STUDY GUIDE LECTURE 8 List the subunits of nucleic acid polymers A nucleic acid polymer polynucleotide is made of monomers called nucleotides Each nucleotide is made of a nitrogenous base a pentose sugar and one or more phosphate groups A nucleotide nucleoside phosphate group o What are the different types of nucleotides Cytosine C Adenine A Guanine G Thymine T Uracil U o Which are found in DNA C A G T o Which are found in RNA C A G U o Which are purines A and G o Which are pyrimidines C U T Explain the difference between a nucleotide and a nucleoside Nucleoside nitrogenous base sugar Nucleotide nucleoside phosphate group o Each nucleotide consists of A nitrogenous base a pentose sugar and one or more phosphate groups Explain which components comprise the backbone of DNA or RNA Nucleotide polymers are linked together to build a polynucleotide Adjacent nucleotides are joined by covalent bonds that form between the OH group on the 3 carbon of one nucleotide and the phosphate on the 5 carbon on the next These links create a backbone of sugar phosphate units with nitrogenous bases as appendages In the DNA double helix the two backbones run in opposite 5 3 directions from each other Explain how nucleic acid polymers are formed It is formed by covalent bonds a sharing of electrons o Is there a polarity to these polymers Yes You need a 3 OH Hydroxyl to link to a 5 PO Phosphate group o How are these polymers extended They are extended downward in one direction and facilitated by covalent linkage Explain the base pairing rule Hydrogen bonds will form between specific nitrogenous bases Adenine purine with thymine pyrimidine Guanine purine with cytosine pyrimidine o How many hydrogen bonds are formed with which base pairs The number of hydrogen bonds formed differs with the nitrogenous base Adenine and thymine forms 2 hydrogen bonds Guanine with cytosine forms 3 hydrogen bonds List the different molecules that can interact with nucleic acids Nucleic acids can interact with themselves DNA RNA and double stranded RNA which is found in some viruses proteins ex ribosomes amino acids ex tRNA other polar molecules nucleic acids have a negative charge Describe the orientation of nucleic acid polymers in DNA and RNA The strand of either DNA or RNA starts with 5 end to 3 end If you have a complementary strand its 5 end matches up with the other one s 3 LECTURE 9 Describe the flow of energy in life Sunlight Green plant cell photosynthesis Glucose Metabolism of glucose in all cells ATP used as a source of energy for cell processes Define metabolism and describe the two main metabolic pathways An organism s metabolism transforms matter and energy subject to the laws of thermodynamics Metabolism is the totality of an organism s chemical reactions Metabolism is an emergent property of life that arises from interactions between molecules within the cell o Which pathway builds molecules Anabolic pathways consume energy to build complex molecules from simpler ones o Which pathway breaks down molecules Catabolic pathways release energy by breaking down complex molecules into simpler compounds Define energy and describe the different types of energy Energy is the capacity to cause change Energy exists in various forms some of which can perform work o Potential energy is energy that matter possesses because of its location or structure o Kinetic energy is energy associated with motion Define and explain the first and second law of thermodynamics o According to the first law of thermodynamics the energy of the universe is constant Energy can be transferred and transformed The first law is also called the principle of conservation of energy o During every energy transfer or transformation some energy is unusable and is often lost as heat According to the second law of thermodynamics Every energy transfer or transformation increases the entropy disorder of the universe Note organized energy is called Free energy G and the change in Free energy Explain the concept of free energy is G A living system s free energy is energy that can do work when temperature and pressure are uniform as in a living cell Free energy is a measure of a system s instability its tendency to change to a more stable state During a spontaneous change Free energy decreases and the stability of a system increases o How do you calculate free energy H change in total energy S change in entropy T temperature in Kelvin G H T S o How do you determine if a reaction is exergonic or endergonic An exergonic reaction proceeds with a net release of free energy and is An endergonic reaction absorbs free energy from its surroundings and is spontaneous nonspontaneous o How do you determine if a reaction is spontaneous or non spontaneous In a spontaneous change The free energy of the system decreases G 0 The system becomes more stable The released free energy can be harnessed to do work Breaking molecules apart by hydrolysis causes DG negative value Spontaneous and exergonic Forming molecules together by dehydration reactions causes Non spontaneous and endergonic Describe an ATP molecule and explain its importance to life DG positive value o ATP powers cellular work by coupling exergonic reactions to endergonic reactions o ATP adenosine triphosphate is the cell s ENERGY shuttle o ATP is composed of ribose a sugar adenine a nitrogenous base and three o ATP is important to live because it allows a cell does 3 main kinds of work phosphate groups Chemical Transport Mechanical Explain what a coupled reaction is o To do work cells manage energy resources by energy coupling the use of an exergonic process to drive an endergonic one Explain how ATP drives endergonic reactions ATP drives endergonic reactions by phosphorylation transferring a phosphate group to some other molecule such as a reactant The recipient molecule is now called a phosphorylated intermediate o What role does the phosphate group play It is transferred to some other molecule such as a reactant Explain how ATP is regenerated from ADP o ATP is a renewable resource that is regenerated by addition of a phosphate group to adenosine diphosphate ADP The energy to phosphorylate ADP comes from catabolic reactions in the cell LECTURE 10 reaction Define a catalyst chemical agent that speeds up a reaction without being consumed by the Define an enzyme catalytic protein the hydrolysis of sucrose by the enzyme sucrase is an example of an enzyme catalyzed reaction o What is a cofactor non protein enzyme
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