LSM2101 Part I Lecture 7 Gluconeogenesis

• Synthesis of glucose from:
• lactate
• glycerol
• glucogenic amino acids, e.g. alanine
• odd fatty acid chains -> propionyl-CoA
• Reverse of Glycolysis, but:
• Hexokinase -> Glucose-6-phosphatase
• Pyruvate Carboxylase: pyruvate -> oxaloacetate
• PEPCK: oxaloacetate -> PEP
• other enzymes are the same
• Location: 90% liver, 10% kidney
• Pyr Carboxylase: in mitochondria
• PEPCK: in mitochondria or cytosol
• Transfer from mitochondria -> cytosol:
• Malate Route (generate NADH)
• Aspartate Route
• PEP channel
• Regulations
• Pyruvate Carboxylase: (+) acetyl-CoA
• PFK: (+) AMP, F2,6BP (-)citrate,ATP vs. FBPase: (-) AMP, F2,6BP
• PFK2: (+)AMP, Pi, F6P (-)citrate, ATP vs. FBPase2: (-) F6P (+)G3P 
• Diseases
• Deficient in Pyruvate Carboxylase: lactic acidosis, hypoglycemia
• Deficient in FBP: no gluconeogenesis
• Anaerobic glycolysis = production of lactate
• in erythrocytes, tissues of eyes, skeletal muscle (short of ATP)
• Recycle of lactate: Cori cycle, in liver
• Adipose Tissue
• store fatty acids as triacylglyceride
• broken to: glycerol + FAs, transported to liver
• Glycerol -> Glucose
• FA (odd) -> propionyl-CoA -> succinyl-CoA -> glucose
• Glucose-Alanine Cycle
• Pyruvate -> Alanine (transamination), in muscles
• Alanine -> Pyruvate, in liver

LSM2101 Part II Lecture 2 Ammonia Production and Detoxification

Conversion of AA to Keto Acids

• Oxidative Deamination
• L-AA Oxidase + FMN + Catalase

• L-Glutamate Dehydrogenase + NAD+

• Transamination
• Mechanism: 
• Transfer of amine group from AA to PLP: 1. Transamination 2. Tauromerization 3. Hydrolysis
• Transfer of amine group from PLP to Keto-Acid: reverse of above

• General: 

• Aspartate-Aminotransferase (Glutamate-oxaloacetate transaminase)

• Alanine-Aminotransferase (Glutamate-pyruvate Transaminase)

• AST & AST: indication of damaged cells if found in blood serum.
• Trasndeamination: Transamination + Oxidative Deamination

• Importance:
• Funneling to glutamate for conversion to ammonia.
• Synthesis of non-essential amino acids.
• Non-Oxidative Deamination
• Ammonia Lyases

• Specific Deaminases:
• Serine dehydratase (L-serine hydrolase)

• Threonine dehydratase

• Cysteine desulfhydrase

Excretion of Ammonia

• AA -> Glu (1 eq NH3) -> Gln (2 eq NH3): happens in everywhere, transported to kidney or liver.
• Gln (2 eq NH3) -> Glu (1 eq NH3) + NH4+: only happens in kidney and liver.
• Ion-trapping mechanism: since NH4+ can't cross cell's membrane, ammonium ions in kidney lumen cannot enter kidney cells.

LSM2101 Part II Lecture 3 The Urea Cycle and Disorders

Lecture 3: Urea Cycle / Ornithine Cycle

• Urea: NH2-CO-NH2 (first N is from Asp, the other one is from ammonia, C is from CO2)
• Carbamoyl Phosphate synthesis is a rate-limiting step

•  Regulation:  Carbamoyl Phosphate Synthetase
• CP I: ammonia dependent, N-acetylglutamate -> activator, mitochondrial
• CP II: Amide-N of glutamine, independent from  N-ace glu, cytoplasmic
• N-acetylglutamate: from Glu + Arg using Acetylglutamate Synthase (N-acteyl Transferase)

• Kreb's Bicycle

 

•  Metabolic Disorder - Hyperammonemia (Defects in enzymes)
• Hyperammonemia Type I: Carbamoyl Phosphate Synthetase I
• Hyperammonemia Type II: Ornithine Transcarbamoylase
• Citrullinemia: Argininosuccinate Synthetase
• Argininosuccinic aciduria/acidemia: Argininosuccinate lyase/Argininosuccinase
• Argininemia: Arginase

• Nitrogen Disposal
• Ureotelic-Urea: Mammals
• Ammonotelic-Ammonia: Fishes
• Uricotelic-Ric Acid: Birds

LSM2251 Lecture 4-5 Population

Part I: Populations & Natural Selection (Molles 4th-C8/5th-C4)

1. What is a population?

• ecology: group of individuals of the same species inhabiting the same area
• genetics: group of interbreeding individuals of the same species isolated from other groups

2. Process of Natural Selection

• Inheritance: by Mendel
• Evolution: change in gene frequency within a population over time.
  • Small-scale evolution: changes in gene frequency in a population from one generation to the next.
  • Large-scale evolution: the descent of different species from a common ancestor over many generations.
• What is Natural Selection? 
• Key mechanishm of evolution.
• The process by which heritable traits that are likely to improve an organism’s chances of survival and successfully reproduce become more common in a population over successive generations.
• VIST
• Variation    : genetic variation upon which selection works
• Inheritance : genetic traits inherited
• Selection    : favourable traits survive and passed on
• Time          : evolution happens over generations (small-scale), speciation takes much longer (large-scale).
• Use it or Lose it: traits that are not actively maintained by natural selection rapidly disappear.
• Relaxed selection: environmental changes eliminates selection pressure that maintain a trait -> degeneration due to the loss of selection against mutations.
• Selected loss: driven by natural selection

3. Population genetics and Natural Selection

 a. Variation within populations

• phenotypic variation among individuals in a population, effects of genes and environments.
• Potentilla glandulosa
• In the same species where there are no genetic difference between populations, all plants would grouw well. (Null Hypothesis)
• In fact, the plants did not grow equally well
• Changes in genotype -> optimalization
• Ecotype: 
• each ecotype performed best under conditions most closely resembling its natural habitat
• genetically distinctive and is best adapeted to an optimal habitat.

b. The Hardy-Weinberg equilibrium

c. Natural Selection

d. Evolution by natural selection

e. Random processes

Part II: Population Distrbution and Abundance (Molles 4th/5th C9)

LSM2101 Part II Lecture 1 Overview

So, Part 2 is about Amino Acid Metabolism.
I skipped the first part since I've rarely attended the lectures. :D But the first part is about carbohydrate metabolism. Maybe I'll post the summary later.


Okay then...
Let's go on to the first lecture of second part of LSM2101:  Overview


1. Why do we need amino acids?
protein synthesis, energy & gluconeogenic substrates, neurotransmitter, hormones, heme & nucleotide biosynthesis.


2. Composition of body
50% dry matter = protein, 1-2% dry matter = free amino acids, no large reservoir of amino acids.


3. Where does body gets amino acids?
dietary proteins (exogenous), breakdown of body's proteins (endogenous), biosynthesis.


4. Dietary Proteins' Fate

• Intake:
• minimum daily req = 30 g for 70kg person
• Digestion:

• Absorption & Transportation:
• Inborn Errors: Aminoacidurias
• Cystinuria: failure to absorp CystineOrnithineArginineLysine -> Cystine Kidney Stones
• Hartnup's Disease: failure to absorp Trp, Phe, neutral AA -> Cerebellar ataxia (coordination of involuntary movement), Pellagra-like symptoms.

5. Nitrogen Balance

• Balance: Intake = Output
• Positive N Balance: Intake > Output (Growth, Pregnancy, Refeeding)
• Negative N Balance: Intake < Output (Starvation, Senescence, Metabolic Stress)

New New New!

Hi again blog! Haha, I left you alone again for quite some time...
:)

To make this not happen anymore, I decided to post a summary after every LSM lectures I attended.
It's a good practice, isn't it? Since I can allocate my time both for blogging and studying. :D
And you'll be a very good place to visit at the end of semester for a quick review. :)

devina

My Holiday! part 1

This summer I'm not going back to my hometown. Well, at first I thought I would have a job here and earning money is better than spending. Sadly, I didn't get those jobs I wanted and end up with doing nothing in this red dot island, Singapore.

Actually, I'm not really doing nothing (of course! at least, I sleep and eat!). Especially for last week, I made some experiments in the kitchen with Tata. :) Last Tuesday I made fried banana (pisang goreng) with some pieces of cheese inside. It was so yummy! But, I spent about 2 hours to make 20+ slices of those. I think the root of the problem is the stove. In Singapore, no open flame is allowed; so, we only have electrical stove here, which made the frying process took a long time to finish. I wish I could have my mother's stove here!

Second experiment was done today! Yay! Again, Tata and I tried to bake cookies. We used the recipe from wikihow. Some problems made us to have another long session in the kitchen. Because of the freezed butter, it took a lot of time to make the dough. The recipe also asked us to pour in some milk, which made the dough became too wet and couldn't be shaped. Desparately, we added in more flour and sugar and made our own recipe. :( Afterall, we could finally baked the dough and made some good-taste cookies! It tasted good but not very well in the texture. I think it was caused by the milk since the cookies were a bit (erm.. how to say..) bantet? Anyway, we have successfully made around 60 cookies using 2 eggs and random amount of flour, sugar, and butter. :p

Several weeks ago, we also tried to bake muffins. We used this recipe. Since it was our first try and we didn't have anything to measure (scale, cups, etc), we (again) put in approximate amount of those ingredients. We made two types of muffins. The first one was a bit, again, bantet (I really don't know the english word for this!) since we put additional egg yolk in it. Second one was over-baked, so the upper part of the muffins were removed and fortunately we could saved the other part! We made about 12 muffins and we gave it to some of our friends who were preparing for their special-sem exams.

Sadly, I don't have the photos to show you! :( Maybe later I can ask Tata to send it to me.

I think I should baked more cakes and try to make a birthday cake for my special someone whose birthday is in this July. Do I have enough time? Well, let's see...

Ah, another problem, it took a looooot of money to buy those ingredients! Gosh... Can I have some sponsorship? :p