Controlling the Code: molecules at work The lac operon 2. (a) Write a description of the role of the operator in B-gal production. • What is the operator? The operator is a segment of DNA located between the promoter and the enzyme genes. It acts as a switch by determining whether RNA polymerase can attach to the promoter and start transcribing.
Marshall Nirenberg and Heinrich Matthaei used mRNA made up of repeating uracil nucleotides in a cell free extract. They obtained amino acid chains consisting of phenylalanine. What did they learn when they asked the question, ”What happens when mRNA made up of only cytosine, alanine, and guanine are placed in a cell free extract?” 10. Explain how the structure of tRNA helps it to deliver the correct amino acid to the corresponding mRNA codon at the ribosome. Sketch the structure of a tRNA molecule, making sure to label the amino acid and the
Other types of mutations in DNA can occur when small part of DNA break off the chromosome. These pieces of DNA may introduced in another region in the chromosome and affect the usual translation of information. This type of mutation can affect coding for specific amino acids, which can affect the type of protein formed, which can alter cellular and organismal function. The most common type of mutation are base pair substitution and insertion and deletion mutation. In substitution mutation one base is substitutes another base in the pair.
The enzyme that is responsible for replicating molecules of DNA by attaching complementary bases in the correct sequence is called ____________________ ____________________. 27. Enzymes called ____________________ are responsible for unwinding the DNA double helix by breaking the hydrogen bonds that hold the complementary strands together. 28. Errors in nucleotide sequences are called ____________________.
All of the following statements correctly describe M-Cdk, EXCEPT: A. M-Cdk causes the cell to enter S phase and begin DNA replication. B. M-Cdk has two subunits, a protein kinase and a cyclin-type protein. C. M-Cdk only becomes active during M-phase. D. M-Cdk triggers many events by phosphorylating other proteins. 7.
3. Describe each stage of the flow of information starting with DNA and ending with a trait. Information will start with the DNA traveling to the RNA and into the protein. This information flow will also be followed through the cell as it travels from the DNA in the nucleus, and the Cytoplasm, then to the Ribosomes and the Endoplasmic Reticulum, and finally to the Golgi apparatus, this system packages the final products for export outside the cell (Science Daily, 2013). Reference UIC.edu.
A ribosome can also be known as the chemical factory. Messenger ribonucleic acid (mRNA) has the job of making copies of parts of the DNA as required by the body and taking it through the chemical factory. So in relation to the topic of this essay, a messenger mRNA comes along and takes a copy of a digestive enzyme from the DNA and squeezes through the pores with it into the cytoplasm . In this environment it heads towards the ribosomes and passes through the ribosome where protein synthesis and translation occurs. The protein then passes to the Golgi apparatus where it is processed and packaged or more simply modified and labelled for its digestive function then released in vesicles to go and perform its specific function.