IB Past paper Gas Exchange Questions

IB DIPLOMA BIOLOGY

PAST PAPER  QUESTIONS ON GAS EXCHANGE

1

A major requirement of the body is to eliminate carbon dioxide (CO 2). In the body, carbon dioxide exists in three forms: f orms: dissoled CO 2, bound as the bicarbonate ion, and bound to !roteins (e" hemo"lobin in red blood cells or !lasma !roteins). #he relatie contribution of each of these forms to oerall CO 2 trans!ort aries considerably de!endin" on actiity, as sho$n in the table belo$. 1.

CO2 Transport in Bloo Plas!a at R"st an D#rin$ E%"r&is"

'or! o( transport

Arterial  –1

mmol l

blood

R"st

E%"r&is"

Venous

Venous

 –1

mmol l  blood

mmol l

blood

 –1

dissolved CO2

0.68

0.78

1.32

 bicarbonate ion

13.52

14.51

14.66

CO2 bound to rotein

0.3

0.3

0.24

!otal CO2 in lasma

14.50

15.5"

16.22

7.4

7.37

7.14

 # o$ blood

%&ource' (eers and (ros) Physiologic (ros) Physiological al Reviews *2000+) Reviews *2000+) )*) a,es 681–715-

*a+

Calcul Calculate ate te ercen ercenta, ta,ee o$ CO 2 $ound as bicarbonate ions in te lasma o$ venous blood at rest. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +,-

*b+ *b+

*i+ *i+

Com Comar aree te te can can,e ,ess in total total CO 2 content in te venous lasma due to e/ercise. ......................................................... ......................................................................................... .............................................................. .................................. .... ......................................................... ......................................................................................... .............................................................. .................................. .... +,-

*ii+ *ii+

denti denti$ $ ic ic $orm $orm o$ CO 2 transort sos te ,reatest increase due to e/ercise. ......................................................... ......................................................................................... .............................................................. .................................. .... ......................................................... ......................................................................................... .............................................................. .................................. .... +,-

2 

(c )

%x!lain the !& differences sho$n in the data. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +.+Total / !ar0s-

 21

As intensit o$ e/ercise increases) umans resond to te increased need $or ,as e/can,e in to as' varin, ventilation rate and varin, tidal volume. /erimental data $or a runner on a treadmill are son belo.

2 .8

80

! id a l v o l u m e V e n t il a t i o n r a t e

2 .6 70 2 .4     1   –

   n     i

2 .2

60

   m     4    e     t    a    r    n    o     i     t    a     l     i     t    n    e     V

2 .0

   s    e    r     t     i     l     4    e

50 1 .8 40

1 .6

   m    u     l    o     V     l    a     d     i     !

1 .4 30 1 .2 1 .0

20

! r e a d m i l l s  e e d   m   – 1 %&ource' .ome.ia.nosteensvents.tm-

3

(a) (a)

Outl Outlin inee the the rela relati tio onshi nshi! ! bet$ et$een een tre treadmil dmilll s!e s!eed and tid tidal ol olum umee. *i+ *i+

 –1

u to 14 m 

......................................................... ......................................................................................... .............................................................. ................................. ... ......................................................... ......................................................................................... .............................................................. ................................. ... +,-

*ii+ *ii+

 –1

above above 14 m 

......................................................... ......................................................................................... .............................................................. ................................. ... ......................................................... ......................................................................................... .............................................................. ................................. ... +,-

 *b+

Comare te te trend in ventilation rate it te trend in tidal volume at a i, treadmill seed. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +,-

 *c+

 – 

Calculate te total volume o$ air inaled er minute en te treadmill treadmill seed is 15 m  1

.

.......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +2-

*d+

&u,,est &u,,est o te te ventilatio ventilation n rate and tidal tidal volume volume mi,t mi,t alter alter i$ treadmi treadmill ll seed ere increased even $urter. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +2+Total  !ar0s-

4

'. ese esear arch ch into into ho$ ho$ the the lun" lun"ss !erf !erfor orm m duri durin" n" "ene "enera rall anes anesth thet etic icss has has incr increa ease sed d beca becaus usee there are so many !ulmonary com!lications durin" o!erations. It is belieed that many inhaled anesthetics affect !ulmonary e!ithelial !ermeability. ulmonar clearin, is an indication i ndication o$ eter te alveolarcaillar barrier as been dama,ed. t can be measured as te rate at ic radioactivit  decreases in lun,s a$ter inalation o$ a radioactive aerosol. !e ,reater te clearin, rate) te ,reater te dama,e to te alveolar caillar barrier. &moin, and lun, diseases *suc as cancers and astma+ also si,ni$icantl increase te clearin, rate o$ radioactive aerosols. n an e/eriment) doctors anted to test te e$$ect o$ inaled anestetics on te ermeabilit  beteen te alveoli and caillaries. atients ere tested b inalin, a radioactive radioactive aerosol one da be$ore teir oeration and one our a$ter teir oeration. !ree ,rous o$ atients eac received a di$$erent te o$ anestetic.

  inaled anestetics (rou 2 '1.59 iso$lurane (rou1 '19 alotane

(rou 3' intravenous anestetic *entanl and roo$ol+ : e v ia ti o n

3 "45

; ean

2 .0

    1   –

   n     i

2 .0

    1   –

1 .5

   n     i

2 .0

    1   –

1 .5

   n     i

   m

   m

   m

    9

    9

    9

    4

    4

    4

   e     t    a    r

   e     t    a    r

1 .0

   e     t    a    r

1 .0

   ,

   ,

   ,

   n     i    r    a    e     l

   n     i    r    a    e     l

   n     i    r    a    e     l

    C

0 .5

0 .0

    C

 b e $ o r e anestetic

a$ter anestetic

( ro u  1

0 .5

0 .0

    C

 b e $ o r e anestetic

a$ter anestetic

1 .5

1 .0

0 .5

0 .0

 b e $ o r e anestetic

( ro u  2

a$ter anestetic

( ro u  3

%&ource' Can,
*a+

Comare Comare te te e$$ect e$$ect o$ o$ eac inaled inaled anesteti anesteticc on te ermeab ermeabilit ilit o$ te te alveoli. alveoli. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +2-

5 

6 

(b) (b) sin sin" " the the data data from from the the "ra "ra!h !hs, s, ex!l ex!lai ain n $he $heth ther er or not not inh inhal aled ed anes anesth thet etic icss are are more more dan"erous than intraenous anesthetics. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +.-

*c+ *c+

&u,, &u,,es estt on" reason  astmatic atients ere not used in tis e/eriment. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +,+Total / !ar0s-

 61

/lain te a te bod acclimati=es to ,as e/can,e at i, altitudes. ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ +Total . !ar0s-

7 

5.

*ra$ a dia"ram of the human "as exchan"e system. +Total 7 !ar0s-

8 

6.

%x!lain the need for, and the mechanism of, entilation of the lun"s in humans. +Total ) !ar0s-

9

(a)

7.

+tate one hormone that increases the blood "lucose leel.

.......................................................... ........................................................................................ .............................................................. ............................................. ............. +,-

*b+

Outline  eav breatin, continues a$ter strenuous e/ercise is comleted. comleted. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +2-

*c+

/lain /lain te e$$ect e$$ect o$ e/ercise e/ercise on ventilation ventilation rate. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +6+Total  !ar0s-

)1

!e sur$ace area to volume ratio is an imortant variable in determinin, biolo,ical structure. structure. *a+

/lain /lain te imorta imortance nce o$ te sur$ace sur$ace area area to volume volume ratio as as a $actor $actor limitin, limitin, cell cell si=e. si=e. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +2-

*b+

:e$ine :e$ine te term term absorption. absorption. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +,-

10 

(c )

+tate one feature of aleoli that ada!ts them to "as exchan"e. exchan"e. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +,-

*d+

>i,ure 1 belo belo sos a crosssecti crosssection on trou, trou, te te small small intestine intestine and and >i,ure >i,ure 2 an enlar,ed enlar,ed lon,itudinal section trou, a sin,le villus.

'i$#r" ,

%&ource' adated $rom ; ?oberts et al.,  Advanced  Advanced Biology) Biology) @elson) 2000) a,e 185-

'i$#r" 2 %&ource' adated $rom !alor et al .) .)  Biological Science Science 1 Cambrid,e niversit ress) 1""7) a,e 244-

sin, tese dia,rams) outline t8r"" as in ic te structure o$ te small intestine is related to its $unction o$ absorbin, $ood. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. +.+Total  !ar0s-

11