Modern Biology HW 1 Ch 1 4 30 pts Name Due Sunday September 23th Group 1 What is a hypothesis and what are the two steps to testing it 3pts proposed explanation for a phenomena state hypothesis and list predictions Design experimental study that can test predictions 2 What determines whether a chemical reaction is spontaneous 1pt a If it decreases the S of substances involved b If it decreases potential energy of the substances involved c Temperature reactions are spontaneous at high T and nonspontaneous at low T d Combined effect of changes in potential energy and S 3 What determines the number of bonds an atom can make 1pt number of unpaired electrons in valence shell 4 Draw two water molecules joined by an H bond and indicate polarity of each molecule 3pts Figure 2 12 5 A Describe exergonic and endergonic reactions in terms of G 4 pts Endergonic nonspontaneous deltG greater than 0 Exergonic spontaneous deltG less than 0 B CO2 g H2O l H2CO3 g is an example of a chemical equilibrium C Adding additional H2CO3 would drive equilibrium dynamics to the LEFT RIGHT 6 Interactions between R groups or between R groups and the peptide backbone create the Name the five types of interactions that R groups can have 2 pts H bonds hydrophic interactions VDW covalent disulfide bonds ionic bonds 7 Draw a 4 amino acid long polypeptide chain that contains one of the following R groups nonpolar polar acidic basic Label the N terminus C terminus and the names of each amino acid Circle the locations of the peptide bonds 5 pts unique sequence of amino acids vs hydrogen bonding of carbonyl group and amino group Alpha helices B sheets 8 Describe how catalysts affect the energy required for a reaction in terms of transition states and activation energy Do catalysts change the temperature that reaction occurs in YES NO 3 pts lowers the activation energy of a reaction by stabilizing transition state molecule and increases the rate of the reaction 9 Compare and contrast competitive inhibition and allosteric regulation 2 pts Competitive inhibitors compete with the substrate for the active site of the enzyme blocking the substrate from binding Allosteric inhibitors bind to a location on the enzyme other than the active size changing the shape of the enzyme either activating or deactivating the enzyme 10 Indicate below each molecule if it is a purine or a pyrimidine base 2 pts Indicate at least two H bond donors in any combination among these four molecules that contribute to base pairing in helical structures 2 pts Indicate at least two H bond acceptors in any combination among these four molecules that contribute to base pairing in helical structures 2 pts Pyrimidine Purine Donors Acceptors
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