2022USABO競賽考試真題解析！

USABO昨天考完啦！同學們(men) 發揮的怎麽(me) 樣？

小編非常理解大家急切對答案的心情，所以給大家奉上2022 USABO真題+答案快來掃碼領取吧！

今年的試題難度如何？著重考察的知識點有哪些？……

為(wei) 了幫助大家更好地總結回顧或備考學習(xi) ，我們(men) 采訪了機構生物導師，給大家帶來關(guan) 於(yu) USABO試卷的整體(ti) 分析！

機構導師點評

今年USABO題目的結構和風格與(yu) 往年類似，依然對閱讀速度和知識量的要求極高。

難度上與(yu) 往年持平，大概三分之一的知識點超出《Campbell Biology》覆蓋內(nei) 容。前幾題較難，考生需要保持心態穩定，但考卷中段（15-30題)出現較多送分題。

細胞、遺傳(chuan) 、動植物生理依然是考試的主體(ti) ，沒有太多超綱知識點，但複雜程度明顯較國際考提升一個(ge) 數量級，這些是考生最應當花時間提升的部分。

化學結構方麵依然是雷打不動的兩(liang) 道題（2、5題），主要考察了amino acid的性質，這對記憶力要求比較高，需要考生背下所有amino acid的性質（non-polar、positively charged和negatively charged)、縮寫(xie) 和全稱。

Animal diversity方麵考察了兩(liang) 道題（49、50題），要求考生掌握動物進化過程中body cavity的演變過程和代表動物，最後一道題是與(yu) phylogeny結合的填充題，需要考生對各個(ge) 進化支點中的代表性動物較為(wei) 熟悉。

Cell communication方麵的知識考查方式較為(wei) 隱蔽，難點在於(yu) 理解題目意思，需要掌握tyrosine kinase receptor的性質。

植物方麵有兩(liang) 道送分題，Pfr對於(yu) 開花的影響依然是考試重點，需掌握其原理，Campbell在這方麵講的並不詳細。

總體(ti) 來說今年的難度與(yu) 往年持平，預祝大家考出好成績！

2022 USABO真題詳解

真題搶先看，快來對答案吧！沒有參考的同學們(men) 也可以用真題資料挑戰一下自己！（文末可領取完整版真題+答案+視頻解析）

Q1.

Linezolid was the first of the oxazolidinone antibiotics to enter clinical use and targets the 23S rRNA ribosomal subunit of Gram-positive bacteria. Staphylococcus aureus has been observed to develop resistance to linezolid by methylation of A2503 in the 23S rRNA. This is an example of antibiotic resistance via:

A. Changes in antibiotic target by mutation.

B. Multidrug efflux pumps.

C. Reduced permeability.

D. Protection by modification.

E. Inactivation by transfer of a chemical group

⏩ 答案：D

Q2.

Which of the following amino acid sequences is MOST likely to be found in a transmembrane domain of a membrane spanning protein?

A. ACLTRLELTFH.

B. APGRHEIPGR.

C. AEDHEDTPGE.

D. AFTAYCLIFFAL.

E. AMMGDEGETM.

⏩ 答案：D

Q3.

In 2006, Dr. Shinya Yamanaka demonstrated that mature cells could be made into pluripotent stem cells (iPSCs) by inserting four transcription factors: Sox2, Oct4, Klf4 and c-Myc. These transcription factors enable the production of a variety of proteins, including telomerase. He did this by constructing a retrovirus with the genes for these transcription factors, which was then introduced into human fibroblasts. Which of the following is NOT correct about iPSCs?

A. Genomic integration of these transcription factors can result in mutation of the host cell genome.

B. After the iPSC divides 1000 times, the daughter cells will still be able to divide.

C. Inserting at a locus with high histone deacetylation prevents the host cell from becoming pluripotent.

D. iPSCs are more susceptible to immune rejection than allografts transplants.

E. Expression of the four transcription factors off plasmids instead of through retroviral transduction reduces the risk of cancer.

⏩ 答案：D

Q4.

The Hedgehog (Hh) signal transduction pathway that plays an essential role during the development of vertebrate embryos and organogenesis. Hh signaling is involved in STEM cell maintenance. Abnormal regulation of this pathway is linked to tumorigenesis, more specifically the development of tumors resistant to chemotherapeutics. Current research is looking into chemicals that target this pathway to serve as a more effective cancer treatment mechanism. Given what you know about signal transduction pathways, what might be the primary targets for potential therapeutics within the Hh pathway?

A. Inhibiting proteins in this pathway from interacting with each other.

B. Irreversibly binding genes that are regulated by the Hh pathway.

C. Mimicking the signaling molecule, ensuring the pathway is always “turned on”.

D. Increasing the production of the receptor protein.

E. Targeting the ribosome to prevent protein synthesis.

⏩ 答案：A

Q5.

You are working in a drug discovery lab that is developing small-molecule inhibitors of the telomerase protein as a potential cancer therapy. Shown below is a model of the key catalytic site of the human telomerase protein. You are responsible for designing a tripeptide molecule that can bind to residues Lys 626, Val 867, and Asp 868. Which of the following tripeptides will bind the strongest to these three amino acids? Assume that the first amino acid in the tripeptide will bind to K626, the second amino acid will bind to V867, and the third will bind to D868.

A. Asp - Ser – His.

B. Glu - Pro – Asn.

C. Asp - Val – Glu.

D. Glu - Ile – Arg.

E. Arg - Ser – Phe.

⏩ 答案：D

 

完整版USABO真題+答案+視頻解析掃描文末二維碼領取！

USABO試題對於(yu) 知識量和閱讀速度要求很高，可以同時準備的BBO也有一定的考查深度！而生物的專(zhuan) 業(ye) 詞匯非常多，也是需要攻克的一大難關(guan) ！準備參加未來USABO/BBO的同學，可以早早準備起來哦！

機構也為(wei) 大家準備了

USABO/BBO班課

助你提升學術能力，高效備賽！

USABO/BBO班課

課程	班型	課時	開課時間
USABO/BBO（全英）	3-8人	40h	5月上旬
USABO/BBO	3-8人	40h	5月上旬
USABO/BBO	3-8人	60h	5月上旬
USABO/BBO	3-8人	40h	12月中旬開課

*以上部分班課可接受插班生

*該學術挑戰活動主辦方為(wei) 海外機構，不與(yu) 任何中國的大學、中學或小學升學加分活動掛鉤，其成績不會(hui) 作為(wei) 任何中國中小學升學或評優(you) 的依據，僅(jin) 定位為(wei) 針對中學生物愛好者的課外興(xing) 趣活動和國際生物教學交流活動。