3.3 Exchange Wrong Answers

Question 1

adv of counter current system

Answer 1

blood and water flow in opposite directions maintaining the steepest concentration gradient at all times. blood always passes water with the highest oxygen concentration, diffusion occurs across the whole length of the lamellae

Question 2

growth of xerophytic plants vs sunflowers

Answer 2

slower growth due to small number of stomata. growth may continue at lower water potentials due to adaptations in enzymes for photosynthesis and respiration

Question 3

consequence of growing plants in soil with little water

Answer 3

closed stomata so no carbon dioxide upake for photosynthesis

Question 4

journey of an oxygen molecule into the blood from the alveolus

Answer 4

diffuses across the alveolar epithelium and across the epithelium of the capillary

Question 5

golgi apparatus role in micelle absorption

Answer 5

modifies the triglycerides and combines them with proteins, they become packaged for release

Question 6

adv of micelles and droplets

Answer 6

droplets increase surface area causing a high, faster rate of hydrolysis.
micelles carry fa’s and mg’s to the membrane and release them so they can be absorbed by diffusion. micelles make them more soluble in water.

Question 7

process of micelle absorption

Answer 7

combine bile salts with fatty acids/monoglycerides
make them more soluble in water
releases them across the membrane
absorbed by diffusion
reform triglycerides in cell
moved to membrane by vesicles

Question 8

to improve scientific drawings

Answer 8

single lines, labels, scale, parts drawn to scale, no shading

Question 9

lowest blood pressure of all vessels

Answer 9

the vena cava

Question 10

action of the aorta

Answer 10

elastic recoil of the aortic wall maintains a steady/smooth rate of blood flow

Question 11

highest ventricular pressure

Answer 11

left ventricle. it pumps blood to the entire rest of the body, not just the lungs.

Question 12

how does AVV maintain a unidirectional flow of blood

Answer 12

closes when VP higher than AP
opens when AP higher than VP

Question 13

binding of HmG for sigmoid dissociatin

Answer 13

the first oxygen to bind causes a change in the tertiary structure and causes another binding site to be uncovered so a second molecule can easily bind.

Question 14

ventricular volume changes connected to valve openings/closings

Answer 14

Ventricular volume large = SL opens
Ventricular vol decreases after SL opens
AV shuts then SL opens
SL shuts then AV opens

Question 15

consequence of a blockage in lymph system

Answer 15

excess tissue fluid cannot be reabsorbed

Question 16

air is forced out tracheole ends in movement

Answer 16

gases diffuse faster in air than water so oxygen to respiring cells faster

Question 17

why do insects pump abdomens when spiracles are closed

Answer 17

to force a mass flow of air into the tracheole ends and increase the concentration gradient for diffusion.

Question 18

how can xylem cope with high pressures from tension

Answer 18

thickened walls to prevent collapse

Question 19

ringing in summer vs winter

Answer 19

in summer, higher rate of PS due to higher LI, temperature etc. higher production of sugars so more accumulation around ringed phloem.

Question 20

high affinity for oxygen means

Answer 20

absorbs more oxygen at lower pp02

Question 21

hmg structure

Answer 21

2 pairs of polypeptide chains, each with a haem group and Fe2+ ion attached

Question 22

different primary structure of hmg leads to

Answer 22

different TS so different affinities for oxygen

Question 23

why does hmg only release one oxygen and reserves 3 on its self when the body is in rest

Answer 23

because if it released them all there would be none in reserve to supply the tissues when the body is more active

Question 24

benefit of constricting lumen

Answer 24

RBCs are flattened against cell wall, forcing them to go slower so there is more time for diffusion

Question 25

why do plants need a large surface area

Answer 25

to capture light for PS

Question 26

mixing of blood in heart

Answer 26

only partially oxygenated and deoxygenated blood reaches the lungs and tissues. the supply of oxygen to the lungs is inadequate so the diffusion gradient decreases. limits rate of o2 uptake.

Question 27

training affects the heart

Answer 27

builds up heart muscles so stroke volume increases. if cardiac output has stayed the same and SV has gone up that means hear rate has to decrease.

Question 28

effect on co2 on hmg curve

Answer 28

shifts curve right, hmg less saturated

Question 29

ice fish can survive in arctic waters without a specialised system

Answer 29

temp low so respiration low so do not need much oxygen. they can survive from dissolved oxygen from the water

Question 30

translocation

Answer 30

sucrose is actively transported into the sieve tube elements by companion cells which decreases the water potential so water is drawn in by osmosis from the xylem. increases hydrostatic pressure so mass flow of movement down to sink where sucrose is used for respiration or for storage

Question 31

high temps effect on phloem pressure

Answer 31

higher rates of transpiration as more water evaporates from stomata. higher tension in xylem so less water movement from xylem to phloem, decreasing pressure.

Question 32

describe cohesion tension theory

Answer 32

water transpired, the lower water potential creates tension. cohesion maintains the column of water

Question 33

heat treatment effect on xylem

Answer 33

xylem movement is passive so heat does not affect it