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Bio A levels Jones > Unit 2.2 Adaptations for Gaseous Exchange > Flashcards

Unit 2.2 Adaptations for Gaseous Exchange Flashcards

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Biology 101 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
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2
Q

As an organism becomes larger…. sa?

A

Surface area to volume ratio becomes smaller

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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
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4
Q

Who does and who doesn’t require specialist exchange surfaces?

A

Does: Large organisms
Doesn’t: Small organisms

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5
Q

3 examples of specialist exchange surfaces?

A
  • Fish gills
  • Alveoli in lungs
  • Villi in small intestine
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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
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7
Q

State the SA to V ratio size of:
1. Unicellular organisms
2. Multicellular organisms

A
  1. Large
  2. Even smaller (or just say small bruh)
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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
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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
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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
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11
Q

Why are most gaseous exchange systems located inside the organism?

A

Most gaseous exchange surface are very delicate and req. protection

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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
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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
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14
Q

Look in page 4 if concerned with less info on lame earthworms

A

Okay

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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
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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
Q

Advantage of cold blooded animals having lower metabolism?

A
  • Aids in ability to handle environments
  • Of low available O2
26
Q

What is the operculum?

A

Outer skin flap that protects gills

27
Q

Steps of ventilation of gills ig?
(6 steps)

A
  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
Q

Explain parallel flow mechanism
(5 things)

A
  • Blood flows in same direction as
  • Water passing thru gills
  • Not efficient
  • Doesn’t maintain steep diffusion gradient
  • Along whole length of gills
29
Q

Main reason parallel flow mechanism not efficient?

A

When equilibrium reached, diffusion stops, no maximum amount of O2 taken

30
Q

Explain counter current mechanism
(4 things)

A
  • Water flows opposite direction to blood flow
  • Helps maintain steep diffusion grad.
  • Across whole length of gills
  • Way efficient
31
Q

Main reason why counter current mechanism efficient?
(3 things, why i make complex?)

A

Equilibrium never reached, diffusion constantly taking place
- Allows maximum amount of O2 to diffuse into blood
- From water available

32
Q

Look at page 12 for tables of both mechanisms which u know I WISH BRAINSCAPE IMAGES WERE FREE

A

True

33
Q

Look at page 16 for labelled diagram of human respiratory system

A

okay….

34
Q

Explain how are alveoli adapted for efficient gaseous exchange
(4 steps)

A
  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
Q

If i started 3 days ago, perhaps i could’ve managed to write the last 2 topics remaining in this booklet

A

Tragic

Bio A levels Jones (5 decks)

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