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59 Cards in this Set
- Front
- Back
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How many naturally occurring elements are there on Earth?
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92
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What percent of the mass of the average human body is made up of Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus (combined?)
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98.8%
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What six elements make up most of the human body?
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Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus
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Why are the atoms of some elements (O, C, H, N, and P) found in greater proportion inside living things than they are outside, on the earth’s crust?
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Organisms collect the necessary building blocks to form, reform, or combine the molecules they require to carry out processes necessary for life
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Why does the energy present in covalent bonds vary depending on the types of atoms forming the bond?
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Because not every covalent bond is the same strength.
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Are linear molecules like CO2 (O=C=O) polar or non-polar?
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Non-polar
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What is the overall significance of polarity in biological molecules?
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It determines the chemical character of part of a molecule.
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What is a macromolecule?
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a molecule with large chains of repeating sub-units
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What is a functional group?
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One or more specific groups of atoms (sub-molecules) often found within a macromolecule
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What are functional groups responsible for?
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The chemical behaviour of a macromolecule
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What does the chemical and physical behaviour of a macromolecule depend on?
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The number, type, and location of functional groups in its structural backbone
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What are the four major types of biological macromolecules?
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Carbohydrates, lipids, proteins, and nucleic acids
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What elements do carbohydrates contain, and in what ratio?
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Carbon, hydrogen, and oxygen in 1:2:1 ratio.
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What is the general formula of a carbohydrate?
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(CH2O)n , where n is the number of carbon atoms
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What is the smallest number of carbon atoms a carbohydrate can have, and what is it called?
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Three - a triose
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What is a six-carbon length carbohydrate called?
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A hexose
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What is the formula of glucose?
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C6H12O6
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What are structural isomers?
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Molecules with the same molecular formula, but different structural formulas
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What are stereoisomers?
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Molecules with the same molecular formula, but their structures are mirror images of one another
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What is the stereoisomer of glucose?
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Galactose
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What is the structural isomer of glucose?
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Fructose
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What happens to the five- and six- carbon monosaccharides in water? Why?
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They form rings and become soluble due to their hydroxyl (OH) groups
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What is a disaccharide?
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When two monosaccharides are linked together
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What two monosaccharides link to make maltose (found in molasses)?
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Two glucose molecules
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What two monosaccharides link to make lactose?
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Glucose and galactose
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What is the formula for sucrose (table sugar)?
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C12H22O11
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What two monosaccharides form to make table sugar/sucrose?
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Glucose and fructose
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Why are complex carbohydrates important?
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For energy storage and structural support in cells.
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What is the typical energy storage molecule in animals?
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Glycogen
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What is the typical energy storage molecule in plants?
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Starch
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What is the structural component of plant cells?
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Cellulose
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What is the molecule that makes the exoskeleton of many invertebrates?
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Chitin
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What are lipids formed from?
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Chains of C, H, and O with other functional groups attached
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What does hydrophobic mean?
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Does not dissolve in, and thus will exclude, water.
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Most lipids are _______________ hydrophobic.
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At least partially
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Why are hydrophobic molecules essential?
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Because they can control or prevent the loss or movement of water
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Why do lipids store energy very effectively?
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Due to their numerous C-C bonds
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What are the four types of lipids?
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Fats, phospholipids, steroids, and waxes
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What is the most effective form of long-term energy storage?
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Fats
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When are fats formed?
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When excess carbohydrates are present
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What is the most common form of fat in both plants and animals?
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Triglycerides
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What are triglycerides comprised of?
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A single glycerol molecule attached to three fatty-acid chains
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Why do stearic acid chains form a straight chain?
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Because they have only straight, single bonds
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Why does a triglyceride made with stearic acid chains have a semi-solid form at room temperature?
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Because they take up less space, as a result of having only straight, single bonds (they are “saturated” with H)
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What are kind of fatty acid chains make up saturated fat?
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Stearic acid
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Why does a triglyceride made with oleic acids tend to be liquid at room temperature?
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Their bent double bonds prevent them from packing together too closely (they are “unsaturated” with H)
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What sort of bonds to triglycerides made of oleic acids have?
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Intermittent, bent double bonds in their hydrocarbon backbones
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What is a eukaryote?
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An organism whose cells contain complex structures enclosed within membranes
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What is a cell membrane?
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The barrier between the internal and external environment; vast sheets composed of a lipid bi-layer of billions of phospholipids.
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What is a lipid-bilayer made up of?
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Pairs of phospholipids
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What forms the inner layer of the lipid-bilayer?
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The hydrophobic, hydrocarbon tails
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What forms the outer layer of the lipid-bilayer?
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The hydrophilic phosphate
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Why do phospholipids add a more fluid character to the cell membrane?
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The kinks created by a rigid double bond in the molecule
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What are some roles of sterols?
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Sex hormones and precursors to vitamins
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What is the sub-unit of proteins?
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Amino acids
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How many different amino acids are joined by peptide bonds to form polypeptides?
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20
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What is the structure of an amino acid?
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An amino group, a carbon atom at its centre, and then a carboxyl group end
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What makes each amino acid different?
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The R-group (side chain)
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How are the 20 amino acids classified?
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By their R-group’s effect on their chemical behaviour (polar, non-polar, or electrically charged)
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