Second year biology knowledge competition questions and answersThe following is a sample of the questions and answers for the biology competition:
** I. Multiple choice questions (2 points for each question, 50 points in total)**
1. The rabbit's mR A was transferred into E. Coli cells. E. Coli could synthesize rabbit's hemoglobin. This experiment explained (D)
- A. Rabbit Hemoglobin-synthesizing Gene Entering E. Coli: mR A is not a gene, A error.
- B. [The synthesis of protein is carried out in the Ribosome. The focus of this experiment is not on the synthesis site. B does not meet the meaning of the question.]
- C. Rabbit DNA can instruct E. Coli to synthesize protein: it's inserted into the DNA instead of the DNA, C error.
- D. The rabbit's messenger messenger acid could allow E. Coli to synthesize the rabbit's hemoglobinduring translation. The messenger acid could be used as a template to guide the synthesis of protein.
2. Which of the following statements about mitochondria and plastids is correct (D)?
- A. Similar protein: The two have different functions, and the type of protein they contain is quite different. Wrong A.
- B. The DNA contained in it was similar: the DNA of mitochondria and the DNA of the plastids had differences in structure and function, B error.
- C. The essence of the production of ATPis the same: mitochondria produce ATPthrough oxyphorification, while the plastids produce ATPthrough photosynthesis. The essence is different, C error.
- D. The gases produced or consumed are similar: mitochondria consume oxygen to produce carbon dioxide, while the plastids consume carbon dioxide to produce oxygen. There are gas production and consumption conditions, D is correct.
3. The eyepieces were not changed. First, the cells were observed with the 10x objective lens of the microscope, and then the 40x objective lens was changed to continue the observation. The result was (C)
- A. Like larger, darker field of vision, more cells: should have fewer cells, A error.
- B. If the image is smaller, the field of vision is brighter, and there are fewer cells, then the image strain is greater, and the field of vision is darker.
- C. The image is larger, the field of view is darker, and the number of cells is fewer. The objective lens is larger, the magnifying factor is larger, the image is larger, the field of view is darker, and the number of cells seen is reduced. C is correct.
- D. The image is larger, the field of view is brighter, and there are many cells. The field of view should be darker, and there should be fewer cells. D is wrong.
4. Which of the following descriptions of transfer DNA is correct (D)?
- A. Each tR A can recognize and transport a variety of aa: each tR A can only recognize and transport one aa, A error.
- B. The three bases of the transfer R A were the codons that determined the position of the aa.
- C. The synthesis of transfer R A is in the plasma, while tR A is synthesized in the nucleus.
- D. The tR A recognizes the codons on the messenger R A. The tR A recognizes the codons on the messenger R A through its anti-codons. D is correct.
5. The scientists have developed a chemical interference technique that is expected to silence the human body's pathogenic genes. This interference technique is likely to interfere with (B)
- A. The decomposition process of the ATP-binding gene: has little to do with the silencing of the pathogenic gene, A error.
- B. The synthesis process of a certain messenger DNA: Silencing the gene may interfere with the synthesis of the messenger DNA, thus preventing gene expression. B is correct.
- C. Many of the DNA replication processes were mainly targeted at the suppression of gene expression, not the DNA replication process.
- D. Transamination during protein metabolism: unrelated to gene silencing, D error.
6. In the description of the picture on the right, the incorrect part was (D)
- A. The cell may not be undergoing mitosis, but it must be in the middle stage of mitosis: this cell may be a cell in the middle stage of mitosis or mitosis, A is correct.
- B. The fourth was a single chopstick, consisting of two chromatids, which were connected by a kinetochore. This was the basic structure of a chopstick. B was correct.
- C. There were two pairs of homolog genes in the cell, namely, a pair of homolog genes, and another pair of homolog genes. According to the definition of homolog genes, C was correct.
- D. is synthesized by
7. A type of genetically modified virus C is formed by the DNA of the A virus and the protein shell of the B virus. Virus C is used to infect host cells, and a large number of descendant viruses are produced in the host cells. The descendant viruses have the characteristics of (C).
- A. The characteristics of the C virus: The characteristics of the offspring virus are determined by the genetic material. The genetic material of C is the DNA of A, and A is wrong.
- B. B virus characteristics: B's protein shell does not determine the characteristics of the offspring, B is wrong.
- C. The characteristics of the A virus: Because the genetic material is the A's DNA, the offspring has the characteristics of the A virus. C is correct.
- D. Unique characteristics of the offspring: mainly determined by genetic material, not unique to the offspring, D error.
8. The expression of traits in an organism follows the expression principle of "DNA→ DNA → protein". The following are several statements related to this. The incorrect one is (D)
- A. In the life of A cell, DNA does not change, but the molecules of DNA and protein change. DNA is relatively stable, while the molecules of DNA and protein change according to the functional needs of the cell.
- B. "DNA→ R A" was generally completed in the nucleus, while "R A → R A" was completed in the plasma. Transcription was mainly in the nucleus, while translation was in the plasma. B was correct.
- C. In different cells of the same individual, the DNA was the same, but the DNA and protein were different. C was correct because of the selective expression of genes.
- D. In the life of a cell, the type and quantity of DNA, DNA, and protein remain the same.
** 2. Non-multiple choice questions (50 points in total)(This is only an example. You can add more questions and answers according to your actual needs)**
1. (10 points) Please briefly describe the steps involved in the process of gene expression.
- Gene expression included two main processes, namely, translation and replication. Transcription referred to the process of using a single strand of DNA as a template to synthesize the DNA. In the nucleus, the DNA template was bound to the DNA primer by the DNA primer, and the DNA primer was synthesized according to the principle of base complementation. During this process, the A (adenine) in the DNA was paired with the U (uracil) in the DNA, the T (thymine) was paired with A, the G (guanine) was paired with C (cystine), and the C was paired with G. The transcribed form of the R A included messenger R A (messenger R A), tR A (transfer R A), and rR A (Ribosome R A).
- Translation was the process of synthesizing a protein using the mR A as a template. After entering the cell's nucleus, the mR A would combine with the Ribosome. The anti-codons of the tR were complementary to the codons on the mR A. The anti-codons were connected according to the order of the codons on the mR A to form a protein chain, which was finally processed to form a protein with specific functions.
2. (10 points) Comparing the similarities and differences between the two types of breathing.
- Similar points:
- (1) It is the process of decomposing organic matter to release energy.
- (2) The first stage takes place in the cellular matrix, and there is a process of decomposition of glucose into methyruvate. This stage will produce a small amount of Ang.
- The difference:
- (1) Aerobic breathing requires oxygen to participate, while anoxia does not require oxygen.
- (2) The places for oxygen breathing include the cellular stroma and mitochondria, while the places for oxygen breathing only include the cellular stroma.
- (3) The products of oxygen breathing are carbon dioxide and water, and the products of oxygen breathing are alcohol and carbon dioxide (such as yeast oxygen breathing) or actic acid (such as animal muscle cell oxygen breathing).
- (4) Aerobic breathing releases a large amount of energy, while anoxia breathing releases a small amount of energy.
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The compulsory questions and answers of the sixth grade mathematics competition in primary schoolThe following are some examples of the types of questions and answers that may be involved in the sixth grade mathematics competition:
##1. Calculation Class
1. [Question: Calculating 1.25×17.6 + 36.1 × 0.8+2.63×12.5]
- Answer:
- First of all, the equation can be transformed into: 1.25×17.6+36.1 × 1 = 1.25×17.6 + 36.1× 1 = 26.3 × 1.25.
- It was further converted to: 1.25×17.6+45.125 + 26.3×1.25.
- Using the distribution law of multiplication: 1.25×(17.6 + 26.3)+45.125.
- First, calculate the value in the parenthesis: 1.25×43.9+45.125.
- Multiplication: 54.875+45.125 = 100.
2. [Question: Calculating 7.5×2.3+1.9×2.5]
- Answer:
- Splitting 7.5 into 2.5×3, the equation becomes 2.5×3×2.3+1.9×2.5.
- That is, 2.5×(3×2.3)+1.9 × 2.5 = 2.5×6.9+1.9×2.5.
- Then, using the distribution law of multiplication: 2.5×(6.9 + 1.9)=2.5×8.8 = 22.
##2. Integer-Based Operations
1. [Question: Calculating 1999+999×999]
- Answer:
- Divide 1999 into 1000+999, and the formula becomes 1000+999+999×999.
- Extracting the common factor 999, you get: 1000+999×(1 + 999).
- First, calculate in the parenthesis: 1000+999×1000.
- After extracting the common factor 1000, it was 1000×(1+999)=1000×1000 = 1000000.
2. [Question **: Calculating 8+98+998+ 9998 + 9998+99998]
- Answer:
- Rounding up each number, the original formula =(10 - 2)+(100 - 2)+(1000 - 2)+(10000 - 2)+(100000 - 2).
- Removing the parenthesis, it was 10+100+ 1000 + 10000+100000-2×5.
- The result was: 111110 - 10 = 111100.
##Three and Four Mixed Operations
1. [Question: Calculating (78.6 - 0.786×25+75%×21.4)/15×1997]
- Answer:
- First, calculate the formula in the parenthesis. 0.75 = 75%, then the formula becomes: (78.6-0.786×25 + 0.75×21.4)/15×1997.
- Distortion of the formula in the parenthesis: 78.6×(1 - 0.25)+21.4 × 0.75 × 15×1997.
- That is,(78.6×0.75+21.4×0.75) × 15×1997.
- Using the law of multiplication: (78.6 + 21.4)×0.75 div15 ×1997.
- First, calculate in the parenthesis: 100×0.75 × 15×1997.
- According to the order of calculation: 75 div15 ×1997 = 5×1997 = 9985.
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