A cruciform structure in which of two strands each forms hairpins by intra-strand hydrogen bonding. Ans: The term recon was coined by S. What is the importance of wobble and degeneracy? The general rule of thumb is that the mark scheme used by the assessors will have 1. Thus, when lactose is absent the lac operon lactose operon repressor prevents synthesis of enzymes that metabolize lactose. Send to friends and colleagues. Ans: This hypothesis accounts for the observed pattern of degeneracy in the third base of a codon.
Ans: Bacteria possess many enzymes whose rate of synthesis depends on the availability of external food molecules. The process is known as a Diversity splicing b Alternative splicing c Conservative splicing d None of the above 25 Lactose Operon is a set of lactose metabolizing gene that are co-coordinately expressed and regulated. If your response is illegible or not visible, you will not earn points. Find materials for this course in the pages linked along the left. In which groups of microorganisms it is found? Think of drafting a flow chart to show the process. Ans: The overlapping genes are two or more genes in which part or complete gene is co-extensive with part of another.
Ans: The formyl group is often removed from formyl-methionine by the enzyme deformylase leaving behind the methionine as the first amino acid in the polypeptide chain. The palindromic sequence is a region of a nucleic acid that contains a pair of inverted repeat sequences. Ans: A mutator gene or mutator is designated as must within which certain mutations cause an increase in the spontaneous mutation rate in other genes, e. Cancel Submit Introduction These multiple choice quizzes are designed to help students check their understanding of each section of the course. Search within a range of numbers Put. What is the outcome of the process? The arabinose operon C protein which is an activator causes making of arabinose enzymes on binding to the inducer arabinose. How is formyl group removed from the fmet polypeptide in bacteria? For example, jaguar speed -car Search for an exact match Put a word or phrase inside quotes.
There's no signup, and no start or end dates. Activators are positive regulators because their presence is required for the regulated enzyme to be made while repressors act as negative regulators because their regulatory activity is to prevent the synthesis of proteins. The regulatory genes work to control the expression of structural genes. It consist of a Purine rich nucleotide sequence b Pyrimidine rich nucleotide sequence c Uracil containing nucleotide sequence d None of above 35 Which of the following is the initiation codon? Some other mutator genes in E. The structural and regulatory genes collectively constitute the genotype which determines the phenotype, i. A good technique for difficult multi-choice questions is to mark the obviously wrong answers on the the question paper and then choose the best answer from the choice remaining. Mark it up like crazy! These factors are involved in.
It is found in bacterial and archaeal cells. Ans: The catabolite repression is the repression of transcription of genes coding for certain inducible enzyme systems by glucose or other readily utilizable carbon sources. You will also need to know how viral genetic material is replicated, mechanisms of gene regulation, and the lac operon. The mutant alleles may differ from the wild type, e. The lac operon occurs in Escherichia coli at ca. Be sure you know what the question is asking. Ans: Hermann Muller and L.
Most of the nuclear structural genes in higher eucaryotes are split genes. A cistron may also be defined as the functional unit of genetic inheritance a segment of genetic nucleic acid which codes for a specific polypeptide chain. Which of the following is true regarding enhancers? Stadler discovered independently in 1927 that X-rays induce mutations. The parents were told by previous physicians that she suffers from Xeroderma pigmentosum and that they should limit her exposure to sun light. The mutation may lead to reduced accuracy in the polymerising nucleotide selection activity or in the proof reading activity of the enzyme.
A double-stranded palindromic sequence can adopt either of two possible formations: 1. According to this hypothesis the third base can undergo with the corresponding first base in the anticodon. However, upon binding an inducer a molecule related to lactose the repressor loses this Ability and permits the production of enzymes. What controls induction and repression? The genes which code for proteins are referred to as structural genes or cistrons while the other genes bearing regulatory function are called regulatory genes. Try to answer the question before you read the options. Inducers and co-repressors act by binding to regulatory proteins referred to as activators and repressors.
You will not earn more than 5 points but including extra responses is a good idea just don't contradict yourself. These are the genes with intervening nucleotide sequences not involved in coding for the gene product. Which of the following is a transcription factor? Be sure to use legible handwriting that is dark enough to read from a scanned image. What are positive regulators activators and negative regulators repressors?. There is no penalty for an incorrect answer.
Multiple choice questions Paper 1 of the exam is composed entirely of multiple choice questions. Ans: The lac operon stands for lactose operon, an operon which contains genes specifying proteins involved in the utilization of 3 -galactosides such as lactose. Who discovered that X-rays induce mutations? In what type of cell? Advice to students These multiple choice questions are self-marking questions You can click on 'check' at any time to see whether you have the answer correct. The term cistron has also been used as a synonym for gene. All materials on this website are for the exclusive use of teachers and students at subscribing schools for the period of their subscription. Any unauthorised copying or posting of materials on other websites is an infringement of our copyright and could result in your account being blocked and legal action being taken against you.