题目

某二倍体植物宽叶（M）对窄叶（m）为显性，高茎（H）对矮茎（h）为显性，红花（R）对白花（r）为显性。基因M、m与基因R、r在2号染色体上，基因H、h在4号染色体上。⑴基因M、R编码各自蛋白质前3个氨基酸的DNA序列如图，起始密码子均为AUG。若基因M的b链中箭头所指碱基C突变为A，其对应的密码子由_________变为_________。正常情况下，基因R在细胞中最多有_______个,其转录时的模板位于________（填“a”或“b”）链中。⑵用基因型为MMHH和mmhh的植株为亲本杂 　　Most people, when they travel to space, would like to stay in orbit for a few days of more．And this stands to reason, if you’re paying ＄20,000 for your trip to orbit! Strain order for tourism to reach its full potential there’s going to be a need for orbital accommodation－or space hotels．What would a space hotel actually be like to visit? Hotels in orbit will offer the services you expect from a hotel－private rooms, meals, bars．But they’ll also offer two unique experiences：impressive views－of Earth and space－and the endless entertainment of living in zero gravity－including sports and other activities that make use of this． 　　The hotels themselves will vary greatly－from being quite simple in the early days to huge luxury structure at a later date．It’s actually surprising that as later as 1997, very few designs for space hotels were published．This is mainly because those who might be expected to design them haven’t expected launch costs to come down far enough to make them possible． 　　Lots of people who’ve been to space have described vividly what it’s like to live in zero gravity．There are obviously all sort of possibilities for dancing, gymnastics, and zero-G sports．Luckily, you don’t need to sleep much living in zero gravity, so you’ll have plenty of time for relaxing by hanging out in a bar with a window looking down at the turning Earth below． 　　Of course all good things have come to an end．Unfortunately, And so after a few days you’ll find yourself heading back enough you’ll be much more expert at exercising in zero gravity than you were when you arrived．You’ll be thinking how soon you can save up enough to get back up again－or maybe you should change jobs to get to work in an orbiting hotel． (1) When traveling in space, most people would like to stay in orbit for a few days because ________． [　　] A． It is expensive to travel in space B． they would find the possible life in other star systems C． they could enjoy the luxury of space hotels D． they want to realise the full potential of tourism (2) Which of the following is a unique experience that space hotels will offer? [　　] A． The gravitational pull B． The special views． C． The relaxation in a bar． D． The space walk． (3) Which of the following is not discussed in the passage? [　　] A． When was the space traveling made possible? B． What are the unique experiences that space hotels will offer? C． Why were there not many published designs for space hotels? D． How can the travelers enjoy themselves in space hotels? (4) This passage is mainly about ________． [　　] A． traveling in space B． the ways of living in space hotels C． zero gravity and space hotels D． the description of space hotels