BIO 108 G
Final Exam Essays
FINAL EXAM ESSAY
1). A cell is in the process of transcription. The single strand of DNA that is being copied has the sequence ATC GCA GGA TGC. Indicate the mRNA strand that will be synthesized from this strand, listing the correct sequence of bases. Describe why this step is important in the process of producing proteins. Explain how gene expression is regulated. The mRNA coding sequence can be described as units of three nucleotides that are called codons. Since mRNA is made from the template strand it has the same information as the coding strand here the code for the mRNA would be identical. Here are two complementary strand examples of DNA
ATGGAATTCTCGCTC using coding sense strand
TACCTTAAGAGCGAG code for antisense strand
AUGGAAUUCUCGCUC mRNA made antisense strand
Because this produces amino acids when forming with ribosomes you generate proteins through this process. Regulation of gene expression includes the processes that cells and viruses that are used to regulate the information in genes and how they are turned into gene products.
2). Explain how nondisjunction may be related to Down syndrome. Describe four syndromes that result from inheritance of an abnormal sex chromosome number. During meiosis chromosomes are separated equally but if they are not separated equally this is known as non-disjunction in males meiosis I accounts for 80% of cases this is where gametes end up with either an extra chromatid or no chromatid. With Down syndrome the offspring carries an extra chromatid in Chromosome 21 which is Trisomy 21. You have Turner syndrome which is one of the three most common chromosome abnormalities found in first trimester they often have extensive edema which results in neck webbing and arched nails and usually have heart defects and kidney malformation. Triple X syndrome which females are tall and are usually fertile but a...
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