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Genetics Questions

1. What are the three types of RNA? What is the function of each?

2. Define mitosis and cytokinesis. What would a daughter cell look like if cytokinesis did not occur after mitosis?

3. Define the following terms: gene, allele, dominant, recessive, true breeding, homozygous, heterozygous, cross-fertilization, self-fertilization.

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1. What are the three types of RNA? What is the function of each?

RNA (ribonucleic acid) is a molecule consisting of a chain of ribose sugars linked together by phosphodiester bonds, with a base connected to each sugar. The bases are: uracil, adenine, cytosine, and guanine. RNA is similar to DNA, another kind of nucleic acid. However, DNA contains a different kind of sugar -- deoxyribose, instead of ribose -- and uses the base thymine in place of uracil.

The three kinds of RNA are:

(1) messenger RNA (mRNA): serves as an intermediate between DNA and protein during protein synthesis by bringing the genetic code from the DNA (in the nucleus) to the ribosomes (in the cytoplasm). mRNA molecules attach to the ribosomes and determine the order in which amino acids are assembled to synthesize a protein.

(2) transfer RNA (tRNA): helps translate the nucleotide sequences in mRNA into amino acid sequences when a protein is being built. tRNA molecules have sites for amino-acid attachment and an anticodon region for codon recognition that binds to a specific sequence on the messenger RNA chain. They transfer a specific amino acid on to the growing polypeptide chain.

(3) ribosomal RNA ...

Solution Summary

The answer to the first question briefly describes RNA and the difference between RNA and DNA, then describes the three main types of RNA. The answer to the second question defines mitosis and the different stages of mitosis, in addition to answering the questions given. The answer to the third question consists of a definition of each term.