Unit 2.2 Gas exchange Flashcards
1
Q
How are single celled organisms able to obtain certain substances such as gases, water and nutrients?
(3 things)
A
- Diffusion
- Osmosis
- Active transport through cell membrane
2
Q
As an organism becomes larger…. sa?
A
Surface area to volume ratio becomes smaller
3
Q
Disadvantage of smaller surface area to volume ratio?
(4 things)
A
- Outside surface not large enough
- To let gases and nutrients to enter body
- Fast enough to keep all it’s cells
- Alive
4
Q
Who does and who doesn’t require specialist exchange surfaces?
A
Does: Large organisms
Doesn’t: Small organisms
5
Q
3 examples of specialist exchange surfaces?
A
- Fish gills
- Alveoli in lungs
- Villi in small intestine
6
Q
4 common features in all exchange surfaces?
A
- Large surface area
- Thin barrier
- Has method of maintaining steep con. gradient
- Permeable to respiratory gases
7
Q
State the SA to V ratio size of:
1. Unicellular organisms
2. Multicellular organisms
A
- Large
- Even smaller (or just say small bruh)
8
Q
Why doesn’t a unicellular organism not need a specialist exchange surface?
(2 things)
A
- Their cell membrane is the gas exchange surface
- it’s a single cell = large sa to v ratio = no need buddy
9
Q
What happens if unicellular organism increases in size?
(4 things)
A
- SA to V ratio decreases
- Distance gases have to diffuse = greater
- Until point diffusion across cell surface membrane
- Is tooooooo slow
10
Q
What it mean for multicellular organisms having a smaller SA?
(4 things)
A
- Higher rate of metabolism
- = req. more O2 to satisfy needs
- Has evolved specialist gaseous exchange mechanics
- Where adequate grads. for diffusion can be maintained
11
Q
Why are most gaseous exchange systems located inside the organism?
A
Most gaseous exchange surface are very delicate and req. protection
12
Q
Why did flatworms evolve into a flattened shape?
(4 things)
A
- Overcome problems with increasing size
- Increases SA to V ratio
- Ensures no part of body far from surface
- Maintaining short diffusion pathway
13
Q
Why did earthworms evolve into tubular and elongated shapes?
(2 things)
A
- Elongated provides large SA to V ratio
- So no need specialist surface for gaseous exchange
14
Q
Look in page 4 if concerned with less info on lame earthworms
A
Okay
15
Q
Explain an insects gaseous exchange system
(7 things)
A
- Has one cuz they got small SA to V ratio; can’t use their body surface
- Has unique gaseous exchange system
- Which occurs through a series of small holes
- Called spiracles running along the side of body
- Spiracles lead to system of air-tubes called tracheae
- Spiracles can open & close and can be shut
- To reduce water loss when necessary
16
Q
What in insects gaseous exchange system is where O2 is delivered to cells?
A
Tracheoles
17
Q
Why can the tracheal method of gaseous exchange limit the potential size of insects?
A
- Insect increase in size = SA to V ratio decrease
- O2 reqs. increase meaning trachea must be
- Much longer and wider to meet O2 demand
- Creates crowding within insect
18
Q
What 2 things gas exchange surfaces need to be?
(seems kinda weak bruh)
A
- Thin
- Permeable with a large surface area
19
Q
Explain gaseous exchange system in amphibians?
(8 things D:,’ )
A
- Takes place through skin and lungs
- Skin moist + permeable
- with well-developed network of capillaries below surface
- Skin alone efficient for gaseous exchange when
- Animal resting
- Lungs = simple elastic sacs w/ good blood supply
- No rib cage/diaphragm to provide ventilation
- Air forced inside by movements of floor of mouth
20
Q
Explain gaseous exchange system in reptiles?
(4 things)
A
- More complex internal breathing system than amphibians
- Better suited to terrestrial life
- Has rib cage similar to that of
- Mammals surrounding lungs and providing ventilation
21
Q
Explain gaseous exchange system in birds?
(5 things)
A
- Breathing system similar to reptiles & mammals
- But more efficient to allow **more O2 to reach
- Respiring tissues**
- Lungs supplemented by system of air sacs
- Acts like bellows blowing air into lungs
22
Q
Describe the gills or summin
(5 things)
A
- Most fish have 4 gills on each side
- Supported by gill arch
- Along each arch are filaments
- Along each filaments are tiny plates called
- Lamellae (that’s where gaseous exchange take place)
23
Q
What u see if lamellae outside of water?
A
Stick together = very difficult to identify
24
Q
Explain gaseous exchange of gills?
(5 things, wow 5th time not actually)
A
- Gotta have large SA to provide fish
- Necessary O2 demands
- Err **water = 4-8 parts per mil of
- Dissolved O2** which gills can extract
- No large SA = suffocation
25
Advantage of cold blooded animals having lower metabolism?
- Aids in ability to handle environments
- Of low available O2
26
What is the operculum?
Outer skin flap that protects gills
27
Steps of ventilation of gills ig?
(6 steps)
1. **Mouth opens**
2. **Vol** of **buccal cavity inc.**
3. **Water pulled in** from outside
4. Mouth **closes** & buccal **cavity contracts**
5. **Water forced** through **gills into gill cavity**
6. **Forces open** the **operculum**
28
Explain parallel flow mechanism
(5 things)
- Blood flows in same direction as
- Water passing thru gills
- Not efficient
- Doesn't maintain steep diffusion gradient
- Along whole length of gills
29
Main reason parallel flow mechanism not efficient?
When equilibrium reached, diffusion stops, no maximum amount of O2 taken
30
Explain counter current mechanism
(4 things)
- Water flows opposite direction to blood flow
- Helps maintain steep diffusion grad.
- Across whole length of gills
- Way efficient
31
Main reason why counter current mechanism efficient?
(3 things, why i make complex?)
Equilibrium never reached, diffusion constantly taking place
- Allows maximum amount of O2 to diffuse into blood
- From water available
32
Look at page 12 for tables of both mechanisms which u know I WISH BRAINSCAPE IMAGES WERE FREE
True
33
Look at page 16 for labelled diagram of human respiratory system
okay....
34
Explain how are alveoli adapted for efficient gaseous exchange
(4 steps)
1. Walls **1 cell thick** - **short** diffusion path
2. **Moist** walls - gases **dissolve in moisture**, help **pass cross** gas exchange surface
3. Extensive blood supply - Ensures O2 rich blood taken away from lungs
and CO2 rich blood taken to lungs
4. Large diffusion gradient - Breathing ensures O2 conc. in alveoli higher than capillaries;
So O2 moves from alveoli to blood and CO2 diffuses in opposite direction
35
If i started 3 days ago, perhaps i could've managed to write the last 2 topics remaining in this booklet
Welcome back, don't lose momentum
Tragic
Okay
36
Tell me about ventilation in lungs for **mammals**
- Mammals ventilate their lungs by negative air pressure
- Are in lungs must be lower than the atmospheric air pressure
37
State **inspiration** in ventilation of lungs (mammals)
Intercostal muscles - contract
Ribs - move up and out
Diaphragm - contracts/flattens
Volume of the thorax - increases
Pressure inside the thorax - decreases
38
State **expiration** in ventilation of lungs (mammals)
Intercostal muscles - relax
Ribs - move down and in
Diaphragm - relaxes/moves up
Volume of the thorax - decreases
Pressure inside the thorax - increases
39
What's the main cause of air being forced out during expiration in a mammals lungs?
The elastic recoil of the lungs
40
Explain additional info of ventilation in the lungs (mammals)
Lining the thorax are pleural membranes, between which is a cavity containing pleural fluid. When breathing the fluid acts as a lubricant, allowing friction free movement against the inner walls of the thorax. To prevent the alveoli collapsing an anti-sticking chemical called surfactant covers the surfaces to reduce surface tension
41
I will save this specific card to hope I do summarise the card above
For sure
42
What's the bronchi?
2 branches of the trachea
43
What's the intercostal muscles?
Muscles between the ribs
44
What's the alveoli?
Air sacs at the end of the bronchioles
45
What's the trachea?
Flexible airway supported by a ring of cartilage
46
What's the diaphragm?
A sheet of muscle at the base of the thorax
47
Difference between day and night for plants gaseous exchange?
Day - photosynthesis and respire
Night - only respire ∴ needs a supply of oxygen from atmosphere
48
Look at page 21 for diagram of an angiosperm leaf
If only adding pictures was free
49
How is **transparent waxy cuticle** for leaf specially adapted for gaseous exchange?
To allow photosynthesis
50
How is **large surface area** for leaf specially adapted for gaseous exchange?
Provide space for stomata
51
How is **spongy mesophyll** for leaf specially adapted for gaseous exchange?
Allow gases to diffuse in and out of cells
52
How is **stomata** for leaf specially adapted for gaseous exchange?
Allow gases to move in and out of the leaf
53
7 ways in which leaves are specially adapted for photosynthesis?
- Large surface area to catch as much light as possible
- Thin to allow light to penetrate the leaf
- Transparent cuticle and epidermis to allow light to pass through
- Palisade cells are elongated to accommodate a larger number of chloroplasts
- Palisade cells contain a large number of chloroplasts to capture as much light as possible
- Chloroplasts can move to capture as much light as possible
- Air spaces in spongy mesophyll allow CO2 to diffuse into photosynthesizing cells
54
How does light cause the stomata to open?
Idk... it don't say
55
Other than that, few questions here and there here so ya gotta do what ya gotta do yano
Do what?
