Organism's exchange substances with their environment Flashcards
1
Q
+how are Alveoli specialised for gas exchange ?
A
- capillary once cell thick
- thin walls - short diffusion pathway
-good blood supply , produces a concentration gradient of oxygen
2
Q
why do all living organisms need to exchange things within their environment ?
A
so organisms can survive . waste products need to be released from body as toxic and harmful to body .
3
Q
what 3 factors will affect how many exchange of substances there are and how easy it is to remove them ?
A
- size of organisms ( bigger the size , the bigger the diffusion pathway)
- surface area : volume ratio( larger organism =smaller SA:Vol )
- level of activity - more metabolic processes = more waste products formed so more exchange substances .
4
Q
how to calculate surface area and volume of a cube ?
A
SA = L x w x how many faces
volume = L x W x H
5
Q
what does it mean to have a larger surface area ?
A
more surface area available for gas exchange of materials , making it easier for the organism to absorb necessary nutrients and eliminate waste products .
6
Q
why do single celled organisms not need specialised exchange surfaces ? Amoeba
A
They use diffusion for gas exchange as it is sufficient . the diffusion pathway is short and cytoplasm is close to the environment so it has a high SA:Vol
7
Q
what are 5 features of specialised exchange surfaces ?
A
- a large surface area relative to volume ratio of organism
- very thin
-selectively permeable - movement of the environment medium
- a transport system
8
Q
why is a large surface area to volume ratio a feature of exchange surfaces ?
A
this increases rate of change
9
Q
why are exchange surfaces relatively thin ?
A
to have a short diffusion distance so materials can cross exchange surfaces rapidly
10
Q
why is an exchange surface suppose to be selectively permeable /
A
to allow selected materials to cross
11
Q
why is movement of environmental medium important feature of specialised exchange surface ?
A
to maintain a diffusion gradient - air
12
Q
why is a transport system important feature of specialised exchange surfaces ?
A
to move internal medium to maintain a diffusion gradient - blood .
13
Q
what are 3 structures of tracheal system in insects ?
A
- tracheae
- tracheoles
-spiracles
14
Q
what is tracheae in insects ?
A
a network pf tubes
supported by strengthened rings to prevent the from collapsing
15
Q
what is tracheoles ?
A
small dead tubes
extend through all body tissue
atmospheric air bright directly respiring tissue ( don’t rely on blood )
diffusion pathway short
16
Q
what are spiracles ?
A
tiny pores which gas enter and leave from on body surface
-these can be opened and closes by valve
- when open water vapour can evaporate from inset
- often kept closed to prevent water loss .
17
Q
what are 3 ways of movement of respiratory gases in tracheal system
A
- along diffusion gradient
- mass transport
-end of tracheoles are filled with water
18
Q
how can respiratory gases move along a diffusion gradient in insects ?
A
- during respiration , cells use oxygen up so now low concentration gradient of o2 near end of cells
- diffusion gradient produced
- o2 diffuses from atmosphere through tracheae , tracheoles sand into cell
- respiring cells have a high concentration of co2 in cell so that diffuses out of insect into atmosphere .
19
Q
how can respiratory gases move by mass transport ?
A
contraction of muscles in insects can squeeze tracheae enabling gas moving in and out
- by rhythmic abdominal movements which increase pressure in body
- move air out of spiracles during vigorous activity
20
Q
how can movement of respiratory gases occur when end of tracheoles are filled with water ?
A
- during high activity muscles can respire anaerobically
- produces lactic acid which is soluble
-lowers water potential in muscles - water moves in from tracheoles by osmosis
-water volume in end of tracheoles decreases
-air drawn within them
-
21
Q
what are limitations of tracheal system ?
A
- relies mostly on diffusion for gas exchange - slow
- pathway NEEDS to be short to be effective
- limits the size the insect can reach
22
Q
where are gills located ?
A
In body of fish behind the head Behind the head
23
Q
what are the 2 structures of a gill
A
- gill filaments
gill lamellae
24
Q
what are gill filaments structure ?
A
stacked fillaments attached to gill arch
25
what are gill lamellae ?
at right angles to filaments , arranged rows , to increase surface area of the gills
26
how are gills adapted to have a large surface area to volume ratio ?
there are many gill filaments covered in many gill lamellae
27
how are gills adapted to have a short diffusion pathway ?
short diffusion distance due to :
- capillary network in every lamellae
- all gill lamellae are very thin
28
how are gills adapted to maintain a concentration gradient ?
counter current flow mechanism
29
describe counter current flow in gills of fish ?
- blood and water flow in opposite directions
- oxygen concentration gradient is maintained along whole length of capillary
- equilibrium is never reached
(so water with lowest oxygen concentration found adjacent to most deoxygenated blood )
30
plants are autotrophs , what does this mean ?
they do respiration in chloroplast
use CO2 to produce O2
31
what is a dicotyledonous leaf ?
a flowering plant or leaf
32
gas exchange processes in palisade mesophyll ?
- lets light through
- photosynthesis occurs
-produces O2 and C6H12O6
33
gas exchange in spongy mesophyll ?
- lots of space
-movement of gases
-large SA to V
34
stomata processes for gas exchange ?
-pores which allow gasses diffuse through
-interconnecting air spaces
-short diffusion pathway
35
how does a leaf have a large surface area ?
spogy mesophyl provides alot of spaces for gases to diffuse
-leaf flat surfacxe
36
how does a leaf have a short diffusion pathway ?
- stomata pores allows gases to diffuse through
37
how do leaves maintain a concentration gradaient ?
level of O2 in cell higher than atmoshperen
-level of CO2 in cell is lower than atmosphere
diffusion takes place
38
3 gas exchange surfaces in plants with cause conflict with limiting water loss ?
-thin
-lge SA:V
-permeable
39
what are xerophytes ?
plants with restricted water supply e.g marram grass and cactus
40
how are xerophytes adapted for limiting water loss
5 ways
-curled leaf's trap moisture , increase humidity
-hairs trap moisture , increase humidity ]
-stomata trap moisture , increase humidity
-thicker waxy cuticle reduce evaporation - longer diffusion pathway
-longer root network - reach more water
41
how do insects limit water loss - 3 ways ?
- small SA:V
-waterproof exoskeleton made of chitin
-spiracles open and close to reduce water loss
42
why are the lungs located inside the body ?
-air is not dense enough to support the structures
- body would lose a large amount of water
43
state the number of different cells and tissues along with the lungs
-ciliated epithelial cells
-goblet cells
-mucous glands
-cartilage
-smooth muscle
-squamous epithelial tissue
44
trachea structure
-first process of respiration
-flexible airway supported by cartilage rings
-cartilage prevents trachea from collapsing
-walls made of muscle
-lined with ciliated epithelial and goblet cells
45
bronchi structure
2 diversions of trachea
amount of cartilage reduced with size of bronchi
46
bronchiole structure
branching subdivisions of bronchi
wall made of muscle , lined with epithelial cells
muscle allow them to constrict and control flow of air
47
ribcage structure
protects lungs
bony box - supports and priotects lungs
ribs can be moved by intercostal muscles (internal and external )
48
lungs structure :
-air sacks absorb o2 and exchange co2 for o2
-provide o2 to deoxygenated blood
49
alveoli structure?
mini air sacs found at bottom of bronchioles
-between alveoli are collagen and elastic fibres to allow it to stick
gas exchange surface
once cell thick
lge SA:Vol
50
2 reasons why humans need to absorb a large volum3e of oxygen from lungs ?
-lge organisams =large volume of cells so they have a high metabolic rate
-high body temperature
51
describe inspiration process ?
-active process- uses energy
- external intercostals contract
-intercostal muscles relax
- ribs pulled upwards and outwards ( increases volume of thorax)
-diaphragm contracts and flattens - increasing volume of thorax
THE INCREASED VOLUME OF THROAX , REDUCES THE PRESSYURE IN LUNGS
ATMOSPHERIC PRESSURE GREATER THAN PULMONERY PRESSURE
AIR SUCKED IN
52
describe expiration process?
-largely passive - requires no energy
-external intercostals relax
-internal intercostals contract
ribs move downwards and inwards - decrease volume of thorax
diaphragm relaxes and domes decreasing volume of thorax
CAUSES DECREASE IN THROAX LEADS TO INCREASED PRESSURE IN THE LUNGS
AIR FOERCED OUTR OF LUNGS
ATMOSPHERIC PRESSURE LESS THA PULMONARY PRESSURE
53
why should environmental medium (air) and internal medium (blood)move during gas exchange ?
to maintain a diffusion gradient to allow efficient gas exchange to occur. (
54
how are alveoli adapted for efficient gas exchange ?
lined with one cell thick squamous epithelial cells with one cell thick membranes.
55
how are alveoli adapted to have a short diffusion pathway ?
- lined with one cell thick squamous epithelial cell
very thin walls
- RBC flatten against capillary walls to diffuse through - diffusion of gases are rapid.
56
how are alveoli adapted to have a large surface area ?
lots of alveoli in each lung - increases surface area = more diffusion of CO2 and O2
57
how do alveoli maintain a concentration gradient ?
surrounded by a capillary network - blood flow (CO2 brought towards and O2 brought away )
breathing movements - ventilating lungs and heart pumps blood - moves around body helps maintain a steep concentration gradient
58
equation for pulmonary ventilation
tidal volume x breathing rate
59
what is tidal volume ? dm3
volume of air taken into lungs taken at resting rate
60
what is breathing rate ?1 min
amount of breaths taken in 1 minute
61
what are 5 risk factors of lung disease ?
- smoking
-air pollution
-genetic make up
infections (frequently having chest infections )
- occupation
62
Where are amalayses produced and what does it hydrolyse
Amalayses produced in salivary glands and pancreas
It hydrilysis the glycosydic bond between the polysacharides and forms disacharides like maltose
63
What is function of maltase in digestioj of carbs
Maltase hydrolysis the glycosidic bond between the disaccharide and produces monosaccharides ( 2 glucose ,molecules ) prodiced by ileum
64
What do sucrase and lactase ( as membrane bound disscharidases )do
Sucrase hydrolysis of sucrose into glucose and fructose
Lactase hydrolysisies lactase into glucose and gulactose
(Both hydrolysis single glycosidic bond )
65
Describe carbohydrate digestion :,
- saliva enters mouth from salivary glands
- amalayse dtarts hydrolysing starch into maltose
- food swallowed and enters stomach
- food passed into small kntestine mixes with pancreatic juices
- pancreatic juice hydrolyses remainingstarch to maltose
Muscle in intestine wall push maltose through ileum . Membrane bound disacharides hydrolyses maltose into alpha glucose
66
Where are lipase enzymes produced and stored
Produced by pancreas
Hydrolyse ester bonds of triglyceride to form monoglyceride and fatty acids
67
What is purpose of lipids in bile digestion
Lipids split into tiny droplets called micelles by bile salts
Produced by liver
Stored in gall bladder
Called emulsification - increases SA of lipids so lipases process is sped up
68
What do endopeptidsses do in digestion
Hydrolyses peptide bonds between amino acids in central region of protein molecule for,ing series of peptide molecules
69
What di exopeptidases do
Hydrolyses peptide bonds on terminal AA of peptide molecules progressivly release dipeptides and single AA
70
Process of dipeptidase
Hydrolyse bond between 2 AA of dipeptide - membrane bound being part of cell surfsce membrane (part cell surface membrane of epethelial cells in linung of ileum.
71
describe 4 ways in which ileum (small intestine ) is adapted for efficient absorption of products for digestion ?
- lge surface area due to large amount of microvilli
-short diffusion pathway (one cell thick )due to thin walls
- maintain a concentration gradient - good capillary network
- muscles = ability to move = maintain diffusion gradient
72
how do the products of protein and starch digestion ( glucose and amino acids ) get absorbed by ileum?
co transport !!
73
describe process of glucose and amino acids being absorbed into ileum :
- na+ions move by active transport from ileum to capillary
- now low concentration of na+ions in ileum
-na+ions from lumen (high concentration )transport by facilitated diffusion into ileum by co transport (amino acid / glucose is here )
-they then diffuse (facilitated)into the capillary
74
how do micelles form ?
monoglycerides and fatty acids are covered in bile salts to form micelles
75
describe how micelles are absorbed into the blood stream ?
-micelles transport the monoglycerides and fatty acids to the epithelial cell
- the micelle vesicle fuses to the epithelial cell and releases its contents
- they diffuse into the epithelial cell due to its small and insoluble ,
-Golgi apparatus converts it back into triglycerides
-triglycerides bind to proteins to form a chylomicron vesicle
this transports contents to end of epithelial cell and by exocytosis releases contents to lymph vessel
-then drained into capillary system.
76
describe the structure of haemoglobin ?:
haemoglobin is a protein found in erythrocytes.
-it has 4 polypeptide chains
quaternary structure protein
-each chain has a haem group which contains ion Fe2+
-this binds to o2
each Fe2+ ion can bind to 4O2 molecules
77
define affinity:
ability of haemoglobin to attract/bind to o2
78
define saturation :
when haemoglobin is holding to maximum amount of o2 it can bind too
79
loading definition :
binding of o2 to haemoglobin
80
unloading definition ;
when o2 detaches /unbinds from haemoglobin
81
oxyhaemoglobin distrubution curve - high pO2 means ?
high O2 partial pressure = high affinity = loading lots of O2
82
oxyhaemoglobin distribution curve - low pO2 means ?
low O2 partial pressure = low affinity =unloading o2
83
describe process of each o2 molecule binding to 1 haemoglobin molecule :
- 1st molecule is very difficult to bind to haemoglobin as it has a low pO2 and low affinity - the shape of haemoglobin is difficult too bind to
2nd and 3rd molecule is easy to bind to as the 1st O2 molecule changes the tertiary shape of haemoglobin causing the quaternary shape to change as well
4th haemoglobin molecule is difficult to bind too due to probability - it is less likely for o2 molecule to bind a empty binding site
84
define Bohr effect :
changes in disassociation curve as a result of CO2 levels
85
describe why bohr affect takes place ?
CO2 dissolves in liquid from water in blood , produces carbonic acid . this lowers the ph causing haemoglobin shape to change .
those who respire (have a low affinity )
86
in bohr effect describe affect of low pCO2
curve sgift t the right as an increase in affinity = lots of O2
87
in bohr effect describe affect of high pCO2
curve shifts to the right , unloads o2 (in respiring tissues )
88
define transport system
substances are transported in a mass of fluid (transport medium) with a mechanism for moving fluid (pump)
89
state and explain 4 features of transport system
- medium needs to be liquid based to be moved around easily
- diffusion isn't used alone as its very time consuming
- it needs to be branched to distribute medium to all parts of organism
- requires pressure differences between a part of system and another
90
what is the transport system called in mammals and what substances are transported ?
- circulatory system
- o2, co2, hormones, enzymes, and inorganic ions
91
what is the mass of fluid called and what's the mechanism for moving the fluid in mammals ?
blood
heart provides force for direct movement
92
why do we need a specialised transport system ?
- enables efficient transport
- bring substances from one exchange site to another
- maintain a diffusion gradient
- ensure effective cell activity
93
describe a single circulatory system
blood passes through heart once for each complete circuit of the body .
eg fish
heart pumps deoxygenated blood to gills , transport through rest of body in one single circuit
94
describe a double circulatory system
mammals
blood [passes through heart twice - i circuit carries blood to lungs and other transports o2 and nutrients around body - systematic circulation
95
a disadvantage of a double circuit is that blood pressure decr3eases as it passes through tiny capillaries - what effect does it have on blood flow and why ?
blood flow is slow as there will be a decrease in rate of exchange (less o2 will be delivered to respiring cells . causing not enough energy to pump blood .
96
why should blood pressure in capillary sytem notbe high
to prevent dammage to capillaries
97
why does the blood pass back into heart after being oxygenated from lungs
blood passes through lungs under low pressure to prevent damage to capillaries , if then transported blood straight to body , exchange of gases will be to slow
98
why does the systematic system carry blood at a higher pressure ?
pressure increases after passing through lungs to allow it to flow more quickly . Maintains a concentration gradient as has greater distance to cover
99
state how blood flows through the circulatory system
deoxy blood enters through the vena cave into the right atrium , right ventricle to the pulmonary artery into lungs to be oxygenated blood. the oxygenated blood enters through the pulmonary vein into left atrium , left ventricle, out through aorta to rest of the body
100
state function of atria
send blood from veins to ventricle
101
right ventricle function
pumps blood to the lungs - it has thinner walls to allow blood transport at a low pressure to prevent damage to capillaries in lungs
102
left ventricle function
pumps blood to rest of the body
has to have thicker walls as it pumps blood to rest of body - needs ability to pump it fast enough
103
which arteries provide oxygen to the heart ?
coronary arteries
104
what causes a myocardial infraction /heart attack ?
when the coronary arteries become blocked causing a lack of blood and o2 arriving to heart and causing cells in that area to die
105
what 4 factors affect the oxyhaemoglobin dissociation curve ?
-pCO2
-pO2
-Temperature
-pH
106
Cardiac cycle what is the key word for at rest ?
Diastole
107
In cardiac cycle , what is the key word for when the heart is contracting
systole
108
Blood moves in from the Vena Cava to the right Atrium. It then passes into the Right ventricle.
What valve opens to allow blood into the right ventricle ?
Tricuspid valve . It is an example of an atrioventricular valve (AV)
109
Blood then passes from the right ventricle to the lungs . what is the name of the valve which transports the blood into the lungs
Semi Lunar valve
110
Blood passes from the lungs into the left atrriumn and then into the left ventricle . What is the name of the valve which which allow blood into the left ventricle ?
Bicuspid /AV valve
111
what is the name of the valve which allows blood from left ventricle into the aorta ?
semilunar valve
112
what causes the AV valves to open and close ?
When there is higher pressure in the atrium then ventricles , vaklves forced open .
when there is a higher pressure in the ventricles then the atrium , the AV valve closes
113
what causes the Semi Lunar valve to open and close ?
when there is a higher pressure in the ventricles than aorta/pulmonary artery .
when pressure is higher in the aorta/pulmonary artery semi lunar valve closes .
114
What are the 3 stages in the cardiac cycle ?
- Diastole
- Atrial Systole
-Ventricle Systole
115
what occurs at diastole in the cardiac cycle ?
The Atrioventricular muscles are relaxed . Blood enters the atria from the pulmonary vein or the vena cava . The blood flow of the blood causes an increase in pressure in the ATRIA .
116
What occurs at Atrial Systole in the cardiac cycle ?
Atria muscles are in systole - contracting . This increases pressure in the atria causing the AV valves to open and blood to flow into the ventricles .Ventricular diastole
117
what occurs at ventricular systole in cardiac cycle ?
ventricle walls contract , increasing pressure beyond atria . AV valve shuts and Semilunar valve opens , blood pushed out into the aorta/pulmonary artery .
118
describe and explain the structure and function of the septum in the heart ?
muscle down the middle of the heart and separates the deoxygenated blood from the oxygenated blood .Helps maintain a high concentration of oxygen in oxygenated blood to maintain diffusion gradient for diffusion .
119
cardiac output equation ?
heart rate x stroke volume
120
define transpiration
the process in which water leaves the plant by osmosis due to the opening of stomata .
121
what 4 factors affect the rate of transpiration ?
humidity , temp, sunlight and wind
122
how does humidity affect transpiration ?
If the air has more water than the leaf it has a more positive water potential than the leaf . Therefore transpiration will be lowered (the leaf will have a lower wp) .
123
how does wind affect transpiration
wind removes the water and allows more evaporation to take place - it helps maintain a concentration gradient .
124
how does sunlight help affect transpiration
stomoata will be open to let co2 in for photosynthesis whe there is more sunlight . This will cause water to evaporate from stomata causing an increase in transpiration .
125
how does temperature affect transpiration ?
particles will have higher amounts of kinetic energy causing it too move more and evaporate more faster .
126
What is the name of the theory where water moves up the plant roots against gravity ?
Cohesion tension theory
127
what are the three concepts of cohesion tension theory ?
- cohesion
capillarity - adhesion
root pressure
128
describe how water is dipolar
oxygen has slightly -ve charge and hydrogen has slightly +ve charge. This measn hydrogen binding can occur between different h2o molecules
129
what causes cohesion between different water molecules
hydrogen boding between different witter molecules - h2o stick together and therefor travel up xylem as a continuous column.
130
what is adhesion
when water molecules stick together by forming hydrogen bonds
131
Describe process of capillarity (adhesion)
water adheres to xylem walls - narrow xylem wall the bigger the impact of capillarity.
132
What does root pressure mean ?
as water moves up by osmosis - volume of liquid inside plant increase causing pressure in root to increase ,
133
describe how water moves up the xylem
1)water vapour evaporates out of stomata onto leaves (loss if water in leaves causes lower pressure)
2)water is lost by transpiration - more water is pulled up xylem to replace it
3)hydrogen bonding between water molecules causes h2o molecules to be cohesive which creates a column of water within xylem
4)water molecules stick to wall of xylem pulling water column upwards
5) as water column pulled up xylem tension is created pulling xylem inwards making it narrower.
134
what is the phloem responsible for?
Transport of organic substances like sugars in plants which occurs during translocation in mass flow hypothesis
135
describe structure iof sieve tube elements
long and thin
arranged as a column - contain no nucleus and very few organelles to make cell more hollow
136
Why are companion cells important?
provide ATP required for active transport of organic substances
137
In mass flow hypothesis, what is the site of production called?
source
138
in mass flow hypothesis what is the site of use called?
the sink
139
Where does photosynthesis occur and hat does it produce ?
it occurs in the leaves and you produce sucrose
140
Describe how sucrose diffuses down into companion cell
due to photosynthesis - there is a high concentration of sucrose at sight of cell , therefore sucrose diffuses down concentration gradient into companion cell via facilitated diffusion .
141
Describe how H+ ions move from companion cell into spaces within the cell wall ?
By active transport using energy from ATP .
142
What does active transport of H+ ions into the spaces within the cell wall produce ?
It produced a concentration gradient as H+ ions move down by carrier proteins into sieve tube elements
143
How does sucrose enter the seive tube elements ?
Co transport with H+ ions via carrier proteins
