AQA A Level Biology Topic 3 Exam Questions with complete solutions

AQA A Level Biology Topic 3 Exam
Questions with complete solutions

The |hydrostatic |pressure |falls |from |the |arteriole |end |of |the |capillary |to |the |venule |end |of |the |
capillary. |Explain |why |- |correct |answer-Loss |of |water



High |blood |pressure |leads |to |an |accumulation |of |tissue |fluid. |Explain |how |[3] |- |correct |answer-
High |blood |pressure |= |high |hydrostatic |pressure;

Increase |outward |pressure |from |(arterial) |end |of |capillary;

(So) |more |tissue |fluid



The |water |potential |of |the |blood |plasma |is |more |negative |at |the |venule |end |of |the |capillary |than |
at |the |arteriole |end |of |the |capillary. |Explain |why |[3] |- |correct |answer-Water |has |left |the |capillary;

Proteins |too |large |to |leave |capillary;

Increasing |higher |concentration |of |blood |proteins;



Describe |and |explain |the |mechanism |that |causes |forced |expiration |[4] |- |correct |answer-Contraction
|of |internal |intercostal |muscles;



Relaxation |of |diaphragm |muscles;

Causes |decrease |in |volume |of |thoracic |cavity;

Air |pushed |down |pressure |gradient;



One |theory |of |translocation |states |that |organic |substances |are |pushed |from |a |high |pressure |in |the
|leaves |to |a |lower |pressure |in |the |roots.




Describe |how |a |high |pressure |is |produced |in |the |leaves. |[3] |- |correct |answer-Water |potential |
becomes |lower;

Water |enters |phloem |by |osmosis;

Increased |volume |(of |water) |causes |increased |pressure;

,During |their |experiment, |the |scientists |ensured |the |rate |of |photosynthesis |of |their |plants |remained
|constant.




Explain |why |this |was |important |[2] |- |correct |answer-Rate |of |photosynthesis |related |to |rate |of |
sucrose |production;

Rate |of |translocation |higher |when |sucrose |concentration |is |higher;



Describe |how |oxygen |in |the |air |reaches |capillaries |surrounding |alveoli |in |the |lungs. |Details |of |
breathing |are |not |required. |[5]

| - |correct |answer-Trachea |and |bronchi |and |bronchioles;

Down |pressure |gradient;

Down |diffusion |gradient;

Across |alveolar |epithelium;

Across |capillary |endothelium;



The |oxygen |dissociation |curve |for |haemoglobin |shifts |to |the |right |during |vigorous |exercise. |Explain |
the |advantage |of |this |shift. |[3] |- |correct |answer-Lower |affinity |for |oxygen;

(To) |muscles;

(For) |rapid |respiration;



Explain |how |the |body |shape |of |a |Weddel |seal |is |an |adaptation |to |living |in |a |cold |environment |[2]
|- |correct |answer-Small |SA:Vol;



reduces |heat |loss;



Describe |the |role |of |enzymes |in |the |digestion |of |proteins |in |a |mammal. |[5] |- |correct |answer-
(Reference |to) |hydrolysis |of |peptide |bonds;

Endopeptidase |act |in |the |middle |of |protein/polypeptide |OR

Endopeptidase |produces |short(er) |polypeptides/ |increase |number |of |ends;

Exopeptidases |act |at |end |of |protein/polypeptide |

OR

, Exopeptidase |produces |dipeptides/amino |acids;

Dipeptidase |acts |on |dipeptide/amino |acids

OR

Dipeptidase |produces |(single) |amino |acids;



Describe |the |processes |involved |in |the |absorption |and |transport |of |digested |lipid |molecules |from |
the |ileum |into |lymph |vessels. |[5] |- |correct |answer-Micelles |contain |bile |salts |and |fatty
|acids/monoglycerides;



Make |fatty |acids/monoglycerides |(more) |soluble |(in |water)

OR

Maintain |high(er) |concentration |of |fatty |acids/monoglycerides |to |cell/lining |(of |the |ileum);

Fatty |acids/monoglycerides |absorbed |by |diffusion;

Triglycerides |(re)formed |(in |cells);

Vesicles |move |to |cell |membrane;



Cells |lining |the |ileum |of |mammals |absorb |the |monosaccharide |glucose |by |co-transport |with |
sodium |ions. |Explain |how. |[3] |- |correct |answer-Sodium |ions |actively |transported |from |ileum |cell |to
|blood;



Maintains/forms |diffusion |gradient |for |sodium |to |enter |cells |from |gut |(and |with |it, |glucose);

Glucose |enters |by |facilitated |diffusion |with |sodium |ions;



Explain |the |advantages |of |lipid |droplet |and |Michelle |formation |[3] |- |correct |answer-Droplets |
increase |surface |areas |(for |lipase/ |enzyme |action);

(So) |faster |hydrolysis/ |digestion |(of |triglycerides/ |lipids);

Micelles |carry |fatty |acids |and |glycerol/ |monoglycerides |carry |fatty |acids |and
|glycerol/monoglycerides |to/through |membrane/ |to |(intenstinal |epithelial) |cell;




Describe |the |role |of |micelles |in |the |absorption |of |fats |into |the |cells |lining |the |ileum. |[3] |- |correct |
answer-Micelles |include |bile |salts |and |fatty |acids;

Make |the |fatty |acids |(more) |soluble |in |water;

Bring/release/carry |fatty |acids |to |cell/lining |(of |the |ileum);