ch 3 cell metabolism Flashcards
1
Q
reactions
A
- A + B -> C + D
- or A + B <–> C + D (bidirectional)
- C6H12O66O2->6CO2+6H2O is cellular respiration
- –> forward
- <– reverse
- whichever reaction is happening faster will determine if you are making more A and B or more C and D
2
Q
catabolic vs anabolic reactions
A
- catabolic: breakdown of larger molecules into smaller. releases energy
- anabolic: production of smaller. requires energy
3
Q
bioenergetics: laws of thermodynamics
A
- first law: energy cannot be destroyed or created, only transformed
- second law: with every transfer or transformation of energy, some useable energy is released as heat
4
Q
first and second law of thermodynamics
A
- first: conversion of light energy into glucose by plants
- second: with every transfer or transformation, some energy that could have been used to do work escapes as heat
- heat is the cost of every reaction
5
Q
endergonic vs exergonic
A
endo: chemical reactions that require an input of energy. products contain more free energy than the reactants. energetically uphill. the products have more energy than the reactants.
exo: chemical reactions that release energy. products will have less free energy. energetically downhill. the reactants have more energy than the products.
6
Q
how do eno reactions occur?
A
- energy from the environment (food) is broken down in exergonic reactions to drive the endo reactions
- for endo to happen exo needs to happen nearby to release energy for endo
7
Q
activation energy
A
- the energy required for the reactants to engage in a reaction
- most molecules lack the activation energy needed for a reaction to occur
- all reactions require activation energy
ex: pool ball deep side, pool ball shallow side: they will eventually touch but if you go in and MAKE them touch it speeds up (catalyst = how quickly it happens) - enzymes speed up chemical reactions by lowering activation energy
8
Q
enzymes
A
- a class of proteins that serve as biological catalysts (increase reaction rate, are not changed by the reaction so can be used repeatedly, have no effect on free energy of reactants or products, in enzymatic reactions reactants are substrates)
9
Q
catalyzed vs noncatalyzed reactions
A
- the energy of both the reactants and the products is not affected by the presence of an enzyme. only thing that changes is the activation energy
- lowers amount of time/energy it takes for reaction to reach its peak
10
Q
ligand - receptor interactions
A
- ligand is anything that binds to a receptor (protein)
- specificity is based on shape
- based on affinity for the protein bc it can make more bonds with the protein
11
Q
naming enzymes
A
- all enzymes end with -ase and first part applies to the function
- phosphatases: removes phosphate groups
- synthetases: catalyze dehydration synthesis
12
Q
enzyme activity
A
- measured by the rate at which substrate is converted to product
- influenced by: concentration of enzyme and substrate, enzyme-substrate affinity, temp, pH, regulation by modulators (allosteric regulation), covalent regulation (regulation by chemical groups), feedback inhibition, feedforward activation)
13
Q
regulation of enzymatic reaction rates
A
- how to speed up reaction?
- add more enzyme but once the enzyme concentration is all binded to the substrate the concentration doesnt matter (affinity)
- temp: increase in temp will increase the rate of reactions until it gets too hot then enzyme is denatured
- pH: function at specific pH. if they’re in the wrong area, they will denature
14
Q
regulation of enzyme reaction rate: covalent regulation
A
- certain enzymes in the body whose sole function is to activate or inactivate other enzymes
15
Q
phosphorylation and de-phosphorylation
A
- kinases add a phosphate group to another enzyme and turns these enzymes ON
- phosphates remove a phosphate group from an enzyme and turn these enzymes OFF
