Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MISS ESTRUCH FLASHCARDS > TOPIC 3: ORGANISMS EXCHANGE SUBSTANCES WITH THE ENVIRONMENT > Flashcards

TOPIC 3: ORGANISMS EXCHANGE SUBSTANCES WITH THE ENVIRONMENT Flashcards

1
Q

Surface area to
volume ratio

A

The surface area of an organism
divided by its volume
the larger the organism, the
smaller the ratio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Factors
affecting gas
exchange

A

diffusion distance
surface area
concentration gradient
temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Ventilation

A

Inhaling and exhaling in
humans
controlled by diaphragm and
antagonistic interaction of
internal and external
intercostal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Inspiration

A

External intercostal muscles
contract and internal relax
pushing ribs up and out
diaphragm contracts and
flattens
air pressure in lungs drops
below atmospheric pressure as
lung volume increases
air moves in down pressure
gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Expiration

A

External intercostal muscles
relax and internal contract
pulling ribs down and in
diaphragm relaxes and domes
air pressure in lungs increases
above atmospheric pressure as
lung volume decreases
air forced out down pressure
gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Passage of gas
exchange

A

Mouth / nose -> trachea ->
bronchi -> bronchioles -> alveoli
crosses alveolar epithelium into
capillary endothelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Alveoli
structure

A

Tiny air sacs
highly abundant in each lung -
300 million
surrounded by the capillary
network
epithelium 1 cell thick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why large
organisms need
specialised
exchange surface

A

They have a small surface area
to volume ratio
higher metabolic rate -
demands efficient gas
exchange
specialised organs e.g. lungs /
gills designed for exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fish gill
anatomy

A

Fish gills are stacks of gill
filaments
each filament is covered with
gill lamellae at right angles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How fish gas
exchange surface
provides large
surface area

A

Many gill filaments covered in
many gill lamellae are
positioned at right angles
creates a large surface area for
efficient diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Countercurrent
flow

A

When water flows over gills in
opposite direction to flow of
blood in capillaries
equilibrium not reached
diffusion gradient maintained
across entire length of gill
lamellae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Name three
structures in
tracheal system

A

Involves trachea, tracheoles,
spiracles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How tracheal
system provides
large surface area

A

Highly branched tracheoles
large number of tracheoles
filled in ends of tracheoles
moves into tissues during
exercise
so larger surface area for
gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Fluid-filled
tracheole ends

A

Adaptation to increase
movement of gases
when insect flies and muscles
respire anaerobically - lactate
produced
water potential of cells lowered,
so water moves from tracholes
to cells by osmosis
gases diffuse faster in air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do insects
limit water loss

A

Small surface area to volume
ratio
waterproof exoskeleton
spiracles can open and close to
reduce water loss
thick waxy cuticle - increases
diffusion distance so less
evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Dicotyledonous
plants leaf
tissues

A

Key structures involved are
mesophyll layers
(palisade and spongy
mesophyll)
stomata created by guard cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gas exchange
in plants

A

Palisade mesophyll is site of
photosynthesis
oxygen produced and carbon
dioxide used creates a
concentration gradient
oxygen diffuses through air
space in spongy mesophyll and
diffuse out stomata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Role of guard
cells

A

swell - open stomata
shrink - closed stomata
at night they shrink, reducing
water loss by evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Xerophytic
plants

A

Plants adapted to survive in dry
environments with limited
water (e.g. marram grass/cacti)
structural features for efficient
gas exchange but limiting water
loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Adaptations of
xerophyte

A

Adaptations to trap moisture to
increase humidity -> lowers
water potential inside plant so
less water lost via osmosis
sunken stomata
curled leaves
hairs
thick cuticle reduces loss by
evaporation
longer root network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Digestion

A

Process where large insoluble
biological molecules are
hydrolysed into smaller soluble
molecules
so they can be absorbed across
cell membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Locations of
carbohydrate
digestion

A

Mouth -> duodenum -> ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Locations of
protein
digestion

A

Stomach -> duodenum -> ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Endopeptidases

A

Break peptide bonds between
amino acids in the middle of
the chain
creates more ends for
exopeptidases for efficient
hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Exopeptidases
Break peptide bonds between amino acids at the ends of polymer chain
26
Membrane bound dipeptidases
Break peptide bond between two amino acids
27
Digestion of lipids
Digestion by lipase (chemical) emulsified by bile salts (physical) lipase produced in pancreas bile salts produced in liver and stored in gall bladder
28
Lipase
Produced in pancreas Breaks ester bonds in triglycerides to form : monoglycerides glycerol fatty acids
29
Role of bile salts
Emulsify lipids to form tiny droplets and micelles increases surface area for lipase action - faster hydrolysis
30
Micelles
Water soluble vesicles formed from fatty acids, glycerol, monoglycerides and bile salts
31
Lipid absorption
Micelles deliver fatty acids, glycerol and monoglycerides to epithelial cells of ileum for absorption cross via simple diffusion as lipid-soluble and non-pola
32
Lipid modification
Smooth ER reforms monoglycerides / fatty acids into tryglycerides golgi apparatus combines tryglycerides with proteins to form vesicles called chylomicrons
33
How lipids enter blood after modification
Chylomicrons move out of cell via exocytosis and enter lacteal lymphatic vessels carry chylomicrons and deposit them in bloodstream
34
How are glucose and amino acids absorbed
Via co-transport in the ileum
35
Haemoglobin (Hb)
Quaternary structure protein 2 alpha chains 2 beta chains 4 associated haem groups in each chain containing Fe2+ transports oxygen
36
Affinity of haemoglobin
The ability of haemoglobin to attract / bind to oxygen
37
Saturation of haemoglobin
When haemoglobin is holding the maximum amount of oxygen it can hold
38
Loading / unloading of haemoglobin
Binding/detachment of oxygen to haemoglobin also known as association and disassociation
39
Oxyhaemoglobin dissociation curve
oxygen is loaded in regions with high partial pressures (alveoli) unloaded in regions of low partial pressure (respiring tissue)
40
Oxyhaemoglobin dissociation curve shifting left
Hb would have a higher affinity for oxygen load more at the same partial pressure becomes more saturated adaptation in low-oxygen environments e.g. llamas/ in foetuses
41
Cooperative binding
Hb's affinity for oxygen increases as more oxygen molecules are associated with it when one binds, Hb changes shape meaning others bind more easily explaining S shape of curve
42
How carbon dioxide affects haemoglobin
When carbon dioxide dissolves in liquid, carbonic acid forms decreases pH causing Hb to change shape affinity decreases at respiring tissues more oxygen is unloaded
43
Bohr effect
High carbon dioxide partial pressure causes oxyhaemoglobin curve to shift to the right
44
Oxyhaemoglobin dissociation curve shifting right
Hb has lower affinity for oxygen unloads more at the same partial pressures less saturated present in animals with faster metabolisms that need more oxygen for respiration e.g. birds/rodents
45
Closed circulatory system
Blood remains within blood vessels
46
Name different types of blood vessels
Arteries, arterioles, capillaries, venules and veins
47
Structure of arteries
Thick muscular layer thick elastic layer thick outer layer small luman no valves
48
Capillary endothelium
Extremely thin one cell thick contains small gaps for small molecules to pass through (e.g. glucose, oxygen)
49
Capillaries
Form capillary beds narrow diameter (1 cell thick) to slow blood flow red blood cells squashed against walls shortens diffusion pathway small gaps for liquid / small molecules to be forced out
50
Arterioles
Branch off arteries thickest muscle layer to restrict blood flow thinner elastic layer and outer layer than arteries as pressure lower
51
Tissue fluid
Liquid bathing all cells contains water, glucose, amino acids, fatty acids, ions and oxygen enables delivery of useful molecules to cells and removal of waste
52
Tissue fluid formation
At arteriole end, the smaller diameter results in high hydrostatic pressure small molecules forced out (ultrafiltration) red blood cells / large proteins too big to fit through capillary gaps so remain
53
Reabsorption of tissue fluid
Large molecules remaining in capillary lower its water potential towards venule end there is lower hydrostatic pressure due to loss of liquid water reabsorbed back into capillaries by osmosis
54
Role of the lymph in tissue fluid reabsorption
Not all liquid will be reabsorbed by osmosis as equilibrium will be reached excess tissue fluid (lymph) is absorbed into lymphatic system and drains back into bloodstream and deposited near heart
55
Cardiac muscle
Walls of heart having thick muscular layer unique because it is: myogenic - can contract and relax without nervous or hormonal stimulation never fatigues so long as adequate oxygen supply
56
Coronary arteries
Blood vessels supplying cardiac muscle with oxygenated blood branch off from aorta if blocked, cardiac muscle will not be able to respire, leading to myocardial infarction (heart attack)
57
Adaptation of left ventricle
Has a thick muscular wall in comparison to right ventricle enables larger contractions of muscle to create higher pressure ensures blood reaches all body cells
58
Veins connect to the heart
Vena cava - carries deoxygenated blood from body to right atrium Pulmonary vein - carries oxygenated blood from lungs to left atrium
59
Arteries connected to the heart
Pulmonary artery - carries deoxygenated blood from right ventricle to lungs Aorta - carries oxygenated blood from left ventricle to rest of the body
60
Valves within the heart
Ensure unidirectional blood flow semilunar valves are located in aorta and pulmonary artery near the ventricles atrioventricular valves between atria and ventricles
61
Opening and closing of valves
Valves open if the pressure is higher behind them compared to in front of them. AV valves open when pressure in atria > pressure in ventricles SL valves open when pressure in ventricles > pressure in arteries
62
The Septum
Muscle that runs down the middle of the heart separates oxygenated and deoxygenated blood maintains high concentration of oxygen in oxygenated blood maintaining concentration gradient to enable diffusion to respiring cells
63
Cardiac output
Volume of blood which leaves one ventricle in one minute. cardic output = heart rate X stroke volume heart rate = beats per minute
64
Stroke volume
Volume of blood that leaves the heart each beat measured in dm^3
65
Cardiac cycle
Consists of diastole, atrial systole and ventricular systole
66
Diastole
Atria and ventricular muscles are relaxed when blood enters atria via vena cava and pulmonary vein increasing pressure in atria
67
Atrial systole
Atria muscular walls contract, increasing pressure further. pressure atria > pressure ventricles atrioventricular valves open and blood flows into ventricles ventricular muscle relaxed
68
Ventricular systole
After a short delay (so ventricles fill), ventricular muscular walls contract pressure ventricle > atria pressure and artery pressure atrioventricular valves close and semi-lunar valves open blood pushed into artery
69
Transpiration
Loss of water vapour from stomata by evaporation affected by: light intensity temperature humidity wind can be measured in a lab using a potometer
70
How light intensity affects transpiration
As light intensity increases, rate of transpiration increases more light means more stomata open larger surface area for evaporation
71
How temperature affects transpiration
As temperature increases, rate of transpiration increases the more heat there is, the more kinetic energy molecules have faster moving molecules increases evaporation
72
How humidity affects transpiration
As humidity increases, transpiration decreases the more water vapour in the air, the greater the water potential outside the leaf reduces water potential gradient and evaporation
73
How wind affects transpiration
As wind increases, rate of transpiration increases the more air movement, the more humid areas are blown away maintains water potential gradient, increasing evaporation
74
How wind affects transpiration
As wind increases, rate of transpiration increases the more air movement, the more humid areas are blown away maintains water potential gradient, increasing evaporation
75
Cohesion in plant transport
Because of the dipolar nature of water, hydrogen bonds can form - cohesion water can travel up xylem as a continuous column
76
Adhesion in plant transport
Water can stick to other molecules (xylem walls) by forming H-bonds helps hold water column up against gravity
77
Root pressure in plant transport
As water moves into roots by osmosis, the volume of liquid inside the root increases therefore the pressure inside the root increases this forces water upwards
78
Cohesion tension theory
As water evaporates out the stomata, this lowers pressure water is pulled up xylem (due to negative pressure) cohesive water molecules creates a column of water water molecules adhere to walls of xylem pulling it upwards this column creates tension, pulling xylem inwards
79
Translocation
Occurs in phloem explained by mass flow hypothesis transport of organic substances through plant
80
Sieve tube elements
Living cells contain no nucleus few organelles this makes cell hollow allowing reduced resistance to flow of sugars
81
Companion cell
Provide ATP required for active transport of organic substances contains many mitochondria
82
Mass flow hypothesis
Organic substances, sucrose, move in solution from leaves (after photosynthesis) to respiring cells source -> sink direction
83
How is pressure generated for translocation
Photosynthesising cells produce glucose which diffuses into companion cell companion cell actively transports glucose into phloem this lowers water potential of phloem so water moves in from xylem via osmosis hydrostatic pressure gradient generated
84
What happens to sucrose after translocation?
Used in respiration at the sink stored as insoluble starch
85
Investigating translocation
Can be investigated using tracer and ringing experiments proves phloem transports sugars not xylem
86
Tracing
Involves radioactively labelling carbon - used in photosynthesis create sugars with this carbon thin slices from stems are cut and placed on X-ray film which turns black when exposed to radioactive material stems will turn black as that is where phloem are
87
Ringing experiments
Ring of bark (and phloem) is peeled and removed off a trunk consequently, the trunk swells above the removed section analysis will show it contains sugar when phloem removed, sugar cannot be transported
88
How do small organisms exchange gases
Simple diffusion across their surface
89
Why don't small organisms need breathing systems
They have a large surface area to volume ratio no cells far from the surface
90
How alveoli structure relates to its function
Round shape & large number in - large surface area for gas exchange (diffusion) epithelial cells are flat and very thin to minimise diffusion distance capillary network maintains concentration gradient
91
How fish gas exchange surface provides a short diffusion distance
Thin lamellae epithelium means short distance between water and blood capillary network in every lamella
92
How fish gas exchange surface maintains diffusion gradient
Counter-current flow mechanism circulation replaces blood saturated with oxygen Ventilation replaces water with oxygen removed
93
Name of gas exchange system in terrestrial insects
Tracheal system
94
Describe structure of spiracles
Round, valve-like openings running along the length of the abdomen
95
Describe trachea & tracheoles structure
Network of internal tubes have rings of cartilage adding strength and keeping them open trachea branch into smaller tubes - tracheoles tracheoles extend through all tissues delivering oxygen
96
How tracheal system provides short diffusion distance
Tracheoles have thin walls so short diffusion distance to cells
97
How tracheal system maintains concentration gradient
Body can be moved by muscles to move air - ventilation Use of oxygen in respiration and production of CO2 sets up steep concentration gradients
98
Amylase
Produced in pancreas & salivary gland hydrolyses starch into maltose
99
Membrane-bound disaccharides
Maltase / sucrase / lactase hydrolyse disaccharides into monosaccharides
100
Enzymes involved in protein digestion
endopeptidases exopeptidases membrane-bound dipeptidases
101
Products of protein digestion
Large polymer proteins are hydrolysed to amino acids
102
Double circulatory system
Blood passes through heart twice pulmonary circuit delivers blood to/from lungs systemic circuit delivers blood to the rest of the body
103
Coronary arteries
Supply cardiac muscle with oxygenated blood for continued respiration and energy production for contraction
104
Blood vessels entering / exiting the kidney
Renal artery carries oxygenated blood to kidney renal vein carries deoxygenated blood to heart
105
Blood vessels entering / exiting the lung
Pulmonary artery carries deoxygenated blood to lung pulmonary vein carries oxygenated blood to heart
106
Blood vessels entering / exiting the heart
Vena cava carries deoxygenated blood to heart (right atrium) aorta carries oxygenated blood to body pulmonary artery - carries blood from the heart to the lungs pulmonary vein - carries blood from the lungs into the heart
107
Describe then structure of veins
Thin muscular layer thin elastic layer thin walls valves
108
Explain role of elastic layer in arteries
Thick elastic layer to help maintain blood pressure by stretching and recoiling
109
Describe the elastic layer in veins
Thin elastic layer as pressure lower cannot control the flow of blood
110
Explain the role of valves in veins
Due to low pressure in veins skeletal muscle usually used to flatten walls of veins for blood flow valves prevent the backflow of blood unidirectional flow
111
What causes the semi-lunar valves to open
Higher pressure in the ventricles than in the arteries

MISS ESTRUCH FLASHCARDS (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions