2.2 - Biological Molecules Flashcards

Question

What is a polymer?

Answer 1

A molecule that is a long chain linking multiple individual molecules (monomers) in a repeating pattern

Answer 2

Carbon, hydrogen, oxygen, nitrogen and sulphur

Answer 3

Carbon, hydrogen, oxygen, nitrogen and phosphorus

Answer 4

An individual subunit that is repeated in a polymer

Answer 5

A sugar (saccharide)

Answer 6

Amino acids

Answer 7

A covalently bonded molecule with regions of positivity and regions of negativity. This occurs due to the unequal sharing of electrons between atoms as a result of different levels of electronegativity.

Answer 8

In a covalent bond, if the two atoms involved have different levels of electronegativity , the electrons will s spend more time closer to one atom than another. The atom with the greater share of electrons will be slightly negative, whereas other atom with less electrons will be slightly positive. If the molecule is not symmetrical, and there is a clear positive and negative end, the molecule is polar.

Answer 9

Yes: the O is slightly negative and the H is slightly positive. Many organic molecules contain O-H bonds (called hydroxyl groups), and are therefore slightly polar

Answer 10

Water contains 2 O-H bonds, which are negative. The oxygen is slightly negative, and the the 2 hydrogens are slightly positive Water isn't symmetrical

Answer 11

a 'giant molecule'

Answer 12

Polysaccharides Polypeptides Polynucleotides These are all also examples of polymers

Answer 13

- it is a condensation reaction (adding monomers to create a polymer) - water molecules are released - new covalent bonds formed - larger molecule (polymer) is formed

Answer 14

- hydrolysis reaction (breaking polymers into monomers) - water molecule added - covalent bond broken - smaller molecules (monomers) formed

Answer 15

Because water has polar molecules, there are many hydrogen bonds between the molecules. Even though these are quite weak, the large number of them results in water being packed close together, making it a liquid.

Answer 16

An intermolecular bond where a slightly positive hydrogen atom in one molecule is attracted to a slightly negative atom in another molecule. In water, the hydrogen atoms in one molecule are attracted to the negative oxygen atom in another molecule

Answer 17

Due to polarity: - liquid at biological temperatures - high latent heat - good solvent - high specific heat capacity - high surface tension - most dense at 4 degrees celsius - capillary action also useful as a reactant

Answer 18

- it takes a lot of energy to change the physical state of water - it is unlikely to change state - its a stable environment to live in as it is less likely to evaporate or freeze than other liquids - evaporation of water takes a lot of energy, so it can be used as a cooling mechanism ( eg panting/sweating)

Answer 19

- organisms can interact with it, live in/on it, use it as a solvent etc which they couldn't if it were a gas - as a liquid, it is incompressible. therefore, it can be used as support - eg turgor pressure in plants and hydrostatic skeletons (eg in worms)

Answer 20

- as a solvent of polar molecules, water can dissolve most biological molecules (except lipds) - reactions can therefore easily take place in water (eg respiration), so organisms can use water as the basis of their cytoplasm - in multiclellular organisms, it can be used as a transport medium (eg it is the base of plasma and xylem fluid (minerals dissolved in water)

Answer 21

- it takes a lot of energy to change the temperature of water therefore it is a stable environment to live in - internal body temperatures are less likely to change

Answer 22

- hydrogen bonds form thin film on top of the water as the bonds between the water molecules are stronger than the intermolecular bonds between the water and air molecules - this allows organisms to live on the surface of the water eg pond skaters - it is also important in capillary action

Answer 23

- the cohesive properties of water mean that it moves in one mass as the molecules are attracted to each other (cohesion) - it also has adhesive properties - the water molecules are attracted to other materials if they are polar or ionic. - this means water can travel up a narrow tube, even if it is against gravity - this is how the xylem transports water up the plant, from the roots to the shoots

Answer 24

- ice (solid water) is less dense than liquid water as hydrogen bonds fix the positions of the molecules further apart than the average distance when in liquid state, meaning the ice is less dense. - this means the ice floats on top of water. - this insulates the lower levels of a body of water so that the entire body doesn't freeze - ice provides a habitat for penguins, polar bears etc it sets up currents in the water which circulates nutrients (particularly in the sea)

Answer 25

- it is used in hydrolysis reactions to split macromolecules into smaller units by adding water - it is a source of ydrogen for reactions of photosynthesis

Answer 26

Attraction between the same type of molecule (eg water and water)

Answer 27

Attraction between two different types of molecules (eg water and the side of a glass)

Answer 28

Also known as a saccharide or sugar. | Made of carbon, oxygen, hydrogen

Answer 29

- a single sugar unit - water soluble - single sugar - taste sweet - general formula Cx(H2O)x - classified according to number of carbon atoms (eg 6 carbons = hexose monosaccharide) - names end in -ose eg glucose, fructose

Answer 30

- energy source for respiration (esp glucose) due to large number of C-H groups which are easily oxidised to yield a lot of energy - building blocks (monomers) for larger molecules ie polysaccharides

Answer 31

- a hexose monosaccharide - has 6 carbons - formula C6H12O6 - Has two isomers, alpha glucose and beta glucose. these have important biological consequences in starch, glycogen and cellulose - fructose and galactose have same molecular formula but different structural formula - polar and soluble in water due to hydrogen bonds formed between hydroxyl groups and water molecules - solubility is important as glucose is dissolved in cytosol of cell

Answer 32

- alpha glucose has hydroxyl group above carbon 1 | - beta glucose has hydroxyl group below carbon 1

Answer 33

- pentose sugar - molecular formula C5H10O5 - component of RNA, ATP and NAD

Answer 34

- an oxygen has been removed from ribose - molecular formula C5H10O4 - component of DNA

Answer 35

- when two monosaccharide residues joined together (called residue as some of monosaccharide has been lost) - joined by condensation reaction - sugars - dissolve easily in water - taste sweet - contain a glycosidic bond

Answer 36

- two hydroxyl groups (OH) link together - the O from one and OH from another creates water - water is produced - a glycosidic bond is formed (oxygen bridge) - successive additions of monosaccharides produce polysaccharides

Answer 37

1) maltose 2) fructose 3) galactose

Answer 38

- a hydrolysis reaction - addition of water - breakdown of polysaccharides/disaccharides into monosaccharides - happens in digestion - catalysed by enzyme amylase

Answer 39

When carbon 1 of one saccharide joins to a carbon 4 of another saccharide

Answer 40

- many monosaccharides bonded together by condensation reactions, forming glycosidic bonds - polymers - macromolecules - inert and insoluble - not sweet

Answer 41

- it is reactive and soluble | - therefore it is stored as a polysaccharide until needed

Answer 42

a) Starch b) Glycogen c) cellulose, used for cell walls in plants

Answer 43

- grains in plant cells - large enough to be seen with light microscope - carbohydrate store in plants - large; cannot escape through membranes - insoluble; can be stored in large quantities without affecting water potential of cells - compact; can be stored easily within cells - branched molecules: the more branching, the more efficient the release of glucose by hydrolysis

Answer 44

Made up of 2 polysaccharides of alpha glucose - amylose (20%) and amylopectin (80%)

Answer 45

- 20% of starch - long, unbranched chains of alpha glucose units - linked via 1,4 glycosidic bonds - chains curve into helix due to hydrogen bonds making a compact molecule - like maltose - less space to store each kJ

Answer 46

- 80% of starch - has 1-4 glycosidic bonds between alpha glucose molecules as well as 1-6 glycosidic bonds, resulting in branched structure. - 1-6 glycosidic bonds occur approximately every 25 glucose subunits

Answer 47

- test with iodine solution at room temp - blue/black with starch - deep blue with amylose - red-purple with amylopectin iodine forms a complex with starch in between the helix shapes to form blue-black solution

Answer 48

- granules in animal cells - carbohydrate store in animals - large; cannot escape through membranes - insoluble; can be stored in large quantities without affecting water potential of cells - compact; can be stored easily within cells - branched molecules: the more branching, the more efficient the release of glucose by hydrolysis

Answer 49

- similar to amylopectin but with shorter chains and more highly branched, making it more compact. This is important as animals are more mobile than plants - has 1-4 glycosidic bonds between alpha glucose molecules as well as 1-6 glycosidic bonds, resulting in branched structure. - branched structure means glucose molecules can easily be added or removed - mainly stored in muscles and liver as granules - shorter chains means it hydrolyses more readily

Answer 50

- polymer of beta glucose - straight, unbranched chains due to beta glucose residues alternating in orientation - one up, next one flipped down - straight chains mean they can pack closely together - 60-70 cellulose molecules become tightly cross - linked to make microfibrils - microfibrils held together in bundles called fibres - typically, cell walls have several layers of fibres running in different directions, which increases strength. - other molecules cross-link the fibres, forming a glue-like matrix - fibres have a high tensile strength which prevents cell walls from bursting (turger pressure).

Answer 51

- found in cell walls of plants - provides strong and permeable cell wall - have a structural role due to mechanical strength due to bonding - insoluble; structure of cell wall not affected by water - exposed OH groups; exposed hydroxyl groups on all directions allow hydrogen bonding to create a string 3D lattice - straight chains (microfibrils); create a strong, permeable, flexible mesh of interwoven strands - not brittle - fully permeable

Answer 52

- found in all living cells - main substrate for respiration - small; passes through membrane easily and has high energy value - soluble; transported easily through fluids - reactive - forms polymers easily

Answer 53

- all monosaccharides - some disaccharides (eg maltose, lactose) - they can donate electrons, or reduce another molecule or chemical

Answer 54

Benedict's test Use Benedict's Reagent (alkaline solution of copper(II) sulfate) 1) place sample in test tube. if not in liquid form, grind up or blend in water. 2) add equal volume of benedicts reagent 3) heat mixture gently in a boiling water bath for 5 mins.

Answer 55

Benedicts test Use Benedict's Reagent (alkaline solution of copper(II) sulfate) 1) test for reducing sugars first. If result is negative, move on to test for non-reducing sugars 2) place fresh sample in test tube. if not in liquid form, grind up or blend in water. 3) boil sample in dilute hydrochloric acid. This will hydrolyse the non-reducing sugar (eg sucrose) into reducing sugars (eg glucose and fructose) 4) add equal volume of benedicts reagent 5) heat mixture gently in a boiling water bath for 5 mins.

Answer 56

Reducing sugars will react with reagent. Cu2+ ions will be reduced (gain electrons) from the reducing sugars, turning them into brick red Cu+ ions. When it is warmed, a brick-red precipitate is formed, indicating a positive result The more reducing sugar present, the more precipitate formed and the less blue Cu2+ ions left in solution. The colour of the solution will depend on the ratio of precipitate to solution. This makes the test qualitative. - green = low concentration of reducing sugar - yellow/amber = medium concentration of reducing sugar - red = high concentration of reducing sugar

Answer 57

- commonly known as fats and oils - contain the elements carbon, oxygen, hydrogen - generally, fats are solid at room temperature and oils are liquid at room temperature - macromolecules

Answer 58

No, they are non polar. This means they are hydrophobic and are not soluble in water. immiscible - doesn't form a homogenous mixture when mixed

Answer 59

A lipid made by combining one glycerol molecule with three fatty acids glycerol + 3 fatty acids -> triglyceride + water

Answer 60

- animal origin - mainly saturated - high levels are more likely to contribute to cardiovascular disease - eg butter, lard

Answer 61

- plant origin - mainly unsaturated - tend to be more healthy than saturated fats - eg olive oil, rapeseed oil

Answer 62

C3H8O3 Type of alcohol Contains 3 hydroxyl groups

Answer 63

Carboxylic acid - have a carboxyl group (-COOH) with hydrocarbon chain attached Can be saturated or unsaturated

Answer 64

glycerol + 3 fatty acids -> triglyceride + water reaction called esterification (type of condensation reaction) hydroxyl groups between the glycerol and fatty acid react, leading to the formation of 3 water molecules. The bond between the glycerol and the fatty acid is an ester bond

Answer 65

Addition of water molecules to reverse the reaction that formed the triglyceride This is known as hydrolysis

Answer 66

- no double bonds between carbon atoms (C=C ) - they form the maximum number of binds with hydrogen atoms ('saturated' with hydrogen) - solid at room temperature as they are straight chains and easier to pack close together

Answer 67

- contains some C=C bonds - therefore, less H atoms than with saturated fatty acids - if only one, it is monounsaturated. If 2 or more C=C bonds, it is polyunsaturated. - the C=C bonds cause the fatty acid to kink or bend. This means they cannot be packed as closely together. - As a result, they have a much lower melting and boiling point, and are often liquid at room temperature

Answer 68

- energy store and energy source when respired - more C-H bonds - thermal insulation - poor conductors of heat - buoyancy - less dense than water - protection of internal organs - around most organs, takes impacts, low melting point so not restrictive - source of water - can be a source of water when respired

Answer 69

Modified triglycerides containing the element phosphorus along with carbon, hydrogen and oxygen.. Inorganic phosphate ions can be found in cytoplasm of every cell The phosphate ions are negatively charged, and are therefore soluble in water One of the fatty acids in a triglyceride is replaced with a phosphate group to make a phospholipid

Answer 70

Similarities: - both have glycerol - both contain ester bonds between glycerol and fatty acids Differences: - phospholipids contain phosphate group - phospholipids have 2 fatty acids rather than 3 -phospholipids have a charged, hydrophilic head and non-polar, hydrophobic fatty acid tail. However, triglycerides are entirely non-polar and hydrophobic.

Answer 71

- they form a thin layer on the surface of the water with the hydrophilic phosphate head in the water and the hydrophobic fatty acid tail sticking out of the water. Because of this, they are called surface active agents or surfactants for short - they also form structures based on a two layered sheet formation (a bilayer) with all the hydrophobic tails pointing inwards and all the hydrophilic heads sticking out. This is called a phospholipid bilayer

Answer 72

- the phospholipid bilayer forms cell membranes. They are able to separate the aqueous environment cells usually exist in and the aqueous cytosol within the cell. - they also make up the myelin sheath on neurones as they are good insulators.

Answer 73

Sterols/steroid alcohols are another type of lipid. They arent fats or oild, and have little in common with them structurally. - they are complex alcohol molecules based on a 4 carbon ring structure with a hydroxyl group at one end. - they have dual hydrophilic/phobic properties like phospholipids - most of the molecule is non-polar, but the O-H group is

Answer 74

Emulsion test 1) mix sample woth ethanol - this dissolves any lipids present. shake 2) pour liquid into another clean test tube containing water 3) if lipids are present, a cloudy white emulsion will form - the lipid comes out of ethanol solution and becomes dispersed as tiny droplets in water

Answer 75

- a sterol - the body manufactures it primarily in liver and intestines - it becomes positioned between the phospholipids with hydroxyl groups at the periphery of the membrane . This adds stability to the cell membranes and regulates their fluidity by keeping membranes fluid at low temperatures and stopping them becoming too fluid at high temperatures

Answer 76

- cell membranes - needed to make some hormones eg testosterone, oestrogen - Vitamin D, and bile are also manufactured with cholesterol - Vit D can be stored if excess is removed, whereas Vit B/C are water soluble and just excreted out.

Answer 77

Polymers that are made up of amino acids, which are the monomers

Answer 78

Consist of one or more polypeptides arranged as complex macromolecules. They have specific biological functions. All proteins contain the elements carbon, hydrogen, oxygen and nitrogen

Answer 79

- structural component- muscle, bones, hair etc - carriers and pores - enzymes - hormones - antibodies

Answer 80

In plants: - are able to manufacture the amino acids they need - require nitrates to do so In animals: - must take in as part of diet - 20 amino acids common in polypeptides - 5 = non essential as body can make them - 9 are essential and can only be obtained by consumption in diet - 6 conditionally essential as only needed by infants and children

Answer 81

One Nitrogen bonded to 2 hydrogens (amine group). This is bonded to a carbon, which is bonded to a hydrogen, an R group (could be anything), and another carbon. This last carbon has a double bond to an oxygen and a single bond to another oxygen. That oxygen is bonded to a hydrogen (hydroxyl group)

Answer 82

- the hydroxyl group of the carboxyl in one amino acid reacts with a hydrogen atom in the amine group of another, producing a water molecule - this means that this is a type of condensation reaction - the bond between the amino acids is a peptide bond (between a carbon atom and a nitrogen) which is covalent - two amino acids = dipeptide, multiple = polypeptide - reaction catalysed by enzyme peptidyl transferase, present in ribosomes - can be broken down by hydrolysis - protease enzymes catalyse breakdown of polypeptides - proteins arent just broken down during digestion - amino acids in di and polypeptides aee known as residues

Answer 83

CAN be - big - positively charged - negatively charged - acidic - basic - hydrophobic - hydrophilic - include sulphur - ring structures

Answer 84

primary secondary tertiary quaternary

Answer 85

- given by the specific sequence of amino acids that make up the polypeptide (determined by the DENA sequence) - there are many different possibilities of amino acid sequences - only bonds involved in primary structure are peptide bonds

Answer 86

- coiling/folding of primary structure in specific areas - held in place by hydrogen bonds, which give stability due to quantity - two types of secondary structure - alpha helix (a coil shape) and beta pleated sheet (folded) - is determined by the R group on the specific amono acids - some regions of primary structure do not have secondary structure

Answer 87

- the folding of the protein into its final shape - held in place by intermolecular bonds and interactions with watery cell environment - determined by the R groups of amino acids - causes protein to have 3D shape vital to its speific function

Answer 88

Possible intermolecular bonds: - disulphide bonds: always formed when 2 cystine are close enough to react. covalent and strongest of bonds. Formed between 2 sulphurs in R groups of different amino acids. - ionic bonds - stronger than hydrogen bonds, form between oppositely charged R groups - hydrogen bonds - weakest of all bonds Interactions with watery cell environment: - hydrophobic regions will turn to the inside of the protein - hydrophilic reactions will turn to the outside of the protein

Answer 89

- more than one polypeptide chain combined to form the functional protein and/or the addition of a non-protein component (prosthetic group) - enzymes often have two identical subunits whereas hormones usually have 2 different polypeptides

Answer 90

Biuret test 1) add sample to test tube. mix with biuret reagent (mic of copper(II) sulphate and an alkali) 2) mix and let stand for 5 mins if proteins are present, peptide bonds will form a violet coloured complex with copper ions in alkaline solutions.

Answer 91

- 3D spherical shape which is specific to the type of protein - sequence of amino acids are much more varied than fibrous proteins - are therefore much more susceptible to temperature and pH changes - soluble in water as hydrophobic R groups turn to inside and hydrophilic R groups move to outside

Answer 92

- the breakdown of the tertiary structure of a protein | - occurs due to high temperatures, some chemicals or pH changes interfering with the intermolecular bonds

Answer 93

- a globular protein - a hormone involved in the regulation of blood glucose concentration - very small so transported quickly - a hormone so must be soluble so that it can be transported via bloodstream - moves quickly through blood and is easily captured by glycoprotein receptors on cell surface for cell signalling

Answer 94

- globular proteins that contain a prosthetic group (non protein component) - there are different types of prosthetic groups - lipids or carbohydrates can join proteins to become lipoproteins or glycoproteins - metal ions and molecules derived from vitamins can also form prosthetic groups

Answer 95

- conjugated protein - red pigment inside red blood cells - transports oxygen in blood - has 4 polypeptides, 2 alpha and 2 beta subunits - each subunit contains a haem group (contains an Fe2+ ion) which can reversibly bind to an oxygen molecule - each molecule can bind to 4 oxygen molecules

Answer 96

- conjugated protein - an enzyme, which catalyse reactions - contains 4 prosthetic haem groups - breaks down hydrogen peroxide (H2O2), which is a common byproduct of metabolism but harmful to proteins

Answer 97

- formed from long molecules - insoluble due to large number of hydrophobic r groups - useful as you don't want hem to react or be carried around the body - form long chains that run parallel to each other - have an elongated shape (not folded into 3D shapes like globular proteins) - chains linked by cross bridges - strong - very stable molecules - can be flexible - high proportion of molecules primary structure is one type of amino acid - very repetitive structure - have a structural function - make up tendons, skin, hair, etc. sometimes used for support

Answer 98

- a structural, fibrous, insoluble, linear and strong protein - 3 uniform polypeptide chains. these are coiled and each coil held together with hydrogen bonds. - the three coiled chains lie close together because of the high proportion of glycine in them (one every 3 amino acids). These form hydrogen bonds - 3 coiled chains are wound tightly together to form a triple helix, which is also stabilised by H-bonds between the chains for more strength (and other bonds too) - triple helix is a collagen molecule - each collagen molecule forms covalent bonds (cross links) with other collagen molecules for even ore strength - many molecules form a fibril. the ends of the molecules are staggered to avoid weak points - many collagen fibrils join together to form a collagen fibre - in some tissues, there are many fibres in a bundle

Answer 99

structure in - walls of arteries - tendons - ligaments - bones (with addition of calcium phosphate) - cartilage and connective tissue - cosmetic treatments eg lip filler

Answer 100

- fibrous protein - rich in cysteine - lots of disulphide bonds making it very strong - often inflexible and used where strength and hardness needed eg nails, hair, claws, hoofs, horns, scales, fur and feathers - provides mechanical protection - resistant to forces - impermeable barrier to infection - waterproof

Answer 101

- fibrous protein - strong and extensible due to cross linking and coiling - made of many stretchy molecules called tropoelastin - used wherever the ability to stretch and recoil is needed eg walls of blood vessels, alveoli of lungs, skin, bladder

2.2 - Biological Molecules Flashcards

(126 cards)