CIE B ms bio

8/11/2019 CIE B ms bio

1/16

[June 2004, P2, Q3]

(a) The table below includes statements about the roles of water

in living organisms

as an environment for living organisms

!om"lete the table b# indicating with a tic$ %& which one of the "ro"erties of water isres"onsible for each role

'ou should "ut onl# one tic$ in each row

"ro"erties of water

roles of waterhigh s"ecific

heat ca"acit#

strong cohesive

forces between

water

molecules

high heat of

va"ori(ation

solvent for "olar

moleculesand

ions

trans"ort mediumin blood "lasma

and "hloem

surface for small

insects to wal$ on

ma)or com"onent

of sweat used in

heat loss

trans"iration "ull

in *#lem

"reventing widevariations in

bod# tem"erature

[+]

[Total +]

[-ov 2004, P2, Q2]

.ig 2/ shows a glucose molecule

Fig. 2.1


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(a) 1tate how glucosediffers from glucose as shown in .ig 2/

* -OH is below/AW (-H) on carbon (atom)[/]

(b) .ig 22 shows a molecule of glucose that is about to be added to the end of a growing

chain of a "ol#saccharide

Fig. 2.2

(i) -ame the bond E

* (1-4) glycosidic

[/]

(ii) se the diagram below to show how the glucose molecule will attach to the end ofthe growing chain of the "ol#saccharide 'ou ma# annotate the diagram if #ou wish

* -OH on free molecule and end of chain indicated

* water eliminated/remoed/condensation reaction

* o!ygen bridge/glycosidic bond drawn in correct "osition relatie to chain

* between #1 and #4$ must be labelled either side of glycosidic bond[3]

(iii) -ame a "ol#saccharide that is formed entirel# from glucose molecules in thewa# shown in .ig 22

* cellulose[/]

[Total ]

[-ov 200+, P2, Q2]

Phos"holi"ids are com"onents of cell surface membranes

(a) escribe how "hos"holi"id molecules are arranged in a cell surface membrane

'ou ma# use the s"ace below for a sim"le annotated diagram if #ou wish

* %ilayer/two layers

* Hydro"hilic "art/"olar head/"hos"hate/choline$ faces$ water/outside


3/16

cell/tissue fluid/cyto"lasm

* Hydro"hobic "art/fatty acid chains$ face each other/AW[2]

.ig 2/ shows the structure of the li"ids

tristearin, which is a trigl#ceride5

"hos"hatid#lcholine, which is a "hos"holi"id

Fig. 2.1

(b) 1tate two wa#s, visible in Fig. 2.1, in which "hos"hatid#lcholine differs from tristearin

&hos"holi"id has

* &hos"hate/"hos"horus

* 'wo fatty acid chains

* atty acids of different lengths (different numbers of carbon atoms in

each chain)

* ifferent fatty acids/one is unsaturated/one has a double bond* #holine/nitrogen/base

[2]

(c) 6*"lain how the structure of trigl#cerides, such as tristearin, ma$es them more suitable

for energ# storage than carboh#drates, such as gl#cogen

* +ong hydrocarbon chain/mostly #H, units re"eated/many #-H bonds Allow

many #-H bonds.

* Higher "ro"ortion of hydrogen/more highly reduced/few o!ygen/AW


4/16

* enerates much energy (when res"ired)/twice as much energy as

carbohydrate

* #om"act

* #an be stored in anhydrous form

* Higher calorific alue/more energy "er unit mass/smaller mass "er unit

energy[2]

[Total ]

[June 200, P2, Q4]

.ig 4/ is an electron microgra"h of a chloro"last from a meso"h#ll cell in a leaf

Fig. 4.1


5/16

(a) !alculate the magnification of the electron microgra"h in .ig 4/

* (calculation) 10$ / 20

* (answers) ! 3$7nswer 8 999999999999[/]

(b) 1tate two features visible in Fig. 4.1that identif# the organelle shown as a chloro"last

* starch grain

* grana / thylaoids / internal membranes* sha"e$ 5ualified 6ty"ical chloro"last sha"e7 is minimum acce"table

[2]

(c) !hloro"lasts absorb "hos"hate ions from the surrounding c#to"lasm 1uggest one wa# inwhich chloro"lasts use "hos"hate ions

* 8A / 98A / nucleotides / named nucleotide

* "hos"horylated sugars / triose "hos"hate

* "hos"holi"ids

* A'&

[/]

(d) 1tarch grains in "lant cells contain both am#lose and am#lo"ectin

6*"lain how bothof these substances are formed from glucose in "lant cells

* condensation (reaction) / described as elimination of water

* glycosidic$ bond / lin

* 1:4 in$ amylose / amylo"ectin / both

* amylose$ heli! / unbranched

* 1:; lins (to gie branches)

* amylo"ectin$ branched[4]

(e) 1tate three functions of the water stored in the vacuoles of "lant cells

* (raw material) for "hotosynthesis

* maintains turgidity / "roides su""ort

* "ushes chloro"lasts to edge of cell

* used in hydrolysis reactions

* solent for$ ions / named ion / "igment / named "igment[3]

[Total //]

[June 200:, P2, Q3].ig 3/ shows seven biological molecules, labelled Dto K


6/16

Fig. 3.1


7/16

(a) Table 3/ contains statements about the biological molecules in .ig 3/

!om"lete the table b# selecting the biological molecule from .ig 3/ that matches each

of the statements ;rite the a""ro"riate letter from .ig 3/ in the table The first one has

been done for #ou

'ou ma# use each letter once, more than once or not at all

Table 3.1

statement letter

an amino acid that is a ma)or constituent of collagen J

a com"onent of


8/16

(a) Table +/ contains statements about four molecules

!om"lete the table b# indicating with a tic$ %& or a cross %& whether the statements

a""l# to haemoglobin, -7, "hos"holi"ids or antibodies

'ou should "ut a tic$ or a cross in each bo* of the table

Table .1

statement haemoglobin -7 "hos"holi"ids antibodies

contains iron

contains"hos"hate

able to re"licate

h#drogen bondsstabilise

the molecule

contains nitrogen

[+]

(b) ;ater is sometimes described as "roviding an ideal environment for man# organisms

6*"lain how the h#drogen bonds between water molecules affect the "ro"erties of water

and hel" to ma$e water an ideal environment for man# organisms

* ref to molecules held together / strong attraction / AW

* detail of hydrogen bonding$ e2g2 slight 2e charge on O$ slight ?e charge on

H* high boiling "oint / boils at 1o#

* high latent heat of a"orisation

* so water is li5uid oer wide range of tem"eratures

* (li5uid so) "roides$ su""ort / buoyancy

* high (s"ecific) heat ca"acity

* stable tem"erature / tem"erature of water does not change 5uicly

* large amount of energy needed to be transferred from water for it to

free@e / high latent heat of fusion

* ma!imum density at 4 # / less dense at #* "roides surface tension

* ref solent[+]

[Total /0]

[-ov 200:, P2v2, Q2]

Pol#saccharides, such as gl#cogen, am#lo"ectin and am#lose, are formed b# "ol#merisation


9/16

of glucose .ig 2/ shows "art of a gl#cogen molecule

Fig. 2.1

(a) ;ith reference to .ig 2/,

(i) describe how the structureof gl#cogen differs from the structure of am#lose5

* branched

* 1$; glycosidic$ lins / bonds

* not$ coiled / helical[2]

(ii) describe the advantages for organisms in storing "ol#saccharides, such as gl#cogen,rather than storing glucose

* com"act so large 5uantity can be stored

* insoluble so no osmotic effect

* glucose would lower water "otential

* (so) water would enter and cell olume would increase

* (so) "lant cells would need thicer cell walls / animal cells might burst

* glucose reactie molecule[3]

(b) =l#cogen ma# be bro$en down to form glucose

.ig 22 shows region > from the gl#cogen molecule in .ig 2/ in more detail


10/16

Fig. 2.2

raw an annotated diagram in the s"ace "rovided to e*"lain how a glucose molecule is

formed from the free end of the gl#cogen molecule shown in .ig 22

* o!ygen bridge / glycosidic bond$ broen

* at left hand end of chain

* water shown to be inoled

* free glucose molecule with -OH drawn on #1

* chain now ends with -OH on #4

[3]

[Total :]

[June 20/0, P2/, Q/]

(a) .ig // shows the brea$down of a molecule of sucrose

Fig. 1.1

(i) -ame the bond indicated b# T


11/16

* glycosidic [/]

(ii) 1tate the name given to this t#"e of reaction in which water is involved

* hydrolysis / hydrolytic [/]

(iii) 1tate two roles of water !ithin "lant cellsother than ta$ing "art in brea$downreactions

assume that the answer refers to within the cell unless told otherwise

* solent / medium for reactions

* trans"ort medium

* maintaining turgidity / ee"ing firm / "reents flaccidity / AW

* (raw material / reactant for) "hotosynthesis / "hotolysis

* e!"ansion / elongation / growth

* maintains$ hydrostatic "ressure / "ressure "otential

* maintains water "otential (gradient) A maintains osmotic gradient /"reents "lasmolysis

* stomatal o"ening

* hydro"hilic interactions of membranes

* (in acuole) "ushes chloro"last to edge of cell

* 9 hydrogen bonding un5ualified by ref2 to membranes[2]

[June 20/0, P22, Q4]

.ig 4/ shows the "rimar# structure of a l#so(#me molecule, an en(#me found in tears, salivaand in l#sosomes


12/16

Fig. 4.1

(a) (i) 6*"lain what is meant b# the term "rimar# structure

* (describes the) se5uence of amino acids (in a "oly"e"tide chain) A

order/arrangement[/]

(ii) The molecular structure of the first two amino acids of l#so(#me, l#sine and valine, isshown below

se the s"ace to show how these amino acids become lin$ed in a condensation

reaction

* H,O/water$ released

* (correct) bond formation between (lysine) carbo!yl grou" and (aline)

amino grou"

* di"e"tide (of lysine and aline) and formed with correct structural formula


13/16

[3]

(b) Proteins, such as the en(#me l#so(#me, have a secondar# structure and a tertiar#

structure

(i) escribe the secondar# and tertiar# structure of an en(#matic "rotein, such asl#so(#me

secondar#

* regular order/"attern$ based on H-bonds

* between #OB grou" of one amino acid and 8HB grou" of another

* al"ha-heli! and C-"leated sheet [2]

tertiar#

* folding coiling

* interactions between$ 9 grou"s side chains

* two correctly named bonds e2g2 hydrogen bonds$ disulfide$

bonds/bridges$ ionic bonds$ hydro"hobic interactions* further descri"tion of bonds e2g2 disulfide between cysteine (DBH)

grou"s hydrogen between "olar grou"s (8HB and #OB) ionic between

ionised amine and carbo!ylic acid grou"s hydro"hobic interactions

between non-"olar side chains

* ref2 actie site$ s"ecific/"recise$ sha"e

* ref2 globular/AW$ sha"e A s"herical/ball

* ref2 amino acids with$ hydro"hilic/"olar$ 9 grou"s facing to outside ora[3]

(ii) 1tate wh# it is im"ortant for en(#mes, such as l#so(#me, to "ossess a tertiar#structure

* enables ("rotein to) function/AW A enables antimicrobial action/AW$

A biological catalyst$ 5ualified

* "roides actie site

* 5ualified ref2 to s"ecificity [/]

(c) 1ome "eo"le have a rare disease caused b# a single change in the -7 nucleotide

se?uence of the gene coding for l#so(#me The change leads to the formation of an

insoluble "rotein that has a different structure to the normal soluble l#so(#me molecule

1uggest how a change in the gene can lead to the differences observed between the

normal l#so(#me and the changed l#so(#me

* altered$ (m98A) codon(s)/tri"let(s) A named ty"e of mutation

* changed/AW$ amino acid(s)

* ref2 to effects of sto" codon e2g2 shortened "oly"e"tide chain

* different$ "rimary structure/described A ref2 to differences in$

transcri"tion/translation


14/16

* ref2 to different "ro"erties of$ 9 grou"/side chain (of normal re"laced

amino acid)

* altered tertiary structure/AW A different 9 grou" interactions$ A

change/loss of$ actie site

* idea of globular to fibrous change/hydro"hilic 9 grou"s no longer to

outside[3]

[Total /3]

[June 20/0, P23, Q3]

The amino acid se?uence of the "rotein hormone insulin is shown in .ig 3/


15/16

Fig. 3.1

(a) ;ith reference to .ig 3/, state

(i) which two levels of "rotein structure are shown


16/16

* "rimary A first

* 5uarternary A fourth[2]

(ii) the name of the structures res"onsible for holding the two "ol#"e"tide chains together

* disulfide (bonds/bridges) [/]

(b) @an# "eo"le with diabetes need to ta$e regular in)ections of insulin Ansulin in the form

shown in .ig 3/ cannot be ta$en b# mouth as it would be h#drol#sed b# "roteases in the

gut

An the s"ace below, draw a diagram to show how the "e"tide bond between glutamine /+

and leucine / in "ol#"e"tide chain 7 could be h#drol#sed and show the "roducts of the

h#drol#sis

* "e"tide bond broen

* correct inolement of water

* free B#OOH/B#OO- and free B8H,/B8H3 ? shown [3]

[Total ]

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