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TLS Online TPP Program

#Question id: 12836

The final layer of control that is critical in the regulation of CDKs is a family of proteins known as CDK inhibitors, or CKIs, which bind directly to the cyclin-CDK complex and inhibit its activity. Which of the following function not done by CKIs?

#Unit 2. Cellular Organization
  1. Binding of INK4s to CDK4 and CDK6 blocks their interaction with cyclin D and hence their protein kinase activity. 
  2. p27 prevents the premature activation of S phase CDKs during G1.
  3. p21CIP plays an important role in the response of metazoan cells to DNA damage by inhibiting G1/S phase CDKs and S phase CDKs, and thereby blocking entry into or passage through S phase.
  4. During ongoing DNA replication and in response to replication stress (slow DNA replication fork movement or DNA replication fork collapse), the ATR-Chk1 protein kinase cascade phosphorylates and inactivates Cdc25C, thereby preventing the activation of mitotic CDKs and inhibiting entry into mitosis.
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TLS Online TPP Program

#Question id: 10793

#Unit 6. System Physiology – Plant

Hydroxyl groups (−OH),  and methoxy groups(−OCH3) modification provides colour variations in case of
TLS Online TPP Program

#Question id: 10794

#Unit 6. System Physiology – Plant

Which one of the following characteristics of about lignin is incorrect?
TLS Online TPP Program

#Question id: 10795

#Unit 6. System Physiology – Plant

basic carbon skeleton of a flavonoid contains 15 carbons arranged in two aromatic rings connected by a three-carbon bridge. This structure results from two separate biosynthetic pathways:
TLS Online TPP Program

#Question id: 10796

#Unit 6. System Physiology – Plant

Flavonoids are one of the largest classes of plant phenolics, structure of flavonoids;
TLS Online TPP Program

#Question id: 10797

#Unit 6. System Physiology – Plant

The colored pigments of plants are of two principal types: carotenoids and flavonoids. Given below some statements of about these pigments;

 a) Anthocyanins are colored flavonoids that attract animals

b) Flavonoids are phenolic compounds that include a wide range of colored substances

c) Carotenoids are coloured terpenoid compounds that also serve as accessory pigments in photosynthesis

d) most widespread group of pigmented carotenoids is the anthocyanins, these are glycosides that have sugars. Without their sugars, anthocyanins are known as anthocyanidins

Which of the following is incorrect statements of these pigments;
TLS Online TPP Program

#Question id: 10798

#Unit 6. System Physiology – Plant

Two other major groups of flavonoids found in flowers and leaves of all green plants. The function of these two flavonoids in plants are____

a) protect plants against being eaten by herbivores and against being infected by microbial pathogens

b) Protect cells from excessive UV-B radiation (280–320 nm) because they accumulate in the epidermal layers of leaves and stems and absorb light strongly in the UV-B region       

c) flavones and flavonols secreted into the soil by legume roots mediate the interaction of legumes and nitrogen-fixing symbionts

d) They are are coloured terpenoid compounds that also serve as accessory pigments in photosynthesis    

Which of the following combination from the above statements is correct?