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Counting and Clock-Keeping in Biology: Telomeres, Bud Scar Counting, and Circadian Rhythms

This article explores various mechanisms of counting and clock-keeping in biology, including telomeres and their role in cell divisions, bud scar counting as a method to determine age in plants, and the importance of circadian rhythms in regulating various physiological processes.

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Counting and Clock-Keeping in Biology: Telomeres, Bud Scar Counting, and Circadian Rhythms

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  1. and a 1, and a 2… Examples of counting and clock-keeping in biology N Kuldell for 20.020(S09) 02.19.09

  2. And a 1: telomeres (TTAGGG)n

  3. And a 1: telomeres (TTAGGG)n

  4. 3’ Telomeric DNA with overhanging 3’ end 5’ Telomerase and telomerase RNA bind overhang

  5. 3’ Telomeric DNA with overhanging 3’ end 5’ Telomerase and telomerase RNA bind overhang

  6. Counting Cell Divisions with Telomere Repeats Cell type Telomerase Telomere length Normal Somatic OFF shortens

  7. Counting Cell Divisions with Telomere Repeats Cell type Telomerase Telomere length Normal Somatic OFF shortens Cancerous ON forever stable

  8. “Astragaloside IV, found in minute traces in Astragalus Membranaceus extract, is known to turn this gene on and 'activate' telomerase.

  9. And a 2: bud scar counting http://organelleview.lsi.umich.edu/orgview2/

  10. And a 2: bud scar counting Annu. Rev. Biochem (1998) 67:307

  11. And a 2: bud scar counting Annu. Rev. Biochem (1998) 67:307 Microbiology (2003)149:3129

  12. Electronics: van der Pol oscillator L = inductor C = capacitor V = vacuum tube containing a tetrode I = voltage supply And a 3: circadian rhythms Oscillation of alertness, sleep, hormone production, body temperature and organ function

  13. And a 3: circadian rhythms Oscillation of alertness, sleep, hormone production, body temperature and organ function Hydraulic Model Negative feedback loop >>water flows into B then through T1 into A and out through T4 >>level of A connected to T3 and T2 which drain A as level rises

  14. And a 3: circadian rhythms Oscillation of alertness, sleep, hormone production, body temperature and organ function Molecular clocks: transcriptional-translational feedback >>RNA is made >>turns protein production on >>protein turns off RNA production >>absence of RNA turns off protein production

  15. and a 1, and a 2, and a 3

  16. the end

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