Metabolism

What is metabolism?

• All the chemical reactions that go on in your body 

• how your body turns food and drink into energy to keep you alive and functioning.

• It’s made up of all the chemical processes happening in your body’s cells every second. These processes help you breathe, move, heal and more. Keeping these processes balanced is called homeostasis.

• It’s what keeps your body running smoothly.

What is anabolism?

• Building small molecules into larger molecules

• Ex: DNA synthesis or replication, protein synthesis 

What is catabolism?

• Breaking down large molecules into smaller ones

• Ex: digestive system, glycolysis, the krebs cycle

What is substrate?

The molecule (s) that is changed by the enzyme 

ex:

•  the enzyme is amylase, so the substrate would be starch

• The enzyme is sucrase is the enzyme that break the substrate              sucrose down

What are enzymes?

• Usually proteins (complicated, delicate, unique 3D structures)

• Biological catalysts (speed up reactions) 

• Reused, after they attack to a substrate they go on the the next one and so on and so forth 

• Usually end in “-ase”

What are some examples of enzymes?

amylase

carbonic anhydrase

maltase

ususally end in “-ase”

What is the enzyme-substrate complex?

• the reactive association formed between an enzyme and its substrate during the enzymatic reaction

• enzyme binding to substrate

• Increasing the temperature generally increases the rate of a reaction, but dramatic changes in temperature and pH can denature an enzyme, thereby abolishing its action as a catalyst.

• substrate binds to an active site and both change shape slightly, creating an ideal fit for catalysis.

• When an enzyme binds its substrate it forms this complex.

• Enzymes promote chemical reactions by bringing substrates together in an optimal orientation, thus creating an ideal chemical environment for the reaction to occur.

• The enzyme will always return to its original state at the completion of the reaction.

What are “enzyme helpers?”

• Cofactor

• Coenzyme

What is cofactor?

• Inorganic minerals

• Ex: Magnesium and calcium

What is coenzyme?

• Organic vitamin

• Ex: Vitamin B₁₂ and folic acid 

What is the active site?

the specific region of an enzyme where a substrate binds and catalysis takes place or where chemical reaction occurs

(insert pic of enzyme susbtrate complex) Enzyme susbstate explanation:

EXAMPLE:

the substrate: sucrose

the enzyme: sucrase

• they fit together at the active site, then at the enzyme substrate complex think of it as a lock and key,

• the substrate(sucrose) is the lock and the enzyme(sucrase) is the key, once this happens where they are locked in with each other we get glucose and fructose as the end product because sucrose + sucrase= glucose and fructose 

All enzymes are proteins, and therefore have….

a distinct 3-D structure

What is denaturation?

• a process that alters a protein's native conformation, typically due to changes in environmental conditions such as temperature, pH, or chemical exposure.

• Importantly, it affects the protein's secondary, tertiary, or quaternary structure, but not its primary sequence.

What are some factors that can cause denaturation?

• temperature: elevated temps

• pH changes

• chemical changes: example, Urea can disrupt hydrogen bonding and hydrophobic interactions, leading to protein denaturation

Identify this:

• loss, of H or e-

• Less potential energy

oxidation

Identify this:

• gain, of H or e-

• More potential energy

reduction

Which means gain, oxidation or reduction?

reduction does

Which has more potential energy, oxidation or reduction?

potential energy:

reduction

Which means loss, oxidation or reduction

oxidation does

Which has less potential energy, oxidation or reduction?

potential energy:

Oxidation 

Glucose comparison, reduced to oxidized

reduced: C6H12O6 —> CO₂ oxidized 

Niacin comparaison, reduced to oxidized

reduced: NADH → NAD oxidized 

What energy form used by the cell frequently is what?

ATP

• adult human turnover of ATP is 75 to 150 kg per day!!!

Write a reversible reaction that shows energy comes from ATP:

ATP + H2O → ADP + Pi + free energy.

Give the balanced reaction for cellular respiration (or the complete oxidation of glucose)

C₆H₁₂O₆ + 6O₂ → 6 CO₂+ 6H₂O + 38 ATP

“fuel” “exhaust” “energy”

What is glycolysis? 

• a series of reactions that extract energy from glucose by splitting it into two three-carbon molecules called pyruvates

• Glucose broken down into pyruvic acid

Where in the cell does glycolysis take place?

In the cytoplasm

What is the beginning reactant in glycolysis?

glucose

What are the three main products in glycoysis?

• 2ATP,

• 2NADH

• 2 pyruvic acids/ pyruvate

Is glycolysis aerobic(requires O₂) or anaerobic(doesnt require O₂)?

anaerobic

What is the intermediate step?

• conversion of pyruvate to acetyl CoA.

  • 2 pryuvic acid from gycolysis —> Acetly-coenzyme A

What is the reactant in the intermediate step?

2 Pyruvic acids

What are the 3 main products in the intermediate step?

• 2 NADH

• 2 CO₂

• 2 Acetyl-coenzyme A 

What is the krebs cycle(citric acid cycle)?

takes acetyl-CoA—produced by the oxidation of pyruvate and originally derived from glucose—as its starting material and, in a series of redox reactions, harvests much of its bond energy in the form of NADH, FADH₂ , and ATP molecules.

The reduced electron carriers NADH and FADH₂—generated in the TCA cycle will pass their electrons into the electron transport chain and, through oxidative phosphorylation, will generate most of the ATP produced in cellular respiration.

Where does the krebs cycle take place?

in mitochondria, in the matrix

What is the beginning reactant in the krebs cycle?

2 acetyl coenzyme A

What are the four main products in the krebs cycle?

• 2ATP

• 6NADH 

• 2FADH2

• 4 CO2 

What is the electron transport chain?`

• a series of four protein complexes that couple redox reactions, creating an electrochemical gradient that leads to the creation of ATP in a complete system named oxidative phosphorylation. 
  

• In the former, the electrons come from breaking down organic molecules, and energy is released. In the latter, the electrons enter the chain after being excited by light, and the energy released is use

• a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH₂ to molecular oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.

Where does the electron transport chain take place?

Mitochondria cristae

What are the beggining reactants of Electron transport chain?

• NADH

• FADH2

• O₂

What are the products of the electron transport chain?

• ATP

• H2O

How many ATP molecules are produced from one NADH+ in the presence of O2?

3 ATP

How many ATP molecules are produced from one FADH₂ in the presence of O₂?

2 ATP

Is the electron transport chain aerobic or anaerobic?

Aerobic, because it requires O₂

What is the final electron acceptor in the electron transport chain?

oxygen

Aerobic respiration includes the Krebs cycle and the electron transport chain why?

If acetyl coenzyme A goes into krebs cycle, it’s irreversible, goes through the electron transport chain

Where do the 38 ATP come from, in the electron transport chain?

Glycolysis

• 2 ATP (energy)

• 2 NADH (potential energy), goes into Electron transport chain, and when they go in it makes 6 ATP

Intermediate step

• 2 NADH (potential energy), goes into electron transport chain, we get 6 ATP

Krebs cycle

• 2 ATP (energy)

• 6 NADH (potential energy), goes into electron transport chain we get 18 ATP

• 2 FADH₂ (potential energy), goes into electron transport chain we get  4 ATP

ADD all of these up we get 34 ATP

How many ATP do we get from glycolysis?

• 2 ATP

• 6 ATP from NADH

  • 8 in total

How many ATP do we get from intermediate step?

6 ATP from NADH

How many ATP do we get from Krebs cycle:

• 2 ATP

• 18 from NADH

• 4 from FADH

  • 24 in total

What is fermentation?

• chemical process by which molecules such as glucose are broken down anaerobically.

• Anerobic, no O₂ involved 

• No ATP produced (2 ATP come from glycolysis)

• a biological process where microorganisms, such as yeasts, bacteria, and molds, convert carbohydrates like starch and sugars into simpler substances, including alcohols, acids, and gases.

What kind of cells usually undergo fermentation?

• Propionibacterium

• Aspergillus lactobacillus streptococcus 

• Saccaromyces

• Clostridium

• Escherichia acetobacter 

• Bacterias

• yeast

What is produced when our cells undergo fermentation?

lactic acid

Is fermentation aerobic or anaerobic?

Anaerobic 

How many ATPs are produced in fermentation?

Produces none, 2 ATP come from glycolysis 

Fermintation in skeletal muscles:

Starts w glucose → glycolysis happens → 2 Pyruvic acid → Lactic acid is the product 

• Happens when we run out of oxygen, lactic acid builds up and our muscles fer fatigues and sore

• Lactic acid goes to the liver to be converted back to glucose 

Anabolism/ anabolic pathways:

• Monosacharides (glucose/ fructose/ galactose)

  • Glycogenesis 

• glycerol and fatty acids —> triglycerides (fats)

• amino acids —> proteins

what are things produced in anabolic pathways of monosaccharides?

• glucose

• fructose

• galactose

List one thing produced in anabolic pathways of fatty acids and glycerol

triglycerides (fats)

List one thing produced in anabolic pathways of amino acids:

proteins

Catabolism/Catabolic pathways, in general what is produced?

• ATP (mainly)

• H₂O

• CO₂ (waste)

What are the “G words”

• Glycogenesis

• Glycogenolysis

• Gluconeogenesis

Glycogenesis: 

Makes glycogen

• Hyperglycemia, high blood sugar

  • Hormone: insulin controls blood sugar 

    • Beta cells release insulin

Glycogenolysis:

Break down glycogen

• Hypoglycemia: Blood sugar is low, Havent eaten for a few hours causes this

  • Hormone: glucagon brings Blood sugar up

    • Alpha cells release glucagon

  • Works if you have stored glycogen

Gluconoegenesis:

Making glucose from noncarbs(proteins/fats)

• Hypogycemia: Blood sugar is low

  • No glycogen stores

  • Hormone: glucagon brings Blood sugar up

What is an essential nutrient?

• Needed in diet

• We cannot make them

List the six classes of nutrients:

• Carbohydrate, 4 cal/gram

• Protein, 4 cal/gram

• Lipid, : 9 cal/gram

• Water: 0 cal/gram

  • solvent/transport/temp. regulation

• Vitamins: 0 cal/gram

  • organic enzyme helpers

• Mineral: 0 cal/ gram

  • inorganic enzyme helpers

Fats have about 2X the energy as carbohydrates and proteins per gram; efficient way to store energy. Why do they have more Calories/ energy?

• Fatty acids- lots of Hydrgogen, highly reduced (more energy)

• Lipids are made up of 3 fatty acids and glycerol 

• Lots of carbon and hydrogen

Ketosis:

• 2 glycerol made into glucose

• normally fatty acid is hard to break down

• 2 carbons as acetly CoA → into krebs cycle, if lots of fatty acids are breaking down, we get ketones 

What is ketosis?

1. Primary source of energy in the body is carbs.

2. Carbs are broken down into glucose for immediate energy or glycogen for future energy

3. When glucose is not available as an energy source your body turns to fat as primary fuel soure

4. Fat gets broken down into glucose and ketones are produced as a byproducts.

5. Body useses ketones as alternative fuel source

6. When body is getting duel from ketones, you are in a state of ketosis 

What pathway is ketosis associated with?

Ketosis can be achieved by and what is it?

• Achieved by: Low carb dieting

• Small amt of ketones in blood

• Not dangerous 

Ketacidosis:

• Dangerously high levels of ketones in blood

• Can cause death

• Generally occurs in diabetics or ppl who are starving/sick

When would ketosis happen?

• Low carb diet/ Low calorie diet- ketosis 

• Uncontrolled diabetes 

• Starving

• Digestive diarrhea

• Vomiting 

• Ketoacidosis 

Deamination:

• the removal of an amino acid group form a molecule

  • amino acid group converted to ammonia while the amino acid itself converts into its corresponding keto acid

• Happens when we have protein catabolism

  • We must remove amine groups (nitrogen waste)

When would deamintation happen?

• when we have protein catabolism- burning muscles/ eating high proteins

Eating a high protein diet is hard on what organs?

liver and kidneys