BIO 162 LAB PRACTICAL 2 DISCUSSION
EXAM QUESTIONS AND ANSWERS
GRADED A+ 2025/2026
Which signal is stronger in plants, gravitropism or phototropism? - ANS Gravitropism
How do the different phototropic and gravitropic responses make sense from a functional
standpoint of the plant organs (i.e. stems, roots, leaves)? - ANS Leaves- Negative gravitropism
and Positive phototropism to get more sunlight for photosynthesis
Roots- Positive gravitropism and Negative Phototropism to get deeper into the soil to find more
nutrients and keep from being dried out by the sun
Stems- Negative gravitropism and Positive phototropism to grow taller to get more sunlight and
get more sunlight to the leaves.
Research what is occurring when the temperature or photoperiod changes. - ANS cytokinine,
auxin, ehtylene
- Temp, and photoperiod are variables that can cause leaf senescence
-Ethylene breaks down walls at abscission zone
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Suppose testosterone regulation suddenly switched from negative to positive feedback. Draw a
graph that shows how testosterone levels would look over time. - ANS Testosterone levels
will start to inhibit your immune system and testes would shrink. Upward positive slope.
What is the main anatomical difference between the anterior and posterior pituitary glands?
What is the main functional difference? - ANS *anterior*(pink): endocrine tissue, makes own
hormones
*posterior*(white): neural tissue, connected to the hypothalamus (axon terminals located in
posterior)
What is the functional connection between the interstitial cells and the developing sperm cells
in the testis? - ANS Interstitial cells or Leydig cells create testosterone and secrete it to the
seminiferous tubules, which hold maturing sperm.
Chronic stress can results in very high levels of cortisol. The hypothalamus and anterior pituitary
stop responding to these levels of cortisol through negative feedback, and as a result cortisol
levels can stay high. Explain the effect this might have on the strength of the immune response
in chronically stressed animals - ANS If cortisol is present in the blood for long times, the
body develops a resistance to cortisol and does not respond to it properly. Instead, it ramps up
the production of substances that actually promote inflammation leading to a state of chronic
inflammation. The prop-inflammaation substances, called cytokines are associated with a host
of chronic inflammatory and autoimmune conditions
Some bodybuilders abuse anabolic steroids like testosterone. What effects would this have on
the size of the testes? Explain. - ANS It would cause the testes to decrease in size bc of
negative feedback- signals would be sent to testes to stop producing testosterone(decreasing
the size)
Which part of celery, onion and carrot is modified? Modified for what purpose? - ANS Carrot-
modified root
Celery-modified stem (petiole)
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
EXAM QUESTIONS AND ANSWERS
GRADED A+ 2025/2026
Which signal is stronger in plants, gravitropism or phototropism? - ANS Gravitropism
How do the different phototropic and gravitropic responses make sense from a functional
standpoint of the plant organs (i.e. stems, roots, leaves)? - ANS Leaves- Negative gravitropism
and Positive phototropism to get more sunlight for photosynthesis
Roots- Positive gravitropism and Negative Phototropism to get deeper into the soil to find more
nutrients and keep from being dried out by the sun
Stems- Negative gravitropism and Positive phototropism to grow taller to get more sunlight and
get more sunlight to the leaves.
Research what is occurring when the temperature or photoperiod changes. - ANS cytokinine,
auxin, ehtylene
- Temp, and photoperiod are variables that can cause leaf senescence
-Ethylene breaks down walls at abscission zone
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Suppose testosterone regulation suddenly switched from negative to positive feedback. Draw a
graph that shows how testosterone levels would look over time. - ANS Testosterone levels
will start to inhibit your immune system and testes would shrink. Upward positive slope.
What is the main anatomical difference between the anterior and posterior pituitary glands?
What is the main functional difference? - ANS *anterior*(pink): endocrine tissue, makes own
hormones
*posterior*(white): neural tissue, connected to the hypothalamus (axon terminals located in
posterior)
What is the functional connection between the interstitial cells and the developing sperm cells
in the testis? - ANS Interstitial cells or Leydig cells create testosterone and secrete it to the
seminiferous tubules, which hold maturing sperm.
Chronic stress can results in very high levels of cortisol. The hypothalamus and anterior pituitary
stop responding to these levels of cortisol through negative feedback, and as a result cortisol
levels can stay high. Explain the effect this might have on the strength of the immune response
in chronically stressed animals - ANS If cortisol is present in the blood for long times, the
body develops a resistance to cortisol and does not respond to it properly. Instead, it ramps up
the production of substances that actually promote inflammation leading to a state of chronic
inflammation. The prop-inflammaation substances, called cytokines are associated with a host
of chronic inflammatory and autoimmune conditions
Some bodybuilders abuse anabolic steroids like testosterone. What effects would this have on
the size of the testes? Explain. - ANS It would cause the testes to decrease in size bc of
negative feedback- signals would be sent to testes to stop producing testosterone(decreasing
the size)
Which part of celery, onion and carrot is modified? Modified for what purpose? - ANS Carrot-
modified root
Celery-modified stem (petiole)
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
