Mr. Cole's Biology Website - Home



DNA Study Guide Answer KeyInvestigate & describe the structure & function of enzymes & explain their importance in biological systems.70. What is the function of enzymes in cells? (Or, what is a catalyst?) Enzymes speed up chemical reactions in cells by lowering the activation energy needed to begin the reaction. 71. Explain the importance of shape to enzyme function. “Work like locks and keys.”72. Explain what determines the shape of an enzyme. It depends on the sequence of amino acids.73. Explain why enzymes are specific. (That is, one enzyme per type of reaction.) Since they work like locks and keys only one enzyme can catalyze one type of substrate(s).74. Explain why enzymes can be reused over and over again. Since enzymes are never used up by the reaction, they go out and search for the same type of substrate(s) to catalyze again.75. How do extreme pH and temperature extremes affect enzymes? (What is denature?) Extreme temperature and/or pH can cause enzymes to denature and no longer function. Denature means that an enzyme literally falls apart (breaks down their bonds) and they cannot be put back together again unless made anew by a ribosome and a piece of mRNA specific for that particular enzyme. 76. Label the picture of the following enzymatic reaction: Substrate, Product(s), Enzyme-substrate complex, EnzymeSubstrate is far left top, Products far right top, enzyme substrate complex is center, enzyme (blue) is same below.All (save for a few) enzymes end in what suffix? -ase What are some examples of enzymes? Lactase, Sucrase, Fructase, ATP synthetase038100077. At what temperature is the best for this enzyme to work? About 40 CHow can you tell? It is where the graph peaks for enzyme reaction (III)78. At which numeral (I, II, III, or IV) does this particular start to denature? IVHow can you tell? The enzyme begins to denature at the end of III where the graph falls and finally drops off (fully denatures) at IV.0609600079. Which enzyme (X or Y) would be used in acidic conditions? XHow can you tell? Because the enzyme works best at pH below 7. Y has no peaks whatsoever in the 0-6 range. It works best in basic conditions.80. What pH is the best for activity for X? 3-4 Y? 8-11How can you tell? It is where the graph peaks for their activity.Goal 3: Learner will develop an understanding of the continuity of life and the changes of organisms over time. 30-35%3.01: Analyze the molecular basis of heredity including: DNA replication, Protein Synthesis (transcription and translation), and gene regulation. 1. Below is a strand of DNA. DNA in the cells exists as a double helix – what needs to be added to it to make it a double helix? Give the complementary nucleotide sequence. CTGGCT (reading left to right)2. Describe the structure of DNA. What are the black pentagons? Deoxyribose sugars The nitrogen bases? ATGC What weak bonds hold the complementary bases together? Hydrogen Bonds3. If the strand of DNA above undergoes transcription, what will the sequence of the mRNA be? CUGGCU051435004. After translation, what would the amino acid sequence be for this section of mRNA? (read from right to left) Leu - Ala5. What is a codon? A 3 letter triplet code used by DNA, read by ribosomes to attach tRNA and amino acids to a growing protein chain.6. Compare RNA and DNA in the following table.RNA DNASugarsRiboseDeoxyriboseBasesAUGCATGCStrands1 strand2 strandsWhereIn CellInside and Outside of the nucleusInside the nucleus onlyFunctionSends a gene message to be translated.Storage center for all genetic material.7. What kind of bond holds the amino acids together in the protein that is formed? Peptide bonds8. What are the three types of RNA and what are their functions?1) mRNA – The message sent from the DNA to code for a particular protein.2) tRNA – the transfer molecules that carry specific amino acids to be attached by ribosomes.3) rRNA – the chemical makeup of Ribosomes.9. What kind of weak bonds hold the two strands of DNA together? Hydrogen Bonds10. Why is it important that these bonds be weak? They need to be weak in order for DNA to make a copy (replication) of itself when a cell divides (mitosis).11. Describe the process of DNA replication. What enzyme breaks apart the hydrogen bonds between bases? DNA Helicase breaks the (hydrogen bonds) strands apart and polymerase adds bases to the growing strand.How many pieces of DNA are made? 2 What does semi-conservative mean? Half old strand; half new strand.12. Describe the process of protein synthesis: What is transcription? The process by which DNA makes a copy of a particular gene to be transcribed into mRNA and sent out to the cytoplasm to be read by the ribosomes.13. What is translation? The process by which mRNA is read by a ribosome which matches mRNA codons to corresponding anticodons on tRNA (and their amino acids) to create a amino acid chain that will become a future protein.14. What happens to DNA when a mutation occurs? A particular base on a codon will not be correct, such as ACG will be ACT.15. How does this affect the mRNA? When the mRNA is transcribed it will carry that mutation, Such as ACT will be UGA instead of UGC.16. How can this affect translation? Depending that the mutation does not cause the wrong amino acid to be paired, it may cause no problem at all. If it does cause the wrong amino acid pair then the protein can suffer from partial function to no function at all.17. How does this affect the structure and shape of the resulting protein? The wrong amino acid sequence affects the shape and structure and hence the function of the protein. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download