Metabolisme

Roy Hove
Flashcards by Roy Hove, updated more than 1 year ago
Roy Hove
Created by Roy Hove about 6 years ago
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1st law of thermodynamics Energy can be transferred and transformed, but it cannot be created or destroyed
2nd law of thermodynamics Every energy transfer or transformation increases the entropy (disorder) of the universe
free energy (aka as G for Gibbs) is energy that can do work when temperature and pressure are uniform, as in a living cell
exergonic reaction proceeds with a net release of free energy and is spontaneous catabolique reaction
endergonic reaction absorbs free energy from its surroundings and is non-spontaneous Anabolique reaction
couplage d’énergie il consiste à employer l’énergie dégagée par une réaction exergonique pour déclencher une réaction endergonique. en grande partie grâce à l’ATP.!
The bonds between the phosphate groups of ATP’s tail can be broken by by hydrolysis
ATP is composed of of ribose (sugar), adenine (nitrogenous base), and 3 phosphate groups
ATP drives endergonic reactions by phosphorylation, transferring a phosphate group to some other molecule, such as a reactant
A ribozyme is a catalytic RNA, e.g. the self- splicing of rRNA
Induced fit of a substrate brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction
Inorganic cofactors are often metals (Zn, Cu, Fe in ionic form)
Organic cofactor are called are called coenzymes, which are often vitamins (e.g. Vitamin B3àNAD+)
Competitive inhibitors bind to the active site of an enzyme, competing with the substrate
Noncompetitive inhibitors bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective
Sarin gas inhibits acetyl-cholinesterase, an enzyme in the CNS
Penicillin blocks enzymes that synthesizes bacterial cell walls
Examples of inhibitors toxins, poisons, pesticides, and antibiotics
Allosteric regulation can be considered reversible non-competitive inhibition/activation
Cooperativity in allosteric regulation is a form of allosteric regulation that can amplify enzyme activity (e.g. O2 & Hb)
(cysteine-aspartic proteases) may help management of Inflammatory responses - e.g. IL-1β Converting Enzyme (ICE = caspase 1) and Apoptosis
In feedback inhibition the end product of a metabolic pathway shuts down the pathway preventing the cell from wasting chemical resources
In oxidation a substance loses electrons, or is oxidized (the amount of positive charge is induced)
In reduction a substance gains electrons, or is reduced (the amount of positive charge is reduced)
• CO2 enters and O2 exits the leaf through microscopic pores called stomata
Chloroplasts are found mainly in cells of the mesophyll, the interior tissue of the leaf
The chlorophyll is in the membranes of thylakoids (connected sacs in the chloroplast); thylakoids may be stacked in columns called grana
• Chloroplasts also contain stroma, a dense fluid
The light reactions (in the thylakoids): – SplitH2O – ReleaseO2 – Reduce NADP+ to NADPH – GenerateATPfromADPby photophosphorylation
carotenoids Accessory pigments called carotenoids absorb excessive light that would damage chlorophyll
photoprotection d
phytochemicals Plants synthesize all protective molecules themselves 2. Animals must get them through diet
Chlorophyll a vs chlorophyll b 1.Chlorophyll a is the main photosynthetic pigment 2.Accessory pigments, such as chlorophyll b, broaden the spectrum used for photosynthesis
Theodor W. Engelmann(1843-1901) discovered positive aerotaxis and the action spectrum of photosynthesis by using a modified microscope made by Carl Zeiss.
1.Porphyrin ring: 1.light-absorbing “head” of molecule; note magnesium atom at center (an inorganic cofactor)
2.Hydrocarbon tail: 2.interacts with hydrophobic regions of proteins inside thylakoid membranes of chloroplasts; H atoms not shown
The light-harvesting complexes (pigment molecules bound to proteins) funnel the energy of photons to the reaction center
a reaction-center complex A photosystem consists of a reaction-center complex (a type of protein complex) surrounded by light-harvesting complexes
A primary electron acceptor in the reaction center accepts A primary electron acceptor in the reaction center accepts an excited electron from chlorophyll a
Photosystem II (PS II) PS II) functions first (the numbers reflect order of discovery) and is best at absorbing a wavelength of 680 nm. The reaction- center chlorophyll a of PS II is called P680
Photosystem I (PS I) is best at absorbing a wavelength of 700 nm. The reaction-center chlorophyll a of PS I is called P700
Cyclic electron flow only 1. uses PSI 2.It can also occur in species with both PSII and PSI 3.
Chemiosmosis is Chemiosmosis is the movement of ions across a selectively permeable membrane, down their electrochemical gradient. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration or photosynthesis.
Fats and carbohydrates are Are reservoirs of electrons associated to hydrogen, these hydrogene bonds are a source of hilltop electrons
NAD+ functions as an As an electron accepter thus it is the oxidizing agent during cellular respiration
What is the reduced form of NAD+ It is NADH, and each NADH represents stored energy that is tapped to synthesise ATP
What is the full name of NADplus Nicotinamide adenine dinucleotide (NAD+), and its a coenzyme
Pellagra is caused by what and what are its symptoms Vitamin b3 deficiency and the symptoms are Dermatitis, Diarrhea, Dementia, and evtl. Death
What are the three stages of cellular respiration 1. Glycolysis (breaks down glucose into two molecules of pyruvate) 2. The citric acid cycle (completesthe breakdown of glucose) 3. Oxidative phosphorylation (accounts for most of the ATP synthesis)
The process that generates most of the ATP is called oxidative phosphorylation because it is powered by redox reactions
A smaller amount of ATP is formed in glycolysis and the citric acid cycle by by substrate-level phosphorylation
what is derived form Vitamin b3 NAD+ is derived from vitamin B3 (aka as niacin)
prosthetic groups r
FAD is derived from from riboflavin or vitamin B2
A signal Transduction Pathway is a series of steps
What is quorum sensing ? When bacteria secrete signaling molecules so that other bacteria can detect population density
How does the hormone Epinephrine work ? By stimulating gylcogen breakdown by activating glycogen phosphorylase
What type of signals are growth factors Local signaling types : Paracrine
Name a type of long distance signaling Hormonal or endocrine signaling and an example is epinepherine
How do paracrine and synaptic signaling work ? Paracrine uses diffusion and synaptic uses electrical signals
Most water soluble molecules bind to specific sites on what ? Of receptor proteins that are in the plasma membrane
Name the diseases that GPCRS are involved with 1.Cholera 2.Hypertension 3.Asthma
What are pertusis toxins s
Which guanine molecule turns a GProtein on GTP
How does Adenyl cyclase act as a GTP-ase in its transduction pathway It removes a phosphate from the GTP rendering the protein to which this GTP was coupled inactive
Possibles Cause of Cancer related to GPCRs : 1.Enzyme in transduction pathway doesnt remove a phosphate group from the Gprotein
Name GTp-ase enzymes 1.G protein 2. Adenyl.Cyclase
What does a Kinase enzyme do ? Catalyzes the transfer of phosphate groups
About 30 percent of breast cancers are due to The RTK receptor named HER2 being overexpressed causing the cell to divide faster
Are all hormones hydrophobic NO
What are transcription factors and why do we talk about them when explaining nuclear recptors Transcritption factors control which genes are turned on and transcribed into mRNA . We say nuclear receptors are turned into transcription factors when certain hormones bind to them
Receptor for neurotransmitters fall into what category of Receptors LGICS
Give examples of LGICS 1.Receptor for Acetylcholine 2.Receptor for Serotonin 3.Receptor for Glutamate 3. Receptor for Etanol
The RTK drug Bevacimab or avastin binds to VEGF to cure what diseases ? IT cures colorectal cancer and wet age related Macular Degeneration AMD
15% of currently used drugs target what type of receptor Target NRs
How is Helix 12 affected in an induced fit It is repositioned upon ligand binding so that it can dock coactivaters and activate transcription : This is what we call an Induced Fit
What are Tamoxifen and Flutamide ? and what are they used for They are NR antagonists that keep the NR in its inactive conformation and they are used to cure Breast cancer and Prostate Cancer respectively.
How big is an Ion Channel The top is 6nm and the intermembrain part is 3nm and the cytoplasma part is 2nm (just remember the 6nm and the rest is two numbers multiplied that give you 6(3,2))
How wide is the opening of an ion Channel 2nm
How wide is the Whole ion channel (circumference) 9nm !
What gives birth to a fat cell A fibroblastlike procuseur cell (its catalized by PPAy (a NR))
Multistep pathways provide more opportunities for Coordination and regulation
What is biofillm an example of? h
What are Pases Protein phosphatases, and they dephosphorylate proteins
What is most likely wrong in men with Prostate cancer Its that the protein PIP3 pathway doesnt receive the Feedback inhibition it needs to stop so it keeps on going hence the cancer. PIP3 pase is mutant in 70% of men with P.Cancer
Protein Kinases most often phosphorylate what and how much of our genome is codes for these P.Ks 2% of our genese code for these PKs and they phosphorylate other proteins and, Serine and Threonine residues mostly
How do caffeine and theophyline act on the signal transduction pathway They completely inhibit Phosphodiesterases which means no one is degrading the cAMP now, and the same messages get sent over and over again
Apoptosis may be involved in deseases such as Parkinsons and Alzheimer
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