BSC 2011 UNIT I STUDY GUIDE The purpose of this study guide is to encourage you to review your notes and text material and to 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 Spears 1 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 sugar mRNA single stranded made in transcription used in translation to attach amino acids to codons Proteins 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 DNA Eurchromatin loosely packed DNA that can be transcribed Heterochromatin 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 in the 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 in the 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 them ii 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 elements v 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 and express 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 dna Genetic engineering using 2 different types of dna put together 3 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 on Enzymes 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 protein 4 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 odor Intracellular receptor hormone receptors bind normal receptors in cytoplasm ex grow hair in men e What is a phosphorylation cascade describe and give purpose and what types of molecules are involved Phosphorylation cascade is a multi step pathway that adds phosphate groups to proteins The molecules involved are kinases and protein phosphatases 5 a i Define genomic equivalence ii all the somatic cells in an organism say the human body
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