BIO 162 LAB PRACTICAL 2 DISCUSSION QUESTIONS.
From question to perfection| Study with confidence!
Which signal is stronger in plants, gravitropism or phototropism? - Answer: Gravitropism
How do the different phototropic and gravitropic responses make sense from a functional
standpoint of the plant organs (i.e. stems, roots, leaves)? - Answer: 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. - Answer:
cytokinine, auxin, ehtylene
- Temp, and photoperiod are variables that can cause leaf senescence
-Ethylene breaks down walls at abscission zone
Suppose testosterone regulation suddenly switched from negative to positive feedback.
Draw a graph that shows how testosterone levels would look over time. - Answer:
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? - Answer: *anterior*(pink): endocrine
tissue, makes own hormones
*posterior*(white): neural tissue, connected to the hypothalamus (axon terminals located
in posterior)
APPHIA – Crafted with Care and Precision for Academic Excellence. 1
, What is the functional connection between the interstitial cells and the developing sperm
cells in the testis? - Answer: 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 - Answer: 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. - Answer: 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? - Answer:
Carrot- modified root
Celery-modified stem (petiole)
Onion- modified leaf
Modified stem and root for maximum nutrient storage
Modified leaf for maximum surface for photosynthesis
At home: choose a fruit NOT discussed in lab and draw it identifying the following:
a. Fruit type
APPHIA – Crafted with Care and Precision for Academic Excellence. 2
From question to perfection| Study with confidence!
Which signal is stronger in plants, gravitropism or phototropism? - Answer: Gravitropism
How do the different phototropic and gravitropic responses make sense from a functional
standpoint of the plant organs (i.e. stems, roots, leaves)? - Answer: 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. - Answer:
cytokinine, auxin, ehtylene
- Temp, and photoperiod are variables that can cause leaf senescence
-Ethylene breaks down walls at abscission zone
Suppose testosterone regulation suddenly switched from negative to positive feedback.
Draw a graph that shows how testosterone levels would look over time. - Answer:
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? - Answer: *anterior*(pink): endocrine
tissue, makes own hormones
*posterior*(white): neural tissue, connected to the hypothalamus (axon terminals located
in posterior)
APPHIA – Crafted with Care and Precision for Academic Excellence. 1
, What is the functional connection between the interstitial cells and the developing sperm
cells in the testis? - Answer: 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 - Answer: 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. - Answer: 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? - Answer:
Carrot- modified root
Celery-modified stem (petiole)
Onion- modified leaf
Modified stem and root for maximum nutrient storage
Modified leaf for maximum surface for photosynthesis
At home: choose a fruit NOT discussed in lab and draw it identifying the following:
a. Fruit type
APPHIA – Crafted with Care and Precision for Academic Excellence. 2
