Plant Hormones and Their Effects

The video tutorial explores the integration of plant systems, focusing on tropisms, which are growth responses to stimuli. It explains positive and negative tropisms, with examples like roots exhibiting positive gravitropism and shoots showing positive phototropism. The role of plant hormones, particularly auxin, in controlling these tropisms is discussed. Auxin's influence on gene expression, cell elongation, and growth is detailed, along with the coordination required for auxin transport. The video also covers other phytohormones like gibberellin and ethylene, highlighting their roles in growth regulation, differentiation, and fruit ripening. Ethylene's function in a positive feedback loop for fruit ripening and its ability to affect nearby plants is explained.

What is a positive tropism?

• Growth away from a stimulus

• Growth towards a stimulus

• Random growth direction

• No growth in response to a stimulus

How do shoots respond to lateral light?

• By growing in random directions

• By stopping growth

• By growing towards the light

• By growing away from the light

What is the primary role of auxin in plants?

• To stop photosynthesis

• To cause leaf fall

• To inhibit growth

• To promote cell division and elongation

How do auxin molecules reach the side of the plant away from the sun?

• Through random diffusion

• By being carried by water

• Via auxin e-lux carriers

• By being absorbed from the soil

What effect does auxin have on the cell wall?

• It has no effect on the cell wall

• It causes the cell wall to elongate

• It causes the cell wall to shrink

• It strengthens the cell wall

Where is auxin primarily produced in a plant?

• In the roots

• In the leaves

• In the shoots

• In the flowers

What is the role of cytokinin in plants?

• To promote root growth

• To inhibit shoot growth

• To promote cell division

• To cause leaf fall

How does ethylene affect fruit ripening?

• It speeds up ripening

• It slows down ripening

• It has no effect on ripening

• It causes fruit to fall off the plant

What is unique about ethylene compared to other phytohormones?

• It is a metal

• It is a gas

• It is a solid

• It is a liquid

Why is seed dispersal important for plants?

• To prevent seed germination

• To avoid competition with offspring

• To ensure seeds grow in the same place

• To increase competition among plants