Biology: Metabolism and Cell Division Notes

Outputs of Glycolysis

• The process of glycolysis results in the production of two molecules of each of the following components:

  • Pyruvic acid: $2$

  • $ATP$: $2$

  • $NADH_2$: $2$

  • $H_2O$ (water): $2$

The Kreb's Cycle (Citric Acid Cycle)

• The Citric Acid Cycle, also known as the Kreb's Cycle, is a series of chemical reactions used by all aerobic organisms to generate energy. The sequence of intermediates and chemical conversions is as follows:

• Entry of Acetyle-co A:

  • Acetyle-co A enters the cycle and combines with Oxalo acetate.

• Intermediates and Transformations:

  • Oxalo acetate to Citric Acid: The combination of Oxalo acetate and Acetyle-co A produces Citric Acid.

  • Citric Acid to Jsocitrave: Citric Acid is converted into Jsocitrave.

  • Jsocitrave to Ketoglutarate: This step involves the release of carbon dioxide ($CO_2$) and the reduction of $NAD$ to $NADH$.

  • Ketoglutarate to Succinyl-CoA: This step also results in the release of carbon dioxide ($CO_2$) and the reduction of $NAD$ to $NADH$.

  • Succinyl-CoA to Succinate: This conversion involves the transformation of $GDP$ to $GTP$, which is eventually used to form $ATP$. During this step, $CoA$ is released.

  • Succinate to Fumarate: This step involves the reduction of $FAD$ to $FADH$.

  • Fumarate to Malate: Water ($H_2O$) is utilized in this transformation.

  • Malate to Oxalo acetate: The cycle completes as Malate is converted back into Oxalo acetate, coinciding with the reduction of $NAD$ to $NADH$.

Mnemonic for Kreb's Cycle Intermediates

• To remember the sequence of the Citric Acid Cycle, the following mnemonic can be utilized:

  • Mnemonic: "All Cute Icecreams Kame successfully to Solapur From Manali On Aeroplane"

• Mnemonic Breakdown:

  • All: Acetyle-co A

  • Cute: Citric Acid

  • Icecreams: Jsocitrave

  • Kame: Ketoglutarate

  • successfully: Succinyl-CoA

  • to Solapur: Succinate

  • From: Fumarate

  • Manali: Malate

  • On Aeroplane: Oxalo acetate

Metabolic Pathway Matching Exercise

• Exercise 1: Glycolysis and Gluconeogenesis

  • Column I:

    1. Glycolysis

    2. Gluconeogenesis

  • Column II:         b. Glucose converted into pyruvic acid         c. Production of glucose from non-carbohydrate sources

  • Answers: (i-b), (ii-c)

Cell Division Matching Exercise

• Exercise 2: Meiosis and Mitosis

  • Column I:

    1. Meiosis

    2. Mitosis

  • Column II (Key Characteristics):         a. Genetic material for repair and growth         c. Genetic variation through crossing over

  • Answers: (i-c), (ii-a)