Carbohydrates Reviewer in General Biology PDF

Reviewer in General Biology I animals, and starch and cellulose, which occur in plants. (e.g. rice, potatoes, wheat & dietary Carbohydrates –Includes simple sugars (which are...

Reviewer in General Biology I animals, and starch and cellulose, which occur in plants. (e.g. rice, potatoes, wheat & dietary Carbohydrates –Includes simple sugars (which are fibers). little ring shape molecule) and complex carbohydrates (also known as long chains). Types of Monosaccharide are a macromolecule, made of carbon, hydrogen and Glucose oxygen. ◉ Most important Also known as sugars ◉ One of the main sources of calories 1:2:1 ratio ◉ It nourishes the brain Simple Sugars Fructose ◉ Plays important role in our diet (e.g. sweet lemonade, yeast, and etc.) ◉ Commonly found in honey, fruits, and root vegetables. Sugars Galactose ◉ Found naturally in fruits, vegetables, grains, as well as animal products like milk and ◉ Galactose is known as the “brain sugar” or cheese. “milk sugar”. It supports the brain development of infants. Types of Carbohydrates TYPES OF DISACCHARIDE Monosaccharides Lactose ▪ Simple sugars; building blocks of all carbohydrates; compounds that contain single ◉ Glucose + Galactose = Lactose carbonyl group and two or more hydroxyl groups. ◉ Found in milk of mammals (e.g. cow and breast milk). ▪ One sugar molecule Sucrose ▪ Simplest form of carbohydrates ◉ Glucose + Fructose = Sucrose ◉ can be a polyhydroxy aldehyde (aldose) or a polyhydroxy ketone (ketose). The simplest ◉ “Table Sugar” monosaccharides contain three carbon atoms ◉ Found in fruits, & vegetables (e.g. sugar cane & and are called trioses, aldoses with four, five, sugar beets). six, and seven carbon atoms are called aldotetroses, aldopentoses, aldohexoses, and Maltose aldoheptoses, respectively. ◉ Glucose + Glucose = Maltose Disaccharides ◉ It is found naturally in a range of different ◉ Two sugar molecules linked together. foods (like cooked sweet potato, pears and honey) and also in a variety of manufactured Oligosaccharides food stuffs like beer, bread, breakfast cereals. ◉ sugars linked by glycosidic bonds; formed Polysaccharides when a few monosaccharides are linked together. (type of carb found in onions, red ◉ When many monosaccharides are linked cabbage, soybeans and etc.). together, the result is a polysaccharide. Polysaccharides that occur in organisms are Polysaccharides usually composed of a very few types of ◉ Formed when many monosaccharides are monosaccharide components. bonded together = glycogen, which is found in GENERAL BIOLOGY I  ◉ Homopolysaccharide = polymer that consists Triglycerides of only one type of monosaccharide Includes fats and oils ◉ Heteropolysaccharide = polymer that consists (Fats: Solid at room temperature, used by of more than one type of monosaccharide. animals for long term energy storage) ◉ A monomer is a single atom, small molecule, (Oils: liquid at room temperature, used by or molecular fragment that, when bonded plants for long term energy storage) together with identical and similar types of monomers, form a larger, macromolecule Triglycerides- contain two types of subunit known as a polymer. molecules: glycerol and fatty acids. ◉ Cellulose is a molecule, consisting of hundreds A fatty acid has a carboxyl group at the polar – and sometimes even thousands – of carbon, end and a hydrocarbon chain at the nonpolar hydrogen and oxygen atoms. Cellulose is the tail. main substance in the walls of plant cells, Amphipathic compounds because the carboxyl helping plants to remain stiff and upright. group is hydrophilic and the hydrocarbon tail is Humans cannot digest cellulose, but it is hydrophobic important in the diet as fibre. Amphipathic refers to a molecule that has one ◉ Starch is a carbohydrate and a natural end with a polar, water- soluble group and component of most plants, including fruits, another end with a nonpolar hydrocarbon vegetables, and grains. Starchy foods are an group that is insoluble in water essential part of a balanced diet, as they provide energy, fiber, and a sense of fullness. Fatty acids can be either Saturated or The body breaks down starch molecules into Unsaturated glucose, which is the body's primary fuel A fatty acid that has only single carbon to source. carbon bonds is known as saturated fatty acids. ◉ Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage Unsaturated fatty acids have one to several in animals, fungi, and bacteria. It is the main double bonds. Double bonds result in kinks in storage form of glucose in the human body. the fatty acid chain. ◉ Chitin is the most abundant Animal fats have saturated fatty acids and are aminopolysaccharide polymer occurring in solid at room temperature while the vegetable nature, and is the building material that gives oils have one or many double bonds and are strength to the exoskeletons of crustaceans, liquid at room temperature. insects, and the cell walls of fungi. saturated = only single bonds Lipids unsaturated = carbon–carbon double bonds in Lipids are group of hydrophobic biomolecules the chain that play a important roles in living organisms. In unsaturated fatty acids, the While the primary function of lipids is long- stereochemistry (relative position) at the term energy storage. double bond is usually cis rather than trans. Categories of Lipids cis = puts a kink in the long-chain Triglycerides hydrocarbon tail Phospholipids trans = like that of a saturated fatty acid in its fully extended conformation. Steroids Phospholipids Waxes GENERAL BIOLOGY I  Phospholipids- are similar to triglycerides in Biological Membrane that they contain glycerol and two fatty acids. ❑ Membrane Structure The phosphate head of the molecule is The disordered structure caused by the hydrophilic. presence of unsaturated fatty acids with cis The fatty acid tails, however, are hydrophobic. double bonds (kinks) in their hydrocarbon chains causes greater fluidity in the bilayer. The presence of cholesterol may also enhance Steroids order and rigidity. The fused-ring structure of Compose of four fused rings of carbon to which cholesterol is itself quite rigid, and the different functional groups are attached. One presence of cholesterol stabilizes the extended well-known steroid molecule is cholesterol. straight-chain arrangement of saturated fatty acids by van der Waals interactions. Cholesterol serves as precursor for the synthesis of other steroids such as ❑ Membrane proteins testosterone, estrogen, vitamin D, and 1. integral membrane proteins = firmly cortisone. embedded in the membrane Cholesterol is present in plasma membranes 2. peripheral membrane proteins = not where it stabilizes the membrane. membrane embedded but remain associated Cholesterol is best known for its harmful with membrane surfaces effects on health when it is present in excess in The protein component of a the blood. It plays a role in the development of membrane can make up from 20% to atherosclerosis > a condition in which lipid 80% of its total weight deposits block the blood vessels and lead to heart disease. Building Blocks of Life: Amino Acids Waxes and Sphingolipids ❑ Proteins are made up of amino acids, which are organic compounds that combine to form Waxes = complex mixtures of esters of long- proteins, serving as the building blocks of life. chain Diverse Functions of Proteins carboxylic acids and long-chain alcohols. ❑ Proteins serve various roles including 🞄 Serve as protective coatings catalyzing metabolic reactions, replicating 🞄 In plants, they coat stems, leaves, and fruit DNA, responding to stimuli, and transporting molecules. 🞄 In animals, they are found on fur, feathers, and skin Amino Acids Myricyl cerotate = the principal component of carnauba wax > extensively used in floor wax GENERAL STRUCTURE: and automobile wax ❑ an amino group, the —NH2 functional group Sphingolipids = no glycerol, but they do ❑ a carboxyl group, the —COOH functional group contain the ❑ both are bonded to the a-carbon long-chain amino alcohol sphingosine ❑ The a-carbon is also bonded to a hydrogen and 🞄 found in both plants and animals to the side chain group (R). 🞄 abundant in the nervous system ❑ The R group determines the identity of the 🞄 The simplest compounds of this class are the particular amino acid. ceramides = consist of 1 fatty acid linked to the amino group of sphingosine by an amide bond. Amino acids structures can also be described based on its symmetry. GENERAL BIOLOGY I  1. chiral = nonsuperimposable mirror images ◆ Importance of primary structure example: ❑ L and D forms = Latin laevus and ⬦ Hemoglobin associated with sickle-cell anemia dexter, meaning “left” and “right,” respectively ⬦ The glutamic acid in the sixth position of normal Hb is replaced by a valine residue in Hb S. > Red ⬦ which comes from the ability of optically active blood cells carrying Hb S behave normally when there compounds to rotate is an ample oxygen supply > When the oxygen pressure polarized light to the left or the right decreases, the red blood cells become sickle- shaped. Secondary structure = the arrangement in space of ⬦ designated as l- and d-amino acids the atoms in the peptide backbone. Example: Alanine and Glyceraldehyde 2 different types: Amino acids structures can also be described based on 1. a-helix its symmetry. 2. b-pleated sheet 1. chiral = nonsuperimposable mirror images ❑ L and D forms = Latin laevus and ◆ Secondary structures have repetitive dexter, meaning “left” and “right,” interactions resulting from hydrogen respectively bonding between the amide N-H and the carbonyl groups of the peptide ⬦ which comes from the ability of optically active backbone. compounds to rotate The collagen triple helix polarized light to the left or the right ◆ Collagen = component of bone and ⬦ designated as l- and d-amino acids connective tissue, is the most abundant protein in vertebrates. Example: Alanine and Glyceraldehyde ◆ It is organized in water-insoluble fibers of ◆ Peptide bond = amide linkage that covalently great strength. joined two amino acid molecules to yield a dipeptide. ◆ A collagen fiber consists of three polypeptide ⬦ Such a linkage is formed by removal of the chains wrapped around each other in a ropelike twist, elements of water (dehydration) from the carboxyl or triple helix. group of one amino acid and the amino group of another. ◆ Includes the three-dimensional arrangement of all the atoms in the protein, including those ⬦ oligopeptide = few amino acids are joined in the side chains and in any prosthetic groups = groups of atoms other than amino acids. ⬦ polypeptide = many amino acids are joined ◆ The conformations of the side chains and the ⬦ Proteins = have thousands of amino acid positions of any prosthetic groups are parts of residues. Although the terms “protein” and the tertiary structure, as is the arrangement “polypeptide” are sometimes used interchangeably, of helical and pleated- sheet sections with molecules referred to as polypeptides generally have respect to one another. molecular weights below 10,000, and those called proteins have higher molecular weights. 1. fibrous proteins = proteins whose overall shape is that Primary Structure of a long, narrow rod ◆ The first order which the amino acids are covalently linked together. 2. globular proteins = protein whose overall shape is more or less spherical. ◆ The one-dimensional first step in specifying the three-dimensional structure of a protein. Tertiary Structure GENERAL BIOLOGY I  ✓ hydrogen bonds = between the side chains of ◆ The two a-chains of hemoglobin are identical, amino acids of proteins; Backbone hydrogen as are the two b-chains. bonding is a major determinant of secondary structure. Nucleic Acids ✓ hydrophobic interactions = Nonpolar residues ❑ Carry the genetic blueprint of a cell and carry cluster together in the interior of protein instructions for the functioning cells. molecules. Two Types of Nucleic Acids ✓ Electrostatic attraction = between oppositely ❑ Deoxyribonucleic acid (DNA) charged groups, which frequently occurs on the surface of the molecule. ❑ Ribonucleic acid (RNA) Example: Myoglobin DNA- is the genetic material found in all living organisms, ranging from single-celled bacteria to ◆ Classic example of globular protein multicellular mammals. ◆ Consists of a single polypeptide chain of 153 ❑ DNA controls all of the cellular activities by amino acid residues and includes a prosthetic turning the genes “on” or “off”. group, the heme group, which also occurs in ❑ Each nucleotide in DNA contains one of four hemoglobin. possible nitrogenous bases: Adenine (A), ◆ Heme - is an essential prosthetic group in Guanine (G), Cytosine (C), and Thymine (T). proteins that is necessary as a subcellular ❑ Adenine and Guanine are classified as compartment to perform diverse biological PURINES. (two carbon-nitrogen rings) functions like hemoglobin and myoglobin. ❑ Cytosine, thymine and uracil are classified as Quaternary Structure PYRAMIDINES. (Single carbon-nitrogen rings) ◆ A protein can consist of multiple polypeptide DNA contains A, T, G and C chains called subunits. The arrangement of subunits with respect to one another is the RNA contains A, U, G and C quaternary structure. ❑ The Pentose sugar in DNA is Deoxyribose and ◆ Commonly occurring examples are dimers, in RNA, the sugar is ribose. trimers, and tetramers, consisting of two, DNA STRUCTURE three, and four polypeptide chains, respectively. (The generic term for such a ❑ Has a double-helix structure. molecule, made up of a small number of ❑ The sugar and phosphate lie on the outside of subunits, is oligomer.) the helix, forming a backbone of the DNA. ◆ Interaction between subunits is mediated by RNA noncovalent interactions, such as hydrogen bonds, electrostatic attractions, and ❑ Mostly involved in the process of protein hydrophobic interactions. synthesis under the direction of DNA Example: Hemoglobin ❑ Single-stranded ◆ Hemoglobin is a tetramer, consisting of four ❑ A ribonucleotide in the RNA chain contains polypeptide chains, two a-chains, and two b- ribose (a pentose sugar). chains. (In oligomeric proteins, the types of ❑ Nitrogenous bases Adenine (A), Uracil (U), polypeptide chains are designated with Greek Guanine (G), and Cytosine (C) Phosphate letters a and b have nothing to do with the a- Groups helix and the b-pleated sheet; rather they just refer to two different polypeptide chain 3 MAJOR TYPES OF RNA subunits.) ❑ Messenger RNA (mRNA) GENERAL BIOLOGY I  ❑ Ribosomal RNA (rRNA) ❑ Transfer RNA (tRNA) ❑ Micro RNA (miRNA) Messenger RNA ❑ Carries the message from DNA, which controls all of the cellular activities in cell. ❑ If a cell requires a certain protein to be synthesized, ❑ The mRNA is read in sets of the three bases known as codons. Each codon codes for a single amino acid. In this way, the mRNA is read and protein product is made. ❑ Transcription- DNA dictates the structure of mRNA in the process. ❑ Translation- RNA dictates the structure of protein. GENERAL BIOLOGY I