试题与答案

下面“细菌繁殖的速度有多快”的探究,并回答后面的问题。 材料用具:菜豆数颗,8只

题型:探究题

题目:

下面“细菌繁殖的速度有多快”的探究,并回答后面的问题。

材料用具:菜豆数颗,8只一次性水杯。

方法步骤:①水杯按1-8编号,而每颗豆子则代表一个细菌细胞。②在1号杯中放入一颗豆子,代表第一代细菌。大约每隔20分钟,一个细菌细胞就会分裂成两个细菌。在2号杯中放入两颗豆子,代表第二代细菌。③如果2号杯中的每个细菌都分裂成两个细胞,那么计算一下第三代细菌的个数。在3号杯中放入正确数量的豆子。④按照第3步,再计算五次。使所有的杯中都有豆子。

(1)第八代细菌会有__________个细菌细胞?从第一代起已过了多长时间?_______________

(2)如果细菌仍按20分钟分裂一次,那么一个细菌分裂八次后,细菌总数是_____________个。

答案:

(1)128   140分钟

(2)256

试题推荐
题型:阅读理解
配对阅读: 请阅读以下人员的相关信息,然后匹配符合他们的介绍,并将答案填在括号里。
( )11. Liu Xiang was born in Shanghai
in July, 1983. He is a great sportsman.
( )12. Ma Ji was born in Beijing in
1934. He was a famous crosstalk master.(相声大师)
( )13. Yang Liwei was born in Liaoning
Province. He is a good astronaut.
( )14. Wang Xuan was born in 1937.
He graduated(毕业) from Beijing
University in 1958.
( )15. Lu Xun was a great writer. He
had deep eyes, thick moustache(胡子)
and short hair.
A. He used to be an excellent pilot with an experience of 1350hour's flight.
B. He contributed(贡献) a lot to China's crosstalk art.
C. He wrote a lot of novels and articles to fight against the
enemy bravely.
D. He was the head of the Chinese Communist Party(中 * * 党) for 41 years.
E. He won the gold medal in the 110-metre hurdles(跨栏) at
the 28th Athens Olympic Games.
F. He was awarded(被授予) as the yearly(每年一次的) top scientist in 2001.
G. He was considered(被认为) as the greatest scientist of the
20th century, and he won the Nobel Prize of physics in 1921.
查看答案
微信公众账号搜索答案