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Miracle Learning Centre Science Tuition Question on DNA. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition)

1 (a) The diagram shows a section of a DNA molecule.

The letters A and G represent 2 of the bases present in the molecule. Describe the structure of DNA. In your answer, you should clearly identify each of the labelled structures. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________ (b) DNA is an information storage molecule. The organic bases present in DNA allow DNA to store information about the sequence of amino acids in a protein. Explain how it acts as an information storage molecule. . _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________

2) Fig. 6.1 shows the four stages of mitosis in an animal cell.

(a) Using the letters P, Q, R and S, list the correct order of the stages. …………………………………………………………………………………... (b) Name the stages. P ………………………………………. Q …………………………………….. R ……………………………………… S ................................................. (c) What is the diploid number of chromosomes in this cell? …………………………………………………………………………………... (d) Describe the characteristics of the resulting daughter cells at the end of the process and state the significance of this to the organism. Characteristics: ………………………………………………………………….. ……………………………………………………………………………………… ………………………………………………………………………………...... significance: ……………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………...... Miracle Learning Centre Answer to Science Tuition Question on DNA. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1 (a) The diagram shows a section of a DNA molecule. The letters A and G represent 2 of the bases present in the molecule. Describe the structure of DNA. In your answer, you should clearly identify each of the labelled structures. 1 DNA molecule made up of two chains/ is a double helix; 2 4 bases: Adenine, guanine, cytosine and thymine 3 A with T; G with C; 4 Held by hydrogen bonds (Y); 5 X is made of sugar and phosphate. [max. 4] (b) DNA is an information storage molecule. The organic bases present in DNA allow DNA to store information about the sequence of amino acids in a protein. Explain how it acts as an information storage molecule. The sequence of bases determines the sequence of amino acids; Three bases code for one amino acid; 2) Fig. 6.1 shows the four stages of mitosis in an animal cell.

(a) Using the letters P, Q, R and S, list the correct order of the stages. Q, P, S and R (b) Name the stages. P: metaphase Q: prophase R: telophase S: anaphase (c) What is the diploid number of chromosomes in this cell? Diploid no. = 4 (d) Describe the characteristics of the resulting daughter cells at the end of the process and state the significance of this to the organism. Characteristics: - the resulting daughter cells are genetically identical to each other; significance: ANY TWO OF THE FOLLOWING: - to increase the number of cells within an organism for growth; - for cell replacement / regeneration of tissues which are damaged or dying such as those lining the stomach wall or in the skin; - or for asexual reproduction; Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.