UCONN BIO 1107 ABBOTT SPRING exam one 100% Correct Answers

Atoms bond to form? - ANS Molecules form when atoms bond to each other. Chemical bonds based on - ANS electron sharing Degree of electron sharing - ANS varies depending on the type of bond formed Why is water important? - ANS water is the most important for life. Water is highly polar and readily forms hydrogen bonds, making it an extremely efficient solvent. What is energy? - ANS Energy is the capacity to do work or supply heat, and can be (1) a stored potential or (2) an active motion. Chemical energy is a form of potential energy, stored in chemical bonds. Spontaneous/Nonspontaneous chemical reactions - ANS spontaneous = lead to lower potential energy and higher entropy,nonspontaneous = require an input of energy. Why is carbon important - ANS Most of the important compounds in organisms contain carbon. Two forms energy exists in - ANS stored potential or as an active motion. Hydrogen bonding makes - ANS makes it possible for almost any charged or polar molecule to dissolve in water. The degree to which electrons are shared in chemical bonds form - ANS s a continuum, from equal sharing in nonpolar covalent bonds, to unequal sharing in polar covalent bonds, to the transfer of electrons in ionic bonds. Chemical reactions are spontaneous - ANS if they proceed on their own, without any continuous external influence such as added energy. Carbon! - ANS Carbon is the most versatile atom on Earth. Because of its four valence electrons, carbon can form many covalent bonds. Carbon-containing molecules can form an almost limitless array of molecular shapes with different combinations of single and double bonds. What do most cell functions depend on? - ANS Most cell functions depend on proteins. What are proteins made from? - ANS Proteins are made of amino acids. Amino acids vary in structure and function. Structure of Protein analyzed at four levels: - ANS amino acid sequence, substructures called alpha helices and beta pleated sheets, interactions between amino acids (shape), combo of individual proteins that make up larger molecules In cells, most proteins are - ANS enzymes that function as catalysts. All proteins are made from just - ANS 20 amino acid building blocks. The 20 amino acids differ only in the - ANS unique R-group attached to the central carbon. The properties of amino acids vary because their R-groups vary. Tasks of Proteins: - ANS Catalysis - enzymes speed up chemical reactions, defense: antibodies complement proteins attack pathogens, movement:motor and contractile proteins, signaling: proteins convey signals, structure: define cell shape, Transport: proteins carry material, control movement in and out of cell Proteins can serve diverse functions in cells because - ANS they are diverse in size and shape as well as in the chemical properties of their amino acids. Enzyme-catalyzed reaction depends on: - ANS Substrate concentration, enzymes intrinsic affinity for substrate, temp, pH. nucleotides consist of: - ANS sugar, phosphate group, and nitrogen-containing base. Ribonucleotides polymerize to form RNA. Deoxyribonucleotides polymerize to form DNA. DNA structure consists of - ANS a sequence of nitrogen-containing bases; its secondary structure consists of two DNA strands running in opposite directions, held together by complementary base pairing, and twisted into a double helix. DNA's structure allows organisms to store and replicate the information needed to grow and reproduce. RNA structure consists of - ANS a sequence of nitrogen-containing bases. Its secondary structure includes short regions of double helices and structures called hairpins. RNA was the first - ANS self-replicating molecule and a forerunner to the first life-form. Enzymes - ANS bring reactants together in precise orientations and stabilize transition states Sugars and carbohydrates are - ANS highly variable in structure. monosaccharides are - ANS Monosaccharides are monomers that polymerize to form polymers called polysaccharides, and are joined by different types of glycosidic linkages. what do carbohydrates do in the cell? - ANS Carbohydrates perform a wide variety of functions in cells: serving as raw material for synthesizing other molecules, providing structural support, indicating cell identity, and storing chemical energy. Describe carbohydrate diversity in cells - ANS serve as precursors to larger molecules, provide fibrous structural materials, indicate cell identity, and store chemical energy. simple sugars polymerize - ANS when a condensation reaction occurs why are there so many different monosaccharides? - ANS because so many aspects of their structure are variable: aldose or ketose placement of the carbonyl group, variation in carbon number, different arrangements of hydroxyl groups in space, and alternative ring forms. Each one has a unique structure and function. Why do most origin-of-life researchers propose that the first life-form was made of RNA? - ANS RNA can copying itself and catalyze the polymerization reactions that would link monomers into a copy of that template. Define amphipathic and give example - ANS Phospholipids are amphipathic lipid molecules - they have hydrophobic and hydrophilic regions. what flows from higher to lower concentration? - ANS ions and molecules