Biology(Hormone)

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  1. A patient having renal surgery suddenly develops massive hypertension and dies during surgery. An autopsy shows the presence of a pheochromocytoma. In your own words, explain how this incident might have happened.
  2. Your favorite cousin, who is 20 years old, has just been diagnosed with type 2 diabetes. He is overweight and spends most of his time playing computer games or watching television. As a health professional, what advice will you give him?
  3. Your patient has just been diagnosed with SIADH. His mother is asking you what this condition is and what she should expect next. What will you tell her?
  4. Your patient has been admitted to the hospital in preparation for a total removal of her thyroid gland to reverse her hyperthyroidism. She suddenly develops thyroid storm. What manifestations will you find, and what is the pathophysiologic basis of thyroid storm?

Topic Altereations in hormone regulation**

 
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Meiosis Lab

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Cellular reproduction in Eukaryotes involves either mitosis or, in the case of sex cells, meiosis. Mitosis involves the reproduction of a cell into two identical daughter cells. Meiosis, however, is a reduction division where a parental diploid cell produces four haploid gametes. Upon fusion, two haploid gametes (in humans the sperm and the egg) will result in one diploid zygote. In this activity you will track chromosomes through meiosis using colored beads.

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Meiosis

Lab 4

 

 

 

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Lab 4: Meiosis

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Introduc on

Meiosis only occurs in organisms that reproduce sexually. The process generates haploid (1n) cells

called gametes (sperm cells in males and egg cells in fe-

males), or spores in some plants, fungi, and pro sts, that

contain one complete set of chromosomes. Haploid cells

fuse together during fer liza on to form a diploid cell with

two copies of each chromosome (2n).

Genes are the units of heredity that have speciĂžc loci

(loca ons) on the DNA strand and code for inheritable

traits (such as hair color). Alleles are alterna ve forms of the same gene (brown vs. blue eyes). Homol-

ogous chromosomes contain the same genes as each other but o en di erent alleles. Non-sex cells

(e.g. bone, heart, skin, liver) contain two alleles (2n), one from the sperm and the other from the egg.

Mitosis and meiosis are similar in many ways. Meiosis, however, has two rounds of division—meiosis I

and meiosis II. There is no replica on of the DNA between meiosis I and II. Thus in meiosis, the parent

cell produces four daughter cells, each with just a single set of chromosomes (1n).

Meiosis I is the reduc on division– the homologous pairs of chromosomes are separated so that each

daughter cell will receive just one set of chromosomes. During meiosis II, sister chroma ds are sepa-

rated (as in mitosis).

 

 

 

 

 

Concepts to explore:

Meiosis

Diploid cells

Haploid cells

Chromosomal crossover

Concepts to explore:

 

There are over two meters of DNA pack-

aged into a cell’s nucleus. It is coiled and

folded into superhelices that form chro-

mosomes, which must be duplicated be-

fore a cell divides.

Each of the 23 human chromosomes

has two copies. For each chromosome,

there is a 50:50 chance as to which copy

each gamete receives.

That translates to over 8 million possi-

ble combina ons!

 

 

Lab 4: Meiosis

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Meiosis:

Prophase I: The sister chroma ds a ach to their homologous counterparts (same chromo-

some – di erent version). This is the stage where crossing over occurs (homologous chro-

mosomes exchange regions of DNA). Structures which will serve as anchors in the cell

(centrioles) during the division process appear.

Metaphase I: The chromosomes line up in the middle of the cell. The orienta on of each

pair of homologous chromosomes is independent from all other chromosomes. This

means they can “ßip ßop” as they line up, e ec vely shu ing their gene c informa on

into new combina ons. Microtubules (long strands) grow from each centriole and link

them together while also a aching to each pair of homologous chromosomes.

Anaphase I: The microtubules pull the homologous chromosomes apart (the sister chro-

ma ds remain paired).

Telophase I: One set of paired chromosomes arrives at each centriole, at which me a nu-

cleus forms around each set.

Cytokinesis: The plasma membrane of the cell folds in and encloses each nucleus into two

new daughter cells.

Prophase II: Before any replica on of the chromosomes can take place, the daughter cells

immediately enter into prophase II. New spindle Ăžbers form as the nucleus breaks down.

Metaphase II: The sister chroma ds align in the center of the cell, while the microtubules

join the centrioles and a ach to the chromosomes. Unlike metaphase I, since each pair of

sister chroma ds is iden cal, their orienta on as they align does not ma er.

Anaphase II: The sister chroma ds are separated as the microtubules pull them apart.

Telophase II: The chroma ds arrive at each pole, at which me a nucleus forms around

each.

Cytokinesis: The plasma membrane of the cell folds in and engulfs each nucleus into two

new haploid daughter cells.

We brießy discussed “crossing over” in Prophase I. Since the chromosomes of each parent undergoes

gene c recombina on, each gamete (and thus each zygote) acquires a unique gene c Ăžngerprint.

The closeness of the chroma ds during prophase I, creates the opportunity to exchange gene c mate-

rial (chromosomal crossover) at a site called the chiasma. The chroma ds trade alleles for all genes

located on the arm that has crossed.

The process of meiosis is complex and highly regulated. There are a series of checkpoints that a cell

must pass before the next phase of meiosis will begin. This ensures any mutated cells are iden Ăžed

 

 

Lab 4: Meiosis

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and repaired before the cell division process can con nue.

 

One of the muta ons that is of par cular concern is a

varia on in the amount of gene c material in a cell. It is

cri cal that the gamete contain only half of the chromo-

somes of the parent cell. Otherwise the amount of DNA

would double with each new genera on. This is the key

feature of meiosis.

Figure 1: The stages of meiosis

Muta ons that are not caught by the cell’s

self-check system can result in chromoso-

mal abnormali es like Down’s syndrome, in

which there are 3 copies of chromosome

21.

 

 

Lab 4: Meiosis

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Experiment 1: Following Chromosomal DNA Movement

Every cell in the human body has two alleles that condense into single chromosomes held together by

a centromere. These “sister” chroma ds replicate and pair with the newly made homologous chromo-

somes. In this exercise we will follow the movement of the chromosomes through meiosis I and II to

create haploid (gamete) cells.

 

 

 

 

 

 

 

Procedure

Meiosis I

A. As prophase I begins, chromosomes coil and condense in prepara on for replica on.

1. a) Using one single color of bead, build a homologous pair of duplicated chromo-

somes. Each chromosome will have 10 beads with a di erent colored centromere

in it.

For example, if there are 20 red beads, 10 beads would be snapped together to

make two di erent strands. In the middle of each of the 10 bead strands, snap

a di erent colored bead in to act as the centromere.

Figure 2: Bead Set-up

Materials

2 sets of di erent colored snap beads (32 of each)

8 centromeres (snap beads)

Blue and red markers*

*You must provide

 

 

Lab 4: Meiosis

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b) Now, repeat these steps using the other color of bead.

2. a) Assemble another homologous pair of chromosomes using only 12 (that’s 6 per

strand) of the Ăžrst color bead. Place another, di erent colored bead in the middle

of each to act is its centromere.

b) Repeat this step (2 strands of 6 beads plus a centromere) with the other color of

beads.

B. Bring the centromeres of two units of the same color and length together so they can be held

together to appear as a duplicated chromosome. Your beads should appear as they do in Fig-

ure 2.

C. Simulate crossing over between the blue and red chromosomes. Bring the two homologous

pairs together (that’d be the two pairs that both have 10 bead strands) and exchange an equal

number of beads between the two. This simulates what occurs during prophase I.

D. ConĂžgure the chromosomes as they would appear in each of the remaining stages of meiosis I.

Use Figure 1 to guide you.

 

Meiosis II

E. ConĂžgure the chromosomes as they would appear in each stage of meiosis II. Use Figure 1 to

guide you.

F. Using the space below, and using blue and red markers, draw a diagram of your beads in each

stage. Beside your picture, write the number of chromosomes present in each cell. This work

will help you answer the ques ons in the lab, but does not need to be submi ed for grading.

 

Meiosis I

Prophase I

 

 

Metaphase I

 

 

 

 

 

Lab 4: Meiosis

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Anaphase I

 

 

 

Telophase I

 

 

 

Meiosis II

Prophase II

 

 

 

Metaphase II

 

 

 

Anaphase II

 

 

 

Telophase II

 

 

F. Return your beads to their original star ng posi on and simulate crossing over again. Track

how this changes the ul mate outcome as you then go through the stages of meiosis I and II.

 

 

Lab 4: Meiosis

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Ques ons

1. Why is crossing over important in heredity?

2. Provide two ways that meiosis I and meiosis II are di erent.

3. a) In this lab, how many chromosomes were present in each cell when meiosis I started?

b) How many chromosomes were present in each daughter cell at the end of meiosis II?

4. If humans have 46 chromosomes in each of their body cells, determine how many chromo-

somes you would expect to Ăžnd in the following:

Sperm ___________________

Egg ___________________

Daughter cell from mitosis ___________________

Daughter cell from meiosis II ___________________

5. Why is it necessary to reduce the chromosome number of gametes, but not of other cells of

an organism?

 
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BIOLOGY ESSAY QUESTIONS

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Answer five of the seven essay questions (no extra credit for extra work)

 

Each essay question is worth 20 points. Response should be at least 150 words long. Sentences should be well developed, show logical and independent critical thinking, understanding of the concepts and their application to provided case studies/scenarios. Answers should be written in your own words.

 

1. While working at an excavation, an archeologist found several small skull bones. She examines the frontal, parietal, and occipital bones and concludes that the skull belonged to a child not even one year old. How can she tell the child’s age from examining the bones? Explain the importance of her finding in relationship to the infant’s postnatal development.

 

2. Michael is a thirty year old salesman who spends approximately 4 days each week traveling to visit with customers in his region. During his routine physical he casually mentions to his physician that he seems to be sweating more profusely than normal and most rooms that once were comfortable are now too “hot”. Michael also reports that he seems to be losing weight even though his appetite has increased. He also complains that he has a shortened attention span and that he always wants to be moving around. Despite the fact that he feels fatigued, Michael claims to have difficulty sleeping and seems to have more frequent bowel movements, occasionally accompanied by diarrhea. The physician checks Michael’s medical history and finds that indeed he has lost 15 pounds since his last physical.

 

Results of Michael’s physical examination and tests performed by endocrinologist concluded that Michael had Grave’s disease, a form of hyperthyroidism believed to be autoimmune in nature. Michael was presented with a number of possible treatment options. After considering all the options, especially the possible effects of radiation on gamete development, Michael chose surgical removal of the thyroid gland. Following successful surgery, Michael was prescribed synthetic thyroid hormone to ensure that his body was receiving adequate thyroid hormone and told to return within 2 months for a follow-up evaluation of circulating thyroid hormone concentrations. He was also cautioned to carefully monitor his calcium intake.

 

a. Thyroid hormones exert their effects on cells in a manner similar to steroid hormones; describe the mechanism of action of thyroid hormones.

 

b. Why would an imbalance in thyroid hormones have such widespread effects on the body?

 

3. Charlie is badly burned in a fireworks accident on the Fourth of July. When he reaches the emergency room, the examining physician determines the severity of the incident as a third-degree burn. What therapeutic measures is the physician likely to recommend? What are the major concerns with third-degree burns? Are third-degree burns more or less painful than the second-degree burns? Explain.

 

4. E.M.S. went to bed about 11 PM after a busy evening of entertaining friends and family. He was awakened at 2 AM with chest pain that radiated to his left shoulder, arm and fingers. His son took him to the emergency room, where he was immediately given oxygen by mask and nitroglycerin. His chest pain was relieved in about 39 minutes. An ECG revealed evidence of myocardial ischemia but no evidence of a myocardial infarction. He was admitted to the cardiac intensive unit for further evaluation.

 

a. What’s the most likely cause of the pain (what’s the name of the condition and what causes it)?

 

b. What kind of medication is nitroglycerin and why does it help to relieve the pain? What are other treatment options for this condition?

 

c. Define the underlined terms.

 

5. Until recently, 6-year-old Billie had no apparent health problems. About 1 week ago, she started to lose weight despite a healthy appetite. She urinated frequently and complained of being tired. Her mom noticed that she was very thirsty and was getting up in the middle of the night to urinate. On examination, her blood sugar was elevated. She was diagnosed with type 1 (juvenile-onset) diabetes mellitus.

 

a. Which homeostatic mechanism is not properly functioning?

 

b. Explain the physiology of this disease, what’s going wrong? Be specific.

 

c. What can happen if the diabetes is not controlled?

 

6. Keith is a college student. He is extremely busy studying and working part-time. Keith sleeps in late and therefore does not take time for breakfast. He rushes off to class. At lunch he has time for only French fries. When he gets home from school, he eats canned corn (only corn, nothing else) and washes it down with water. Then, he goes to work, only to start the same routine the next day.

 

When Keith is confronted about his poor diet, he responds, “The French fries are a good source of carbohydrates. Since they are fried in oil, I get my daily requirement of fat. At supper time, I eat corn and it has a lot of amino acids in it.” You, a medical student, suggest that Keith see a doctor. Keith complies and makes an appointment with a doctor. The doctor’s report looks like this: Keith is pale and underweight, his urine and blood pH are low, and the ketones in the urine and blood are high. The Na+ concentration in the blood is low. Keith seems to have possible nerve problems. The doctor explains that Keith is pale due to anemic conditions brought on by the poor diet. With a poor protein diet, Keith’s erythrocytes may not be making adequate hemoglobin. Because his diet is very low in carbohydrates, his body is metabolizing fat, which is causing the weight loss. By products of fat metabolism are ketones, which are acidic. This accounts for the increase in ketones in the urine and the blood and a drop in the pH. A drop in blood pH will inhibit the small intestine from putting Na+ into the bloodstream. Sodium ions are necessary for proper nerve function. In short, Keith needs to begin eating well-balanced meals.

 

a. Why is corn considered to be an incomplete protein?

 

b. How are ketones formed?

 

c. How are sodium ions involved in the nervous system?

 

d. How does this scenario relate to fad diets?

 

7. Analyze the need of climbers of Mt. Everest to set up camps at various levels and stay in those camps for a predetermined amount of time before proceeding with their climb to the top of the mountain.

 

 
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2100 Anthropology Exam.

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ATH2100L LAB 5: READING

 

DIRECTIONS: Please read the materials that follow and then complete the Lab 5 Quiz on PILOT.

 

By the time you finish reading these materials, you should be able to answer the following questions about primates:

1. What ancestral traits do primates share with other mammals?

2. What derived traits characterize primates compared to other mammals?

3. What is the value of studying primates to understand human evolution?

 

Primates are mammals (and therefore, so are you!)

Taxonomic classification organizes organisms based on shared characteristics due to common ancestry. The Linnean classification system is a nested hierarchy that becomes more exclusive with each taxonomic level (for example, a phylum contains more groups than a class and so on). Below is the taxonomic classification for modern humans.

 

Linnean Classification of Human

 

GENERAL KINGDOM Animalia (we’re ANIMALS)

(inclusive)

PHYLUM Chordata (we’re animals with SPINAL CORDS)

 

CLASS Mammalia (we’re a kind of spined animal MAMMALS)

 

ORDER Primates (we’re a type of mammal called a PRIMATE)

 

FAMILY Hominidae (includes us and apes, aka HOMINIDS)

 

GENUS Homo (this is us and closely related enchephalized bipeds)

SPECIFIC

(exclusive) SPECIES Homo sapiens (we’re a special group called HUMANS)

 

From this classification, we see that modern humans are grouped within the order Primates which falls within the class Mammalia. This means that humans are primates, a special type of mammal that shares a common ancestry with OTHER mammals. As a result of this ancestry, primates and mammals share many ANCESTRAL TRAITS.

 

Mammals are diverse. On the surface, it may seem hard to find similarities between humans and a dog or cat, etc. However, we all share traits found in our common mammalian ancestor that indicate a closer evolutionary relationship among all animals grouped within the Class Mammalia than other animals.

 

 

Mammalian characteristics

 

1. Homeothermy/endothermy: Mammals have the ability to regulate body temperature. This means mammals can adapt to different climates.

 

2. Heterodonty: Mammals have different types of teeth. Mammals have four kinds of teeth with different shapes and characteristics: incisors, canines, premolars, and molars. Other animals, such as crocodiles and sharks are homodonts (the teeth are all the same).

 

http://inside.ucumberlands.edu/academics/biology/faculty/kuss//courses/Digestive%20system/HomodontHeterodont.jpg

 

3. Viviparity: Mammals have internal gestation and give birth to live young (there are a few exceptions). Young are then dependent upon the mother for milk produced by mammary glands.

 

4. Pentadactyly: Mammals have five fingers and toes. The basic structure of the mammalian “hand” and “foot” is similar, but many groups have modified this condition (i.e. ungulates have hooves, felids have paws with claws). Primates retain the primitive structure of pentadactyly.

http://www.evolutionnews.org/Panda%27s%20Thumb.jpg

5. Brain: The mammalian brain tends to be larger for body size compared to other vertebrates. Mammals also have a unique area of the brain known as the neocortex. The neocortex is involved in higher level functions such as spatial reasoning and sensory perception. This area reaches its greatest expansion among primates.

 

 

What makes primates different from other mammals?

 

Primates are defined by a group of features, known as DERIVED TRAITS. Derived traits are modified from the ancestral (in this case, mammalian) condition. The tricky thing about ancestral and derived traits is that their status (or polarity) depends on the context. For example, if we are comparing mammals and primates, the features below are considered DERIVED. However, if we are comparing different groups of primates, those same features are considered ANCESTRAL because all primates share them.

 

In the next lab, you will explore more in-depth what distinguishes primates from other mammals. Here are a few key features of primates:

 

1. Vision: Vision is the most important sense for most primates. They have forward-facing eyes and stereoscopic vision. This means that a primate’s eyes are located in the front of the skull. This allows the fields of vision to overlap, and provides depth perception (very important if you primarily live in the trees). Furthermore, the primate eye socket features post-orbital closure or a post-orbital bar. You will explore this characteristic more in Lab 6.

 

2. Hands, feet, and limbs: Primates retain the ancestral condition of pentadactyly. They also have prehensile (gripping) fingers and toes, nails instead of claws (with some exceptions), tactile pads, and an opposable thumb. Primates also have very flexible and generalized limbs that allow us to locomote (move) in many different ways.

 

3. Brains and speed of growth: As mentioned above, primate brains are more complex than other mammals, and our brains tend to be larger than expected for body size (this is seen to the extreme among hominins). Primates also feature longer gestation periods and slower postnatal growth than most other mammals.

 

The utility of non-primates for understanding evolution

 

Non-human primates (NHP) are fascinating because they are so like us in both appearance and behavior (and many are very cute!) NHP studies help us to understand:

a) the relationship between dental and skeletal form and their behavioral functions (to reconstruct things like locomotion, group structure, and diet in fossil species),

b) the evolutionary underpinnings of some of our behaviors (tool use, group living, social politics, etc.)

c) evolutionary processes, adaptation, and speciation.

 

HOWEVER, we have to remember that extant NHP are not “living fossils,” and they were evolving and changing long before hominins (our ancestors) ever came on the scene. Therefore, we must be cautious in our use of NHP as analogies for hominin evolution.

 

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