biological molecules

Question 1

what does polar and dipolar mean

Answer 1

polar- dosent have a charge. dipolar- 2 different charges

Question 2

why are water molecules polar?

Answer 2

it has a partial negative charge on one side (oxygen) , and a partially positive on the other (hydrogen). this causes an unevenly distributed charge

Question 3

how do hydrogen bonds occur between water molecules

Answer 3

the partially positive hydrogen end of one water molecule attracts towards the partially negative oxygen end of another molecule

Question 4

water as a solvent

Answer 4

• it dissolves ions and polar molecules to transport them to cells that need them for biological reactions

Question 5

water as a transport mediant

Answer 5

polar substances dissolve and are easily transported in water around animals or plants

Question 6

what is cohesion? why is it important

Answer 6

cohesion- water molecules bonding together this allows them to transport substances

Question 7

what is adhesion? why is it important

Answer 7

adhesion- water molecules bonding to other polar substances, this forms a stream in materials (Capillary action) where water can flow up tubes

Question 8

water as a coolant

Answer 8

water is a good buffer to temp changes because of the high specific heat capacity, a lot of energy is needed to break the large volume of hydrogen bonds. water also has a high latent heat of vaporisation, due to the large volume of hydrogen bonds alot of energy is needed to transform liquid water to vapour

Question 9

water as a habitat

Answer 9

provides a stable environment for aquatic life as it buffers temp changes
cohesion provides surface tension to water, this provides habitat for organisms
ice is less dense than liquid water because there are larger spaces between water molecules causing ice to float on water

Question 10

how is surface tension caused

Answer 10

caused by molecules being cohesive, at the surface there are less water molecules to hydrogen bonds, this causes them to be more compact

Question 11

examples of water as a solvent for eukaryotic and prokaryotic cells

Answer 11

-chemical reactions in the cytoplasm

Question 12

examples of water as a transport mediant for eukaryotic and prokaryotic cells

Answer 12

-in humans, important ions can dissolve in the water in blood and then transported around the body

Question 13

examples of water as a coolant for eukaryotic and prokaryotic cells

Answer 13

shc- internal temps of animals and plants should remain constant, this is important so enzymes dont denature during chemical reactions. high latent heat of vaporisation- evaporation provides a cooling effect for animals and plants temps eg. sweating

Question 14

examples of water as a habitat for eukaryotic and prokaryotic cells

Answer 14

this provides an insulating layer for organisms ontop of water, the water below dosent freeze so organisms under water dont freeze

Question 15

monomer, polymer, macromolecule

Answer 15

monomer- small basic molecular units
polymer- large complex molecules composed of long chain molecules joined together
macromolecule- complex molecules with relatively large molecular mass

Question 16

condensation reaction

Answer 16

when two molecules are joined together to form a larger more complex molecule with the loss of water, occurs between two facing hydroxyl groups (OH)

Question 17

hydrolysis reaction

Answer 17

a large molecule is split into smaller sections bye breaking a bond using a molecule of water, adding hydrogen to one section and a hydroxyl group to the other

Question 18

what are the chemical elements that make up carbohydrates

Answer 18

carbon (C), hydrogen (H) and oxygen (O)

Question 19

what is a monosacchride and what are they

Answer 19

the monomers that make up carbohydrates.
glucose, fructose, galactose

Question 20

what is the difference between a hexose and pentose monosacchride

Answer 20

hexose is a monosacchride with six carbon atoms, pentose has five carbon atoms

Question 21

what is a disacchride

Answer 21

when two monosacchrides join together

Question 22

glucose properties

Answer 22

glucose is a hexose monosacchride with two forms, alpha and beta. glucose’s structure makes it soluble so it can easily be transported. its chemical bonds contain alot of energy that can be released through respiration

Question 23

what is the difference between alpha and beta glucose

Answer 23

alpha- the hydroxyl group is below carbon 1 whereas beta’s hydroxyl group is above carbon 1

Question 24

go and draw glucose and ribose ring structure

Answer 24

check flashcards

Question 25

what bonds are monosacchrides formed by

Answer 25

glycosidic bonds

Question 26

what happens during synthesis (condensation)

Answer 26

one hydrogen atom on a monosacchride bonds to a hydroxyl group on the other releasing a molecule of water

Question 27

what happens during reverse synthesis (hydrolysis)

Answer 27

a molecule of water reacts with the glycosidic bond, breaking it apart

Question 28

what is the breakdown of sucrose

Answer 28

disacchride where alpha glucose and fructose joined by a glycosidic 1-4 bond, in a condensation reaction

Question 29

breakdown of lactose

Answer 29

disacchride where alpha or beta glucose joined with galactose by a glycosidic 1-4 bond by condesation reaction

Question 30

breakdown of maltose

Answer 30

disacchride two alpha glucose molecules are joined by a 1-4 glycosidic bond through a condensation reaction

Question 31

what is a polysacchride and examples

Answer 31

more than two monosacchrides joined together eg. starch, glycogen and cellulose

Question 32

structure of starch

Answer 32

mixture of two polysacchrides of alpha glucose, amylose and amylopectin

Question 33

structural differences between amylose and amylopectin

Answer 33

amylose is a long, unbrached chain of alpha glucose, the angles of the glycosidic bongs give it a coiled structure which makes it more compact so it can store more starch. amylopectin is a long unbranched chain of alpha glucose, it has side branches which allow the molecule to get at the glycosidic bonds easily, this means glucose can be released quickly

Question 34

how does starch's structure relate to living organisms

Answer 34

starch is the main energy storage material in plants, cells get energy from glucose and plants store excess glucose as starch, starch is insoluble in water so it dosent cause water to enter the cells by osmosis so this dosent affect the water potential this makes it good for storage.

Question 35

glycogen structure

Answer 35

long branched chain of alpha glucose, joined by 1-4-1-6 glycosidic bond

Question 36

how does glycogen's structure relate to living organisms

Answer 36

main storage material in animals, animals store excess glucose as glycogen. it has alot of branches which means that stored glucose can be released quickly this is important for animals. it is also very compact which is good for storage

Question 37

structure of cellulose

Answer 37

long unbranched chains of beta glucose, they form straight cellulose chains which are linked together by hydrogen bonds to form strong fibres called microfibrils.

Question 38

how does cellulose's structure relate to living organisms

Answer 38

cellulose contains alot of microfibrules joined together by high volume of hydrogen bonds. this means is required alot of energy to break the bonds so the cellulose keeps the cell rigid and strong

Question 39

chemical elements that make up lipids

Answer 39

C,H,O

Question 40

what are fatty acids

Answer 40

fatty acids are lipids made up of a carboxyl group, hydrogen group and methyl group

Question 41

structure of saturated fatty acids

Answer 41

saturated fatty acid tails are straight so they can be tightly packed leading to solid animal fats

Question 42

structure of unsaturated fatty acids

Answer 42

the inclusion of double bonds in the fatty acids tails means that the chain is 'kinked' so they cant link closely together, this makes the lipid more fluid than oils

Question 43

breakdown of triglyceride

Answer 43

made up of 3 fatty acid chains, 1 molecile of glycerol held together by 3 ester bonds which are formed through 3 condensation reactions + 3 h2o

Question 44

why are triglycerides excellent energy storage molecules

Answer 44

-glycerol can be converted to glucose -chemical energy in carbon- carbon and carbon-hydrogen bonds

Question 45

what is esterification

Answer 45

the chemical process which occurs between two facing hydroxyl groups for energy storage

Question 46

other functions of triglycerides

Answer 46

- thermal insulation to reduce heat loss - cushioning to protect vital organs - buoyancy for aquatic animals (like whales) - electrical insulation, myelin sheath

Question 47

stucture of phoshpholipids

Answer 47

phosphate, glycerol, 2 fattu acid chains, 2 ester bonds

Question 48

function of phospholipids

Answer 48

main components of biological molecules, eg cell membrane structure phospholipid heads are hydrophilic and tails are hydrophobic, they form double layer with heads facing out centre is hydrophilic so water can’t easily pass through it, membrane acts as a barrier

Question 49

cholesterol functions

Answer 49

helps regulate fluidity of cell membrane by interacting with phospholipid bilayer cholesterol is small and flat so it can fit in between the molecules in the membrane at high temps, they bind to hydrophilic tails in phospholipids, causing them to pack more tightly and reduces fluidity at low temps, cholesterol prevents phospholipids from packing too tightly together so increases membrane fluidity

Question 50

general structure of amino acid

Answer 50

a carboxyl group and amino acid attached to a carbon atom. carbon, oxygen, hydrogen, nitrogen, sometimes sulfur C,H,O,N,S

Question 51

what are the chemical elements that make up proteins

Answer 51

proteins are made up of one or more polypeptides, C O H N and sometimes S

Question 52

describe the synthesis and breakdown of dipeptide and polypeptides

Answer 52

amino acids are linked together by peptide bonds to form dipeptides and polypeptides, a molecule of water is released during the reaction- condensation. the reverse adds a molecule of water to break the peptide bond- hydrolysis reaction

Question 53

what are the levels of protein structure

Answer 53

primary- sequence of amino acids in polypeptide chain secondary structure- alpha helix or beta pleated sheets caused by hydrogen bonds between a.a tertiary- makes 3D shape established through interactions of R groups of a.a, held together by hydrogen, ionic, disulphide or hydrophilic/phobic quaternary- multiple polypeptide chains, prosthetic group

Question 54

what are the roles of ionic, hydrogen, disulphide and hydrophilic/phobic bonds in proteins

Answer 54

ionic- attractions between negative and positive charges in R groups hydrogen- weak bonds that form between positively charged hydrogen atoms and negatively charged atoms in R groups disulphide- strongest, covalent bond between two sulphurs, resistant to high temps hydro..- when phobic R groups are close together they clump so philic R groups are pushed outside which affects how protein folds up into final structure

Question 55

recall the structure and function of globular and conjugated proteins

Answer 55

globular proteins are round and compact, they’re soluble and easily transported in fluids because the philic and phobic interactions in tertiary structure cause the philic R groups to be pushed on outside of molecule. conjugated protein- protein with a non protein group attached

Question 56

examples of structure and cut ion with haemoglobin, insulin and amylase for globular proteins

Answer 56

haemoglobin- carries oxygen around body in red blood cells, it’s a conjugated protein- the non protein part is a prosthetic group. each four polypeptide chains has a prosthetic group called haem, it contains iron which oxygen binds too. insulin- hormone secreted in pancreas, regulates blood glucose level. insulin molecule consists of two polypeptide chains held together by disulphide bonds. when in pancreas, six molecules bind together to form globular protein amylase- enzyme that catalyses the breakdown of starch in digestive system. it’s made of single chain of amino acids, secondary structure contains both pleated sheets and helix

Question 57

recall the properties and functions of fibrous proteins including collagen keratin and elastin

Answer 57

fibrous proteins- tough and rope shaped, insoluble and strong, structural proteins are fairly unreactive. collagen- found in animal connective tissues,strong, minerals can bind to protein to increase rigidity keratin- found in external structures of animals, flexible or hard and tough elastin- found in elastic connective tissue, allows tissues to return to original shape when stretched