AP生物考试样题及解题思路

　　新东方在线AP频道为大家带来AP生物考试样题及解题思路一文，希望对大家AP备考有所帮助。更多精彩尽请关注新东方在线AP频道!

　　1、单选题

　　AP生物选择题数目为69道，每个选择题有4个选项，考试时间为90分钟。分成两种题型：如下图所示：

　　以下列举几个例子：

　　Question(1)

　　(1)Membranes-bound organelles have been animportant component in the evolution of complex, multicellular organisms. Whichof the following best summarizes an advantage of eukaryotic cells havinginternal membranes?

　　(A)Eukaryotic cells are able to reproducefaster because of the presence of organelles.

　　(B)Some organelles, such as mitochondriaand chloroplasts, are similar to prokaryotic cells in structure.

　　(C)Organelles isolate specific reactions,increasing metabolic efficiency.

　　(D)Compartmentalization leads to a highermutation rate in DNA, which leads to more new species.

　　解答：本题问的是真核细胞中内膜结构的优势是什么。考查了Essential Knowledge 2.B.3: Eukaryotic cells maintain internalmembranes that partition the cell into specialized regions。细胞的内膜系统在细胞内部构建了一个代谢反应的内部环境，一方面可以保证不同的反应在不同的地点发生，不相互影响;另一方面，也能保护细胞免受代谢反应可能带来的伤害。所以，这题正确答案是C。

　　Questions (2)-(5)

　　A biologist spent many yearsresearching the rate of evolutionary change in the finch populations of a groupof islands. It was determined that the average beak size (both length and mass)of finches in a certain population increased dramatically during an intensedrought between 1981 and 1987. During the drought, there was a reduction in thenumber of plants producing thin-walled seeds.

　　(2)Which of the following procedures was mostlikely followed to determine the change in beak size?

　　(A)A few finches were trapped in 1981 andagain in 1987, and their beak sizes were compared.

　　(B)The beak size in fifteen finches wasmeasured in 1987, and the beak size in the original finches was determined byestimation.

　　(C)The beak size in a large number offinches was measured every year from 1981-1987.

　　(D)Finches were captured and bred in 1981,and the beak size of the offspring was measured.

　　解答：本题考查了Essential Knowledge 1.C.3: Populations of organisms continue toevolve。本题比较简单，实验做的是1981-1987年间，干旱对于finch的beak size的影响。需要每年都进行测量，然后比较，所以正确答案是C。

　　(3)Which of the following statements might bestexplain the increase in average beak size in the finch population during thedrought?

　　(A)Finches with bigger beaks are betterable to crack thick-walled seeds and produce more surviving offspring.

　　(B)Finches with bigger beaks can attackand kill finches with smaller beaks.

　　(C)Finches with bigger beaks possessmore-powerful flight muscles and are able to find more food.

　　(D)Finches that crack large seeds developlarger beaks over time.

　　解答：本题考查了Essential Knowledge 1.C.3: Populations of organisms continue toevolve。题目问的是为什么干旱能够导致beak size的增加。Beak size的大小跟前文中资料的seeds肯定相关，因为干旱减少了thin-walled的数量。所以正确答案是A。

　　(4)Which of the following best describes themechanism behind the change in beak size in the finch population?

　　(A)The formation of two new finch speciesfrom a single parent species.

　　(B)A change in gene frequencies in thefinch population due to selective pressure from the environmental change.

　　(C)A new allele appearing in the finchpopulation as a result of mutation.

　　(D)The achievement of dynamic equilibriumin the finch population as a result of homeostasis.

　　解答：本题考查了Essential Knowledge 1.C.3: Populations of organisms continue toevolve。题目要求描述beak size大小变化的机制。在evolution中，selective pressure导致的结果是frequency of alleles的改变。所以，本题的正确答案是B。

　　(5)The biologist discovered that from 1988 to1993, the average beak size declined to pre-1981 levels. The reversal in beaksize from 1988 to 1993 was most likely related to which of the followingevents?

　　(A)A loss of food supply for the finches

　　(B)The end of the drought

　　(C)An increase in drought conditions

　　(D)An increase in predators consumingfinches

　　解答：本题考查了Essential Knowledge 1.C.3: Populations of organisms continue toevolve。题目问的是1988年到1993年间，beak size的大小又回落到1981年的水平。由于1981-1987期间，beak size变大是因为plant seeds的原因，而plant seeds的变化是因为干旱的原因。所以，只要干旱停止，beak size就会回落。所以，这一题的正确答案是C。

　　2、简答题

　　有8道，考试时间也为90分钟。如下表所示：

　　(1)Long Free Response

　　In acertain prairie community, a dominant prairie grass species has recently beeninfected with a virus that disrupts one of the electron transport proteins inthe chloroplasts of infected cells.

　　(a)Describe themost likely effects on cellular processes (be specific as to which processesand molecules are most likely to be directly affected).

　　(b)Describeandexplain the most likely effects onindividual infected plants.

　　(c)Predict theshort-term effects (within a year of infection) on the infected plantpopulations and their communities. Justifyyour prediction.

　　(d)Predict thelong-term effects (years to decades after infection) on the infected plantpopulations and their communities. Justifyyour prediction.

　　答题思路：

　　(a)本题要求描述题干中的事实对于“cellularprocess”的影响。分析题干可知，植物被一种病毒所感染，这种病毒可以干扰叶绿体电子转移链的一个蛋白。需要注意的是本题问的是对于细胞行为过程的影响，尤其还特别强调了“Process or molecules”这些单词。所以必须回答的是细胞内发生了什么事情。而不能从大的方面回答，比如说，最大的影响是影响了光合作用(photosynthesis)就不对，需要描述到细节，比如，由于ETC正常工作受到影响，所以电子转移受到影响，ATP的产生会减少等，同样，NADPH的生成也会减少。随后影响到Calvin cycle中的碳的固定等。

　　参考回答如下：

　　Since ATP and NADPH generated in the ETS oflight reactions are required for dark reaction (Calvin cycle), if one of theETC proteins is disrupted by a virus, production of ATP and NAPDH decreases andthe cell will be unable to produce the organic molecules using CO2via Calvin cycle. In the non-cyclic phosphorylation, the breakdown of water bythe photosystem Ⅱwill release O2,and its electrons can be transferred by ETC. If ETC is disrupted by a virus, O2production will also decrease.(b)本题要求描述和解释对于植物个体的影响。需要注意的是，不同于(a)，这一题既要“describe”，又要“explain”，并且是对植物个体的影响。可以采用倒推的方式进行分析。由于光合作用受到影响，所以光合作用的产物受到影响，由此，植物获得的能量减少，可能导致生长，生殖等都受到影响，也会影响到其它有用分子的生成。参考回答如下：

　　Plant can’t produceglucose because of the decrease in photosynthetic products. Due to the lack ofenergy for building molecules, such as amino acids and nucleic acid, plantbecomes weakened and growth slowly, even may die. For getting energy for surviving,plant may use up pre-infection energy stores. The growth, repair andre

　　production of plant are also stunted due to the deficiency of energy.(c)本题既要求预测(prediction)也要求解释(justify)。考查了对于生态系统中“population”和“community”的短期(short-term)影响。Population指的是同一物种间的影响，community指的是对于生态系统中所有物种的影响。一方面，能量摄取的减少，影响到了本物种数量的减少，进而影响到以此植物为食的动物数量的减少;另一方面，其它植物由于可以获得更多的资源，数量能够得以增加。参考回答如下：

　　Because plant needs a lotof energy for growth and increasing the population size, if a prairie grassspecies is infected by a virus, the population size of this affected grasswould decrease due to death of infected members. In the ecosystem, plant actsas the producer which provides and transfers the energy to the high trophiclevels. The reduction of grass population size can lead to the decrease inconsumer population size since less energy can be transferred from producers.However, uninfected plant species can gain more resources for growth due to thedecreased competition by infected plants. Thus, these plants can have moreoffspring and the population size increases.

　　(d)本题要求预测病毒的感染对其长期的影响(long-term)。长期来看，植物数量不断减少，可能会导致灭绝，并且以此为食的消费者(consumer)的数量也会减少，也可能导致灭绝。这题的难点在于从长期看，这种影响最终的结果可能影响到了基因的频率，涉及到自然选择的内容。因为被感染的植物有可能突变产生抗性，进而影响到基因频率的变化，导致进化。参考回答如下：

　　Plant species becomesextinct in this region and the consumer species which specifically feeds onthis plant species may also become extinct. The genetic variability reduces dueto the extinction of these species and the frequency of alleles in the affectedspecies changes. In this community, the infected grass can be replaced by otherspecies of plants, which stabilizes the community. In turn, the members of thefood chains change. In addition, some members of the affected plant species maybecome resistant to the virus and get more common, leading to no long-termeffect to the community.

　　(2)Short Free Response:

　　Matter continuously cycles through anecosystem. A simplified carbon cycle is depicted below.

　　(a)Identifythe key metabolic process for step Ⅰand the key metabolic process for step Ⅱ, and briefly explainhow each process promotes movement of carbon through the cycle. For eachprocess, your explanation should focus on the role of energy in the movement ofcarbon.

　　(b)Identify an organism that carries out bothprocesses

　　答题思路：

　　本题在考试的时候分值为4分，其中两个“Identify”各1分，“explain”2分。本题难度不是很高，图形描述了“photosynthesis”和“respiration”。关键是题目的要求是要从能量在碳的转移中的作用这一方面进行描述。参考回答如下：

　　(a)The metabolic process for step Ⅰis photosynthesis and for step Ⅱis cellular respiration. In the photosynthesis, lightenergy is converted into chemical energy. In the light reaction, ATP and NADPHare produced using the light energy. In Calvin cycle, carbon is fixed intoorganic molecules (such as glucose) using ATP and NADPH generated in the lightreaction. In the cellular respiration, organic molecules are broken down intosmall molecules to release chemical energy, which is used to synthesize ATP. Inthis process, carbon is transferred from organic molecules to small ones, andfinally, forms CO2.

　　(b)An organism that carries out both processescan be plant.

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