Chapter 2100 — Patentability

Ninth Edition, Revision 01.2024

Contents

Patent Bar study guide: MPEP Chapter 2100

Chapter 2100, Patentability, is the examiner's guide to whether a claimed invention can be patented at all. It covers subject-matter eligibility and utility under 35 U.S.C. 101 (§ 2104 to § 2107), how claims are read under the broadest reasonable interpretation (§ 2111), prior art and anticipation (§ 2120 to § 2139, with the AIA's first-inventor-to-file rules in § 2150 to § 2159), obviousness under 35 U.S.C. 103 (§ 2141 to § 2146), and the disclosure and claiming requirements of 35 U.S.C. 112: written description, enablement, best mode, definiteness and means-plus-function claims (§ 2161 to § 2187).

Most of the chapter is about reading claims and judging them against the specification and the prior art, which is what exam questions ask you to do: is this dependent claim proper, does this reference anticipate, is this limitation definite. The AIA's changes to 35 U.S.C. 102 and 103 apply to applications filed on or after March 16, 2013 (§ 2159), so older questions built on pre-AIA 102 are no longer reliable. The questions below test rules that did not change.

Most-tested sections of Chapter 2100

  1. § 2173 Claims Must Particularly Point Out and Distinctly Claim the Invention — 43 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.
  2. § 2152 Detailed Discussion of AIA 35 U.S.C. 102(a) and (b) — 38 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.
  3. § 2144 Supporting a Rejection Under 35 U.S.C. 103 — 25 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.
  4. § 2163 Guidelines for the Examination of Patent Applications Under the 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, first paragraph, “Written Description” Requirement — 22 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.
  5. § 2111 Claim Interpretation; Broadest Reasonable Interpretation — 17 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.
  6. § 2131 Anticipation — Application of 35 U.S.C. 102 — 16 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.
  7. § 2143 Examples of Basic Requirements of a Prima Facie Case of Obviousness — 16 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.
  8. § 2159 Applicability Date Provisions and Determining Whether an Application Is Subject to the First Inventor To File Provisions of the AIA — 16 of the released USPTO exam questions (1999–2003) cite this section or one of its subsections.

Free 10-question Chapter 2100 quiz

  1. Question 1

    A claim limitation reads “having 10 to 20 grams of iron, preferably 13-18 grams of iron.” The specification preceding the claim supports not only the limitation, but also the broader amounts of iron. Which of the following statements is correct?

    1. The limitation may be indefinite.
    2. Since the limitation properly sets forth outer limits, it is definite.
    3. As long as the limitation is supported in the written description, it is proper.
    4. The limitation is definite since the limitation sets forth a preferred range.
    5. The applicant, having set forth a limitation in the claim, i.e., a range of 10 to 20 grams, is precluded by the doctrine of equivalents from expanding the claim coverage beyond the 10 to 20 grams of iron.

    Answer: (A) Under MPEP § 2173.05(c), a claim that recites both a broad range and a preferred narrower range within that broad range may be indefinite if the boundaries of the claim are not clearly discernible. The limitation being described (a preferred narrower range set within a broader range supported by the specification) may render the claim indefinite because a skilled artisan cannot determine the actual scope of protection — whether it is the broader range or the narrower preferred range. This principle remains unchanged under the current MPEP 9th Edition, Rev. 01.2024. Answer (A) is still correct.

    Question from the USPTO registration exam, April 2000 PM, question 33. Answer shown is the answer under current law. See MPEP § 2173.05(c).

  2. Question 2

    Independent claim 1, fully supported by the specification in a patent application states:

    Claim 1. An apparatus comprising: a plastic valve; a copper pipe connected to the plastic valve; and an aluminum pipe connected to the plastic valve.

    Which of the following claims, presented in the application, provide the basis for a proper rejection under 35 U.S.C. § 112, second paragraph?

    Claim 2. The apparatus of claim 1, wherein said pipe is statically charged.

    Claim 3. The apparatus of claim 1, wherein the outer surface of said copper pipe is statically charged.

    Claim 4. The apparatus of claim 1, further comprising a thermostat connected to said plastic valve.

    1. Claim 2.
    2. Claim 3.
    3. Claim 4.
    4. Claims 2 and 3.
    5. Claims 3 and 4.

    Answer: (A) Claim 2 recites 'said pipe' without proper antecedent basis. Claim 1 recites two pipes — a copper pipe and an aluminum pipe — so 'said pipe' in Claim 2 is ambiguous and lacks a specific antecedent basis, rendering it indefinite under 35 U.S.C. § 112(b) (post-AIA) / § 112 second paragraph (pre-AIA). Claim 3 recites 'the outer surface of said copper pipe,' which has clear antecedent basis ('copper pipe' in Claim 1) and 'outer surface' is an inherent structural feature requiring no separate antecedent. Claim 4 recites 'said plastic valve,' which has clear antecedent basis in Claim 1. Therefore, only Claim 2 is properly rejected for indefiniteness. The substantive standard for definiteness under § 112 second paragraph (pre-AIA) and § 112(b) (post-AIA) is the same for purposes of antecedent basis analysis, and the MPEP guidance in § 2173.05(e) remains controlling and unchanged.

    Question from the USPTO registration exam, October 2000 AM, question 10. Answer shown is the answer under current law. See MPEP § 2173.05(e).

  3. Question 3

    In accordance with patent laws, rules and procedures as related in the MPEP, which of the following transitional phrases exclude additional, unrecited elements or method steps from the scope of a claim?

    1. Comprising;
    2. Containing;
    3. Characterized by;
    4. Including; or
    5. None of the above.

    Answer: (E) Under MPEP § 2111.03 (9th Ed., Rev. 01.2024), the transitional term 'comprising' is synonymous with 'including,' 'containing,' and 'characterized by.' All four terms are open-ended (inclusive) transitional phrases that do NOT exclude additional, unrecited elements or method steps. Therefore, none of the listed options (A through D) exclude additional elements — making (E) 'None of the above' the correct answer. A closed transitional phrase such as 'consisting of' would exclude additional elements, but that option is not presented here.

    Question from the USPTO registration exam, October 2003 AM, question 40. Answer shown is the answer under current law. See MPEP § 2111.03.

  4. Question 4

    In accordance with USPTO rules and procedures set forth in the MPEP, which of the following statements regarding claim interpretation during patent prosecution is incorrect?

    1. A claim is to be given its broadest reasonable interpretation in light of the supporting disclosure in the specification.
    2. Because a claim is read in light of the specification, the claim may properly be narrowed by interpreting it as including elements or steps disclosed in the specification but not recited in the claim.
    3. If an applicant does not define a claim term in the specification, that term is given its ordinary meaning in the art.
    4. When an explicit definition of a claim term is provided in an applicant’s specification, that definition controls the interpretation of the term as it is used in the claims.
    5. Means plus function language in claims which defines the characteristics of a machine or manufacture includes only the corresponding structures or materials disclosed in the specification and equivalents thereof.

    Answer: (B) Under current MPEP 9th Edition, § 2111 and § 2111.01, the broadest reasonable interpretation (BRI) standard still applies during prosecution. Choice (B) is incorrect because reading a claim in light of the specification to interpret explicitly recited limitations is proper, but narrowing claim scope by importing limitations from the specification that have no express basis in the claim is improper. This principle remains unchanged from In re Prater and is still codified in MPEP § 2111. The other choices (A, C, D, E) correctly state current examination principles: (A) BRI in light of the specification; (C) ordinary meaning when not defined by applicant; (D) explicit definitions in specification control; (E) means-plus-function claims under 35 U.S.C. § 112(f) (formerly § 112, 6th paragraph) are limited to corresponding structures and equivalents disclosed in the specification.

    Question from the USPTO registration exam, April 2003 PM, question 49. Answer shown is the answer under current law. See MPEP § 2111, MPEP § 2111.01.

  5. Question 5

    To satisfy the written description requirement of the first paragraph of 35 U.S.C. § 112, an applicant must show possession of the invention. An applicant’s lack of possession of the invention may be evidenced by:

    1. Original claims which recite an essential feature where the feature is not described in the specification or the claims, and is not conventional in the art or known to one of ordinary skill in the art.
    2. A specification of a patent application that describes the claimed invention with all of its limitations using such descriptive means as words, structures, figures, diagrams, and formulas that fully set forth the claimed invention.
    3. A specification of a patent application that describes an actual reduction to practice of the claimed invention.
    4. An amendment to a claim seeking to add a limitation that is supported in the specification through implicit or inherent disclosure.
    5. An amendment to a claim seeking to correct an obvious error by the appropriate correction.

    Answer: (A) Under the current MPEP 9th Edition (Rev. 01.2024), § 2163 addresses the written description requirement under 35 U.S.C. § 112(a) (post-AIA, formerly § 112, ¶ 1). The principle that an applicant must show possession of the invention remains unchanged. Lack of possession may be evidenced when the claims require an essential or critical feature that is not described in the specification and is not conventional in the art or known to one of ordinary skill in the art. Choice (A) correctly identifies this scenario. Choices (B), (C), (D), and (E) all describe situations that either demonstrate possession or do not constitute new matter, and thus would not evidence lack of possession.

    Question from the USPTO registration exam, October 2001 PM, question 22. Answer shown is the answer under current law. See MPEP § 2163.

  6. Question 6

    With respect to the examiner’s burden in making an enablement rejection under 35 USC 112, first paragraph, which of the following statements is or are in accordance with the patent laws, rules and procedures as related in the MPEP?

    (1) The examiner may properly make an enablement rejection before construing the claims.

    (2) The examiner has the initial burden to establish a reasonable basis to question the enablement provided for the claimed invention.

    (3) The examiner need not give reasons for the uncertainty of the enablement when there is no evidence of operability beyond the disclosed embodiments.

    1. Statement (1) only
    2. Statement (2) only
    3. Statement (3) only
    4. Statements (1) and (2)
    5. Statements (1) and (3)

    Answer: (B) Under current MPEP 9th Edition (Rev. 01.2024), § 2164.04, the examiner's burden in making an enablement rejection under 35 U.S.C. § 112 (now § 112(a) under AIA) remains the same: (1) the examiner must first construe the claims before analyzing enablement — making statement (1) false; (2) the examiner has the initial burden to establish a reasonable basis to question the enablement provided for the claimed invention — making statement (2) true; and (3) the examiner must give reasons for the uncertainty of the enablement even when there is no evidence of operability beyond the disclosed embodiments — making statement (3) false. Therefore, only statement (2) is correct, and answer (B) remains the correct choice.

    Question from the USPTO registration exam, October 2003 AM, question 32. Answer shown is the answer under current law. See MPEP § 2164.04.

  7. Question 7

    Which of the following statements concerning reliance by an examiner on common knowledge in the art, in a rejection under 35 U.S.C. § 103 is correct?

    I. Applicant can traverse an examiner’s statement of common knowledge in the art, at any time during the prosecution of an application to properly rebut the statement.

    II. An examiner’s statement of common knowledge in the art is taken as admitted prior art, if applicant does not seasonably traverse the well known statement during examination.

    III. If applicant rebuts an examiner’s statement of common knowledge in the art in the next reply after the Office action in which the statement was made, the examiner can never provide a reference to support the statement of common knowledge in the next Office action and make the next Office action final.

    1. I
    2. II
    3. III
    4. I and II
    5. None of the above.

    Answer: (B) Under MPEP § 2144.03, an examiner may rely on common knowledge in the art to support a rejection under 35 U.S.C. § 103, but the applicant must seasonably traverse such a statement. If the applicant does not seasonably traverse, the matter is taken as admitted prior art (per In re Chevenard). Statement I is incorrect because traversal must be timely/seasonable, not 'at any time during prosecution.' Statement III is incorrect because a subsequent action relying on common knowledge can potentially be made final. Statement II correctly reflects the principle that an examiner's reliance on common knowledge must be seasonably traversed or it is treated as admitted prior art. This rule is procedural and unchanged by the AIA.

    Question from the USPTO registration exam, October 2000 PM, question 25. Answer shown is the answer under current law. See MPEP § 2144.03.

  8. Question 8

    Upon examination of your client’s patent application, the patent examiner is considering whether and what rejections to apply to the claims. One or more of the limitations in the claims is indefinite or lacks supporting disclosure. The examiner may not properly take which of the following actions or inactions?

    1. If the claim is subject to plural interpretations due to a limitation being indefinite, the examiner may disregard any possibility of multiple interpretations.
    2. If a claim is subject to more than one interpretation due to a limitation being indefinite, at least one of which would render the claim unpatentable over the prior art, the examiner should reject the claim as indefinite under 35 U.S.C. § 112, second paragraph, and should reject the claim over the prior art based on the interpretation of the claim that renders the prior art applicable.
    3. If no reasonably definite meaning can be ascribed to certain claim language, the examiner should reject the claim as indefinite under 35 U.S.C. § 112, second paragraph, and not reject the claim as obvious.
    4. When evaluating claims for obviousness under 35 U.S.C. § 103, all the limitations of the claims, including new matter lacking supporting disclosure in the originally filed specification, must be considered and given weight.
    5. (C) and (D).

    Answer: (A) The question asks which action an examiner may NOT properly take. Under MPEP § 2143.03, when a claim contains an indefinite limitation, the examiner must consider all possible interpretations and cannot simply disregard multiple interpretations. Option (A) states that the examiner may disregard any possibility of multiple interpretations when a claim is subject to plural interpretations due to an indefinite limitation — this is improper and thus the correct answer to what the examiner may NOT do. Options (B), (C), and (D) all describe proper examiner procedures under MPEP § 2143.03: considering all limitations for obviousness, treating indefinite claims as indefinite rather than obvious, and considering limitations lacking specification support. The underlying principles of MPEP § 2143.03 remain fully intact under the AIA regime.

    Question from the USPTO registration exam, October 2001 PM, question 36. Answer shown is the answer under current law. See MPEP § 2143.03.

  9. Question 9

    Paprika is a known product. A patent application discloses a composition which is made by subjecting paprika to processing steps X, Y and Z. The composition is disclosed to be useful in treating cancer. The application was filed June 1, 2002. A reference published May 1, 2001 discloses a food product made by subjecting paprika to processing steps X, Y and Z. The reference does not disclose that the resulting composition has any properties that would make it useful for treating cancer. In accordance with USPTO rules and procedures set forth in the MPEP, which of the following claims is not anticipated by the reference?

    1. A composition made by the process of subjecting paprika to processing steps X, Y and Z, wherein the composition is effective for treating cancer.
    2. A composition for treating cancer, made by the process of subjecting paprika to processing steps X, Y and Z.
    3. A method of making a cancer-treating composition, comprising subjecting paprika to processing steps X, Y and Z.
    4. A method of treating cancer, comprising administering an effective amount of a composition made by subjecting paprika to processing steps X, Y and Z.
    5. All of the above.

    Answer: (D) Under current MPEP 9th Edition and post-AIA law, the anticipation analysis remains substantively identical. The reference was published more than a year before the application was filed, so it is prior art to every claim. The core principles of anticipation are unchanged: (A) is anticipated because the same starting material subjected to identical processing steps produces the same product, and the 'effective for treating cancer' language is merely an inherent property per MPEP §2112.01; (B) is anticipated because 'for treating cancer' in the preamble is merely a statement of intended use that does not structurally distinguish the composition per MPEP §2112.02; (C) is anticipated because the method steps are identical and 'cancer-treating' in the preamble is merely a statement of intended use per MPEP §2112; (D) is NOT anticipated because it claims a method of treating cancer by administering the composition — this is a specific method of use that is not disclosed or inherently suggested by the reference, which only discloses the composition as a food product. A method claim requires each step to be found in the prior art, and the therapeutic administration step is not disclosed. Therefore (D) remains the correct answer identifying the claim not anticipated.

    Question from the USPTO registration exam, April 2003 PM, question 42. Answer shown is the answer under current law. See MPEP § 2131, MPEP § 2112, MPEP § 2112.01, MPEP § 2112.02.

  10. Question 10

    In connection with the utility of an invention described in a patent application, which of the following conforms to the USPTO rules and the procedure set forth in the MPEP?

    1. A deficiency under 35 USC 101 also creates a deficiency under 35 USC 112, first paragraph.
    2. To overcome a rejection under 35 USC 101, it must be shown that the claimed device is capable of achieving a useful result on all occasions and under all conditions.
    3. A claimed invention is properly rejected under 35 USC 101 as lacking utility if the particular embodiment disclosed in the patent lacks perfection or performs crudely.
    4. To overcome a rejection under 35 USC 101, it is essential to show that the claimed invention accomplishes all its intended functions.
    5. A claimed invention lacks utility if it is not commercially successful.

    Answer: (A) Under the current MPEP 9th Edition, the principle that a deficiency under 35 U.S.C. 101 also creates a deficiency under 35 U.S.C. 112, first paragraph (now 35 U.S.C. 112(a) under AIA) remains valid. MPEP § 2107.01 continues to state that a lack of utility under § 101 necessarily means the specification fails to teach how to use the invention, creating a § 112(a) deficiency because the specification cannot teach how to use the invention. This relationship between § 101 and § 112 has not changed under AIA. The other answer choices remain incorrect as they misstate the standard for utility rejections — a claimed invention need not be useful on all occasions and under all conditions to satisfy § 101.

    Question from the USPTO registration exam, April 2003 PM, question 19. Answer shown is the answer under current law. See MPEP § 2107.01.

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Chapter 2100 FAQ

How many patent bar questions come from MPEP Chapter 2100?

278 of the 899 questions the USPTO released from its 1999–2003 registration exams cite a section of Chapter 2100 (Patentability), more than any other chapter. 180 of them are still answered the same way under current law. The USPTO does not publish how many questions on today's exam come from each chapter, so treat these counts as a guide to what the exam has emphasised, not a quota.

Which sections of MPEP Chapter 2100 are tested most?

In the released questions, the most-cited sections are § 2173 (Claims Must Particularly Point Out and Distinctly Claim the Invention, 43 questions), § 2152 (Detailed Discussion of AIA 35 U.S.C. 102(a) and (b), 38 questions), § 2144 (Supporting a Rejection Under 35 U.S.C. 103, 25 questions). Counts include questions that cite a subsection.

Are the old USPTO questions on Chapter 2100 still useful?

Yes, if you check them against current law. Of the 278 released questions citing Chapter 2100, 180 are marked current under today's rules; the rest turn on rules that have since changed, most often pre-AIA 35 U.S.C. 102. Every question in the quiz on this page is a current one, and the answer shown is the answer under current law.

How are these counts worked out?

Each released question is mapped to the MPEP sections that govern it under the current edition. A question counts once for each section it cites (and once for the chapter), and a section's count includes its subsections. The questions come from the 899 questions the USPTO released for its exams from 1999 to 2003.