Homeostasis

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Assignment 9: Homeostasis

Goal: Interpret Data

In this assignment, you will practice reporting and interpreting basic data on a case involving ghrelin and weight loss. Download the handout below to get started. Answer 10 questions in Parts II and III. Include answers to Part IV in your post to earn full credit on this assignment. Making graphs in Excel is suggested, but not required. Scan or take a picture/screenshot of your graphs.

Some helpful tips:

Example of error bars on a line graph (hint: add SE above and below each point):

Example of a line graph

Independent variable = x-axis

Dependent variable = y-axis

If all else fails, try Google/YouTube for help with graphs.

Grading Rubric

Attempted assigned questions

Submitted answers to Parts II and III (20 points)
Skipped at least one question (15 points)
Attempted bonus question(s)

Submitted answers to Part IV (5 points)
Did not attempt Part IV (0 points)
Total possible = 25 points

NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

The Hunger Pains: Ghrelin, Weight Loss, and Maintenance by Lynn M. Diener Sciences Department Mount Mary College, Milwaukee, WI

Part I – You Look Fantastic! Mallory Messner Hey Sara, it was great to see you during break! It’s been way too long. And by the way, congratulations on the weight loss, you look fantastic. Do you mind if I ask how you did it? April 5 at 1:32pm Like

Sara Finnegan Mal, it was great to see you too! Tanks for noticing the weight loss, it required a lot of hard work. I started exercising 5 days a week and restricting calories (eating smaller portions mainly). April 5 at 1:45pm Like

Mallory Messner You’d think I would already have realized that there is no trick when it comes to weight loss, being a biology major and all–sigh–I just hoped maybe you had found some magic solution. Haha. April 5 at 1:50pm Like

Sara Finnegan I gotta tell you though, I’m having a heck of a time keeping the weight of. It seems like I’m always hungry! You know, they always say that only 5% of people who lose weight ever keep it of long term. I’m hoping to remain in the 5% but right now I’m not so sure. =(

Have you heard about some hormone called ghrelin in any of your biology classes? I’ve been reading about it in the news lately, I wonder if it has anything to do with my struggles
 April 5 at 1:55pm Like

Mallory Messner Actually I do recall learning something about ghrelin in class. Let me take a look and get back to you. I’ll send you an email! April 5 at 1:57pm Like

Questions 1. Craft an email from Mallory to Sara explaining some of the basics of ghrelin. Your email should explain what a

hormone is and what kind of hormone ghrelin is. It should also explore ghrelin’s efect on growth hormone and metabolism. Feel free to use your textbook and reliable internet sources.

2. What is the efect of growth hormone on metabolism? Pay special attention to its efect on protein, bone, fatty tissue, and carbohydrates.

3. What does anabolic mean? What about catabolic? How would you classify growth hormone?

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Part II – Sleep Is Important Mallory Messner So ghrelin seems like an intriguing possibility, huh? Did you know that it’s generally elevated in people after they lose weight? Even a whole year after they lost the weight! April 5 at 6:03pm Like

Sara Finnegan Yeah, thanks for the email. I can’t believe that a chemical like ghrelin can help to increase your appetite. And the fact that it’s elevated in people after they lose weight, ugh! April 5 at 6:09pm Like

Mallory Messner I found some other really interesting studies about ghrelin. How are you sleeping lately? April 5 at 6:12pm Like

Sara Finnegan I’m a college sophomore, just like you, how do you think I’m sleeping? April 5 at 6:14pm Like

Mallory Messner Haha, point taken. Well one study found some correlations with sleep and ghrelin levels. More sleep, less ghrelin! I found their data on the correlation between hours of sleep and BMI interesting as well.

Hours of sleep Average BMI Standard error 6.10 32.15 0.70 6.55 31.4 0.25 7.40 31.05 0.25 8.25 31.4 0.30 9.10 31.6 0.50

April 5 at 6:23pm Like

Questions 1. Make a line graph of this data using the space below. Don’t forget to include error bars using the standard error.

Identify and label the dependent and independent variables; this will dictate their placement on your graph.

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NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

2. Explain the trend you see in the data you graphed.

3. Using a ruler, show which error bars overlap and don’t overlap on the graph above.

4. Without knowing the results of any statistics done on the data, which data point(s) may be signifcantly diferent from each other based on the data provided? Which data did you rely on to come to your conclusion?

5. Knowing that less sleep means more ghrelin, what suggestions might you make to Sara if you were Mallory? What is a take-away message for this study?

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Part III – Dessert for Breakfast Sara Finnegan Maybe I need to start prioritizing my sleep just a little bit
 April 5 at 7:01pm Like

Mallory Messner Seriously! Me too
 =) Another really fascinating recent study looked at the timing and composition of calories ingested, focusing specifcally on breakfast. Are you familiar with those high protein diets? April 5 at 7:04pm Like

Sara Finnegan Oh yeah, my roommate is trying to lose weight that way. April 5 at 7:06pm Like

Mallory Messner Well researchers had one group of obese individuals eat a small (calorie-wise), protein enriched breakfast in the morning. Te other group ate many more calories high in carbohydrates and enriched in protein. Both ingested the same number of calories over the course of the whole day, the diferences were in the timing and quantity of fats, carbs and protein. Te amusing part is that the second group of dieters also had dessert with every breakfast. =D April 5 at 7:10pm Like

Sara Finnegan Seriously??? I’d love to start every morning with dessert. I bet I know who lost weight and who didn’t. April 5 at 7:13pm Like

Mallory Messner Seriously! And we’re talking doughnuts, cake, chocolate bars. You might fnd the results surprising though. Here, take a look at the weight loss data. Tey were “dieting” from weeks 0 till 16. Week 16–32 was follow up, when they were trying to maintain their weight loss.

Low calorie breakfast Dessert for breakfast Time (weeks) average weight (kg) average weight (kg)

0 89 91 4 85 87 8 82 85 12 77 82 16 75 78 20 78 76 24 81 74 28 84 72 32 87 71

April 5 at 7:21pm Like

Questions 1. Make a line graph of the data above in the space provided below.

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2. What is the trend the researchers saw? You should focus on which group lost more weight and had more successful weight loss maintenance.

3. Do you think Sara is surprised by the results?

4. Does ghrelin make you hungry or leave you feeling satisfed?

5. Knowing what you do about ghrelin, in which case do you think the researchers saw a greater decrease in ghrelin after eating?

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NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Part IV – Easier Weight Loss? Sara Finnegan Mal, that’s a seriously cool study. 30 minutes ago Like

Mallory Messner I know! And they saw all sorts of other things change in the dessert group. Levels of ghrelin decreased after meals, feelings of satiety (satisfaction) increased, and cravings decreased. 28 minutes ago Like

Sara Finnegan Haha, maybe I’ll try the dessert for breakfast diet to combat my difculty in maintaining. 25 minutes ago Like

Mallory Messner Well, it’s only one study. I’m not sure I’d change your whole diet outlook based on one study, but the results are defnitely compelling. Tere really is a lot left to learn about ghrelin and weight loss in general. 20 minutes ago Like

Questions 1. Speculate about why the dessert for breakfast group saw decreases in cravings and increases in satiety.

2. Would you change your diet based on the study? What kind of evidence is necessary to make you “believe” a research study?

3. If you were doing research in this area, what would be your next step?

2

Credit: Licensed image in title block © Konstantin Andy #1627988 | Fotolia. Case copyright held by the National Center for Case Study Teaching in Science, University at Bufalo, State University of New York. Originally published September 17, 2012. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

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Page 1“Crazy About Cryptids!” by Matthew P. Rowe

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Part I – Introduction Victoria adored her older brother Travis. She had good reason: their father had died when they were kids, leaving them and their younger twin sisters to be raised by their mother and grandmother. Growing up was tough; their mother’s salary as a social worker was meager, and their grandmother suff ered from a chronic medical condition that took much of the family’s income. As the oldest, Travis started working early to help support the family, a sacrifi ce not lost on Victoria and her sisters. Victoria so respected her brother that she couldn’t help comparing her high school and now her college suitors to Travis, and the admirers always fell short. Travis was kind, courageous, generous to a fault, and oh so smart—he even, while helping raise his siblings, put himself through law school and was now working as a public defender in Chicago. But he had a weakness that worried Victoria. Outside of the courtroom, Travis was gullible. He had a fondness for all things extraordinary—from ghosts to alien abductions to new-age therapies. His true passion, however, was cryptids. He was simply crazy about cryptids.

Victoria was majoring in Integrative Biology at Michigan State. Her training, including courses in ecology, wildlife biology, and the philosophy of science, made her appropriately skeptical of chupacabras, yetis, bigfoot, the Loch Ness monster, and other storied beasts. Th e fact that her brother, a lawyer whose career depended on the critical examination of evidence, could be so credulous was unsettling to her. While sensitive to his feelings, she hoped she could use her growing understanding of science in general, and ecology in particular, to empower her brother. A “just touching base” phone call from Travis presented Victoria with an opportunity.

“Hi sis, how are classes?” Travis asked supportively when Victoria picked up the phone.

“Great,” she replied, “in my wildlife techniques course, we’re studying all the cool things you can learn about an animal just by analyzing a tiny drop of its feces, or a hair or two snagged on a scratching post. It’s pretty amazing.”

“Yeah,” Travis replied with unrestrained enthusiasm, “did you hear about the recent study of hair samples collected from a bunch of diff erent sites in the U.S. and Canada that proved the existence of bigfoot, and showed they were interbreeding with humans?”

Victoria, remembering one of the principles she learned in her philosophy course, responded: “Travis, science isn’t about ‘proving’ an idea or explanation, it’s about marshaling all of the evidence you can to determine which of various competing explanations is best supported.” She continued, “I don’t mean to sound scientifi cally snobbish or anything, but the study you mention by Melba Ketchum and her coauthors lacks credibility. A team led by Bryan Sykes published a more rigorous analysis of hair sent in by bigfoot and yeti enthusiasts from around the world; the results showed that the hair belonged to bears and raccoons and other mammals one would expect to be wandering around in the woods, not to bigfoot or a bigfoot-human hybrid.”

by Matthew P. Rowe Department of Integrative Biology Michigan State University, East Lansing, MI

Crazy About Cryptids! An Ecological Hunt for Nessie and Other Legendary Creatures

 

 

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Page 2“Crazy About Cryptids!” by Matthew P. Rowe

“You’re breaking my heart here kiddo, you know I’m a true believer in Sasquatch,” Travis replied with feigned sadness. “Besides, isn’t it possible that a species of giant man-ape unknown to science exists somewhere on the planet?”

“Sure,” Victoria chimed encouragingly, “species unknown to science are occasionally discovered, like the mega-mouth shark or the saola. And creatures that scientists thought went extinct millions of years ago like the coelacanth are rediscovered. So I’m not saying that bigfoot doesn’t exist, only that the evidence presented so far is insuffi cient for me to accept that it does.”

After a short pause, Travis responded thoughtfully, “Ok, little sister, I think I see where you are coming from; in a jury trial, which is something I know about, the guilt or innocence of a suspect is determined by the preponderance of the evidence. Th e jury has to determine whether the accused is guilty beyond a reasonable doubt, not beyond any shadow of a doubt. Absolute certainty is unlikely. What matters is that the jurists, before reaching a verdict, carefully examine each of the explanations and all of the evidence off ered by both the prosecution and the defense. I guess it’s the same thing in science.”

Sensing an opening, Victoria slyly suggested, “Didn’t you say you wanted to see a Spartan football game? Well, homecoming is in two weeks; why don’t you come for a visit. We can catch the game, and then afterwards we’ll go hunting for the Loch Ness Monster.”

Nessie was Travis’s favorite cryptid, so his sister’s off er aroused his curiosity. “How can we go hunting for a population of aquatic monsters in Scotland from your apartment in the middle of Michigan?” Travis asked inquisitively.

“We’ll track her down using the science of ecology,” Victoria answered.

Questions 1. Two articles were mentioned in the story. Th e fi rst, titled “Novel North American Hominins, Next Generation

Sequencing of Th ree Whole Genomes and Associated Studies” by lead author Melba Ketchum and her co- authors, was published in the journal DeNovo. Th e second, titled “Genetic Analysis of Hair Samples Attributed To Yeti, Bigfoot, and Other Anomalous Primates” by Bryan Sykes and his team, was published in the journal Proceedings of the Royal Society B: Biological Sciences. Th e two reports apply similar techniques using similarly obtained samples but reach diff erent conclusions. Summarize the main conclusions of each.

2. Credibility is an important concept both in science and in courts-of-law. Which of the two publications is more credible, and why?

3. Occam’s Razor, also known as the Principle of Parsimony, can be useful when trying to determine which explanation, among two or more, is most likely to be correct. What is the Principle of Parsimony? Apply the principle to the diff erent explanations off ered by Ketchum’s team and Syke’s team. Which of the competing explanations best passes the razor test, and why?

 
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Asexual Reproduction

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1) For this assignment you must interview two people. Ask them this multiple choice question:
From where is the large majority of the mass of a block of wood of derived? (Show them a real piece of wood or a picture of a piece of wood)
1. Nutrients in the ground taken up by the roots
2. Water in the ground taken up by the roots
3. Out of thin air
4. The Sun

Then ask them why they think that their answer is correct. Finally report to them the correct answer and explain why it is correct.
In your write-up, please include the answers and explanations of the persons you interviewed.

2) For this assignment you are to demonstrate your knowledge of the advantages and disadvantages of sexual and asexual reproduction. Watch the following two videos:
http://www.youtube.com/watch?v=pAXeVFeHwEA

http://www.youtube.com/watch?v=F07cI3s1_1I
Next, to get credit for this assignment, please 1) submit at least three advantages of asexual reproduction; 2) submit at least three advantages of sexual reproduction; and 3) describe the example of the fish in the ponds of Sonora mexico and what it demonstrates about the importance of sexual reproduction.

 
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BIOLOGY HELP

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1-The final shape of a protein is very important to its function. When proteins undergo an irreversible change in shape called ________________ they ________________ perform their usual functions.

  naturation/can
  naturation/cannot
  denaturation/can
  denaturation/cannot
  dehydration reaction/cannot

 

 

2-Which group of lipids will contain hydrophilic heads that face outwards and hydrophobic tails that face inwards that will form a barrier?

  phospholipids
  steroids
  triglycerides
  saturated acids
  trans-fatty acids

 

3-DNA codes for the sequence of amino acids in the primary structure of a protein, but not for sugars or lipids. This is because

  only proteins are involved in living metabolic reactions.
  sugars and lipids code for their own replication.
  sugars and lipids are ever present in the living environment and are not used in living structures.
  other hereditary molecules code for sugars and lipids.
  proteins are the main structural and functional components of cells.

 

4-Which statement about the cellular nucleic acids DNA and RNA is incorrect?

  DNA is double-stranded, and RNA is single-stranded.
  The sugar in DNA is deoxyribose, and in RNA the sugar is ribose.
  DNA has a helix shape; RNA does not.
  RNA and DNA have the same four nitrogen-containing bases.
  Both DNA and RNA are polymers of nucleotides.

 

5-All carbohydrate molecules

  contain amino acids.
  contain nitrogen and phosphate.
  are organic acids.
  are composed of atoms of C, H, and the functional group -OH.
  are composed of atoms of C, H, O, and N.

 

6-Two molecules of glucose combine to form a disaccharide molecule during a(n) ________ reaction.

  dehydration
  hydrolysis
  hydrogen bond
  ionic bond
  inert

 

7-One carbon atom can form covalent bonds with up to ___ other atoms to form an organic molecule.

  2
  3
  4
  6
  8

 

8-Enzymes are organic compounds classified as

  nucleic acids.
  carbohydrates.
  lipids.
  steroids.
  proteins.

 

9-Organic molecules

  always contain carbon.
  always contain hydrogen.
  always contain carbon and hydrogen.
  are found only in organisms, hence their name.
  are always food molecules.

 

10-The water strider is an insect that skates across the water without sinking. The tips of its feet must be coated with molecules that are

  ions.
  hydrophilic.
  hydrophobic.
  basic.
  acidic.

 

11-Nucleic acids are polymers of

  amino acids.
  nucleotides.
  glycerol.
  monosaccharides.
  fatty acids.

 

12-DNA codes for the sequence of amino acids in the primary structure of a protein, but not for sugars or lipids. This is because

  only proteins are involved in living metabolic reactions.
  sugars and lipids code for their own replication.
  sugars and lipids are ever present in the living environment and are not used in living structures.
  other hereditary molecules code for sugars and lipids.
  proteins are the main structural and functional components of cells.

 

 

13-The moon lacks life and varies dramatically in temperature. If we could keep a layer of water spread on the surface of the moon, what effect would it have?

  Life would be possible but it would have to withstand these extremes in temperature.
  Water would absorb and hold heat and moderate the temperature extremes.
  The temperatures would drop to the lower extremes.
  Because water has a high heat of vaporization, the temperatures would rise to the upper extremes.
  Physical conditions would remain the same.

 

 

14-____ is a polysaccharide that is found in plant cell walls and accounts for their strength.

  Cellulose
  Chitin
  Glycogen
  Starch
  Cholesterol

 

 

 

15-The primary function of carbohydrates is

  quick fuel and short-term energy storage.
  structural reinforcement of plant and fungal cell walls.
  encoding the hereditary information.
  to speed chemical reactions in cells.
  to transport molecules across cell membranes.

 

16-Which of the following types of lipid is the most abundant constituent of cell membranes?

  cholesterol
  phospholipid
  triglyceride
  neutral fat
  fa
 
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