Differences between DNA and RNA Grade 12 Life Sciences Notes with Activities Questions and Answers

DNA vs. RNA: Understanding the Contrast

1. Structure:

• DNA: DNA is a double-stranded helix composed of two polynucleotide chains. Each chain consists of nucleotides with a deoxyribose sugar, a phosphate group, and one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
• RNA: RNA is typically single-stranded and contains ribose sugar instead of deoxyribose. It also comprises nucleotides with adenine, cytosine, and guanine, but instead of thymine, it has uracil (U) as its complementary base pair to adenine.

2. Function:

• DNA: DNA serves as the primary genetic material, carrying the hereditary information of an organism. It stores the instructions necessary for the development, functioning, and reproduction of living organisms.
• RNA: RNA plays various roles in protein synthesis, gene expression, and regulation. It serves as a messenger (mRNA), transfer (tRNA), and ribosomal (rRNA) RNA, facilitating different stages of protein production.

3. Stability:

• DNA: DNA is generally more stable than RNA due to its double-stranded structure and the presence of thymine, which forms stable hydrogen bonds with adenine.
• RNA: RNA is relatively less stable, often prone to degradation by enzymes called ribonucleases (RNases). However, this instability allows for dynamic regulation of gene expression.

4. Location:

• DNA: DNA is primarily located in the cell nucleus (nuclear DNA) of eukaryotic cells, where it is tightly packed into chromosomes. In prokaryotic cells, DNA is found in the nucleoid region.
• RNA: RNA can be found in various cellular locations, including the nucleus, cytoplasm, and organelles like mitochondria and chloroplasts, depending on its type and function.

Activities:

1. Model Building: Divide into groups and construct models of DNA and RNA using candy or craft materials. Label the components of each molecule and explain their significance.
2. Transcription Simulation: Role-play the process of transcription, with one student acting as DNA and others as RNA polymerase and nucleotides. Discuss the importance of RNA in transferring genetic information.
3. Comparative Analysis: Research and present a comparative analysis of DNA and RNA viruses, highlighting their structural and functional differences.

Differences between DNA and RNA

Below is the the differences between DNA and RNA in a table format:

Video Lesson on: Differences between DNA and RNA

Questions and Answers:

1. What are the main structural differences between DNA and RNA?
   • DNA is double-stranded with deoxyribose sugar and thymine, while RNA is typically single-stranded with ribose sugar and uracil.
2. How does DNA store genetic information?
   • DNA stores genetic information in the sequence of its nitrogenous bases, which encode the instructions for protein synthesis and other cellular processes.
3. What role does RNA play in protein synthesis?
   • RNA serves as a messenger, transferring genetic information from DNA to ribosomes, where proteins are synthesized. It also helps in decoding the genetic information and catalyzing peptide bond formation.

Question and Answers Activities:

Find short and long questions for Grade 12 Life Sciences, which will help you to prepare for the exams, tests, practical tasks, and assignments.

EXAM TIP: The structure of the DNA and RNA molecule is very important and is often examined almost every year in Grade 12. Make sure that you know the labels of each component. Remember to label the diagram first and then move onto the questions

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