问题 解答题

请看下图并回答问题:

(1)构成染色体的物质主要是______和______.

(2)遗传信息的载体是______,它的结构象一个______的梯子.

(3)每种生物______数目是一定的.细胞分裂时______已经复制.

答案

(1)染色体由DNA和蛋白质两种物质构成.

   (2)染色体中遗传物质是基因,但遗传物质的主要载体则是DNA.

   (3)每一种生物细胞内染色体的形态和数目都是一定的,细胞分裂时,细胞核中的染色体由一份复制为形态和数目均相同的两份,平均分到即将分裂成的两个细胞中.

故答案为:(1)DNA;蛋白质(2)DNA;螺旋状(3)染色体;染色体

单项选择题
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Do you know the open-air art gallery in London's Blackall Street? Probably -not. Not many  Londoners know it either, but Henri does and he is willing to show it to you.

Henri used to sleep in parks until he met a charity(慈善机构) that helps homeless people get  back on their feet by becoming tour guides.

Rather than show traditional London sights, “Unseen Tours" take people off the beaten track. Henri has been teaching tourists about the history and architecture of Shoreditch, where he slept on public benches for three years.

When he felt separated from the society, contact with the volunteer network "The Sock Mob" gave Henri hope. "Not everyone just looked down on me," he said. The tours aren't the only actions trying to help those who have suffered a misfortune to stand tall again.

An innovative(创新的) college for homeless people in London, the first of its kind in the country, is attracting hundreds of students. The Recovery College, set up by St Mungo's charity, is providing courses designed to improve technical skills and life skills.

According to Andy Williams, who helps to organize the college, the most popular courses have proved to be about raising self-confidence and developing self-pride.

Steve, now in his 50s, told a reporter how much of a difference it makes to "have a bit of confidence". He had difficulty learning to read and had to leave school when he was 12. Because Steve's problem was not recognized at the time, he was "seen to be unable to read or write", and suffered with depression and alcohol addiction. He says the status of "student" is itself important for people who are used to being treated as outcasts(被遗弃者)

Some charities aim not only to help the homeless become independent but also to make them popular. The Homeless World Cup started ten years ago. Today the tournament draws teams from 48 countries made up of players-men and women-who are, or have been, living in the streets.  It gives them a chance to become football heroes.

小题1:The underlined part "take people off the beaten track" means "take people to______.”

A.famous galleries

B.traditional sights

C.unusual places

D.public benches小题2:How does the Recovery College help the homeless people?

A.By training them to be guides

B.By offering them different courses.

C.By keeping in contact with them.

D.By asking more students to help them.小题3:At the age of 12, Steve _______ .

A.wasn't treated as a normal student

B.had much confidence in himself

C.didn't want to study at school

D.left school because of depression小题4:The purpose of the Homeless World Cup is to help the homeless people _______.

A.become football stars

B.improve life skills

C.gain self-confidence

D.find proper jobs小题5:Which is the best title for the passage?

A.Confidence Back Now.

B.London Tour.

C.The Popular Homeless.

D.Football Heroes.