Biology 1 9, explain each question

Wrong, it should be: the selective expression of genes leads to cell differentiation;

False, autologous bone marrow stem cells can differentiate into pancreatic islet-like cells after transplantation of human pancreatic tissue because of the different expression of genes, their genes are not lost, and the genetic material is not changed;

That's right; That's right;

False, the germination and growth of corn seeds into new plants is the growth and development process of plants, which reflects cell differentiation but not the totipotency of cells.

False, wheat pollen developed into haploid plants through ex vivo culture is parthenogenesis, which does not reflect cell totipotency;

False, the larger the cell size, the lower the efficiency of exchanging with external substances;

In the process of frog embryonic development, the nutrients required mainly come from the fertilized egg, so the total amount of organic matter obtained by the frog embryo from the environment is constantly decreasing;

False, in the process of frog embryo development, the nutrients required mainly come from the fertilized egg, so the total amount of organic matter in the frog embryo will continue to decrease.

The essence of cell differentiation is the selective expression of genes.

False: Bone marrow stem cells can only differentiate into red blood cells, white blood cells, and platelets.

It has a specific structure and function for cells that have been differentiated.

False: The disappearance of the tadpole tail is the result of apoptosis.

Wrong plants are formed by embryonic development in seeds. Totipotency can only be demonstrated when the plant develops from the beginning of the fertilized egg cell.

Plant tissue culture techniques were applied to the process.

False should be an increase in the relative surface area and a faster exchange of substances.

For embryonic development, the number of cells increases, and the need for oxygen and nutrients also increases.

Wrong At the beginning of embryonic development, the fertilized egg has not yet implanted in the uterus, and the organic matter consumed is stored by itself, and the organic matter is reduced.

It mainly examines how to use biological knowledge to improve yields. A weed removal has nothing to do with the number of rice pests, b rice and weeds belong to the producer, as long as the producer is not completely removed, the trophic level of energy flow will not be reduced, d remove all weeds, of course, the diversity of species is reduced, so this question chooses answer c. Thank you!

The first exclusion is that the diversity of species is reduced, and there is one species missing. aPests eat rice, and do not eat weeds, besides, when the grass is gone, there is only rice left that can be eaten, and the density of pests should have increased. b, rice and weeds have the same trophic progression, weeds are gone, and rice is still acting as that trophic progression.

There are no weeds to share the sun, so the solar energy of the rice has increased.

Others basically agree with Li Xiaoyu's answer.

The density of pests in rice, independent of weeds.

2009 Hainan College Entrance Examination Questions 20th Multiple Choice Question Answer C

This is the test paper of the library, so you can look at it yourself. I hope it helps.

a The total number of pests decreased, while the number of rice pests remained unchanged and the density increased.

b Rice and weeds have the same trophic level and remain unchanged.

c With less weeds, the contact area between rice and sunlight increases, and the fixed solar energy increases.

d There is a clear decline in diversity.

Therefore, choose C.

Wrong, normal cells have both proto-oncogenes and tumor suppressor genes;

False, if the somatic cells of animals become cancerous, they cannot be passed on to their offspring;

That's right; Wrong, the metabolism of cancerous cells is very vigorous;

That's right; That's right;

False, both of these substances are chemical carcinogenic agents;

False, multiple mutations in proto-oncogenes or tumor suppressor genes can lead to cancer, but cancerous changes cannot be passed on to future generations if they occur in the somatic cells of animals.

If the light intensity given is x klx (a x b) and 12 hours of light per day, the dry weight of plant A will (increase) and plant B will (decrease) during the day and night.

Because it can be seen from Figure 2 that for plant A, when the light intensity is 0, that is, at night, only respiration is carried out, and CO2 is only released, and the amount released is 1 (unit omitted), so the 12 hours of darkness in the day, the organic matter consumption is 12 units; At the intersection of the curve and the horizontal axis, the photosynthesis of a plant is exactly equal to respiration; When the light intensity is a, photosynthesis is greater than respiration, and then the organic matter is a process of continuous accumulation, and at this point, it happens that net photosynthesis (i.e., photosynthetic amount - respiration) = 1, if the light is illuminated for 12 hours at this point, then the accumulation amount = 12 units.

So at this light intensity of x klx (a x b), the net photosynthesis of plant a (the accumulation of organic matter for 12 hours during the day) is greater than the amount of respiration (the consumption of organic matter for 12 hours at night). So a dry weight will increase.

In the same way, for plant B, net photosynthesis (accumulation of organic matter during the day) = 2 = respiration (consumption of organic matter at night) at the light intensity of B. So at a light intensity of x klx (a x b), the net photosynthesis (accumulation of organic matter for 12 hours during the day) of plant b is less than the amount of respiration (consumption of organic matter for 12 hours at night). So the b dry weight will be reduced.

The dry weight of plant A will increase, and the dry weight of plant B will decrease Problem solving process Assuming that the light intensity is a, plant A is exposed to light for 12 hours a day, and the net accumulation of organic matter in a day and night is 0, and the light intensity given is X klx (a x b), and the net accumulation of organic matter in a day and night is greater than 0 in a day and night for plant A is 12 hours of light per day, so it increases; Assuming that the light intensity is b, plant B has 12 hours of light per day, and the net accumulation of organic matter in one day and night is 0, and the light intensity given is x klx (a x b), and the net accumulation of organic matter in plant B is less than 0 in one day and night after 12 hours of light per day, so it is reduced.

False, the outer epidermal cells of the purple onion scale leaves are mature plant cells, and the nucleus is very visible under the microscope, and it is impossible to see this base clearly;

False, nuclear pores allow proteins and RNA to move in and out freely, but not freely, but selectively.

That's right; That's right;

That's right; False, cyanobacteria are prokaryotes and do not have a nucleus;

That's right; False, the nuclear liquid is a passage for macromolecular substances to enter and exit, and small molecules are not allowed to pass through; That's right;

False, enzymes are mostly proteins, and a few are RNA, so the constituent units are amino acids and ribonucleotides;

Correct, the substance here is amylase, the chemical essence is protein, which contains a carboxyl group;

False, methylase is an enzyme that is chemically RNA;

That's right; Wrong, low temperature cannot destroy the spatial structure of the enzyme, but can only temporarily reduce the activity of the enzyme;

Wrong, protease hydrolyzes proteins, and the effect of removing oil is not good;

False, enzyme-catalyzed chemical reactions reduce the activation energy of the reaction, not the energy supply;

False, when the temperature is affected on the activity of the enzyme, the enzyme and the substrate should be kept warm at the preset temperature before mixing to ensure that the preset temperature is reached at the beginning of the reaction.

1.False Enzymes: The vast majority of enzymes are proteins and the basic unit of composition is amino acids A few enzymes are RNA The basic unit of composition is ribonucleotide So 1 is false.

Wrong, the pigments in chloroplasts are distributed on the body membrane of the sactoplast, not in the lumen;

False, this process occurs on the chlorophylloid cavity thylakoid membrane, not in the stroma;

That's right; False, the second half of the sentence should be: chemical energy in cellular respiration is converted into chemical energy in heat and ATP;

That's right; No, respiration is going on all the time;

That's right; Wrong, oxygen is produced on the thylakoids of chloroplasts, so oxygen can continue to be produced in the outer high-growth membrane of chloroplasts;

That's right; That's right;

Wrong, there is no accumulation of [H] in anaerobic respiration, and the [H] generated in the middle reduces pyruvate to carbon dioxide and alcohol, or to lactic acid;

Wrong, the intermediate product of anaerobic respiration is pyruvate, and the final product of the most friendly cherry blossom is carbon dioxide and alcohol, or lactic acid;

Wrong, although nitrifying bacteria do not have mitochondria, they have enzymes related to aerobic respiration in their cells, so they also carry out aerobic respiration;

Wrong, when there is no oxygen, the cells will carry out anaerobic respiration, which will produce the toxic effect of alcohol on the cells, and the sub-zero low temperature environment will freeze the water in the cells, destroy the nutrients of the fruit, and fail to achieve the purpose of preservation.

Wrong, the energy required by the human body during strenuous exercise is provided by glucose decomposition, and the muscle cells will carry out anaerobic respiration to produce lactic acid, and the energy required by the human body during strenuous exercise is provided by glucose decomposition, at this time, muscle cells will carry out anaerobic respiration to produce lactic acid, and the lactic acid produced is discharged from the body through metabolic poor fingers; That's right;