问题 选择题

生物体的不断长大,要靠细胞数目的增加,即细胞分裂.下列各项,不发生在体细胞分裂过程中的是(  )

A.遗传物质的复制

B.细胞质被分成两份,每份各含一个细胞核

C.形成两个子细胞,每个子细胞中的染色体数目为母细胞的一半

D.染色体在分裂中平均分配

答案

A、在细胞的分裂过程中,细胞核内的遗传物质先经过复制,然后平均分配到连个新的细胞中,使新细胞内的遗传物质与亲代细胞保持一致.故不符合题意.

B、细胞分裂的过称为:先是细胞核一分为二,接着细胞质一分为二,最后在两个细胞中央形成新的细胞膜.故不符合题意.

C、细胞分裂后,新形成的细胞和原细胞的遗传物质是一样的.遗传物质是DNA,DNA和蛋白质组成染色体,因此新细胞和原细胞的染色体也是一样的.故符合题意.

D、染色体的数量在细胞分裂时已经加倍,在细胞分裂过程中,染色体分成形态和数目相同的两份,分别进入两个新细胞中.故不符合题意.

故选:C

选择题
单项选择题

The questions in this group are based on the content of a passage. After reading the passage, choose the best answer to each question. Answer all questions following the passage on the basis of what is stated or implied in the passage.

While most people agree that the Golden Age of comic books began with the introduction of Superman in 1938 in Action Comics #1, there is less agreement about when exactly the Golden Age ended. There is a general consensus, however, about the factors that brought the Golden Age to a close: the rise of the horror comic book in the late 1940s, and the resulting backlash against comic books in the early 1950s.

Superhero comic books reached their peak of popularity in the early 1940s because of all the GIs in Europe and Japan who eagerly read about Superman, Batman, and The Spirit. When these soldiers came home, they still wanted to read comic books, but they sought out more adult content. William Gaines of EC Comics was happy to meet the market demand with such grim and gritty titles as Weird Fantasy and The Crypt of Terror. The creators of superhero comic books, not wanting to be left behind, responded by matching their protagonists against darker criminals in more violent encounters.

These darker comic books aroused the anger of child psychologist Fredric Wertham, who believed that comic books were leading the nation’s youth into crime, violence, and drug abuse. Wertham’s book, The Seduction of the Innocent, was a national best-seller that helped bring about congressional investigations into the corrupting influence of comic books. The Senate committee that reviewed Wertham’s charges decided to create the Comics Code Authority, a regulatory body that prohibited comic books from mentioning sexuality, alcohol, drugs, criminal behavior, or any themes related to the horror genre.

These regulations had a numbing effect on the industry. EC Comics was nearly driven out of the comics business, and the other major players canceled many of their most prominent titles. The comics business did not recover until the Marvel revolution of the early 1960s ushered in the Silver Age.

According to the passage, what can we infer to be the central message of Fredric Wertham’s The Seduction of the Innocent ?()

A. Adults reading violent comic books were as likely to be corrupted by them as young people were.

B. The horror comic books of the late 1940s were inferior to the superhero comic books that gained popularity during World War Ⅱ.

C. Comic books were leading the nation’s youth into crime, violence, and drug abuse.

D. Creating a regulatory board to censor the comic book industry would drive the worst offenders out of the business.

E. Comic books would never be able to convey stories of any serious literary merit.