L05 GRQs - 5th GRQs UNC Chapel Hill Bio101 PDF

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5th GRQs UNC Chapel Hill Bio101...

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Guided Reading Qs (Do these before the Mastering Assignment.)

Cell Signaling with Hormones (Reading 26.1-26.3, 26.7-26.9 plus a 13-min podcast interview, and an article on Sakai, “The Origins of Transgender”) Reading Objectives  Differentiate between chemical and electrical signaling to cells  Describe how the two types of chemical signaling mechanisms affecting target cells differently.  Apply the two mechanisms of chemical signaling to insulin signaling and sex hormone signaling.  Explain the consequences of endocrine disruptors.  Explain how testosterone and estrogen affect gender development. 1. What two type of signals does the body use to communicate? The body uses the endocrine system (secreting hormones) as well as the nervous system to communicate vital information between cells. -Endocrine cells release chemical signals called hormones which travel in the bloodstream to all parts of the body -In the nervous system, the signals are primarily electrical and transmitted via nerve cells aka neurons How do they affect different responses in the body? -Endocrine system: coordinates gradual changes such as responses to dehydration/ undereating / vitamins / sexual maturity development -Nervous system: coordinates more immediate and environmental responses such as the flick of a tongue to catch a fly or feeling and scratching an itch

2. What does a target cell have that allows it to respond to a hormone secreted from a distant gland that a non-target cell is lacking? Only target cells have receptors for specific hormone molecules which are secreted into the bloodstream by the endocrine cells. This allows so that hormones only go to specified parts of the body. Hormones will not affect cells without these receptors. 3. List and describe the three stages of hormone signaling: i. Reception: a hormone binds to a specific receptor protein that is on or in the target cell ii. Signal transduction: (triggered by the reception of the hormone) the signal is converted from one form to another iii. Response: (triggered by signal transduction) a change in the cell’s behavior occurs

4. Are hormone receptors on the plasma membrane or inside cells? Hormone receptors can be on the membrane of the target cell or inside the target cell

5. Draw a quick diagram outlining the differences between:

water-soluble hormone signaling

vs.

lipid soluble hormone signaling

-Water-soluble hormones cannot pass through the phospholipid bilayer so they bring about changes without entering the target cells 1. A polar or water-soluble (non steroid) hormone binds to the receptor protein and activates it 2. A signal transduction pathway is initiated, which includes a series of changes in relay molecules (cellular proteins) that converts an extracellular chemical signal to form that can lead to a response 3. The final relay molecule activates a protein that carries out the cell’s response, which could be something that occurs in the cytoplasm, such as an action that another system needs to complete, or in the nucleus, such as regulating gene expression

-Lipid-soluble hormones do pass through the phospholipid bilayer and enter the target cell

1. A lipid soluble (steroid) hormone enters the cell by diffusion 2. (If it’s a target cell) the hormone binds to an open receptor protein that is in the cytoplasm or nucleus. It does not trigger a signal pathway, but instead the hormone receptor itself carries out the transduction of the hormone signal 3. The hormone receptor + hormone attaches to specific sites on the cell’s DNA in the nucleus 4. The binding to DNA stimulates gene regulation, which either turns genes on (promoting transcription of certain genes into RNA) or off

6. Why can steroid hormones pass through the plasma and nuclear membranes? Steroid hormones are not soluble in water, so they are nonpolar and can pass through the phospholipid bilayer. 7. Scientific Thinking module: What hypothesis were the scientists testing? The scientists hypothesized that long-term exposure to low levels of atrazine during development would have negative effects on reproductive function in amphibians What were the control and experimental groups? Control group: frogs unexposed to atrazine Experimental group: frogs of equal weight, exposed to very low levels of atrazine for three years What was the independent variable? atrazine exposure (or lack thereof) Dependent variables? Success in reproduction with female frogs What were the results? The frogs that were exposed to atrazine at low levels were significantly less successful in their reproduction rates and also had deficient levels of testosterone (male sex hormone) This was a controlled laboratory study—does it have any implications for the real-world environment? Yes – in the real world these same results would most likely occur because the amount of atrazine that the frogs were exposed to was very similar to the amount they are exposed to in the water in most environments Feel free to skip directly to Module 26.7: 8. What are the three major categories of sex hormones? a. Estrogens: maintain the female reproductive system and promote the development of breasts and wider hips b. Progesterone: primarily involved in preparing and maintaining the uterus to support an embryo c. Androgens: stimulate the development and maintenance of male reproductive system (main one = testosterone) Do males have estrogen? _Yes__ Do females have testosterone? _Yes__ Explain differences. Males have more androgens (testosterone) in comparison to estrogens, and females have more estrogen in comparison to androgens The sex hormones are produced by the gonads (ovaries and testes) but affect cells in distant parts of the body. What are some of the distant targets affected?

9. What happens when testosterone is made but cannot bind its receptor inside the cell? When testosterone is made but cannot bind to its receptor inside the cell, it is basically the same as if no testosterone was made in the first place. When this happens, someone has androgen insensitivity syndrome, and affected individuals have external female genitalia, but male testes inside their abdomen. 10. What are some ways testosterone affects other animals besides humans? Testosterone causes aggressive male behavior in elephant seals, increased singing in male songbirds, and the development of antlers in male deer and elk

11. What organ secretes insulin and glucagon? The pancreas secretes insulin and glucagon What are the target cells of insulin? What affect does insulin have on cells? Target cells of insulin are any cells (really all of them) that need glucose to do work, but especially liver and muscle cells where glucose in the form of glycogen can be stored. What are the target cells of glucagon? What affect does glucagon have on target cells?

12. Diabetes (as a group of diseases) affects 1 in _11_ Americans. What is diabetes? Diabetes is a serious hormonal disorder caused by the body’s inability to produce or correctly use insulin, which decreases the absorption of glucose from the blood, resulting in hyperglycemia.

13. Compare and contrast the differences in hormone signaling defects in type 1 vs type 2 diabetes: Type one: white blood cells of the body’s own immune system attack and destroy beta cells that release insulin. Insulin is absent completely, so target cells do not receive the signal that leads to glucose transporters being moved into the plasma membrane. Type two: insulin is produced, but the insulin signal is not relayed normally inside the target cells. Insulin is present, but glucose transporters are not as readily available at the plasma membrane to take up glucose from the blood and target cells are said to be “insulin resistant”.

What condition occurs if too much insulin is produced or injected? If too much insulin is produced or injected, hypoglycemia occurs, which means there is too little glucose in the blood. It can cause hunger, sweating, weakness, nervousness, and even convulsions or death. 14. Listen to a 13-min interview with Raleigh author, Tim Anderson, about his book, Sweet Tooth: http://wunc.org/post/life-after-hormones-and-blood-sugar-go-beserk and answer these questions as you listen: What were the first signs for Tim that he was developing type 1 diabetes? How old was he? He had symptoms like extreme dehydration and thirst (but didn’t realize it at first). Tim was 15 when he started experiencing symptoms. On the night he was brought to the ER, what behavior during that day made his sugar level so incredibly high? He was drinking lots of coca colas on the bus of a school field trip because he isn’t allowed to at home and also, he was very thirsty, so he kept drinking more. What does he mean when he says the first few years were the “honeymoon period” of diabetes? You’ve been diagnosed, but your pancreas kind of produces it sporadically so you have weird episodes because you won’t know when you have too much insulin or not. What were some of the symptoms he describes associated with too much insulin (hypoglycemeia)? Sweating, convulsing, inability to even talk

He talks about educating people to some degree by writing this book because most people misunderstand diabetes because they don’t realize its more than just injecting insulin--it is a complex, “__balancing____ act”. Most people don’t know there times where you need more sugar too How did #showmeyourpump come about? What is a pump? It is a campaign about embracing diabetes and showing your pump. Started with a Miss Idaho girl wearing her pump in a pageant show. A pump is something that releases insulin when needed (don’t need injections). Functions kind of like a external pancreas. Describe the nurse that took care of Tim in his first week: She didn’t care that he was miserable and frustrated. He described her as a venus fly trap. She had a “suck it up” mentality and was not caring or supporting at all. Tim hated pricking his finger for blood readings then, but now he easily does this _8-10_ times per day. Tim’s story of “accepting his new life with diabetes” was complicated by what else that he was also learning to accept about himself? He was also learning at the same time to accept his sexuality as a gay teenager in the 80s.

Diversity Focus; Read: The origins of Transgender: Hormones and Gender Identity (Article on Sakai) 1. Early in the article, the author explains that the article is going to take a binary perspective. What does the author mean by this and what is being excluded by taking this perspective? ?

2. What happens at 7 weeks to a human XX embryo? A human XY embryo? XX: ovaries develop and begin to secrete both estrogen and progesterone XY: testis send a massive blast of testosterone equal to that of puberty 3. What is different about hormone blasts at birth between XX and XY embryos? At birth, the male (XY) has a second blast of testosterone while the female (XX) does not. 4. What is congenital adrenal hyperplasia (CAH) and why was studying these female children important to Professor Melissa Hine’s research? What did Dr. Hines find? CAH is a genetic disease where girls have high exposure to androgens (testosterone). Studying these female children was important to her research because it helped her understand how the hormone blasts we receive in the utero and at birth impact our gender identity. She found that female children with CAH were just as likely to choose male toys as the male control group and that girls with more masculine tendencies had mothers with high levels of testosterone. 5. Based on the work of Catherine Dulac, what would you predict would be the adult behavior (male sexual behavior or female sexual behavior) for each of these scenarios with mice? 

  

A male mouse not exposed to a testosterone blast at birth but is exposed to testosterone as an adult? -The male mouse would not have any change in behavior when receiving the adult blast of testosterone, because the blast of testosterone later in life only masculinizes the subject if they received a prior blast at birth A male mouse exposed to a testosterone blast at birth and is exposed to testosterone as an adult? -The male mouse will have masculinized behavior tendencies after being exposed to the testosterone as an adult A female mouse exposed to testosterone blast at birth but exposed to estrogen as an adult? -will have masculine tendencies and will not be have an effect after the estrogen blast as an adult A female mouse NOT exposed to testosterone blast at birth and exposed to estrogen as an adult?

-will have have more feminized behaviors after the blast as an adult 6. What is the take-home message of the article?

-our hormones play a major role in how we identify our gender and our masculine or feminine tendencies Feeling like you want to know more about using these terms and discussing ideas in a safe space? Head over to a Safe Zone training at the LBGTQ center. I did, and I learned a great deal about being an ally. https://lgbtq.unc.edu/programs-services/safe-zone...