biology

Mark Ptashne

Mark Ptashne is a biology 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 Mark Ptashne rather than just read about it. In short: Mark Ptashne (born June 5, 1940, in Chicago) is a molecular biologist. He is the Ludwig Chair of Molecular Biology at Memorial Sloan–Kettering Cancer Center in New York City.

Key takeaways

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

Reference excerpt

Mark Ptashne (born June 5, 1940, in Chicago) is a molecular biologist. He is the Ludwig Chair of Molecular Biology at Memorial Sloan–Kettering Cancer Center in New York City. Ptashne grew up in Chicago. He earned his undergraduate degree at Reed College in Portland, Oregon in 1961 and his PhD from Harvard in 1968, after which he joined the faculty of Harvard. He was made professor there in 1971 and became chair of the Department of Biochemistry and Molecular Biology in 1980. In 1993 he was awarded an endowed chair, and in 1997 he left Harvard for MSK. The focus of his scientific career has been gene regulation. Ptashne was the first scientist to demonstrate specific binding between protein and DNA, and his lifelong work has been the elucidation of the molecular mechanisms of switch between lytic and lysogenic lifecyle of bacteriophage lambda, as well as how the yeast transcriptional activator Gal4 works. He was the originator of the "ball and stick" model of transcription factor function, demonstrating in bacteria and in yeast that they typically consist of separable regions that mediate DNA binding and interaction with transcriptional activators or repressors. In 1980 he cofounded Genetics Institute, Inc. with Thomas Maniatis. The founding of a company by a Harvard scientist was something new at the time, and was very controversial. In 1985, he was awarded the Louisa Gross Horwitz Prize from Columbia University. He won the Albert Lasker Award for Basic Medical Research in 1997, and the Massry Prize from the Keck School of Medicine, University of Southern California in 1998. He has written popular books for a wider scientific audience, including his book Genes and Signals.

Selected works Books Ptashne, M; Gann, A (2002). Genes and Signals. Cold Harbor Spring Laboratory Press. ISBN 978-0-87969-633-7. Ptashne, M (2004). A Genetic Switch: Phage Lambda Revisited (3rd ed.). Cold Harbor Spring Laboratory Press. ISBN 978-0-87969-716-7. Papers Ptashne, M (1967). "Specific Binding of the λ Phage Repressor to λ DNA". Nature. 214 (5085): 232–234. Bibcode:1967Natur.214..232P. doi:10.1038/214232a0. PMID 6034235. S2CID 4209094. Ptashne, M; et al. (1980). "How the λ repressor and cro work". Cell. 19 (1): 1–11. doi:10.1016/0092-8674(80)90383-9. PMID 6444544. S2CID 54281357. Ptashne, M. (2011). "Horace Judson (1931–2011)". PLOS Biology. 9 (7) e1001104. doi:10.1371/journal.pbio.1001104. PMC 3134443.

References

External links Mark Ptashne information at Cooperstown Chamber Music Festival Site Mark Ptashne's page at Sloan-Kettering Institute Site

Illustrations

Worked examples

Example 1 — a first encounter with Mark Ptashne

Start with the simplest possible case. Write down what Mark Ptashne claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Mark Ptashne 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 Mark Ptashne 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 Mark Ptashne

In research: Mark Ptashne appears in biology 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 Mark Ptashne 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: Mark Ptashne is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1940 births, 21st-century American violinists, American biologist stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Mark Ptashne 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 Mark Ptashne in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Mark Ptashne 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 Mark Ptashne out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Mark Ptashne in simple terms?

Mark Ptashne (born June 5, 1940, in Chicago) is a molecular biologist. He is the Ludwig Chair of Molecular Biology at Memorial Sloan–Kettering Cancer Center in New York City.

Why does Mark Ptashne matter?

Because it connects several biology 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 Mark Ptashne?

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 Mark Ptashne.