Multicellular Systems - Molecular Theory of the Living Cell - page 517

Table 15.2 The triadic control principle or mechanism applied to five levels of biological organization
Level Production X Degradation Control Function

Conformational strains a of
biopolymers (Chap. 8 )

1. Subcellular Substrate binding, chemical

reactions

Molecular work
processes (e.g.,
catalysis, active
transport)

Evolutionary information
encoded in biopolymers
(Sect. 11.3.3 )

Time- and space-organized
molecular processes
(e.g., active transport,
gene expression)

Transcript-ion
(transcriptosome)

RNAs (Chap. 12 ) Transcript degradation

(degradosome)

Biochemical signals (e.g.,
ATP, transcription
factors, miRNAs)

Controlling metabolic activities
(e.g., glycolysis, respiration,
cell cycle, morphogenesis)

Phosphorylation (kinases) Phosphoproteins (e.g.,

activated enzymes)

Dephosphorylation
(phosphatases)

Biochemical signals (e.g.,
cholesterol, cAMP,
ATP)

Cell type-specific cell functions
(production of key
metabolites)

2. Cellular Mitosis Cells Apoptosis Intercellular messengers Morphogenesis, organogenesis,

carcinogenesis

3. Tissue Blood inflow Tissue blood content Blood outflow Hormones, nerve signals Tissue-specific activities

(e.g., brain activity)

4. Organ
(e.g., blood)

Activation (e.g., by
proteolysis)

Activated coagulation
factors

Inactivation (by
proteolysis, protein
phosphatases)

Biochemical signals (e.g.,
from ruptured vessels)

Homeostasis of organ function
(e.g., prevention of blood
loss, i.e., hemostasis)

5. Body Vasoconstriction,

"

Blood pressure Vasodilation

#

Renin, angiotensin,
aldosterone

Homeostasis of body perfusion
(microcirculation) cardiac output cardiac output

Activation (e.g., pleasurable
stimuli)

Reward system activity Deactivation (e.g.,

painful stimuli)

Habit, will To promote the survival of

individuals and species

a Also called conformons (Chap. 8 )