Cytokinesis

With the exception of higher plants, the division of the cell is brought about by a contractile ring made of actin and myosin

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#Id: 2334

#Unit 3. Fundamental Processes

The E. coli rrn  promoters are also regulated by a pair of small molecules: the initiating NTP (the iNTP) and an alarmone,  guanosine 5 -diphosphate 3-diphosphate (ppGpp). 

1. An abundance of iNTP indicates that the concentration of  nucleotides is high, and therefore it is appropriate to synthesize plenty of rRNA. 

2. Accordingly, iNTP stabilizes the open promoter complex, stimulating transcription. 

3. On the other hand, when cells are starved for amino acids, protein synthesis cannot occur readily and the need for ribosomes (and rRNA) decreases. 

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#Id: 1031

#Unit 5. Developmental Biology

In secondary neurulation, 

the neural tube arises from the aggregation of mesenchyme cells into a solid cord that subsequently forms cavities that coalesce to create a hollow tube.

 

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#Id: 7400

#Unit 5. Developmental Biology

GD cleaves Snake to its active form and forms a complex with Snake and uncleaved Easter proteins.

Easter protein is cleaved into its

active form.

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#Id: 9730

#Unit 6. System Physiology – Plant

Conifer resin ducts produces bicyclic monoterpenes such as a-pinene and b-pinene, monocyclic terpenes like limonene and terpinolene, and tricyclic sesquiterpenes, including longifolene, caryophyllene, and d-cadinene, as well as resin acids, which are released immediately upon damage by herbivores

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#Id: 3331

#Unit 3. Fundamental Processes

TFIIH is responsible for two separate functions: 

Its strand-separating helicases melt the DNA around a lesion during nucleotide excision repair (including transcription-coupled repair) and also help to open the DNA template during the process of gene transcription.