Metabolism and energetics part 2 Flashcards
in the pentose phosphate pathway, what is the source of reducing power?
NADH + H+
Witch pathway produces most of the NADH + H+?
pentose phosphate pathway
which pentose is used to produce ribose and deoxyribose?
Ribose 5‐phosphate
The pentose phosphate pathway leads to what?
the generation of a diversity of sugars. (gluconeogenesis)
where does pentose phosphate pathway take place (Prokaryotes and Eukaryotes) ?
In the cytoplasm
EUKARYOTES: where are the enzymes of the TCA cycle for respiration and oxidative phosphorylation located?
in the mitochondria
EUKARYOTES: where are the enzymes of glycolysis and fermentation located?
in the cytoplasm.
PROCARYOTES: where is the respiratory chain located?
cytoplasmic membrane
PROCARYOTES: where are the enzymes of glycolysis, TCA cycle and fermentation located?
cytoplasm
EUKARYOTES: where does the pentose phosphate pathway occur?
cytoplasm
PROCARYOTES: where does the pentose phosphate pathway occur?
cytoplasm
what is the cytoplasm made of?
Cytoplasm is a solution of salts, sugars, amino acids, nucleotides, and many other substances.
why is it important for the cytoplasmic membrane to be hydrophobic?
The hydrophobic portion of the cytoplasmic membrane prevents the diffusion of those substances. Those referring to what the cytoplasm is made of.
in other words, it acts like a permeability barrier: prevents leakage and functions as a gateway for transport of nutrients into, and waste out, of the cell.
What can/cannot diffuse through the cytoplasmic membrane?
• Some small hydrophobic molecules can diffuse through the membrane (O2, CO2)
• Water can freely diffuse, and is helped along by aquaporins
• Polar and charged molecules cannot diffuse, must be transported
another way
Name the different types of transport events and explain the difference:
- Facilitated diffusion can only transport solutes down a gradient. For uncharged substrates, the concentration gradient alone will determine the direction of the flow. For charged substrates, the concentration gradient and the charge will determine the direction of the flow. (channel mediated and carrier mediated)
- Active transport can transport solutes against the concentration (or electrochemical) gradient. But requires energy. (simple transport, group translocation, ABC transporter)
explain these concepts concerning the transport system:
- saturation
- specificity
- Transport systems can be saturated; the rate of uptake becomes maximal and addition of more substrate does not increase the rate.
- Transport systems are specific; transport single molecule or a class of closely related molecules.
which transport system do multicellular organism use to acquire nutrients? unicellular?
- In multicellular organisms, cells usually acquire nutrients by means of diffusion or facilitated diffusion (from blood / plasma).
- In unicellular organisms, including bacteria, archaea and eukaryotes, nutrients are usually acquired by active transport.
explain the difference between channel mediated and carrier mediated facilitated diffusion:
• 1) Channel‐mediated:
– Specificity is relatively low
– Can be closed by the cell (gated channel)
• 2) Carrier‐mediated:
– The binding of the substrate on one side of the membrane induces a conformational change in the carrier.
– The substrate is released on the other side.
– Tends to be more specific than channel‐mediated diffusion.
what does ‘going against the gradient’ imply for substrates?
the cells need to concentrate building blocks and energy‐ rich molecules.
explain simple trasnport
- driven by the energy in the proton motive force
- requires energy because against the concentration gradient
- you have uniporter, symporter, antiporter
- Sodium-Proton Antiporter: H+ goes in and Na+ goes out
- Lac permease H+ goes in with lactose
