©THEBRIGHTSTARS 2024
EEB 162 Lecture 15 – Auxins Exam
Questions With Correct Answers
*What are the 5 classical plant growth regulators (hormones)? - answer✔1) Auxin
2) Gibberellins
3) Cytokinins
4) Ethylene
5) Abscisic acid (ABA)
Why is auxin required in plants? - answer✔- Auxin, with cytokinin, is required for viability
- No mutants lacking either auxin or cytokinin have been found
*What are the "stress" hormones"? - answer✔Abscisic acid
Ethylene
Jasmonic acid
How was auxin response first discovered? - answer✔- Darwin and his pointed to an auxin
response (phototropism of the grass coleoptile)
- Coleoptile will grow towards the light, but if it's covered, this response is blocked
- Concluded that there was a signal that was produced in the tip and moved to the growth zone
How was auxin finally acquired? - answer✔- Went showed that a chemical could be collected
from coleoptiles → causes bending in the absence of light
- Substance was named auxin ("to grow" in Greek)
What is auxin's chemical identity? - answer✔*Indole-3-acetic acid (IAA)*
Most abundant and physiologically important
In which parts of the plant is IAA biosynthesis observed? - answer✔- Associated with rapidly
dividing and growing tissues, especially shoots
EEB 162 Lecture 15 – Auxins Exam
Questions With Correct Answers
*What are the 5 classical plant growth regulators (hormones)? - answer✔1) Auxin
2) Gibberellins
3) Cytokinins
4) Ethylene
5) Abscisic acid (ABA)
Why is auxin required in plants? - answer✔- Auxin, with cytokinin, is required for viability
- No mutants lacking either auxin or cytokinin have been found
*What are the "stress" hormones"? - answer✔Abscisic acid
Ethylene
Jasmonic acid
How was auxin response first discovered? - answer✔- Darwin and his pointed to an auxin
response (phototropism of the grass coleoptile)
- Coleoptile will grow towards the light, but if it's covered, this response is blocked
- Concluded that there was a signal that was produced in the tip and moved to the growth zone
How was auxin finally acquired? - answer✔- Went showed that a chemical could be collected
from coleoptiles → causes bending in the absence of light
- Substance was named auxin ("to grow" in Greek)
What is auxin's chemical identity? - answer✔*Indole-3-acetic acid (IAA)*
Most abundant and physiologically important
In which parts of the plant is IAA biosynthesis observed? - answer✔- Associated with rapidly
dividing and growing tissues, especially shoots
