Biochem block 2 Flashcards
What is the difference between catabolism and anabolism?
Anabolism is the build up of complex organic molecules from simpler ones, reactions are called anabolic or bio synthetic. They involve dehydration synthesis-release water- and are endergonic
Catabolism. Is the breakdown of complex organic molecules into simpler ones. Reactions are called catabolic or degradative reactions, usually hydrolytic reactions and are exergonic.
Define and distinguish oxidation and reduction.
Oxidation: loss of electrons
Gain of oxygen
Loss of hydrogen
The reaction where a substance loses electrons going from a reactant to a product. Reactions where the gain of oxygen is more obvious than the gain of electrons includes combustion-burning- and rusting. The loss of hydrogen can be as oxidation like methyl alcohol- wood alcohol being oxidized to formaldehyde.
Reductions: the gain of electrons
The loss of oxygen
Gain of hydrogen
Reduction often is seen as gain of electrons lie in electroplating silver onto a tea pot, silver is reduced to silver metal by the gain of an electron. The loss of oxygen can be seen in iron ore being reduced to iron metal in a furnace when it reacts to carbon monoxide. Sometimes it can be the gain of hydrogen atoms like carbon monoxide and hydrogen gas being reduced to methyl alcohol.
Summarize the metabolic need for molecular oxygen
Molecular oxygen is an essential nutrient as a key substrate for mitochondrial ATP production and a lot of intracellulaire rxns. It’s a common oxidizing agent- electron acceptor, like in aerobic respiration. In Aerobic respiration oxygen is needed to create ATP. One molecule of glucose is converted to 2 molecules of pyruvate to get 2 net molecules of ATP. We also repair our body with ATP, from oxygen
List Metabolic fuel sources
Glycogen- muscle carbohydrate stores, blood sugar- glucose, blood fatty acids, triacylglyerols, protein
Besides energy, what else do we need to work efficiently?
Enzymes- coenzymes, cofactors: trace minerals and vitamins
What is energy for us?
ATP and heat
What are the 4 major biochemical macromolecules?
Proteins- amino acid polymers, TAG’s- lipid polymers, DNA,RNA- nucleic acid polymer, Polysaccaride- carbohydrate polymer
What is oxidative phosphorylation?
OXPHOS is a process where the oxidation of carbon substrate provides REDUCED COENZYMES. The reduced coenzymes are used to establish a proton gradient. This gradient is coupled to the production of ATP from ADP.
What is the difference between oxidative phosphorylation and substrate level phosphorylation?
They are two types of phosphorylation processes that occur. Phosphorylation is the transfer of a phosphate group from one compound to another, usually describing the production of ATP. Substrate level phosphorylation is a direct phosphorylation of ADP with a phosphate group by using the energy obtained from a coupled reaction whereas OXPHOS is the production of ATP from the oxidized NADH and FADH.
What is substrate level phosphorylation?
It’s an enzymatically coupled reaction that produces ATP by the transfer of a phosphate group from a reactive intermediate generated during catabolism to ADP. An example is glycolysis- the catabolism of glucose to pyruvate. Pyruvate go through TCA cycle which breakdown the carbon intermediates to 6 CO2, 6H20 and 38 ATP for one glucose molecule
Are B vitamins water soluable?
Yes
What is B1?
Thiamine. Alcoholics are deficient
What is B2?
Riboflavin
What is B3?
Niacin
What is B9?
Folate
What is B5?
Pantothenic acid
What is B6?
Pyridoxine
What is B7?
Biotin
What is B12?
Cobalamin
Where to deficiencies manifest themselves?
In rapidly growing tissues. Skin, tongue, GI tract, fragile tissue in the corner of lips ( cheilitis)
How to Niacin/B3 deficiencies present?
Often in corn based diets. Pellagra. Dermatitis, Diarrhea, Dementia, and Death.
Vitamin B3/Niacin can be what in contrast to the other B vitamins?
Can be produced from tryptophan in a vitamin B6-dependent reaction.
What is required to synthesize vitamin B3/niacin?
- NAD+ (oxidation, glycolysis, TCA)
2. NADPH (fatty acid synthesis, oxidative phosphorylation)
What is Kwashiorkor?
Inadequate nutrition, adequate total calories, deficient in protein. Edema in extremities, distended belly from lack of albumin production.
What is Marasmus?
Inadequate calories with respect to protein and carbohydrates. Overall muscle wasting.
Where do the central metabolic pathways occur?
ETC, and oxidative phosphorylation take place in the mitochondrial membrane.
Glycolysis, pentose phosphate pathway and FA biosynthesis happen in the cytosol of the cell.
Describe the essential role of Folate- B9?
Absorption: Duodenum and jejunum- adversely effected by EtOH
Requirements: no true store- maybe weeks to months
Deficiency markers: hypersegmented neutrophils, elevated homocysteine
Deficiency symptoms: megaloblastic anemia, neural tube defects in pregnancy
DNA synthesis: select forms directly required for dTMP and all purines
Describe the essential role of Colbalamin- B12?
Absorption: terminal ileum (requires R-binders and IF)
Requirements: Liver stores (4-6 years)
Deficiency markers: Hypersegmented neutrophils elevated homocysteine, *ELEVATED METHYL MALONIC ACID
Low serum B12
Deficiency symptoms: megaloblastic anemia *PERIPHERAL NEUROPATHY
DNA synthesis: indirectly required due to methyl trap
Describe the essential role of Pantothenic acid- B5?
Required for beta-oxidation, TCA, Acetyl-CoA formation
Deficiencies are rare due to an abundance in a variety of food sources
Describe the essential role of Thiamin- B1?
Largely in decarboxylation rxns.
Cofactors for: pyruvate dehydrogenase- glycolysis to TCA, alpha-ketogluterate hydrogenase- TCA cycle, alpha-ketoacid dehydrogenase- BCAA and transketolase-PPP
