The pattern of majority of biology exams are multiple choice questions. Some of the most frequently asked questions are as follows:- Q. You will not earn more than 5 points but including extra responses is a good idea just don't contradict yourself. Play attention to the , so you actually address what the question is asking. 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. It has the structural: promoter-operator lac Zr-lac Y-lac A. 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.
It is found in bacterial and archaeal cells. The phenomenon of overlapping genes maximizes the coding capacity of a genome and can also provide a means for the regulation of expression of genes. Gradually new quizzes will appear for the gaps, e. The term cistron has also been used as a synonym for gene. It is sometimes reasonable to assume that highly conserved protein like globin and cytochorme c can be used as a molecular clock to measure how long the species have been diverging from each other. Thus, when lactose is absent the lac operon lactose operon repressor prevents synthesis of enzymes that metabolize lactose.
Which of the following enzyme activity is most directly affected by this drug? After learning each topic, come here, work it out and grow in confidence for your exam. The lac operon occurs in Escherichia coli at ca. X Exclude words from your search Put - in front of a word you want to leave out. . 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. The split genes have also been regarded as interrupted genes. Inducers and co-repressors act by binding to regulatory proteins referred to as activators and repressors.
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. The general rule of thumb is that the mark scheme used by the assessors will have 1. As you are drafting your response, predict how points will be awarded on the mark scheme. 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. The structural and regulatory genes collectively constitute the genotype which determines the phenotype, i. If your response is illegible or not visible, you will not earn points. Be sure to use legible handwriting that is dark enough to read from a scanned image.
How is formyl group removed from the fmet polypeptide in bacteria? 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. The regulatory genes work to control the expression of structural genes. Think of drafting a flow chart to show the process. A double-stranded palindromic sequence can adopt either of two possible formations: 1. Most of the nuclear structural genes in higher eucaryotes are split genes.
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. Once you have selected which question you will respond to, begin writing an outline to your response to each part. The arabinose operon C protein which is an activator causes making of arabinose enzymes on binding to the inducer arabinose. Who discovered that X-rays induce mutations? Ans: While one proceeds from lower to higher eukaryotes, the odd thing in the mitochondrial genome is that it gets smaller, e. Find materials for this course in the pages linked along the left. We have included many questions appeared in different biology exams.
Ans: It occurs in human mitochondria. These are the genes with intervening nucleotide sequences not involved in coding for the gene product. 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. For example, jaguar speed -car Search for an exact match Put a word or phrase inside quotes. Mark it up like crazy! Lastly, include a sentence for each prompt A, B and C that ties the prompt to the others in the question. Which of the following factors facilitates the initiation codon? Ans: Bacteria possess many enzymes whose rate of synthesis depends on the availability of external food molecules.
Ans: The evolution of the organisms from a common ancestor is represented by a branched pathway known as geological tree also known as phylogenetic or evolutionary tree. Coli include in the mismatch repair system. All materials on this website are for the exclusive use of teachers and students at subscribing schools for the period of their subscription. . Ans: The regulatory genes that produce a regulator protein controls induction i. There is no penalty for an incorrect answer.