biological molecules Flashcards

Question

whats maltose

Answer 1

glucose joined to glucose

Answer 2

glucose joined to fructose

Answer 3

glucose joined to galactose

Answer 4

1. created via condensation reactions, and broken down via hydrolysis reactions 2. these reactions involve formation or breakdown of a covalent bond known as a glycosidic bond

Answer 5

1. when 2 monosaccharides join, a hydroxyl group (OH) of one monosaccharide reacts with a hydroxyl group (OH) of another monosaccharide 2. this forms a glycosidic bond, and a water molecule is released

Answer 6

water molecule is added to a disaccharide, the glycosidic bond is broken to release the 2 monosaccharides

Answer 7

complex carbohydrates made up of many monosaccharides joined via glycosidic bonds

Answer 8

1. starch, branch and unbranched 2. cellulose 3. glycogen

Answer 9

1. example of a polysaccharide used by plants to store excess glucose 2. this means that starch can be hydrolysed back into glucose when plants require energy 3. starch is made of many alpha-glucose monomers joined via 1-4 and 1-6 glycosidic bonds to form chains 4. these chains come in 2 forms = branched and unbranched

Answer 10

1. insoluble= doesnt affect the water potential of the cell, so water isnt drawn in by osmosis 2. large = cant diffuse out of cells 3. many side branches= allow enzymes to hydrolyse the glycosidic bonds easily to rapidly release glucose 4. coiled= makes it compact so that a lot of glucose can be stored in a small space 5. hydrolysis releases alpha-glucose monomers= readily used in respiration

Answer 11

1. example of a polysaccharide used by animals to store excess glucose. this means that glycogen can be hydrolysed back into glucose when animals require energy 2. glycogen is very similar to starch but used by animals instead of plants 3. made up of many alpha-glucose monomers joined via 1-4 and 1-6 glycosidic bonds to form highly branched chains

Answer 12

1. insoluble= doesnt affect water potential of cells, water doesnt enter cells by osmosis 2. compact= a lot of glucose can be stored in a small space 3. more highly branched than starch= enzymes can easily hydrolyse the glycosidic bonds to rapidly release glucose 4. large= cant diffuse out of cells 5. hydrolysis releases alpha-glucose monomers= these are readily used in respiration

Answer 13

1. polysaccharide formed from beta-glucose 2. primary use is to provide structural support for plant cell walls

Answer 14

1. cellulose is made up of many beta glucose monomers joined together via glyosidic bonds 2. however, if 2 beta-glucose monomers line up next to each other, the hydroxyl groups on carbon 1 and carbon 4 are too far from each other to react 3. to fix this, every other beta-glucose molecule is inverted by 180 degrees (flipped upside down). this brings the hydroxyl groups close enough together to react

Answer 15

1. the alternating inversion of the beta glucose molecules also allows for hydrogen bonds to form between individual chains 2. altho each hydrogen bond itself is relatively weak, the huge no of these bonds provides great strength to cellulose as a whole

Answer 16

1. multiple cellulose chains become tightly cross linked via hydrogen bonds to form bundles called microfibrils 2. these microfibrils join together to make macrofibrils which combine to make strong cellulose fibres in the plant cell wall

Answer 17

1. long, straight and unbranched chains= provide rigidity to the cell wall 2. hydrogen bonds= cross link the chains to add collective tensile strength 3. microfibrils= provide additional strength

Answer 18

1. reducing sugars= all monosaccharides and some disaccharides such as maltose/lactose 2. non reducing sugars= some disaccharides such as sucrose and all polysaccharides

Answer 19

1. place 2cm^3 of ur sample into a test tube 2. add an equal volume of benedict's reagent 3. heat the mixture in a gently boiling water bath for 5 mins 4. if a reducing sugar is present, the solution goes from a blue solution to a red precipitate

Answer 20

1. blue = no reducing sugar is present 2. green = low concentration 3. orange = a medium conc 4. brick-red = high conc

Answer 21

1. use a colorimeter to measure the absorbance of each solution 2. filter the solution and weigh the precipitate

Answer 22

1. NRS give a negative result for the normal reducing sugars test 2. to test for these, you must first hydrolyse them into their monosaccharide components

Answer 23

1. negative result for reducing sugars test 2. add 2cm^3 of the food sample to 2cm^3 of dilute hydrochloric acid 3. heat the mixture in a gently boiling water bath for 5 mins (acid hydrolyses disaccharides into monosaccharides 4. neutralise this mixture by adding sodium hydrogencarbonate solution 5. retest this mixture using the test for reducing sugars 6. if non-reducing sugars were present at the start, the mixture will change from a blue solution to a brick red precipitate

Answer 24

1. place 2cm^3 of ur food sample into a test tube 2. add a couple drops of iodine solution and shake 3. if starch is present, the solution goes from orange to blue-black

Answer 25

1. biological molecules that contain the elements: carbon, hydrogen, oxygen. lower proportion of oxygen than carbohydrates 2. not made of a long chain of monomers so their not considered polymers

Answer 26

1. energy supply= lipids can be oxidised to provide energy for cells 2. structural components= phospholipids are used in cell membranes 3. water-proofing= insoluble lipids are used to form water-resistant barriers 4. insulation= lipids can help retain heat or act as electrical insulators 5. protection= delicate organs are surrounded by a layer of fat

Answer 27

1. most lipids are made up of fatty acids combined with an alcohol (usually glycerol) 2. fatty acids consist of a carboxyl group attached to a hydrocarbon chain (R group)

Answer 28

1. have hydrocarbon chains that are 'saturated' with hydrogen, meaning all carbon atoms are bonded to the max no of hydrogen atoms 2. hydrogen carbon has no carbon-carbon double bonds 3. lipids that contain saturated fatty acids have higher melting points and so are usually solid at room temperature

Answer 29

1. have hydrocarbon chains that dont contain the max no of hydrogen atoms bonded to the carbon atoms 2. hydrocarbon chain has atleast one carbon-carbon double bond, causes the chain to kink 3. lipids that contain unsaturated fatty acids have lower melting points and so are liquids at room temp

Answer 30

1. monounsaturated= one double bond 2. polyunsatured= 2 or more double bonds

Answer 31

1. place ur food sample in a test tube 2. add 2cm^3 of ethanol 3. shake 4. add 2cm^3 of distilled water 5. if lipids are present, a milky white emulsion appears

Answer 32

1. type of lipid used as a store of energy in animals, plants and some bacteria 2. consists of a glycerol backbone attached to 3 fatty acid tails 3. each fatty acid tail contains a hydrocarbon chain (R) which can vary in length, may be saturated or unsaturated

Answer 33

1. long hydrocarbon tails= their many carbon-hydrogen bonds can be broken to release energy 2. low mass to energy ratio= lots of energy stored in a small volume 3. insoluble= dont affect water potential of cells as their large and non-polar 4. high ratio of hydrogen to oxygen atoms= release water when oxidised

Answer 34

1. hydroxyl groups (OH) on the glycerol and on the 3 fatty acids react together to release 3 water molecules (h20) 2. results in 3 ester bonds between the glycerol and fatty acids

Answer 35

1. addition of 3 water molecules breaks the ester bonds 2. separates the glycerol and fatty acids

Answer 36

1. type of lipid used as a structural component of the cell membrane 2. similar to triglycerides except one of the fatty acid tails is replaced by a phosphate group

Answer 37

1. hydrophilic head= contains glycerol and phosphate 2. hydrophobic tail= contains fatty acids

Answer 38

1. when phospholipids are placed in water, they arrange themselves into a double layer so that the hydrophilic heads are facing out (towards the water) and hydrophobic tails are facing in (away from the water) 2. creates a hydrophobic centre in the bilayer so water-soluble molecules cant pass through

Answer 39

1. amino acids, which are essential macromolecules involved in various functions within living organisms 2. amino acids are monomers, can join together via peptide bonds to form dipeptides and polypeptides

Answer 40

1. enzymes= proteins used to breakdown and synthesise molecules 2. antibodies= proteins involved in the immune response 3. transport= some can move molecules or ions across membranes 4. structural components= keratin and collagen used to create strong fibres 5. hormones= proteins that act as chemical messengers in the body 6. muscle contraction= muscles are made of proteins

Answer 41

1. central carbon atom 2. amino group 3. carboxyl group 4. hydrogen atom 5. R group or variable side group

Answer 42

1. different R group which determines its properties 2. e.g= amino acid cysteine contains a sulphur atom in its R group, allows cysteine to form disulphide bonds

Answer 43

1. dipeptides are synthesised via condensation reactions, broken down via hydrolysis reactions 2. these reactions involve the formation or breakdown of a covalent bond known as a peptide bond

Answer 44

1. when 2 amino acids join, the hydroxyl in the carboxyl group of one amino acid reacts with the hydrogen in the amino group of another amino acid 2. this releases a water molecule and forms a peptide bond between the carbon of one amino acid and the nitrogen of another

Answer 45

1. when a water molecule is added to a dipeptide 2. the peptide bond is broken to release the 2 amino acids

Answer 46

1. place ur food sample in a test tube 2. add an equal volume of biuret solution (sodium hydroxide and copper sulfate) 3. if proteins are present, solution goes from blue to purple, if not it stays blue

Answer 47

1. made up of the unique sequence of amino acids in the polypeptide chain 2. structure held together by peptide bonds 3. a change to just one of the amino acids can result in a change to a protein's structure and function

Answer 48

1. hydrogen bonds forming between the amino group of one amino acid and the carboxyl group of another amino acid further down the chain 2. causes the polypeptide chain to coil into either an alpha-helix or a beta-pleated sheet

Answer 49

polypeptide chain folds and twists further to create a complex 3D structure

Answer 50

1. hydrogen bonds= individually weak, provide strength in large numbers 2. ionic bonds= form between positive and negative R groups 3. form between R groups that contain sulfur like cysteine 4. hydrophobic and hydrophilic interactions= weak interactions between polar and non-polar R groups

Answer 51

1. involves 2 or more polypeptide chains held together by same bonds found in tertiary structure 2. can also involve the addition of non-protein groups as prosthetic groups

Answer 52

1. globular proteins with complex and unique tertiary structures 2. known as catalysts, speed up the reaction without being used in the reaction

Answer 53

1. energy required for a chemical reaction to be started 2. without sufficient activation energy, the reactant molecules wont have enough energy to break their bonds and form new ones to form the desired products 3. enzymes work by lowering the activation energy for a chemical reaction, this means reactions are able to take place at lower temperatures (e.g= body temperatures)

Answer 54

act within cells that produce them

Answer 55

act outside the cells that produce them, and are secreted

Answer 56

1. enzymes have unique tertiary structures which determine the shape of their active site, shape is complementary to the substrate 2. substrate binds to the active site to form an enzyme-substrate complex 3. temporary bonds form between the R groups within the active site and substrate. these bonds lower the activation energy to help break down the substrate into products 4. the products are released from the active site, leaving the enzyme free to be used again

Answer 57

substrate fits perfectly into the enzyme's active site

Answer 58

1. substrate doesnt fit perfectly into the enzyme's active site 2. as the substrate enters the enzyme, the active site shape changes slightly 3. this puts a strain on the substrate's bonds which lowers the activation energy

Answer 59

1. temperature 2. pH 3. substrate conc 4. enzyme conc

Answer 60

1. as temp increases, rate of reaction increases 2. max rate is reached at the optimum temp 3. as temp reaches past the optimum, rate of reaction decreases until the reaction stops

Answer 61

1. the molecules have more kinetic energy, causing more collisions and enzyme-substrate complexes 2. optimum temp is the temp the enzyme works fastest at 3. too much kinetic energy causes the active site to change shape and the enzyme denatures

Answer 62

1. below the optimum ph, the rate of reaction is low 2. max rate of reaction is reached at the optimum ph 3. above the optimum ph, the rate of reaction is low/zero

Answer 63

1. in acidic conditions, H+ ions break ionic/hydrogen bonds and denature enzymes 2. optimum ph is the ph the enzyme works fastest at 3. in alkaline conditions, OH- ions break ionic bonds/hydrogen bonds and denature enzymes

Answer 64

1. as substrate conc increases, the rate of reaction increases 2. as substrate conc increases further, the rate of reaction levels off

Answer 65

1. more substrate molecules to form ES complexes 2. this is the saturation point, which is when all active sites are occupied by a substrate and enzyme conc becomes the limiting factor

Answer 66

1. as the enzyme conc increases, the rate of reaction increases 2. as the enzyme conc increases further, the rate of reaction levels off

Answer 67

1. there are more enzymes to form ES complexes 2. all substrate molecules available are being acted upon and substrate conc becomes the limiting factor

Answer 68

molecules that bind to enzymes to reduce their activity

Answer 69

1. reversible= form weak bonds (hydrogen/ionic) with the enzyme 2. irreversible= form strong bonds (covalent) with the enzyme

Answer 70

1. competitive= bind to the active site 2. non competitive= bind away from the active site

Answer 71

1. bind to the active site of an enzyme to prevent ES complexes 2. similar shape to the substrate and so they bind to the active site of enzyme 3. this prevents the substrate from binding, reducing formation of ES complexes 4. decreases rate of enzyme-catalysed reaction 5. most of these are reversible, temporarily bind to the active site

Answer 72

1. increasing the substrate conc 2. the higher the substrate conc the more likely it is that the substrates will bind to the active site rather than inhibitor molecules 3. reduces effect of competitive inhibitors

Answer 73

1. bind to enzymes away from the active site (allosteric site) to prevent ES complexes 2. this binding changes the tertiary structure of an enzyme, causing the active site to change shape 3. results in the active site no longer complementary to the substrate so less ES complexes are formed and rate of enzyme catalysed reaction decreases

Answer 74

1. non comp inhibitors cant be overcome by increasing substrate conc 2. they dont compete with the substrate to bind to the active site, so increasing substrate conc has no effect on the rate of reaction

biological molecules Flashcards

(98 cards)