Exchange Flashcards
1
Q
How do you calculate surface area?
A
Area of each side added together
2
Q
How do you calculate volume?
A
Length x Width x Depth
3
Q
What happens to SA:vol ratio as size decreases?
A
Increases which increases rate of movement in and out of cells
4
Q
What are general features of specialised exchange surfaces?
A
- large SA:vol ratio
- very thin for a short diffusion pathway
- selectively permeable
- movement of environmental medium to maintain diffusion gradient
5
Q
What are the structures in an insect gas exchange system?
A
Spiracles, tracheae, tracheoles and an exoskeleton
6
Q
What are spiracles in the insect gas exchange system?
A
Openings to the environment
7
Q
What are tracheae in the insect gas exchange system?
A
Internal network of tubes with rings of chitin to prevent them collapsing
8
Q
What are tracheoles in the insect gas exchange system?
A
Smaller dead end tubes that go directly to respiring tissues
9
Q
What is the exoskeleton of an insect gas exchange system?
A
Hard protective layer on the outside
10
Q
How does oxygen move into the insect gas exchange system?
A
- respiring cells use oxygen
- creating a concentration gradient between tracheoles and the air
- oxygen diffuses down its concentration gradient from the air to the tracheoles into he respiring cells
11
Q
How does carbon dioxide move out of the insect gas exchange system?
A
- respiring cells produce carbon dioxide
- creating a concentration gradient between tracheoles and the air
- carbon dioxide moves out of the tracheoles into the air down its concentration gradient
12
Q
What happens in the insect gas exchange system when the insect is respiring anaerobically?
A
- lactic acid produced by anaerobic respiration dissolves into water
- lowers water potential so water inside tracheoles moves out by osmosis
- more volume in tracheoles for oxygen
- more air moves into tracheoles down its pressure gradient from the
13
Q
What are the consequences of the insect gas exchange system?
A
- water loss
- limits the size of insects as pathways must be short
- relies on diffusion
14
Q
What are the adaptations of the insect gas exchange system that aid diffusion of gases?
A
- highly branched tracheoles for a large SA
- tracheoles are 1 cell thick for a sort diffusion pathway
- selectively permeable
- abdominal pumping to maintain diffusion gradient
15
Q
What is abdominal pumping in insects?
A
- abdominal muscles contract which decreases volume and increases pressure so air moves from inside to outside the insect down its pressure gradient
- abdominal muscles relax which increases volume and decreases pressure so air moves from outside to inside of the insect down its pressure gradient
16
Q
What are the adaptations in the insect gas exchange system that prevents water loss?
A
- spiracles can open and close
- hard exoskeleton
- sunken spiracles
17
Q
What are the adaptions of gills for fish gas exchange systems?
A
- lots of gill filaments and lamellae for large SA
- lamellae 1 cell thick for short diffusion pathway
- selectively permeable
- lots of capillaries and counter current flow for maintenance of diffusion gradient
18
Q
What are the structures that make up the gills?
A
Gill arch, filaments, lamellae
19
Q
What is the gill arch?
A
What filaments attach to
20
Q
What are gill filaments?
A
Stacked in a pile on the gill arch
21
Q
What are the gill lamellae?
A
Form at right angles to filaments to increase SA
22
Q
What are the issues with the fish exchange system?
A
- water has much less oxygen than air
- rate of diffusion much slower in water
23
Q
What is the counter current flow?
A
Blood and water flow in opposite directions so blood always meets water that has a higher oxygen concentration so there is always diffusion across the entire filament without reaching equilibrium
24
Q
What are the structures in a leaf?
A
Waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll, lower epidermis, stomata, guard cells, xylem and phloem
25
Why do leaves have a large surface area?
Fo maximum light absorption
26
Why are leaves arranged to minimise shadowing?
Maximum light absorption
27
Why are leaves thin?
Short diffusion pathway
28
Why is the cuticle and epidermis transparent?
To allow light to pass through
29
Why are palisade mesophyll long and narrow?
To fit lots of chloroplast
30
Why are there lots of stomata?
For gas exchange
31
Why do the stomata open and close?
In response to light intensity to control water loss
32
Why are there air spaces in the spongy mesophyll?
Allow diffusion of oxygen and carbon dioxide
33
What is the role of the xylem?
Bring water to cells for photosynthesis
34
What is the role of the phloem?
Carries sugars away that are produced in photosynthesis
35
What is the net movement of carbon dioxide during day and night?
- day = net movement in (for photosynthesis)
- night = net movement out (no photosynthesis happening)
36
Why do the stomata open during the day?
- more photosynthesis
- more glucose produced
- lower water potential
- water moves in
- guar cells swell
- stomata open
37
Why do stomata close during the night?
- use of glucose in photosynthesis
- higher water potential
- water moves out of
- guard cells shrink
- stomata close
38
How do all plants control water loss?
- waterproof coverings
- closing stomata
- decrease SA
- thick cuticle
39
How do xerophytes minimise water loss?
- rolling leaves
- hairy leaves
- sunken stomata
- reduced SA:vol ratio
40
What adaptations does marram grass have?
- thick, way cuticles
- sunken stomata
- rolled, hairy leaves
- high water potential in both gap in rolled leaf and in leaf so no water potential gradient
41
How does a thick cuticle prevent water loss?
- forms a waterproof barrier
- less escape of water by osmosis as here is longer diffusion pathway
42
How do rolled leaves prevent water loss?
- traps region of still air that becomes saturated with water vapour so has a higher oxygen concentration water potential
- so there is no water potential gradient between air surrounding and inside leaf
- no osmosis of water
43
How do hairy leaves prevent water loss?
- traps moist still air
- so there is no water potential gradient
- no movement of water by osmosis as here
44
How do sunken stomata prevent water loss?
- traps still moist air
- no water potential gradient
- no movement of eater by osmosis as here
45
How does a reduced SA:vol ratio of leaves reduce water loss?
- less movement of water by osmosis as here
46
Why is rate of water uptake no equal to rate of transpiration?
Water can be made in chemical reactions e.g. photosynthesis and respiration
47
What are the structures in the human gas exchange system?
Alveoli, bronchioles, bronchi, trachea, lungs and goblet cells
48
What are the alveoli?
Tiny air sacs that does gas exchange
49
What are the bronchioles?
Smallest division of branches in lungs that don’t have cartilage
50
What are the bronchi?
Division of trachea that has rings of cartilage
51
What is the trachea?
Supported by rings of cartilage, the tube that transports air to ling that’s lined with goblet cells and cilia
52
What are the lungs?
Lobed structures made up of highly branched tubes
53
What are goblet cells?
Cells that line trachea and bronchi that release mucus
54
What are adaptations of the human gas exchange system?
- epithelial cells flattened for short diffusion pathway
- capillaries one cell thick for short diffusion pathway
- alveoli are highly fooled for large SA:vol
- good blood supply to maintain diffusion gradient
55
What happens in inspiration?
- external intercostal muscles contract
- pulls rib cage up and out
- diaphragm contracts and flattens
- increases volume of thorax
- higher pressure outside the lungs that in so air moves in down its pressure gradient
56
What happens in expiration?
- internal intercostal muscles contract
- rib cage moves down and in
- diaphragm relaxes and domes up
- volume of thorax decreases
- pressure inside the lungs is higher than outside so air moves out down pressure gradient
57
What is pulmonary ventilation and the equation?
- total volume of air that over in an out of lungs in 1 minute
- Tidal volume x Breathing rate
58
What is tidal volume?
Volume of air taken in per breath
59
What is breathing rate?
Number of breaths per minute
60
What is the salivary gland?
Produces and secretes saliva that contains amylase
61
What is the oesophagus?
Tube that links mouth to stomach
62
What is the liver?
Makes bile and stores glycogen
63
What is the stomach?
Has acidic conditions for protease and to kill pathogens
64
What is the gallbladder?
Stores bile
65
What is the pancreas?
Releases enzymes
66
What is the small intestine?
For digestion and absorption
67
What is the large intestine?
Absorbs water and stores faeces
68
What is the anus?
Muscle that releases faeces
69
How is carbohydrates digested?
- salivary amylase hydrolyses glycosidic bonds between glucose in the mouth
- pancreatic amylase hydrolyses glycosidic bonds between glucose in small intestine
- membrane bound disaccharidases that are attached to membrane of ileum hydrolyse glycosidic bonds between disaccharides
70
What is an examples of a membrane bound disaccharidase?
Maltase hydrolysis glycosidic bonds in maltose
71
How are lipids digested?
- bile salts emulsifies lipids into smaller droplets for a larger SA
- lipase hydrolyses ester bonds creating micelles
72
What are the advantages of lipid droplet and micelle formation?
- lipid droplets have a larger SA so lipase can work quicker
- micelles prevent hydrophobic lipid droplets attracting each other and carry fatty acids and glycerol to ileum membrane
73
How are proteins digested?
- endopeptidases hydrolyse peptide bonds in the middle of the polypeptide chain
- exopeptidases hydrolyse peptide bonds at the terminal ends of the polypeptide chain
- dipeptidases hydrolyse peptide bonds between dipeptides
74
What are the properties of the ileum that increases efficiency of absorption?
- villi and microvilli for a large SA:vol ratio
- thin walls for a short diffusion pathway
- good blood supply to maintain concentration gradient
75
How is glucose and galactose absorbed?
- Na/K pump pumps 3 sodium ions out and 2 potassium ions in
- lowers concentration of sodium ions in epithelial cell
- co transport of sodium ions moving down their concentration gradient with glucose/galactose
- facilitated diffusion of glucose/galactose out of epithelial cell down concentration gradient into the blood
76
How is fructose absorbed?
Facilitated diffusion via a transporter protein
77
How are amino acids absorbed?
- Na/K pump pumps 3 sodium ions out and 2 potassium ions in
- lowers concentration of sodium ions in epithelial cell
- co transport of sodium ions down their concentration gradient with amino acids
- amino acids move out of epithelial cell into blood by facilitated diffusion down concentration gradient
78
How are lipids absorbed?
- micelles drive at epithelial cell
- bile salts removed
- monoglyceride and fatty acids move into epithelial cell by simple diffusion
-monoglyceride and fatty acid converted into triglyceride in endoplasmic reticulum
- triglycerides combined with cholesterol and lipoproteins to make chylomicrons in golgi body
- chylomicrons leave cell by exocytosis into lacteal vessel
