BSC 2011 UNIT I STUDY GUIDE The purpose of this study guide is to “encourage” you to review your notes and text material, andto integrate numerous facts and terms into broad but meaningful concepts. Please try and work on your own at first, but don’t hesitate to ask for assistance from either me or your TA. We will randomly select a question (or part thereof) to use on your Unit I exam. – Dr. Spears1. (a) Compare and contrast the structure and function of (i) DNA, (ii) mRNA, and (iii) protein.DNA- double helix, phosphate backbone, nucleotide bases (TCAG), deoxyribsose sugarmRNA- single stranded, made in transcription, used in translation to attach amino acids to codonsProteins- single linear chain of amino acids bound together by carboxyl group and amino group. (b) For eukaryotes, what is the function of (i) replication, and where does it occur, (ii) transcription, and where does it occur, and (iii) translation, and where does it occur?Replication- occurs in the nucleus and is semiconservative (one parent, one new)Transcription-takes place in nucleus, mRNA made by dna strand, RNA strands are made here, when gene expression occurs, RNA polymerase II, AAUAA (signature sequence)Translation- After mRNA passes through nucleus into cytoplasm, making proteins from mRNA strand, mRNA hooked between ribosome, rRNA helps the process move. (c) What is the role of (i) ribosomes and (ii) tRNA?Ribosomes- consist of a small subunit in the nucleolus, the major component of translation,their DNA in rRNA guides translation.tRNA- has an anticodon and its respective amino acid, it brings the anticodon to the ribosome to attach its complimentary base and in turn, adds to the amino acid chain. (d) (i) What is meant by the “genetic code”? (ii) distinguish between codons and anticodons.Genetic code- claims that the genetic information is found in DNA and eventually expressed as proteins.Codons- represented by 3 nucleotide bases, example seen in the mRNA strand.Anticodons- attached to the tRNA (e) (i) What is a mutation? (ii) what are the different types of genetic mutations? (iii) why are mutations important to cells/organisms?i) Mutation- a complication in the expression of genes.ii) point mutations, silence, missense, and nonsense mutations, substitution, addition, deletion, frameshift.iii) they affect evolution in a sense of “survival for the fittest” and certain things are expressed (f) What is a gene?Gene- a discreet unit of heredity information on part of a chromosome. Human genome consists of 25,000 genes. (g) what is a chromosome?Chromosome- has chromatin; DNA that is tightly packed. (g) What is chromatin? Distinguish between euchromatin and heterochromatin with respect to structure and function. Chromatin- made of proteins and DNAEurchromatin- loosely packed DNA that can be transcribedHeterochromatin- where genes are not expressed because it has methylation in it, tightly packed. (h) Define control elements and explain how they influence transcription.Control elements are segments of non coding DNA that serve as binding sites for the proteins in transcription.2. (a) Define differential gene expression. At what level is gene expression generally controlled?What is meant by “gene regulation”? why is it important/necessary to cells/organisms? Explain the relationship between differentiation and differential gene expression.Differential gene expression the process of which cells are differentiated and is controlled inthe nucleus. Gene regulation is what is expressed and what isn’t. It’s important to cells/organisms to maintain balance in the body. Differentiation is the process of the cells inthe embryo where gene expression is when the genes are told what to do. (b) What is the role of each of the following with respect to gene regulation (i.e., in what way does each affect gene regulation):(i) transcription factors, (ii) control elements, (iii) histone acetylation, (iv) DNA methylation, (v) miRNA, (vi) describe two additional ways gene expression may be regulated (e.g., explain how gene expression may be controlled at the translational and post-translational level).i) type of protein that are needed for transcription to happen, proteins would not be made without themii) a non coding segment of DNA that allow for the binding of transcription factors iii) which gene is expressed and which isn’t by adding methylated or acetylation (loosely packed); increases positive charge and favors euchromatin.iv) suppresses repetitive elementsv) miRNA- can attach to mRNA and affect translation or destroy the strand, can also potentially destroy maternal CD’s.vi) siRNA (c) The field of genetic engineering utilizes “recombinant DNA”, made by inserting a gene or genes from one organism into another and getting the recipient organism to regulate andexpress the inserted gene(s) as part of its own genome. Please look up (internet okay) familiarize yourself with an example of genetic engineering that utilizes recombinant DNA.Recombinant- synthesized dnaGenetic engineering- using 2 different types of dna put together3. List four different types of proteins, describe their function in a cell/organism, and provide an example (one not mentioned in class) of each.Transcription factors- allow for rna polymerase to latch onEnzymes- they help speed up and catalyze cell processes (ex: hydrolytic eats away at sperm jelly layer)Thyroid hormone- secretes thyroxin (ex: the frogs that had the thyroid removed were big tadpoles)Cytoplasmic determinants- early gene expression in the egg, made up of protein4. (a) Broadly, and in general terms, how and why do cells communicate?They communicate because they need to regulate what is and isn’t being expressed (b) List and describe the three stages of cell signaling. Reception (a single molecule is received by a receptor molecule), transduction (stepwise series of chemical reactions, activated by a receptor molecule to elicit a certain response), response (the end/what happens.) (c) Name some of the types of molecules that play a role in cell signaling.Hormones, neurotransmitters, autocrine signaling, endocrine signaling, (d) Provide three examples of actual signal molecules and what they are intended to do.G-protein link receptor- involved in vision and light signals/odorIntracellular receptor- hormone receptors
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