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Copy the diagram into your answer book and then complete it to show the complementary base pairs of the DNA molecule - Leaving Cert Biology - Question 13 - 2004
Question 13
Copy the diagram into your answer book and then complete it to show the complementary base pairs of the DNA molecule. Label all parts not already labelled. The gene... show full transcript
Worked Solution & Example Answer:Copy the diagram into your answer book and then complete it to show the complementary base pairs of the DNA molecule - Leaving Cert Biology - Question 13 - 2004
Step 1
Copy the diagram into your answer book and then complete it to show the complementary base pairs of the DNA molecule. Label all parts not already labelled.
Answer
The completed diagram should include the following components:
- Two additional sugar molecules (deoxyribose for DNA).
- Two base pairs: adenine pairing with thymine and cytosine pairing with guanine.
Label all parts clearly, showing the correct arrangement of the nucleotides.
Step 2
List these RNA molecules and briefly describe the role of each of them.
Answer
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mRNA (messenger RNA): mRNA is responsible for carrying genetic information from the DNA to the ribosomes, where proteins are synthesized. It transcribes the gene and leaves the nucleus to be translated into a protein.
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tRNA (transfer RNA): tRNA is involved in bringing the correct amino acids to the ribosome during protein synthesis. It matches its anticodon with the mRNA codons, ensuring the correct sequence of amino acids.
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rRNA (ribosomal RNA): rRNA forms the structural and functional components of the ribosome. It aids in the translation process, ensuring that mRNA and tRNA are correctly aligned for protein synthesis.
Step 3
What is the difference between a nucleus of an egg cell and that of a somatic (body) cell of an animal?
Answer
The nucleus of an egg cell (haploid) contains half the number of chromosomes compared to the nucleus of a somatic cell (diploid), which contains the full set. The somatic cell's nucleus carries all the genetic information necessary for the organism's development, while the egg cell's nucleus only carries the genetic material needed for fertilization and early development.
Step 4
Suggest an advantage of producing genetically identical animals.
Answer
One advantage of producing genetically identical animals is the uniformity in traits, which can be beneficial in agriculture and research. This consistency can make breeding more predictable, ensuring that desired characteristics are reliably expressed.
Step 5
Suggest a disadvantage of producing genetically identical animals.
Answer
A significant disadvantage is the reduced genetic diversity, which can lead to increased vulnerability to diseases and environmental changes. If all animals are genetically identical, a single disease could wipe out an entire population.
Step 6
Comment on this statement: "genetic information is only passed on from the mother to the offspring."
Answer
This statement is misleading. Genetic information is passed on from both the mother and the father. During fertilization, the egg cell contributes half of the genetic material, while the sperm cell contributes the other half. Thus, offspring inherit genetic information from both parents.
Step 7
What is meant by the phrase "artificially fertilised egg"?
Answer
An "artificially fertilised egg" refers to an egg cell that has been fertilized through human intervention, usually in a controlled laboratory environment, rather than occurring naturally. This process often involves techniques like in-vitro fertilization (IVF), where sperm and egg are combined outside the body before being implanted into the mother.