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24 Dec 2018

The body uses apoptosis to remove damaged cells, and to selectively remove cells during normal development. In an adult human, which of the following tissue types would be expected to use apoptosis for tissue repair?

female germ cells

gastrointestinal epithelium

neurons

retinal ganglion cells

cardiac muscle cells

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Patrina SchowalterLv2

24 Dec 2018

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1- Cancers are more common in tissues with high rates of celldivision. Based on this information, which of the following tissueswould be most likely to deveolp cancerous tumors.

Skeletal muscle

Cardiac muscle

Neural tissue

Skin epithelium

Use this information to help answer the following question:

When the suffix -clast is present, it refers to a cell thatdestroys - for example, a chondroclast is a cell that destroyscartilage. When the suffix -blast is present, it refers to a cellthat builds - for example, a chondroblast is a cell that buildscartilage.

Now answer:

In the normal 30 year old skeleton, osteoclast activity ismatched by osteoblast activity. What would happen if osteoclastactivity was greater than osteoblast activity?

The bones would become stronger

There would be no effect on the skeleton

The bones would become weaker

During transcription, the small and large ribosomal subunitscombine to read the mRNA strand and synthesize an polypeptide(amino acid chain).

True

False

Neurons are specialized for communication. They are capable ofsending electrical signals due to the presence of many ion channelsand pumps on the cell membrane that they constantly maintain orreplace as needed. Which of the following would be NOT consistentwith this information?

Neurons have a high ATP demand

Neurons are very permeable to certain ions

Neurons are anucleate (they do not have nuclei)

Neurons have many rough ER

bronzerat265

Summary

please!

Multipotent versus restricted

Morphologically detectable neural crest cells usually are first observed as the cells individualize and delaminate upon emigration from the neural tube, following their epithelial to mesenchymal transition (EMT), in which they convert from a tightly adherent sheet of cells to a dispersed and more individual mesenchymal population. Prior to EMT, however, it is difficult or impossible at most axial levels and in most species to distinguish presumptive neural crest cells from cells that will form dorsal neural tube derivatives. However, there are exceptions, such as a subpopulation of cranial neural crest cells in chick and mouse that appears to be set aside and morphologically distinct at midbrain levels. In addition, some species such as axolotl have a clearly segregated population of neural crest cells that exists as a ridge on the dorsal neural tube.

A long-standing debate in the neural crest literature has been whether neural crest cells are multipotent and/or restricted in their developmental potential. In other words, can a single neural crest precursor form only one type of derivative or are the cells multipotent and able to produce multiple derivatives. Single cell lineage experiments (Bronner-Fraser and Fraser, 1988), in which individual cells within the chick dorsal neural tube are labeled with vital dye, show that some of the labeled clones contribute to multiple differentiated cell types in the periphery, including melanocytes, sympathetic and sensory ganglion cells. Thus, the original precursor was âmultipotentâ in its developmental potential to form neural crest derivatives. In addition to neural crest derivatives, single dorsal neuroepithelial cell also give rise both to migrating neural crest cells and cells that remain in the dorsal neural tube, such as roof plate cells and dorsal sensory neurons and/or interneurons. This suggests a shared lineage between the neural tube and neural crest, at least at this stage. However, labeling migrating neural crest cells in vivo also produced clones that could contribute to more than one neural crest lineage (Fraser and Bronner-Fraser, 1991), again supporting the idea that some of the migrating population retained multipotency.

Clonogenic culture of neural crest cells cultured shortly after their emigration from the neural tube definitely shows that many early migrating neural crest cells are multipotent in vitro as well (Baroffio et al., 1988, Calloni et al., 2007, Calloni et al., 2009, LeDouarin et al., 2008a, LeDouarin et al., 2008b, Sieber-Blum and Cohen, 1980 and Stemple and Anderson, 1993). Exposure to different growth factors can profoundly influence their lineage decisions (e.g. Lahav et al., 1998). Furthermore, they have a capacity for self-renewal, at least for a few cell divisions (Stemple and Anderson, 1993 and Trentin et al., 2004).

The fact that individual neural crest cells can form multiple derivatives has led to the idea that they have stem cell properties. Stem cells are defined as individual progenitor cells that can generate one or more specialized cell types. A cardinal feature of stem cells is their ability to self-renew, that is, to divide so as to give rise to at least one daughter cell that maintains the multipotent character of its parent. The fact that cloned neural crest cells have a limited ability to self-renew has led to the idea that they are stem-like (progenitors) cells rather than true stem cells. Interestingly, however, neural crest stem cells can be derived from adult tissues (Fernandes et al., 2008 and Shakhova and Sommer, 2010; see Chapter Dupin and Sommer), suggesting that they can remain quiescent for long periods of time or maintain long term self-renewal ability when left in situ.

The presence of some multipotent neural crest precursors cannot, however, rule out the possibility that other precursors may be more restricted in their developmental potential. In fact, experiments in zebrafish suggested that neural crest cells contribute to different sets of derivatives accordingly to their migration order (Raible and Eisen, 1994). However, if the leader cell was ablated, the next cell in line took up the fate that would have been filled by the ablated cell (Raible and Eisen, 1996). Similarly, early migrating neural crest cells normally exhibit a broader range of derivatives than later migrating cells; however, when the early population is ablated and replaced by late migrating cells, the late migrating cells assume a broader developmental potential than that prescribed by their normal fate (Baker et al., 1997). This raises a very important issue: that developmental potential is greater than or equal to a cell's normal fate. Only by challenging the cell by putting it into a new environment can one test for restriction of cell fate. This is best exemplified by experiments in which the potential of neural crest populations was challenged by performing heterotopic transplants between different axial levels (LeDouarin and Teillet, 1974), such as exchanging cranial and trunk, or vagal and trunk populations. The results demonstrate a combination of flexibility in cell fate and some axial level-autonomous characteristics. For example, cranial neural crest cells normally make cartilage and bone of the face whereas trunk neural crest cells do not. Transplantation of cranial neural folds to the trunk results in production of many normal trunk derivatives, as well as the formation of ectopic cartilage nodules (Le Lievre et al., 1980 and LeDouarin and Teillet, 1974). Conversely, transplantation of trunk neural folds to the head results in contributions to cranial neurons and glia of cranial ganglia, but not to cartilage, although some connective tissues and pericytes derive from this graft (Nakamura and Ayer-le Lievre, 1982). This reveals some flexibility in fate, but a more limited ability to form skeletal derivatives (LeDouarin et al., 2004). However, trunk neural crest cells can form cartilage in vitro under appropriate culture conditions (Calloni et al., 2007 and McGonnell and Graham, 2002). Because challenging prospective neural crest fate is a difficult experiment, it is much easier to prove multipotency than restricted cell fate, leaving the question of whether or not there are lineage-restricted neural crest precursors still open to debate (see Krispin et al., 2010).

Directions: Write out your answers in the word document and then copy and paste everything into the text box. If you do not include the question along with your answer, you will be marked down.

1. What would happen if you put pGLO directly onto an agar plate and you checked on it after letting it incubate?

a. It would glow

b. It would grow

c. Nothing

d. E.Coli would grow

2. Explain in a short sentence or two your reasoning for question 1.

3. What shape is a plasmid?

4. How is a plasmid different from human DNA? Write one difference.

5. Bacteria can share DNA through a unique method called transformation. What are the TWO requirements a bacteria cell must possess in order to share DNA with another bacteria cell?

6. Why during our experiment did we put our e.Coli with pGLO inserted in it onto agar plates with ampicillin (Amp)?

a. So that it would kill the e.Coli and serve as our control

b. To kill all the e.Coli that did not take up the pGLO

c. To create antibiotic resistant bacteria

d. To cause the e.Coli to glow

7. Yeast cells are what type of cell?

a. Bacteria

b. Eukaryotes

c. Prokaryotes

d. Archaea

8. Why would someone study yeast cells instead of human cells?

9. Do you agree or disagree with the following statement: If your cells is exposed to UV light and it causes a thymidine dimer, your cell is doomed to die.

10. Are wildtype (control) yeast immune to UV light damage?

11. BTB was a dye we used to directly measure ________

a. PH

b. Oxygen

c. Carbon Dioxide

d. Carbon

12. BTB was a dye we used to INDIRECTLY measure ________

a. PH

b. Oxygen

c. Carbon Dioxide

d. Carbon

13. What is one reason why a plant would want to close its stomata?

14. What is one function that ground tissues provides for a plant?

15. List one difference between monocots and dicots

16. Why is it important for a plant to have stomata? Write one reason why

17. What is the purpose of xylem in a plant cell?

18. Pholem is also important to plant cells, what is itâs purpose?

19. This theory explains why trees can grow to such tall heights and still provide water to their leaves.

a. Translocation

b. Transpiration

c. Cohesion-Tension

d. Vacuum

20. Fill in the blank

Pholem is considered to be a(n) _________ transport system while xylem is considered a(n) _______________transport system.

21. Apical meristems are found in these two places on a plant

a. At the site of new leaf growth and the roots closes to the top of the soil

b. Vascular tissue and ground tissue

c. Ground tissue and dermal tissue

d. The point of new growth on the stem and root

22. Fill in the blank.

Xylem moves substances _____ while phloem moves substances _____ a plant.

23. What are the two types of digestive mechanisms?

24. What is one benefit that mastication has for digestion?

25. What is an example of an organism that digests food intracellularly?

26. What is an example of an organism that digests food extracellularly?

27. Give two examples of where surface area is increased in a small space to aid in absorption within the human body

28. Name one difference between arteries and veins.

29. What is the role of capillaries in the circulatory system?

30. How are the terms âexcretionâ and âdefecationâ different?

31. What is the role of the ADH hormone?

32. What does the term âMedullaâ refer to when talking about mammalian tissue?

a. The outer edges of a tissue

b. The middle of a tissue

c. The top of a tissue

d. The bottom of a tissue

33. Fill in the blank

Mammals have a _______ circulatory system while insects have a _______ circulatory system.

34. What is one benefit a closed circulatory system provides?

35. What is hemolymph?

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