Chapter 1A Student Copy Biochemistry PDF

Section 18.1 Biochemistry—An Overview ASYNCHRONOUS MODALITY AUGUST 19, 2024 Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 1  S...

Section 18.1 Biochemistry—An Overview ASYNCHRONOUS MODALITY AUGUST 19, 2024 Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 1  Section 18.1 Biochemistry—An Overview The Study of Living Things Biochemistry: Study of the chemical substances found in living organisms and the chemical interactions of these substances with each other Biochemical substance: Chemical substance found within a living organism Types of biochemical substances: – Bioinorganic substances - Water and inorganic salts – Bioorganic substances - Carbohydrates, lipids, proteins, and nucleic acids Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 2  Section 18.1 Biochemistry—An Overview Bioinorganic and Bioorganic Substances As isolated compounds, bioinorganic and bioorganic substances have no life in and of themselves – When these substances are gathered together in a cell, their chemical interactions are able to sustain life Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 3  Section 18.2 Occurrence and Functions of Carbohydrates Plants and Carbohydrates It is estimated that more than half of all organic carbon atoms are found in the carbohydrate materials of plants Human uses for carbohydrates of the plant kingdom extend beyond food – Carbohydrates in the form of cotton and linen are used as clothing – Carbohydrates in the form of wood are used for shelter and heating and in making paper Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 4  Section 18.2 Occurrence and Functions of Carbohydrates Carbohydrates Most of the matter in plants, except water, is carbohydrate material Carbohydrates account for 75% of dry plant material and are produced by photosynthesis – Cellulose - Structural element – Starch/glycogen - Energy reservoir Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 5  Section 18.2 Occurrence and Functions of Carbohydrates Photosynthesis Process in which plants produce carbohydrates using carbon dioxide, water, and solar energy Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 6  Section 18.2 Occurrence and Functions of Carbohydrates Functions of Carbohydrates in the Human Body Carbohydrate oxidation provides energy Carbohydrate storage, in the form of glycogen, provides a short-term energy reserve Carbohydrates supply carbon atoms for the synthesis of other biochemical substances (proteins, lipids, and nucleic acids) Carbohydrates form part of the structural framework of DNA and RNA molecules Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 7  Section 18.2 Occurrence and Functions of Carbohydrates Functions of Carbohydrates in the Human Body Carbohydrates linked to lipids are structural components of cell membranes Carbohydrates linked to proteins function in a variety of cell–cell and cell–molecule recognition processes Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 8  Section 18.3 Classification of Carbohydrates Empirical formula of simple carbohydrates - – CnH2nOn or Cn(H2O)n (hydrate of C) n is the number of atoms Carbohydrate: Polyhydroxy aldehyde, ketone, or a compound that produces such substances upon hydrolysis Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 9  Section 18.3 Classification of Carbohydrates Monosaccharides Contain single polyhydroxy aldehyde or ketone unit Cannot be broken down into simpler substances by hydrolysis reactions Contain 3–7 C atoms 5 and 6 carbon species are more common Pure monosaccharides - Water soluble white, crystalline solids Monosaccharides - Glucose and fructose Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 10  Section 18.3 Classification of Carbohydrates Disaccharides Contain 2 monosaccharide units covalently bonded to each other Crystalline and water soluble substances Common disaccharides - Table sugar (sucrose) and milk sugar (lactose) Upon hydrolysis, they produce 2 monosaccharide units Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 11  Section 18.3 Classification of Carbohydrates Oligosaccharides Contain three to ten monosaccharide units covalently bonded to each other Free oligosaccharides are seldom encountered in biochemical systems Usually found associated with proteins and lipids in complex molecules – Serve structural and regulatory functions Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 12  Section 18.3 Classification of Carbohydrates Polysaccharides Contain many monosaccharide units covalently bonded Number of monosaccharide units varies from a few 100 units to 50,000 units Examples: – Cellulose - Paper, cotton, wood – Starch - Bread, pasta, potatoes, rice, corn, beans, and peas Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 13  Section 18.4 Chirality: Handedness in Molecules Objects and Handedness Most biological molecules, including carbohydrates, exhibit the property of “handedness” (form of isomerism) Most molecules that possess “handedness” exist in two forms: – “Left-handed” form – “Right-handed” form Related in the same manner as two hands that are “mirror images” of each other Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 14  Section 18.4 Chirality: Handedness in Molecules Mirror Images Mirror image: Reflection of an object in a mirror Classes of objects based on mirror images - – Superimposable mirror images: Images that coincide at all points when the images are laid upon each other Achiral molecule – Nonsuperimposable mirror images: Images where not all points coincide when the images are laid upon each other Chiral molecule (handedness) Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 15  Section 18.4 Chirality: Handedness in Molecules Chirality Chiral center: C atom attached to 4 different groups A molecule with chiral center is said to be chiral A C atom must have four different groups attached to it in order to be a chiral center A chiral C is usually denoted by * Bromochloroiodomethane is a chiral organic molecule Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 16  Section 18.4 Chirality: Handedness in Molecules Responses of Left and Right Handed Forms of a Molecule in a Human Body Both forms may be active, one may be more active, or one may be active and other non-active Example: – Response of the body to the right-handed hormone epinephrine is 20 times greater than responses to the left-handed form Almost all monosaccharides are right handed Amino acids are always left handed Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 17  Section 18.5 Stereoisomerism: Enantiomers and Diasterioisomers Stereoisomers Isomers that have the same molecular and structural formulas but differ in the orientation of atoms in space Two types: – Enantiomers: Stereoisomers whose molecules are non-superimposable mirror images of each other Molecules with chiral center – Diastereomers: Stereoisomers whose molecules are not mirror images of each other Example: Cis-trans isomers Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 18  Section 18.6 Designating Handedness Using Fischer Projection Formulas Fischer Project Formula Two-dimensional structural notation for showing the spatial arrangement of groups about chiral centers in molecules According to this formula, a chiral center is represented as the intersection of vertical and horizontal lines Functional groups of high priority will be written at the top Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 19  Section 18.6 Designating Handedness Using Fischer Projection Formulas Tetrahedral Arrangements The four groups attached to the atom at the chiral center assume a tetrahedral geometry governed by the following conventions: – Vertical lines from the chiral center represent bonds to groups directed into the printed page – Horizontal lines from the chiral center represent bonds to groups directed out of the printed page Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 20  Section 18.6 Designating Handedness Using Fischer Projection Formulas Fischer Project Formulas L and D system used to designate the handedness of glyceraldehyde enantiomers are shown below Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 21  Section 18.6 Designating Handedness Using Fischer Projection Formulas Fischer Project Formulas We now consider Fischer projection formulas for the compound 2,3,4-trihydroxybutanal, a monosaccharide with four carbons and two chiral centers – There are four stereoisomers for this compound and two pairs of enantiomers Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 22  Section 18.6 Designating Handedness Using Fischer Projection Formulas Fischer Project Formulas The D,L system used to designate the handedness of glyceraldehyde enantiomers can be extended to other monosaccharides with more than one chiral center – The carbon chain is numbered starting at the carbonyl group end of the molecule, and the highest-numbered chiral center is used to determine D or L configuration Epimers: Diastereomers whose molecules differ only in the configuration at one chiral center Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 23  Section 18.6 Designating Handedness Using Fischer Projection Formulas ACTIVITY 1 For the next 45 mins, Create a concept Map showing the relationships between or among the following terms: 1. Enantiomers 7. ketones 2. Diasteriomers 8. carbohydrates 3. Chiral Center 9. aldehydes 4. Epimers 10. monosaccharide 5. D and L forms 11. disaccharide 6. Fischer projection 12. oligosaccharide 13. Polysaccharides 14. Hemiacetals 15. Anomers Return to TOC Copyright ©2016 Cengage Learning. All Rights Reserved. 24