问题 读图填空题

大麻是一种雌雄异株的植物,请回答以下问题:

(1)在大麻体内,物质B的形成过程如上图所示,基因Mm和Nn分别位于两对常染色体上。

①.据图分析,能产生B物质的大麻基因型可能有____________种。

②.如果两个不能产生B物质的大麻品种杂交,F1全都能产生B物质,则亲本的基因型是_____和_____。F1中雌雄个体随机相交,后代中能产生B物质的个体数和不能产生B物质的个体数之比应为___________。

(2)下图为大麻的性染色体示意图,X、Y染色体的同源部分(图中Ⅰ片断)上的基因互为等位,非同源部分(图中Ⅱ1、Ⅱ2片断)上的基因不互为等位。若大麻的抗病性状受性染色体上的显性基因D控制,大麻的雌、雄 个体均有抗病和不抗病类型。请回答:

①.控制大麻抗病性状的基因不可能位于右图中的_____________片段。

②.请写出具有抗病性状的雄性大麻个体可能有的基因型_______________。

③.现有雌性不抗病和雄性抗病两个品种的大麻杂交,请根据以下子代可能出现的情况,分别推断出这对基因所在的片段:如果子代全为抗病,则这对基因位于___________片段。如果子代雌性全为不抗病,雄性全为抗病,则这对基因位于___________片段。如果子代雌性全为抗病,雄性全为不抗病,则这对基因位于________片段。

答案

(1)①.4  ②.MMnn  mmNN   9:7

(2)①.Ⅱ2   ②.XDXD、XDXd、XdXD、XDY     ③.Ⅰ Ⅰ Ⅰ或Ⅱ

填空题
单项选择题

The objective of the migrant health program of the United States government is to provide grants for the development and enhancement of high quality health care services in rural areas for migrant and seasonal farm workers and their families so as to raise the status of health care for these people to that of the general population. This amelioration can be achieved by providing comprehensive heahh services, which are made aeeessible to people who move frequently, and by improving the physical environment so as to assure healthful living and working conditions wherever workers are located.

Grants are available to state and local health departmenls and other nonprofit agencies, organizations, and institutions. These funds can he used for the following purposes: to establish and operate general family health service facilities and clinics; to provide heahh education, training, and sanitation services to upgrade health conditions; and to initiate preventive health services. Preventive care in the form of immunization programs is the oldest aspect of the program.

The program further attempts to promote flexibility in locating health services where they will be accessible at times and places convenient to migrant workers and their families. The family heahh care clinic, with additional outreach services by field nurses and aides who visit migrant families in camps and at their homes for counseling and follow-up, constitutes the newest and most significant innovation in the initiate preventive health services. However, despite the introduction of innovative approaches, heahh care services for migrant workers are still limited and highly inadequate.

Although the migrant health program has no fixed matctling ratio, a grantee is required to pay part of the cost, which varies from project to project. Many rural counties do not have enough money to cover matching payments, nor do many states consider migran! workers’ health a budget priority. The costsharing requirement limits the potential effectiveness of the program, and literally hundreds of communities with a yearly influx of nngrant workers still lack organized local programs to provide the needed services.A major problem for local or state health agencies is their inability to develop case histories and ongoing communication with migrant workers. Lack of knowledge regarding migrant workers’ health needs is another reason for the dearth of services. There has been little communication about health problems among communities, health professionals, and migrant workers themselves. Ignorance of a group’s special needs often leads to exclusion and rejection of that group and its prohlems. This is often the case with migrant workers, as evidenced by the enforcement of state residency requirement. It is, of course, impossible for most migrant workers to meet these requirements and become eligible fro" existing state and local heahh and welfare aid.

What does the word "amelioration" (Para. 1) most probably mean()

A. Complexation

B. Population

C. Improvement

D. Comprehension