Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AQA A-level Biology Year 1 > Chapter 6 - Exchange between organisms + their environment > Flashcards

Chapter 6 - Exchange between organisms + their environment Flashcards

(62 cards)

Start Studying
1
Q

What exchange is done passively?

A

Diffusion + osmosis

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

What exchange is done actively?

A

Active transport

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

What is the relationship between SA:V?

A

As the side Increases, Vol increases + SA increases.

Relationship between SA:VOL

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

What is the features of specialized exchange surfaces?

A

Large SA:Vol = Increases rate of exchange
Very thin = short diffusion pathway
Selectively permeable
Maintenance of conc gradient

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

How have some organisms have evolved to increase the rate of exchange?

A

Flattened shape = no cell far from surface (flatworm, leaf)

Large area = increased SA:VOL

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

What is the equation for the rate of diffusion?

A

Rate of diffusion is proportional to SA X conc gradient

divided by length of diffusion pathway

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

What are an adaptation for the exchange of gas in single celled organisms?

A

Small = large SA:VOL
O2 absorbed by diffusion across body surface
Covered by CSM
CO2 diffuses out

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

How have insects evolved to allow efficient exchange if gases?

A

Evolved Tracheae + tracheoles

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

What are tracheae and their function?

A

They are supported by strenth rings
They prevent collapsing
They are then divided into tracheoles

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

What are tracheoles and their function?

A

they extend throughout all body tissues
atmospheric air + O2 brought directly to respiring tissues by a short diffusion pathway
(tracheole + body cells)

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

How do respiratory gases move in + out of the tracheal system along a diffusion gradient?

A

when cells respire O2 is used up -> conc towards end of tracheoles fall
- this creates a diffusion gradient
(O2 -> tracheae -> tracheoles -> cells)

CO2 produced from respiration
-Creates diffusion gradient in opposite direction
(CO2 -> TRACHEOLES -> TRACHEAE)

Respiratory gases exchnaged quickly

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

How do respiratory gases move in + out of the tracheal system through mass transport?

A

Contraction of muscles squeeze tracheae enabling air in + OUT
Speeds exchange of respiratory gases

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

How do respiratory gases move in + out of the tracheal system through the ends of tracheoles filled with water??

A

Periods of major activity cause muscles to respire (anaerobically)
Produces lactose
H2O, therefore, moves into cells from tracheoles by osmosis
H2O at ends of tracheoles -> low VOL -> draws air further into them
Final diffusion is in a gas therefore more RAPID DIFFUSION
HIGHER rate of air in tracheoles -> but greater water evaporation

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

How do gases enter + leave the tracheae?

A

Through spiracles
Open (Water evaporates) + closes (prevents water loss) by valve

Periodically keep it open for gas exchange

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

What are the limitaions of a tracheal system?

A

Relies mostly on diffusion for gas exchange
Diffusion needs to be short to be effective (insect small)
Short diffusion path (small insect)

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

How have fish adapted for gas exchange?

A

Have waterproof therefore gas tight, outer covering covering
Relatively larger = small SA:VOL
Body surface therefore not adequate for gas exchange (not evolved)

HAVE EVOLVED GILLS

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

What are gill filaments?

A

they are stacked up in a pile

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

What are right-angled to gill filaments?

A

Gill lamellae

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

what are gill lamellae?

A

Increase SA of gills

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

What is the process of how the gills work?

A

H2O taken through mouth + forced over gills + out through the opening on each side of body

Flow of H2O over gill lamellae + flow of blood within are in opposite direction

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

What is countercurrent flow?

A

Flow of H2O over gill lamellae + flow of blood within are in opposite direction

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

What are the countercurrent exchange principles?

A

LOOK AT GRAPH IN BOOK

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

What happens when plants photosynthesize?

A

most CO2 obtained from air
Most O2 used in respiration diffuses out
When photosynthesis doesn’t occur (in dark e.g) O2 diffuses into leaf constantly for respiration

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

How does the structure of the leaf allow better gas exchange?

A

No living cell far from external air
Diffusion takes place in air (rapid)

= short, fast diffusion pathway
air spaces = large SA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What adaptations in leaf have for rapid diffusion?
Stomata (small pores) - Short DP Numerous Interconnecting air spaces occur throughout mesophyll gases readily in contact with mesophyll cases -> large SA = Rapid diffusion (mesophyll cells)
26
How are stomata structured?
Minute pores Each STOMA surrounded by guard cells open + close STOMATAL PORE Controls rate of gas exchange
27
Why are stomata important?
Lose H2O by evaration Evolved to balance gas exchnage + H2O loss Do this by open + closing
28
How is water loss limited in insects?
SMALL SA:VOL Water proof coverings Spiracles
29
How is water loss limited in plants?
Transpiration -> XEROPHYTES | Adapted to live in areas with short H2O supply
30
How have xerophytes adapted to live in areas with short H2O supply?
Thick cuticle - waxy cuticle not enough, makes it thicker Rolling up leaves - protects lower epidermis Hairy leaves - traps moist air on L.epidermis Stomata in pits/groves - traps moist air Reduced in SA:VOL
31
What are lungs?
pair of lobed structures made of bronchioles, which end in alveoli
32
What are tracheae?
``` Flexible airway supported by rings cartillage (prevents tracheae collapsing) Tracheal walls (made of muscle lined with ciliated epithelium + goblet cells) ```
33
What are bronchi + functions?
2 divisions of tracheae leading to 1 lung Produce mucus -> traps first particles Have CILIA move dirt mucus to throat Large bronchi supported by cartilage
34
What are bronchioles?
Branching subdivisions of bronchi walls -> muscles lined with epithelial cells Muscles allow constricting -> control flow of air in + out of alveoli
35
What are alveoli?
Minute air sacs -> end of bronchioles Between alveoli -> collagen + elastic fibres -> allows stretch when air filled Lined with epithelium
36
What is breathing?
Maintaining diffusion of gases across alveolar epithelium air moved in + out of lungs
37
What is inspiration?
Breathing in -> Active process
38
Describe the process of inspiration?
External intercostal muscle
39
What is expiration?
Breathing out largely passive process (not reuire energy)
40
Describe the process of expiration?
Internal intercoastal muscle
41
What happens during normal breathing?
Recoil of elastic tissue in lungs -> main cause air forced out Under Strenous conditions -> various muscle -> major part
42
What is the role of alveoli in gas exchange?
Alveolus lined with eithelial cells Around alveolus is network of pulmonary capilaries RBC flattened against thin capillary walla in order to squueze through Capillaries walls -> single layer
43
Why is the diffusion of gases between alveoli alveoli + blood rapid?
``` Short diffusion pathway V.thin walls V.large toal SA Steep conc gradient (maintains) More time for diffusion (RBC slowed) ```
44
What is the definition of digestion system?
exchange surface through which food substances are absorbed
45
What is an oesophagus?
Carries food mouth -> stomach
46
What is the stomach?
Muscular sac, inner layer produces enzymes
47
What is the stomachs function?
Store + digest (esp protein) | Has glands that produce enzymes -> digest proteins
48
What is the ileum?
``` Long muscular tube Food further digested by enzymes Inner walls folded into villi - increases SA Surface further increased microvilli Absorbs into bloodstream ```
49
What is the large intestine?
Absorbs H2O -> from secretions of many digestive glands
50
What are salivary glands?
Situated near mouth Pass secretions via duct Contain enzyme amylase hydrolyse starch
51
What is the rectum?
Faeces stored -> periodically removed by anus | Final rection of intestines
52
What is the pancreas?
Large gland situated below stomach Produces secretion -> pancreatic juice Protease hydrolyse protein lipase -> lipids, amylase -> starch
53
Describe the physical breakdown journey of food?
Large food broken into smaller pieces by teeth
54
Describe chemical digestion?
Hydrolyses large, insoluble molecules into smaller soluble ones -> by enzymes
55
Describe what happens during carbohydrate digestion?
Saliva enters via salivary glands
56
Describe what happens during lipid digestion?
Hydrolysed by enzyme : lipase
57
Describe what happens during protein digestion?
large complex molecule | hydrolyse by enzymes peptidases
58
What is an endopeptidase?
Hydrolyses peptide bonds -> AA central region of protein molecule -> form series of peptide molecules
59
What is an exopeptidase?
Hysrolyses peptide bonds on terminal AA of peptide molecules formed endopeptidases -> release dipeptides + single AA
60
What are dipeptidases?
Hydrolyses bond between 2AA of dipeptide membrane bound, part of CSM of EC lining ileum
61
What are the adapted functions of the ileum?
Walla folded + possess villi -increases SA + rate of aborption Thin Lined with epithelial cells other sides -> sides network of blood capillaries Villi situated at the interface between lumen (cavity) of intestines + blood other tissues in the body
62
What properties of the ileum increase absorption?
digestion protein produces AA Carbohydrates -> monosacharides, fructose, galactose Absorbing methods -> diffusion + co-transport

AQA A-level Biology Year 1 (10 decks)

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