Ch.5 The Structure and Function of Large Biological Molecules Flashcards
Macromolecules
A giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction (ex: proteins)
Polymer
A long molecule consisting of many similar or identical building blocks linked by covalent bonds
Monomers
The subunit that serves as the building block of a polymer (some have functions of their own)
Enzymes
Specialized macromolecules that speed up chemical reactions
Dehydration Reaction
A reaction in which two molecules are covalently bonded to each other with the loss of a water molecule
Hydrolysis
Reverse of the dehydration reaction; bond between monomers is broken by the addition of a water molecule
Carbohydrates
Include sugars and polymers of sugars
What are the simplest carbohydrates?
Monosaccharides
Disaccharides
Double sugars consisting of two monosaccharides joined by a covalent bond
What are carbohydrate macromolecules?
Polymers called polysaccharides, which are composed of many sugar-building blocks
What are types of monosaccharides?
Glyceraldelcyde, ribose, glucose, galactose, and fructose
What are types of disaccharides?
Sucrose, lactose, and matose
Sucrose
Glucose + fructose
Lactose
Galactose + glucose
Matose
Glucose + glucose
What are types of polysaccharides?
Starch, glycogen, and cellulose
Monosaccharides
The simplest carbohydrate active alone or serving as a monomer for disaccharides and polysaccharides
What is the most common monosaccharide that is of central importance to the chemistry of life?
Glucose (C6H12O6)
What do monosaccharide molecular formulas typically have?
Some multiple of CH2O
What does the location of the carbonyl group in sugar affect?
Whether a sugar is either an aldose or ketose
What is typically the size of the carbon skeletons of sugars?
Ranges from three to seven carbons
Aldoses (aldehyde sugars)
Carbonyl group at the end of the carbon skeleton
Ketoses (ketone sugars)
Carbonyl group within the carbon skeleton
Trioses
Three carbon sugars (ex: glyceraldehyde)
Pentoses
Five carbon sugars (ex: ribose)
Hexoses
Six carbon sugars (ex: glucose)
Polysaccharides
Macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages
Function of polysaccharides
Some serve as storage material, others as building material for structures that protect the cell
How do plants and animals store sugar for later use?
In the form of storage polysaccharides
What is the architecture and function of a polysaccharide determined by?
Its sugar monomers and the position of the glycosidic linkages
Starch
A polymer of glucose monomers that plants store as granules within cellular structures known as plastids
What does starch represent?
Stored energy because the glucose it is made up of is a major cellular fuel
Glycogen
A polymer of glucose that is like amylopectin but more extensively branched (stored by animals)
Where do vertebrates store glycogen?
Mainly in liver and muscle cells
Cellulose
A major component of the tough walls that enclose plant cells
What is the most abundant compound on earth?
Cellulose
What are the two ring forms for glucose called?
Alpha (a) and Beta (b)
Microfibrils
In plant cell walls, they are parallel cellulose molecules held together by hydrogen bonds and grouped into units
Purpose of microfibrils
A strong building material for plants
Chitin
The carbohydrate used by arthropods to build their exoskeleton
What do fungi use chitin for?
As building material for their cell walls
Lipids
Any of a group of large biological molecules, including fats, phospholipids, and steroids that mix poorly, if at all, with water
Why are lipids hydrophobic?
They consist mostly of hydrocarbon regions
What are the most important lipids (biologically)?
Fats, phospholipids, and steroids
Fat
A lipids consisting of three fatty acids linked to one glycerol molecule (also called a triglyceride)
Fatty acid
A carboxylic acid with a long carbon chain (usually 16-18 carbons). Fatty acids differ in length and in the number/location of double bonds
Saturated fatty acid
A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that are attached to the carbon skeleton
Unsaturated fatty acid
A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton
What is the form of saturated fats at room temperature?
The molecules of saturated fats are packed closely together forming a solid
What is the form of unsaturated fats at room temperature?
The molecules of unsaturated fats cannot pack together closely enough to solidify because of the kinks in some of their fatty acid hydrocarbon chains (thus they stay in liquid form)
Trans fats
An unsaturated fat formed artificially during hydrogenation of oils and containing one or more trans double bonds
What is a major function of fats?
Energy storage
Where do humans and other mammals store their long-term food reserves?
In adipose cells which swell and shrink as fat is deposited and withdrawn from storage
Phospholipids
A lipid made up of glycerol joined to two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids act as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head
What do phospholipids form?
Bilayers that function as biological membranes
Steroids
Lipids are characterized by a carbon skeleton consisting of four fused rings
Cholesterol
A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids such as many hormones
What is an enzymatic protein’s function?
Selective acceleration of chemical reactions
What is a defensive protein’s function?
Protection against disease
What is a storage protein’s function?
Storage of amino acids
What is a transport protein’s function?
Transport substances
What is a hormonal protein’s function?
Coordination of an organism’s activities
What is a receptor protein’s function?
Response of cell to chemical stimuli
What is a contractile/motor protein’s function?
Movement
What is a structural protein’s function?
Support
How do enzymatic proteins regulate metabolism?
By acting as catalysts
Catalysts
Chemical agents that selectively speed up chemical reactions without being consumed in the reaction
Polypeptide
A polymer of many amino acids linked together by peptide bonds
Protein
A biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure
Amino acid
An organic molecule that possesses both a carboxyl and an amino group. Amino acids serve as the monomers of polypeptides.
Peptide bond
The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction
Sickle cell disease
An inherited blood disorder caused by the substitution of one amino acid (valine) for the normal one (glutamic acid) at the position of the sixth amino acid in the primary structure of hemoglobin, the protein that carries oxygen in the red cells
Denaturation
A process in which a protein loses its native shape due to the disruption of weak chemical bonds and interactions, thereby becoming biologically inactive
Gene
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA
Nucleic acids
Polymers made up of monomers called nucleotides
Deoxyribonucleic acid (DNA)
A nucleic acid molecule, usually a double-stranded helix, in which each polynucleotide strand consists of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases of adenine, cytosine, guanine, and thymine
Ribonucleic acid
A type of nucleic acid consisting of a polynucleotide made up of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine, cytosine, guanine, and uracil; usually single-stranded and have functions in protein synthesis and gene regulation
Gene expression
The process by which info encoded in DNA directs the synthesis of proteins
Nucleoside
Portion of a nucleotide without any phosphate groups
Pyrimidine
Has one six-membered ring of carbon and nitrogen atoms. Cytosine, thymine, and uracil are pyrimidines
Purines
Characterized by a six-membered ring fused to a five-membered ring. Adenine and guanine are purines
Deoxyribose
The sugar component of DNA nucleotides, having one fewer hydroxyl group than ribose
Ribose
The sugar component of RNA nucleotides
Antiparallel
Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (run in opposite 5’ S 3’ directions)
DNA sequencing
Determining the sequence of nucleotides along a DNA strand
Genome
The entire sequence of the full complement of DNA
Bioinformatics
The use of computer software and other computational tools that can handle and analyze these large data sets
Genomics
The systematic study of whole sets of genes (or other DNA) and their interactions within a species, as well as genome comparisons between species
Proteomics
The systematic study of sets of proteins and their properties, including their abundance, chemical modifications, and interactions
