BIOL 1406 Info for Test 2: Cellular Metabolism and Cell Respiration

Flashcards covering key concepts of cellular metabolism and cell respiration from BIOL 1406 lecture notes, including definitions of metabolic processes, enzymes, cellular respiration stages, and related pathways like fermentation and ketosis.

Metabolism

All of chemical reactions in the body

Anabolism

Building small molecules into larger molecules ex: DNA synthesis

Catabolism

Breaking down large molecules into smaller ones

ex: Digestive system, glycolysis, the Krebs cycle

Enzyme

• Usually Proteins: Complicated, delicate unique 3d structures

• Biological catalysts

• Reused

• end in -ase

Substrate

Molecule that is changed by the enzyme

Enzyme-substrate complex

molecule formed when an enzyme binds specifically to its substrate

Active site

region on an enzyme where a substrate binds and where catalysis takes place

Cofactor

Enzyme helper: Inorganic minerals

Ex: calcium & magnesium

Coenzyme

Enzyme helper: Organic vitamin

Ex: Vitamin B12 & Folic acid

Denaturation

process where proteins lose their 3D structure,

causes loss of biological activity

Factors causing denaturation

High heat and extreme pH levels

ATP (Adenosine Triphosphate)

The primary energy of the cell, providing energy for most cellular processes through its hydrolysis.

ATP hydrolysis reaction

A reversible reaction that shows energy coming from ATP:

• ATP + H2O ⇌ ADP + Pi + Energy.

Balanced reaction for cellular respiration

The complete oxidation of glucose:

• C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy (ATP + Heat).

Glycolysis

Breaks down one glucose into two pyruvates, yielding ATP and NADH

Glycolysis location

Cytosol of the cell

Products of glycolysis

2 pyruvate molecules, 2 net ATP, and 2 NADH molecules

Oxygen requirement for glycolysis

Doesn’t need O2 it is an anaerobic process

Intermediate step (Pyruvate Oxidation)

Pyruvate is converted to acetyl-CoA before the Krebs cycle.

Products of the intermediate step

For each pyruvate, one acetyl-CoA, one CO2, and one NADH are produced

Krebs cycle

A central metabolic pathway that completes the breakdown of glucose derivatives, generating ATP, NADH, FADH2, and CO2.

Krebs cycle location

mitochondrial matrix in eukaryotes.

Products of the Krebs cycle (per glucose molecule)

After two turns, 6 NADH, 2 FADH2, 2 ATP, and 4 CO2 molecules are produced.

Electron transport chain (ETC)

a series of protein complexes in the inner mitochondrial membrane that transfers electrons from NADH and FADH2 to oxygen

ETC location

inner mitochondrial membrane in eukaryotes

Products of the ETC

ATP, and water

Oxygen requirement for ETC

 requires oxygen, making it an aerobic process.

Net ATP from Glycolysis

2 net ATP molecules are produced

Net ATP from Krebs Cycle

2 ATP (or GTP) molecules are produced

Net ATP from Electron Transport Chain

approximately 26-28 ATP.

ATP produced from one NADH (aerobic)

Approximately 2.5 ATP in the presence of O2.

ATP produced from one FADH2 (aerobic)

Approximately 1.5 ATP in the presence of O2.

Fermentation

process that regenerates NAD+ from NADH, lets glycolysis continue and produce a small amount of ATP without oxygen.

Cells undergoing fermentation

Some bacteria, yeast, and muscle cells often undergo fermentation

Oxygen requirement for fermentation

Fermentation is an anaerobic process; it does not require O2.

ATP produced in fermentation

2 ATP molecules

Common products of fermentation

Lactic acid, ethanol, carbon dioxide, and acetic acid

Anabolic pathways of monosaccharides

are metabolic routes that convert simple sugars into more complex molecules, such as polysaccharides or nucleic acids, requiring energy in the form of ATP.

Anabolic pathways of fatty acids, glycerol, and amino acids

Fatty acids and glycerol can form fats (triglycerides); amino acids can form proteins.

General products of catabolic pathways

produce ATP (energy), CO2, H2O, and metabolic intermediates.

Ketosis

a metabolic state where your body uses fat for fuel instead of carbohydrates, a process that generates ketones

Pathway associated with Ketosis

Ketosis is associated with the catabolism of fatty acids (beta-oxidation) and amino acids, especially during prolonged fasting or low-carb diets.

Likely to exhibit ketosis

Individuals on very low-carbohydrate (ketogenic) diets, those in starvation, or people with uncontrolled type 1 diabetes

Symptoms of Ketosis

Symptoms can include nausea, headache, altered mental status, and a fruity breath odor (due to acetone), potentially leading to diabetic ketoacidosis.

Deamination

The removal of an amino group (-NH2) from an amino acid or other compound, typically occurring during amino acid catabolism.

Pathway associated with deamination

associated with the catabolism of amino acids, especially when they are used for energy or converted to glucose/fat.

Fate of deaminated portion

The carbon skeleton (alpha-keto acid) of the deaminated amino acid can enter the Krebs cycle, be converted to pyruvate, or be used to synthesize glucose or fatty acids.

Fate of -NH2 portion (amino group)

The -NH2 portion is converted to ammonia (NH3), which is then typically transformed into urea in the liver (in mammals) and excreted by the kidneys.

Energy density of fats

9 kcal/gram, about twice the energy per gram compared to carbohydrates and proteins, making them an efficient way to store energy.

Organic Compound: Carbohydrates

Building blocks: Monosaccharides (e.g., glucose, fructose).

Organic Compound: Lipids

Building blocks: Fatty acids and glycerol (for triglycerides); steroid nucleus (for steroids).

Organic Compound: Proteins

Building blocks: Amino acids.

Organic Compound: Nucleic acids

Building blocks: Nucleotides.

Catabolism of nucleic acids

The breakdown of DNA and RNA into their nucleotides, which are further broken down.

Products of nucleic acid catabolism

Nitrogenous bases (e.g., purines like adenine and guanine lead to uric acid, pyrimidines), pentose sugars, and phosphate groups.