exam Q's

Question 1

describe and explain why people with VSD (hole in the septum of heart) can easily become tired

Answer 1

-oxygenated and deox blood mix
-deox blood passes into left ventricle
-less oxygenated blood is pumped to cells
-less oxygen available for ATP production

Question 2

suggest why reduced heart rate is sometimes seen n people who are very aerobically fit

Answer 2

-increased stroke volume
-increased strength/ thickness of heart muscles

Question 3

what breathing instruction should be given to a person when measuring forced expirations and inspirations

Answer 3

-breath in as deeply as possible
-force as much air out as possible

Question 4

describe the differences between forced expiration and relaxed breathing

Answer 4

forced expiration is
-active
-required energy
-ribs pull down hard
-abdominal muscles contract forcing diaphragm up

Question 5

why can expiration be a passive proccess

Answer 5

-it doesn’t use muscle contraction they just relax

Question 6

suggest how the upper respiratory tract of a person with sjorens syndrome might be affected

Answer 6

-irritation and coughing

Question 7

Blood in the arteries has a high hydrostatic pressure
state how this hydrostatic pressure is generated in the heart

Answer 7

by the contraction of the ventricular wall

Question 8

explain why the hydrostatic pressure of the blood drops as blood moves away from the heart

Answer 8

-vessels get smaller
-arteries stretch/ expand = lower pressure

Question 9

describe and explain how the walls of an artry are adapted to withstand and maintain high hydrostatic pressure

Answer 9

to maintain high pressure:
1. elastic fibres= can recoil
2. Smooth muscle = can contract and narrow lumen

to withstand high pressure:
1. thick wall and collagen = provide strength
2.endothelium folded = no damage as it can stretch

Question 10

explain why the delay between the excitation of the atria and excitation of the ventricles is essential

Answer 10

-allows time for all the blood to empty from atria to ventricle
-so atria has time to fully contract and makes sure ventricle doesnt contract at the same time

Question 11

outline the benefit of the Bohr shift to actively respiring tissue

Answer 11

-respiring tissue need more oxygen
-for aerobic respiration
-Bohr shift causes oxygen to be given up more readily

Question 12

distinguish between the term transpiration and the transpiration stream

Answer 12

transpiration stream is movement of water up xylem vessel but transpiration is the evaporation out of aerial parts of the plant

Question 13

Sodium chloride in solution dissociates into Na+ and Cl−.
Explain how the Casparian strip prevents these ions from reaching the xylem of the plant by the
apoplast pathway

Answer 13

1 strip is impervious to, water / solutions (1)
2 forces water / solutions, to pass through,
plasma / cell surface, membrane (1)
3 phospholipid (bilayer), repels / AW, ions /
charged particles (1)

Question 14

what is a similarity between xylem and phloem

Answer 14

both are tubes

Question 15

what examples of assimilates are carried in the phloem

Answer 15

sucrose and amino acids

Question 16

Students carried out a practical investigation into the effect of enzyme concentration on the rate
of reaction.
They were provided with:
* a 1% solution of the enzyme trypsin
* a supply of distilled water
* test tubes labelled 1– 4
* 10 cm3 syringes.
(a) (i) Describe how they would create four different enzyme concentrations using tenfold
serial dilutions. They started by using a syringe to transfer 1 cm3 of the 1% trypsin
solution into tube 1. With a clean syringe, they then added 9 cm3 of distilled water to
tube 1

Answer 16

-shake tube one to mix contents
-remove 1cm3 of mixture from tube 1 add it to tube 2 and add 9cm3 of distilled water to it
-repeat for tubes 3+4.

Question 17

how do u calculate initial rate of reaction from a graph

Answer 17

initial= first block of seconds/ time

-draw a tangent from zero touching the plotted graph
-pick two points on the tangent e.g (0,0) and (18,4)
-use formula change in y over change in x
= 18/4 = 0.22 cm3 s-1