Biological molecules Flashcards
1
Q
What are inorganic ions
A
- variety of inorganic ions required for many cellular proceses
- eg muscle contraction and nervous coordination
- also known as electrolytes
- some needed in minute amunts (micronutrients0 eg zinc and others in small amounts (macronutriens)
2
Q
What is the role of magnesium ions
A
- consituent in chlorphyll
- needed for photosynthesis
- when lacking leaves appear yellow (chlorosis)
- as well stunted growth
3
Q
What is the role of Iron II ions
A
- constituent of haemoglobin
- involved in transport of oxygen
- lack of iron in diet lead to aneamia
4
Q
What is the role of calcium ions
A
- structural componeneet of bones and teeth
- phophate also required
5
Q
What is the role of phosphate ions
A
- needed to make nucleotides including ATP
- constituent of phospholipids and membrane
6
Q
Describe water
A
- vital to life allow important reaction to take place and forms a habitat
- many of it’s properties because it’s a dipolar molecule
- positivley charged end (hydrogen) and negativley charged end (oxygen) an no overall charge
- hydrogen bonds from between hydrogen on one molecule and oxyygen on another
- although individullay weak collectlivley make moleucles difficult to seperate from each other
- excellent olvent due to dipolar nature attract charged particles on other polar molecules allowing them to dissolve
7
Q
How is water a good solvent
A
- involved in many biochemical reactions eg hydrolysis and condensation
- allow polar molecules eg glucose and ions to dissolve
- acts a a transort medium eg blood
8
Q
How does water have a high specific heat capacity
A
- large amount of heat energy needed to increase temperature of a body of water (large number of hydrogen bonds needed to be broken)
- large fluctation in temperature are prevented
- aquatoc habitats are relativley thermally stable
9
Q
How does water have a high latent heat of vaporisation
A
- large amount of heat energy needed to vapourise water
- often used as a cooling mechanism
- eg sweatig in mammals
10
Q
How is water a good metabolite
A
- involved in many biochemical reaction
- eg hydrolyis and condensation
- reactant in photosynthesis
11
Q
How does water have high cohesion
A
- water molecules attract each other to form hydrogen bonds between themselves
- allow water to be drawn up xylem vessels of trees and creates surface tension allow insects such as pond skaters to be supported
- provised support for other aquatic organsisms eg jellyfish
12
Q
How does water have high density
A
- maximum density at 4 degrees celcius
- result ice floats act as inulator prevent water beneath freexing completley
- protect aquatic habitat
13
Q
Why is water transparent
A
- allow light to pass throguh
- enabling aquatiic plants to photosynthesise
14
Q
What are carbohydrates
A
- small organic molecules containing carbon hydrogen and oxygen
- building blocks for more complex molecules eg ribose a constituent molecule of RNA
- sources of energy eg glucose and starch
- structural support eg cellulose and chitin
15
Q
What are monosaccharides
A
- sweet tasting and soluble in water
- single sugar contain carbon, hydrogen and oxygen
- (CH20)n n between 3 and 6
- triose sugar - respiration pathway - 3
- pentose sugar - ribose and deoxyriobe important consituent of RNA and DNA
- glucose is a hexose sugar - 6- starting material for respiration and building blocks for glycogen and other polypeptides
- other hexose sugars are galactose and fructose
16
Q
What are isomers
A
- substances with same formular but different structures
17
Q
What are the two iomer of glucose
A
- alpha glucose - H on top OH on bottom
- beta glucose - OH on top and H on the bottom
18
Q
Wha are disaccharides
A
- formed by joining two monosaccharides together
- involve loss of water molecule formation of glycoidic bond via condenation reactions
- breaking down of disaacharides into monosaccharise involves chemical addition of water know as hydrolysis
19
Q
What is maltose
A
- glucose + glucose
- in germinating seeds
20
Q
What is sucrose
A
- glucose + fructose
- transport in phloem of flowering plants
21
Q
What is lactose
A
- glucose + galactose
- in mammalian milk
22
Q
What are types of dissacharides
A
- maltose
- sucrose
- lactose
23
Q
What is the test for reducing sugars
A
- reducing sugars donate an lectron to reduce blue copper (II) ions present in copper sulfate to red copper (II) oxide
- equal volume of benedicts reagant (blue) to the solution being testes and strongly heating in a boiling water bath
- it a reducing sugar ssuch as glucose is present solution will gradually turn form blue to green to yellow to oraange and brick red precipitate forms
- eg maltose and lactose
- all monosaccharides and some disaccharides are reducing sugars
24
Q
What is the test for non reducing sugars
A
- like sucrose negative test cannot reduce copper (II) ions in copper sulfate to copper (I) oxide
- heat with hydrochloric acid then neutra;ize by adding alkali slowly until fizzing stops
- add benedicts reagant and strongly heat as before
- if solution turns blue to red a non reducing sugar is present
25
What are polysaccharides
* when monosaccharides combine forming a polymer which is a polysaccharide
* number of structural molecules are formed
* composed solely of glucose or in case of chitin glucose with an acetylamine group
* only different is how glycosidic bonds are formed
26
Why are polysaccharides good storage molecules
* unable to diffuse out of the cell
* compact in shape so glucose can be stroed in a cell
* insoluble in water so does not alter water potential and therefore no osmotic efffect
* easily hydrolysed into constituent monosacchaides which can be used in respiration with exception of cellulose which is difficult to digest since it a fibrous structure
27
What is starch
* main energy store in plants found in starch grains
* most plant cells chloroplasts more commonly in seeds
* stored as starch until required immediatley for respiration
* made of many alpha glucse molecules bonded together
* made of two polymer amylose and amylopectin
28
What is amylose
* linear unbranches glycosidic bonds between C1 and C4 on other molecule referred as 1-4 glycosidic bonds
* repeat forming straight chain coilds into a single helix held by hydrogen bonds
29
What is amylopectin
* bracnhed molecule fits in amylose
* 1-4 and 1-6 glycosidic bonds
* when 1-6 bonds form a side branch
* due to branched structure more exposed ends can be hydrolysed results in more rapid release of glucose
30
What is the test for starch
* iodine solution (iodine dissolved in an aqueous solution of potassium iodide)
* orange to bluey black
* unreliable as temperature increase so does collour intensity so indication of concentration not reliable
31
What is glycogen
* main storage products in animals
* similar to amylopectin but more branched
32
What is cellulose
* structural polysaccharides most abundant molecule as found in plant cell walls
* beta glucose bonded together by adjacent glucose molecule rotated by 180 degrees forming long straight parallell chains cross linked by hydrogen bonds
* highly cross linked form bundles microfibrils turning into arranged fibres which are bundles
* strong
* gaps make them freely permeable allowing water and solutes to penetragte through cell membrane
33
What is chitin
* structural polyaccharides
* exeskeleton of insects
* cell wasll of fungi
* strong, light and waterproof
* siilar to cellulose
* long parallel chain of beta glucose (with acetylamine groups) cross linked by hydrogen bonds forming microfibrils due to adjacent glucose molecules rotated by 180
34
What are lipids
* non polar compojds
* insoluble water
* contin carbon, hydrogen and less oxygen compared to carbs
35
What are triglycerides
* combination of one glycerol and three molecules of fatty acids via condensation reaction where three molecule of water removes and ester bond formed between glycerol and each fatty acid
36
What are unsaturated and saturated fats and identify the states
* differences in fats and oils variation in fatty acids
* hydrocarbon chain no C-C double bonds then fatty acid is saturated as all C atoms linked to possible maximum H
* these dats are semi solid at room temp useful troage of fats in mammals
* high intake of saturatedd fats factore of heart disease
* animal lipids are often saturated whereas plants are unsaturated and occurs as oild
* when one C=C bond present referred as monounsaturated
* many C=C bonds polyunsaturated
* where bond is double chain may kink
37
What are waxes
* melt at temperatures above 45 degree celcius
* waterproofing in anima;s and plants eg leaf cuticle
38
What are the roles of lipids
* structure of plasma membranes
* mylein sheath that surround neurones
* presence in myelein increases speed at which nerve impulse prporgate along neurone
39
how are fats energy reserves
* lipids are excellent energy reserves in both animals and plants
* contain C-H bonds more than carbs
* one gram of fat when oxidised ueiles twice as much energy as the same mas of the carb
40
How do fats help with thermal insulation
* stored under skin
* acts as an inuslator against heat loss
41
How do fats help with protection
* stored around delicate internal organs (fats)
* eg kidneys protection against physical damage
42
How do fats help produce metabolic water
* triglyceirde produce a lot of metabolic water when oxidised
* important in deert animals survive on metabolic water from respiration of its fat intake
43
How do fats help with waterproofing
* fats are insoluble in water and important in land organisms such as inect where waxy cuticle cuts down watrer loss
* water loss is then only usually posible via stomata through transpirtation
44
What is the test for lipids
* lipids emulsion tet
* sample mixed with ethanol to dissolve any lipids present
* then sample shaken with equal amount of water
* insoluble in water so lipids fall out causing cloudy emulsion
45
What are phospholipids
* fatty acid tail replaces by phosphate group
* molecule where one end is soluble in water and other is not
* fatty acid part is non polar and inssoluble in water so referred as hydrophobic
* glycerol part and phosphate froup are polar and dissolve in water so hydrophillic
* important formation and functioning of plasma membrane in cells
46
What are implicationss of saturated fats on human health
* athersclorosis build up fatty deposits of plaques called atheromas within artery walls
* low density lipoproteinss (LDL) from diet high in saturated fats
* lead to narrowing of arteries
* loe elasticity restrict blood flow limits oxygen delivery to the heart result in angina eventually a heart attack
* atheroma cause endothelial lining to rupture causes clot to form caussing tokes
* dietss high in unsaturated fats combined with excercies reult in high density lipoproteins (HDL) which carry harmful fats to liver for disposal
* higher ration HDL:LDL patients blood loewr risk of cardiovascular disease
47
What are proteins
* large compounds built up of sub units called amino acids
* 20 amino acids used to make up proteins and order determines protein structure hence its function
* contain carbon., hydrogen , oxygen, nitrogen and sometime sulphur
* very larg emolecules consists of long chains of many amino acids joined together polypeptides
48
What do amino acids contain
* amino group
* carboxyl group
* variable group - r
* Hydrogen atom
49
What is the formation of a pepetide bond
* proteins built linear sequence of amino acids
* condensation reaction between amino group of one acid and carboxyl group of another
* eleminating water
* bond formed is a peptide bond
50
What is the primary structure of a protein
* order of amino acids in a polypeptide chain
* determines by DNA sequence on one strand of DNA molecule
51
What is the secondary structure of a protein
* involves folding of primary structure into a 3D shape held by hydrogen bonds between =O annd on - COOH and H on NH2 groups
* create an alpha helix and Beta plaeated sheet
52
What is the teritiay structure of a protein
* forms from folding of alpha helix into a more complex shape
* disulphide bridges
* hydrogen bonds
* hydrophobic interactions
* globular proteins their shape
53
What is the quantenary structure of a protein
* combination of two or more polypeptides chains in tertiary form combined
* non protein group
* large complex molecules eg haemolglobin
54
What are the roles of proteins
* depend on molecular shape
* fibrous and lobular proteins
55
What are fibrous proteins
* structural functions
* polypeptides in parallel chains or sheets with cross linkages to form long fibred eg keratin
* insoluble in water
* stong and tough
* collagen provides tough properties needed in tendones
* a ssingle fivre consists of three polypeptide chain twisted around like a rose linked by cross bridges making it a very stable molecule
56
What are globular proteins
* variety of different functions - enzymes , anitbodies, plasma proteins and some are hormones eg insulin
* proteins are compact and folded as spherical molecules
* soluble in water
* haemoglobin conists of four folded polypeptide chainsa t centre of which is an iron containing group called haem
* each protein is unique and has a specific shape
57
What is the test for proteins
* few drops of biuret
* prescence of protein shown by a colour change from blue to purple
58
Condensation
* the removal of a water molecule and the formation of a covalent bond between two biochemical groups
59
Hydrolysis
* the breaking down of large molecules into smaller ones by the addition of a molecule of water
60
Dipolar
* a polar molecule with a positive and negative charge
61
Hydrogen bond
weak attractive force between a postivley charges hydrogen atom and a negativley charges oxygen or nitrogen atom
62
Isomer
* molecules with the same chemical formular but with a different arrangement of atoms
63
Polymer
* a large molecule made up of many repeating units (monomers) bonded together
64
Hydrophobic
* water hating ie cannot interact with water due to the lack of any charge on the molecule
65
Hydrophillic
water loving can interact with water due to the presecence of chanrge on the molecule
