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