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Biology Unit 2 > 2.3 Adaptation in transport > Flashcards

2.3 Adaptation in transport Flashcards

1
Q

Briefly describe the vascular system of insects

A

-OPEN circulatory system
-dorsal-tube shaped heart
-respiratory gases not carried in blood

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2
Q

What is an open circulatory system?

A

-transport medium pumped by the heart isn’t contained within vessels but moves freely
-transport fluid comes into direct contact with cells

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3
Q

Briefly describe the vascular system of earthworms

A

-vascularisation
-CLOSED circulatory system
-respiratory gases carried into blood

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4
Q

What is a closed circulatory system?

A

-blood pumped by the heart is contained within blood vessels
-blood doesn’t come into direct contact with the cells.

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5
Q

What are the advantages of a closed CS?

A

-blood pressure can be maintained
-blood supply to different organs can vary
-lower volumes of transport fluid required

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6
Q

What type of CS do fish have?

A

single CS

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7
Q

What is a single CS?

A

CS in which the blood travels through the heart once in one circuit
-blood flows through the heart and is pumped around the body before returning to heart

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8
Q

What type of CS do mammals have?

A

double CS

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9
Q

What is double CS?

A

-CS in which blood flows through the heart twice in 2 circuits
-blood is pumped from the heart to lungs before returning to heart
-its then pumped around body then returns to heart again

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10
Q

Whats the benefits of a double CS?

A

-maintains blood pressure around whole body
-uptake of o2 is more efficient
-delivery of o2 ad nutrients is more efficient
-blood pressure can differ in pulmonary and systematic circuits

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11
Q

Describe the double CS in humans

A

blood flows through heart twice in 2 circuits
1.pulmonary circuit
2.systematic circuit

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12
Q

Name 4 chambers of the mammalian heart

A

1.left atrium
2.right atrium
3.left ventricle
4.right ventricle

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13
Q

Describe the pathway of blood around the body

A
  1. pulmonary vein
    2.left artium
    3.left ventricle
    4.aorta
    5.body
    6.vena cava
    7.right atrium
    8.right ventricle
    9.pulmonary artery
    10.lungs
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14
Q

Where are the atrioventricular valves found and what’s their function?

A

-found between atria and ventricles
-prevent back flow of blood from ventricles into atria

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15
Q

What 2 types of atrioventricular valves are there?

A

1.bicuspid (left)
2.tricuspid (right)

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16
Q

Where are the semilunar valves found and what is their function?

A

-found between ventricles and arteries
-prevent back flow of blood from the arteries into ventricles

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17
Q

Name 5 types of blood vessels

A

-arteries
-arterioles
-capillaries
-venules
-veins

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18
Q

Describe the pathway of blood through the blood vessels

A

1.heart
2.arteries
3.arterioles
4.capillaries
5.venules
6.veins
7.heart

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19
Q

What is the function of arteries?

A

carry blood away from heart to the tissues under high pressure

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20
Q

Relate the structure of arteries to their function

A

-thick, muscular walls to handle pressure without tearing
-elastic tissue allows recoil to prevent pressure surges
-narrow lumen to maintain pressure

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21
Q

What is the function of the vein?

A

carry blood towards the heart under low pressure

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22
Q

Relate the structure of veins to their function

A

-thin walls due to lower pressure
-require valves to ensure blood doesn’t flow backwards
-have less muscular and elastic tissue as don’t have to control blood flow

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23
Q

What is the function of capillaries?

A

form a large network through the tissues of body and connect the arterioles to venules

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24
Q

Relate structure of capillaries to their function

A

-walls one cell thick so short diffusion pathway
-very narrow, so can permeate tissues and RBC can lie flat against the wall, reducing diffusion distance
-numerous and highly branched that provides a large SA

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25
What is function of arterioles?
connect arteries and capillaries
26
What is function of venules?
connect capillaries to veins
27
Relate the structure of arterioles and venules to their function
-branch off arteries and veins in order to feed blood into capillaries -smaller than arteries and vein so change in pressure is more gradual as blood flows to capillaries
28
What is the cardiac cycle?
-sequence of evens involved in one complete contraction and relaxation of the heart -3 stages 1.atrial systole 2.ventricular systole 3.diastole
29
What happens during ventricular diastole?
-heart is relaxed -blood enters atria, increasing pressure and pushing open the AV valves -allows blood to flow into ventricles -pressure in heart is lower than in arteries so SL valves=closed
30
Describes what happens during atrial systole
-atria contracts, pushing remaining blood into ventricles -AV pushed fully open
31
Describes what happens during ventricular systole
-ventricles contract -pressure in ventricles increases, closing AV valves to prevent back flow -opens SL valves -blood flows into arteries
32
Why is cardiac muscle described as myogenic?
it initiates its own contraction without outside stimulation from nervous impulses
33
Explain how the heart contracts
-Sinoatrial node (SAN) initiates and spreads impulse across atria so contracts -Atrioventricular node (AVN) receives, delays then conveys impulse down the bundle of His -impulse travels into Purkyne fibres which branch across ventricles so contracts from bottom up
34
What is an electrocardiogram? (ECG)
graph showing electrical activity in heart during cardiac cycle
35
Explain the characteristics patterns displayed on a typical ECG
P wave = depolarisation of atria during atrial systole QRS wave = depolarisation of ventricles during ventricular systole T wave = repolarisation of ventricles during ventricular diastole
36
Describe role of haemoglobin
-present in RBC -o2 molecules bind to haem groups and are carried around body then released where they are needed in respiring tissues
37
How does partial pressure of o2 affect oxygen haemoglobin binding?
haemoglobin has variable affinity for oxygen depending on partial pressure of oxygen p(o2) -high p(o2), oxygen ASSOCIATES to form oxyhaemoglobin -low p(o2), oxygen DISSOCIATES to form deoxyhaemoglobin
38
Explain the shape of oxyhaemoglobin dissociation curves
SIGMOIDAL CURVE (s shape) -first o2 molecule binds, it changes tertiary structure of haemoglobin so easier for 2nd and 3rd molecules to bind -3rd molecule changes tertiary structure so more difficult for 4th to bind
39
How does metal haemoglobin differ from adult haemoglobin?
has higher affinity for o2 than adult haemoglobin due to presence of 2 different subunits that allow o2 to bind more readily
40
Why is the higher affinity of fetal haemoglobin vital?
enables the fetus to obtain o2 from mothers blood
41
Compare the dissociation curve of adult and fetal haemoglobin
-FH dissociation curve to the LEFT -at same p(o2), % of o2 saturation is greater due to fetal haemoglobin having higher affinity
42
Predict the shape of the dissociation curves of animals adapted to low oxygen level habitats
-haemoglobin has a greater affinity for o2 -haemoglobin is saturated at a lower p(o2) -dissociation curves to LEFT
43
Describe the structure and function of erythrocytes
-type of blood cell that is anucleated and biconcave -contains haemoglobin which enables the transport for o2 and co2 to and from tissues
44
What is the chloride shift?
-process by which chloride ions move into erythrocytes in exchange for hydrogen carbonate ions which diffuse out of the erythrocytes -one to one exchange
45
Why is the chloride shift important?
maintains the electrochemical equilibrium of the cell
46
What is the function of carbonic anhydrase?
catalyses the reversible reaction between water and co2 to produce carbonic acid
47
State the Bohr effect
the loss of affinity of haemoglobin for o2 as the p(co2) increases
48
What is tissue fluid?
-fluid that surrounds the cells of animals -same composition as plasma but doesn't contain RBC or plasma proteins
49
Describe the different pressures involved in the formation of tissue fluid
HYDROSTATIC PRESSURE -higher at arterial end of capillary than venous end OSMOTIC PRESSURE -changing water potential of capillaries as water moves out, induced by proteins in plasma
50
How is tissue fluid formed?
-as blood is pumped through increasingly smaller vessels, HP is greater than OP so fluid moves out of capillaries -it then exchanges substances with cells
51
Why does blood pressure fall along the capillary?
-friction -lower volume of blood
52
What happens at the venous end of the capillary?
-osmotic pressure is greater than hydrostatic pressure -fluid moves down its water potential gradient back into capillaries
53
Where does some tissue fluid drain?
some tissue fluid drains into lymphatic system and returns to blood
54
Define vascular bundle
-vascular system in herbaceous dicotyledonous plants -consists of 2 transport vessels; 1. xylem 2.phloem
55
Describe the structure and function of the vascular system in the roots of dicotyledons
-xylem arranged in X shape providing resistance against force -phloem found as patches between arms -surrounded by endodermis, aiding water passage
56
Describe the structure and function of the vascular system in the stem of dicotyledons
-vascular bundles organised around central pith -xylem on inside of bundle to provide support and flexibility, phloem on outside -cambium found between the 2
57
Which structure in plants is adapted for the uptake of water and minerals
root hair cells
58
How is water taken up from soil?
-root hair cells absorb minerals by AT reducing water potential of root -water potential of RHC is lower than soil -water moves into root via osmosis
59
Outline how plant roots are adapted for the absorption of water and minerals
plant roots are composed of millions of root hair cells which have; -long hairs that extend from cell body, increasing SA for absorption -many mitochondria to produce energy for AT of mineral ions
60
State 3 pathways which water moves via root
1. apoplast pathway 2.symplast pathway 3.vacuolar pathway
61
Describe the apoplast pathway
water moves in via intercellular spaces between cellulose molecules in cell wall. it diffuses down its water potential gradient by OSMOSIS
62
Describe the symplast pathway
water enters cytoplasm via plasma membrane and moves between adjacent cells via plasmodesmata. water diffuses down its water potential gradient via OSMOSIS
63
Describe the vacuolar pathway
water enters the cytoplasm via plasma membrane and moves between vacuoles of adjacent walls. water diffuses down its water potential gradient via OSMOSIS
64
Describe the structure and function of the endodermis
-innermost layer of the cortex of a dicot root -impregnated with the Suberin which forms casparian strip -endodermal cells actively transported mineral ions into the xylem
65
What is the function of the casparian strip?
-blocks apoplast pathway, forcing water through symplast route -enables control of the movement of water and minerals across root into xylem
66
What molecule makes the casparian strip waterproof?
suberin
67
Relate the structure of the xylem to its functions
-long, continuous columns made of dead tissue allowing transportation of water -contains bordered pits allowing sideways movements of water between vessels -walls impregnated with lignin providing structural support
68
Define transpiration
-loss of water vapour from parts of plant exposed to air due to evaporation and diffusion -consequence of gaseous exchange occurs when plant opens stomata to exchange o2 and co2
69
What is the transpiration stream?
flow of water from roots to leaves in plants where its lost by evaporation to the environment
70
How does water move up the stem?
-root pressure -cohesion tension theory -capillarity
71
What is root pressure?
force that drives water into and up xylem by osmosis due to AT of minerals into xylem by endodermal cells
72
Explain the cohesion tension theory
-water molecules form hydrogen bonds with each other causing them to stick together -surface tension of the water creates sticking effect -as water is lost through transpiration, more is drawn up the stem from roots
73
Define capillarity
tendency of water to move up the xylem against gravity due to adhesive forces that prevent water column dropping back
74
State the factors that affect rate of transpiration
-light -temp -humidity -air movement
75
How does temp affect rate of transpiration?
higher temp increases random motion and rate of evaporation so ROT increases
76
How does light affect the rate of transpiration?
higher light intensity increases rate of photosynthesis causing more stomata to open for gas exchange so ROT increases
77
How does humidity affect rate of transpiration?
high humidity = water content of air next to leaf is high which reduces concentration gradient so ROT decreases
78
How does air movement affect rate of transpiration?
large amounts of air blow moist air away from leaves creating steep concentration gradient so ROT increases
79
What is a hydrophyte?
plants that are adapted to live and reproduce in very wet habitats e.g. water lilies
80
Give adaptations of hydrophytes that allow them to live in wet conditions
-thin/absent waxy cuticle -stomata often open -wide, flat leaves -air spaces for buoyancy
81
What is a xerophyte?
plants able to live and reproduce in very dry habitats where water availability is low e.g. cacti
82
Give adaptations of xerophytes that allow them to live in dry conditions
-small/rolled leaves -densely packed mesophylls -thick waxy cuticle -sstomata often closed -hair traps moist air
83
What are mesophytes?
-terrestrial plants adapted to live in environments with average conditions and an adequate water supply -have features that enable their survival at unfavourable times of the year
84
Relate the structure of the phloem to its functions
-sieve tube elements transport sugars around plant -companion cells designed for AT of sugars into tubes -plasmodoesmata allow communication and exchange of substances between sieve tubes and companion cells
85
What are cytoplasmic strands?
small extensions of cytoplasm between adjacent sieve tube elements and companion cells
86
Describe the function of cytoplasmic strands
-allow communication and exchange of materials between sieve tube elements and companion cells -holds nucleus in place
87
Define translocation
movement of organic compounds in the phloem from sources to sinks
88
Summarise the mass-flow hypothesis of translocation
-sugar loaded into sieve tubes via AT -lowers water potential causing water to move in from the xylem -hydrostatic pressure causes sugar to move towards the sink
89
What is a potometer?
apparatus used to measure water uptake from a cut shoot
90
What is autoradiography?
technique used to record the distribution of radioactive material within a specimen

Biology Unit 2 (4 decks)

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