex molecules to small simple molecules releasing ATP
Example of a catabolic pathway?
Breakdown of glucose during respiration with the release of ATP
Example of an integrated pathway?
Catabolic reaction of respiration supplies energy for the synthesis of protein molecules from amino acids
What does it mean by a reversible step?
Metabolite A can be converted to metabolite B and B can then be converted back to A and used perhaps in an alternative pathway
What does this give the cell? (reversible step)
Control over the metabolic pathway
What is an irreversible step?
Irreversible step results in one metabolite fully converted into another, no alternative pathway is available
How does an alternative route work?
it allows specific steps to be by passed in a pathway
Differences between a prokaryote and a eukaryote?
Prokaryotes have no membrane bound organelles or nucleus. they have circular chromosomes and several smaller plasmids
Eukaryotes have membrane bound organelles and nucleus. Linear DNA in nucleus. Circular in mitochondria and chloroplasts.
Function of mitochondria membrane?
Localising the enzymes for different stages of aerobic respiration. Site of proteins required for ATP production
Function of chloroplasts membrane?
Localising chlorophyll and the enzymes for different stages of photosynthesis
Function of Lysosomes membrane?
Localises powerful digestive enzymes required for cell defense as they would other wise destroy the cell
Surface area to volume ratio in small structures?
have a larger surface area relative to its volume
Having smaller compartments and smaller folds in the membrane means what?
a larger surface area upon which metabolic reactions can take place. small compartments ensure high concentration of substrates increasing reaction rates
Fluid mosaic model membrane consists of what?
proteins and phospholipids
describe the fluid mosaic model?
phospholipid molecules form a double layer (bilayer) and are in constant motion giving a fluid nature to the membranes making them flexible. Proteins scattered in a patchy mosaic pattern
Why is compartmentalisation of the inner membrane of a mitochondrion important in terms of metabolic pathway?
Compartmentalisation isolates and brings together specific metabolites within a metabolic pathway.
What is diffusion?
Diffusion is the movement of molecules from a high concentration to a low concentration down a concentration gradient through the phospholipid bilayer
What is a concentration gradient?
the concentration gradient is the difference in concentration between two areas
Shape of concentration gradient slope depends on?
the greater the difference in concentration gradient the steeper the slope, the faster diffusion occurs
the smaller the difference in concentration gradient the shallower the slope the slower diffusion occurs
What is osmosis?
Osmosis is the movement of water molecules only from a region of high water concentration to a region of low water concentration through a selectively permeable membrane.
What is active transport?
movement of molecules or ions from a region of low concentration to a high concentration against a concentration gradient.
what does active transport require?
energy provided by aerobic respiration and protein pumps
what are pores?
channel forming proteins have pores that control the passive diffusion of certain molecules, depending on their size.
these pores make the cell membrane selectively permeable or porous
What are pumps?
active transport involves specialised protein pumps in the plasma membrane so require energy
these pumps recognise specific molecules and transfer them across the membrane
What is ATP synthase?
ATP synthase is an enzyme embedded in the membrane of mitochondria and chloroplasts where it catalyses the synthesis of ATP.
Explain the advantage of membrane bound compartments in cells?
Localise the metabolic activity of the cell
the larger surface to volume ratio of small compartments allow high concentrations of reactions to occur
High reaction rates are possible
Provide more favourable conditions of reactions to take place
membrane folds in organelles provide a large surface area for metabolic reactions to take place
