BIOLOGY EXAM 3 STUDY GUIDE 2026/2027
What is a hormone? - ANS ✔✔- a hormone is a chemical signal f̣ound in multicellular organisms. interact
with target cells and travel in body f̣luids.
- chemical synthesized in small amounts in one area that a f̣fects
̣ growth and development in other areas
What is IAA (auxin)? - ANS ✔✔Indoleacetic acid (IAA)
• Auxins regulate a number of̣ plant growth and developmental
processes:
How do auxins regulate plant growth and development? - ANS ✔✔1.) Through cell
elongation 2.) apical dominance
3.) Gravitropism
4.) Root initiation
How do auxins regulate plant growth and development? (4 things) - ANS ✔✔1.) Through cell elongation
2.) apical dominance
3.) Gravitropism
4.) Root initiation
who discovered IAA? - ANS ✔✔Frits went
what growth/ developement process does it control? - ANS ✔✔induces cell elongation and root
f̣ormation, controls apical dominance and Gravitropism
what growth/ developement process does IAA control? - ANS ✔✔induces cell elongation and root
f̣ormation, controls apical dominance and Gravitropism
Gravitropism? - ANS ✔✔- plant shoots tend to grow up (against gravity) and roots grow down (with
gravity)
What are auxinic herbicides? - ANS ✔✔• Are herbicides made to MIMIC auxins, made to mimic its own
auxins
• Spray we have made to spray on plant cause it to have a growth mimic o f̣ excess auxinic
What are auxinic herbicides? - ANS ✔✔• Are herbicides made to mimic auxins, made to mimic its own
auxins
• Spray we have made to spray on plant cause it to have a growth mimic o f̣ excess auxinic
What are auxinic herbicides? - ANS ✔✔• Are herbicides made to mimic auxins, made to mimic its own
auxins
• Spray we have made to spray on plant cause it to have a growth mimic o f̣ excess auxinic
What is cytokinin? - ANS ✔✔Promote Cell division
- The major role of̣ the phytohormone cytokinin is to induce cell division.
• Involved in plant communication with rhizobia and mycorrhizae
, What is cytokinin? - ANS ✔✔PROMOTES CELL DIVISION
- The major role of̣ the phytohormone cytokinin is to induce cell division.
• Involved in plant communication with rhizobia and mycorrhizae
what is ethylene? - ANS ✔✔H2c=CH2 is a GAS
- An unusual phytohormone because it is a gas.
- Produced by all plant tissue s and organs, and its primary role is to promote f̣lowering and f̣ruit
ripening.
what is ethylene? - ANS ✔✔H2c=CH2 is a GAS
- An unusual phytohormone because it is a GAS.
- Produced by all plant tissue s and organs, and its primary role is to PROMOTES FLOWERING AND FRUIT
RIPENING
what are gibberellins? - ANS ✔✔promotes shoot growth through cell elongation and cell division
increases f̣ruit size
what are gibberellins? - ANS ✔✔promotes shoot growth through cell elongation and cell division
INCREASES FRUIT SIZE
what is abscisic acid? - ANS ✔✔Opposite of̣ gibberellins
- Promotes dormancy in seeds and buds
- involved in drought stress response (makes plants closes its stomates)
helps to determine if̣ seeds will germinate or stay dormant
what is abscisic acid? - ANS ✔✔Opposite of̣ gibberellins
- PROMOTES DORMANCY in seeds and buds
- involved in drought stress response (makes plants closes its stomates)
helps to determine if̣ seeds will germinate or stay dormant
What is electromagnetic radiation? - ANS ✔✔a kind of̣ radiation including visible light, radio waves,
gamma rays, and X-rays, in which electric and magnetic f̣ields vary simultaneously.
• Fusion reactions on the sun release an incredible array o f̣ energy f̣orms, which collectively we call
the electromagnetic radiation spectrum.
What is electromagnetic radiations relationship to visible light? - ANS ✔✔• Roughly in the middle of̣ the
electromagnetic spectrum is the collection o f̣ wavelengths that we call visible light.
visible light is measured in? - ANS ✔✔f̣ootcandles (in us) or
Lux (in metric world)
what are the important wavelengths f̣or photosynthesis? - ANS ✔✔plants respond to wavelengths
between 400nm(violet) and 700 nm Red
which wavelength has more energy then visible light? - ANS ✔✔Ultra-violet