physics

J. Richard McIntosh

J. Richard McIntosh is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand J. Richard McIntosh rather than just read about it. In short: J. Richard McIntosh is a Distinguished Professor Emeritus in Molecular, Cellular, and Developmental Biology at the University of Colorado Boulder.

Key takeaways

J. Richard McIntosh belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect J. Richard McIntosh to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of J. Richard McIntosh from memory before moving on to harder problems.

Reference excerpt

J. Richard McIntosh is a Distinguished Professor Emeritus in Molecular, Cellular, and Developmental Biology at the University of Colorado Boulder. McIntosh first graduated from Harvard with a BA in Physics in 1961, and again with a Ph.D. in Biophysics in 1968. He began his teaching career at Harvard but has spent most of his career at the University of Colorado Boulder. At the University of Colorado Boulder, McIntosh taught biology courses at both the undergraduate and graduate levels. Additionally, he created an undergraduate course in the biology of cancer towards the last several years of his teaching career. McIntosh's research career looks at a variety of things, including different parts of mitosis, microtubules, and motor proteins.

Research interests

Mitosis Most of McIntosh's work focuses on the process of mitosis in the cell. Mitosis is the process of cell division that includes distinct movements of chromosomes in the cell and formation of mitotic spindles. Additionally, McIntosh is very interested in the role of microtubules and motor proteins in this process. Mitotic spindles, composed of microtubules and other proteins, ensure that each of the two new cells during cell division both get one copy of every chromosome. After the chromosomes are separated, then the cells are able to completely separate as well through cytokinesis. In mitosis, there are multiple phases. In prophase, the DNA starts to package itself for division and microtubules reorganize to prepare to form the mitotic spindle. In prometaphase, kinetochores develop where the chromosome will attach to the mitotic spindle. After that, chromosomes move towards the middle of the cell (metaphase plate) and the two copies separate during anaphase. In some of McIntosh's work he looks specifically at the anaphase A portion, which is related to where the chromosome is in relation to the pole it is moving towards. Lastly, in telophase, the cell is wrapping up the stages of mitosis with creating a new nuclear envelope.

Use of electron tomography Additionally, in many of the works outlined below, McIntosh commonly uses electron tomography to image and study the cells. In electron tomography, many different images are put together to create a 3-D image of the subject being studied. This technology is best suited to observe extremely complex structures and can image thinner sections of samples than can be physically made to study.

1970s and 1980s One of McIntosh's earlier studies in the field of cell biology is in 1974, where his team published a paper on the structures of flagella of Pyrsonympha, an organism found in termites. In this work, his team described the axostyle, a collection of microtubules, and presented that the axostyle's attachment to other parts of the cell controls its function. In 1980, McIntosh's curiosity with microtubules continued in "Visualization of the structural polarity of microtubules". The polarity of microtubules is essential to generate the force needed to separate the chromosomes during mitosis, but at the time it was difficult to determine what the polarity is. McIntosh's team uses basal bodies and HeLa cells to study how protofilaments 'hook' onto them—either in right-handedness or left-handedness—in vitro to determine polarity. A few years later, McIntosh published a study in 1984 on how tubulin moves in mammalian cells with a focus on the cell cycle. To study the movements in tubulin in cells during mitosis and interphase, McIntosh used two imaging methods: labeled (dichlorotriazinyl-aminofluorescein or DTAF-) tubulin and fluorescence redistribution (or recovery) after photobleaching (or FRAP). Using the labeled tubulin, McIntosh observed how quickly the freely-added labeled tubulin was polymerized to the existing microtubule structures in the cell. It was noted that measuring the tubulin addition in interphase was difficult due to the lack of structures, while it was more observable in a mitotic cell. While using FRAP, McIntosh noticed that the tubulin redistributed throughout the cytoplasm in both a rapid phase as well as a slower phase. Overall, the redistribution or movement of the labeled tubulin in cells undergoing mitosis was much faster than the redistribution observed for cells in interphase. The next year, McIntosh's interests started to shift towards motor proteins. Kinesin, a motor protein found to move around vesicles in the cell, was recently discovered on another paper published the same year. Here, McIntosh explored the possibility of kinesin as an important part of mitosis, as it can be found in the mitotic spindle. Some of the possible functions that McIntosh suggested kinesin may have in mitosis are that they move chromosomes down microtubules or move microtubules in different areas within the mitotic spindle. The next year, McIntosh's interests started to shift towards motor proteins. Kinesin, a motor protein found to move around vesicles in the cell, was recently discovered on another paper published the same year. Here, McIntosh explored the possibility of kinesin as an important part of mitosis, as it can be found in the mitotic spindle. Some of the possible functions that McIntosh suggested kinesin may have in mitosis are that they move chromosomes down microtubules or move microtubules in different areas within the mitotic spindle.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with J. Richard McIntosh

Start with the simplest possible case. Write down what J. Richard McIntosh claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to J. Richard McIntosh before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about J. Richard McIntosh ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of J. Richard McIntosh

In research: J. Richard McIntosh appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses J. Richard McIntosh in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: J. Richard McIntosh is common in secondary-school and first-year university syllabi. It links to neighbouring topics 20th-century American biologists, American Cancer Society people, American biophysicists, so understanding it makes those chapters shorter.
In everyday life: Look for J. Richard McIntosh outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study J. Richard McIntosh in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what J. Richard McIntosh means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain J. Richard McIntosh out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is J. Richard McIntosh in simple terms?

J. Richard McIntosh is a Distinguished Professor Emeritus in Molecular, Cellular, and Developmental Biology at the University of Colorado Boulder.

Why does J. Richard McIntosh matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study J. Richard McIntosh?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on J. Richard McIntosh.