Organic Molecules Flashcards
(21 cards)
1
Q
Macromolecules
A
- carbohydrates, proteins and nucleic acids
- chain-like molecules called polymers
2
Q
Polymer
A
- large molecule consisting of many similar or identical building blocks linked by covalent bonds (monomers)
3
Q
Enzymes
A
- specialized macromolecules that catalyze chemical reactions
4
Q
Dehydration reaction
A
- monomers are connected in a reaction where two molecules are covalently bonded with the loss of a water molecule
- dehydration removes a water molecule, forming a new bond
5
Q
Hydrolysis
A
- bond between monomers is broken with the addition of a water molecule
- hydrolysis adds a water molecule, breaking a bond
6
Q
Carbohydrates
A
- sugars or polymers of sugars
7
Q
Monosaccharide
A
- in the form CnH2nOn with a carbonyl group and many hydroxyl groups
- can be aldoses or ketoses
- range from 3-7 carbons (trioses, pentoses, hexoses)
- differ in the arrangement of groups around the asymmetrical carbon (carbon bonded to four different atoms/groups)
- often exists as rings in aqueous solution
- major nutrient in cells, especially glucose- broken down in a cellular respiration
- serve as raw material for the synthesis of other types of small organic molecules (amino acids and fatty acids)
- others are incorporated as monomers in the synthesis of disaccharides and polysaccharides
8
Q
Disaccharides
A
- two monosaccharides linked by glycosidic linkages (covalent bonds between two monosaccharides formed in a dehydration reaction)
- maltose= glucose + glucose
- sucrose = glucose + fructose (plants transport carbohydrates from the leaves to the roots and other non-photosynthetic organs in the form of sucrose)
- lactose = glucose + galactose
9
Q
Polysaccharides
A
- macromolecule of a few hundred or thousand monosaccharides connected by glycosidic linkages
10
Q
Starch
A
- polymer of glucose that plants store as granules within plastids
- represents stored energy that is released by hydrolysis
- animals and humans have enzymes that can hydrolyze plants starch
- most glucose monomers are connected by 1-4 glycosidic linkages (amylose- unbranched) and some are connected by 1-6 linkages (amylopectin- branched)
11
Q
Glycogen
A
- polymer of glucose that is extensively branched (allows more free ends for hydrolysis)
- used for energy storage in animals (in the liver and muscle cells of humans/vertebrates)
- stored fuel does not last long and must be replenished through the diet
12
Q
Cellulose
A
- major component of plant cell walls (most abundant organic molecule on Earth)
- polymer of glucose (β configuration)
- straight and unbranched
- OH groups are free to H bond with hydroxyl groups on other cellulose molecules- grouped into units called microfibrils
- enzymes that hydrolyze plant starch cannot hydrolyze the β linkages in cellulose (few organisms possess these enzymes)
- cellulose has an important role in the diet as it abrades the walls of the digestive tract and stimulates mucus secretion to facilitate the smooth movement of food
13
Q
Chitin
A
- used by arthropods to build their cytoskeletons and by fungi in their cell walls
- has β linkages with the glucose monomers having an N-containing appendage
14
Q
Lipids
A
- hydrophobic due to largely hydrocarbon regions
- generally not large enough to be macromolecules
15
Q
Fats
A
- consist of a glycerol and fatty acids- long carbon skeletons (16-18 C) with a carboxyl group at one end
- three fatty acids joined to a glycerol by ester linkages forms a triacylglycerol
- saturated fatty acids- only single bonds
- unsaturated fatty acids- one or more double bonds- mostly cis bonds in naturally occurring double bonds that cause a kink in the hydrocarbon chain
- animal fats are saturated- solid at room temperature due to flexibility allowing close packing of fatty acids
- fats in plants and fishes (oils) are unsaturated- liquid at room temperature due to kinks in the hydrocarbon chain preventing tight packing and solidification
- primary function is energy storage (1 g of fat contains 2x energy of 1 g of polysaccharide) which is beneficial for motile organisms
- animals and humans store their long-term food reserves in adipose tissue (provides cushioning for vital organs and a subcutaneous layer of insulation)
16
Q
Phospholipids
A
- major component of plasma membranes- forms a boundary between the external and internal environments
- two fatty acids attached to a glycerol with a phosphate group attached to the third hydroxyl group of glycerol
- usually, an additional small charged/polar molecule is attached to the phosphate group (choline)
- has a polar hydrophilic head and two non polar hydrophobic tails
- arrange themselves into bilayers in water with hydrophilic heads on the outside of the bilayer, in contact with the aqueous solutions inside and outside of the cell
17
Q
Steroids
A
- composed of four fused rings
- lipid
18
Q
Cholesterol
A
- a type of steroid that is crucial in animals
- present in animal cell membranes an is a precursor from which other steroids (vertebrate sex hormones) are synthesized
- in vertebrates, cholesterol is synthesized in the liver and is obtained from the diet
- high levels of cholesterol may contribute to atherosclerosis
19
Q
Catalysts
A
- chemical agents that selectively speed up chemical reactions without being consumed by the reaction
20
Q
Proteins
A
- composed of 20 different amino acids, linked in unbranched polymers (polypeptides)
- bond between amino acids is a peptide bond (covalent bond formed by a dehydration reaction)
- biologically functional molecule made up of 1 or more polypeptides foiled and coiled into a specific 3D structure
- the amino acid sequence of each polypeptide determines its 3D structure
21
Q
What are the functions of proteins?
A
- enzymatic- selective acceleration chemical reactions (digestive enzymes)
- hormonal- coordination of organism’s activities (insulin)
- defensive- protection against disease (antibodies)
- transport- movement of substances (hemoglobin)
- contractile and motor- movement (actin and myosin)
- structural- support (keratin, collagen)
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