Phyllotaxy

This is usually are of four types – alternate, opposite, spiral and whorled

In alternate type of phyllotaxy, a single leaf arises at each node in alternate manner, as in china rose, mustard and sunflower plants

Phyllotaxy

In opposite type, a pair of leaves arise at each node and lie opposite to each other as in Calotropis and guava plants.

If more than two leaves arise at a node and form a whorl, it is called whorled, as in Alstonia (Devil Tree) Apocynaceae

Spiral phyllotaxy

Fibonacci sequence

Golden Angle

the divergence angle between successively arising leaves is fixed at the golden angle of 137.5°

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#Id: 8898

#XL - R Botany

If Amphitelic attachment occur  Microtubules pull kinetochores; cohesins resist this pulling force. The resulting tension leads to the outer kinetochore component Ndc80 being pulled away from the protein kinase Aurora B

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#XL - R Botany

According to the guard hypothesis, R gene products “guard” cellular proteins, which are called guardees or decoys

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#XL - Q Biochemistry

In mammalian cells, Rab5 protein (early endosomes) and its effector protein known as EEA1 (early endosome antigen 1)

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#XL - T Zoology

Activated Ste11 then phosphorylates Ste7, a dual-specificity MEK.

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#XL - T Zoology

Adaptation is a characteristic that enhances the survival or reproduction of organisms .

Adaptations have evolved by natural selection, which is the centerpiece of On the Origin of Species