Gas Exchange

Question 1

How are leaves adapted for diffusion in plants

Answer 1

Thin flat surface provides Large surface area
Arrangement of leaves to avoid overlapping
Thin-short diffusion pathway
Transparent cuticle and epidermis that allow light through
Narrow upper mesophyll cells packed with chlorophyll

Question 2

Which way does gas exchange happen in insects

Answer 2

From end of tracheole meets muscle

Question 3

Three differences between structure of gas exchange systems in insects and mammals

Answer 3

Mamals many trachea and insects only one
Insects do not have alveoli
Insects have many spiraled and mammals don’t
Insect gas exchange happens directly to tissue but humans via blood or capillaries

Question 4

Advantage of gas exchange system to insects

Answer 4

Gas exchange happens directly with tissue so shorter diffusion distance
No need for circulatory system to transport gases so faster

Question 5

Disadvantage of insect gas system

Answer 5

Limits insect size
Takes up lots of space

Question 6

What happens to diaphragm inhalation

Answer 6

Contracts and flattens/ moves down

Question 7

Explains how diaphragm lets air move in

Answer 7

D contracts
Increases volume of thorax
Dear eases the internal presssure
Air moves in from high to low pressure

Question 8

How does oxygen in air whether blood in capillaries

Answer 8

Diffusion across alveoli epithelium / capillary endothelium

Question 9

Substances that are interchanged in organisms

Answer 9

Respiratory gases
Nutrients
Excretory products
Heat

Question 10

Single celled organisms

Answer 10

Bacteria substances can diffuse directly into the cell
Have Marge SA to V ratio

Question 11

Human adaptations

Answer 11

Large surface area
Thin exchange surface for short diffusion path
Selectively permeable surface
Transporting system to maintain diffusion gradient

Question 12

Alveoli adoptions

Answer 12

Large surface area
Thin walls
Network of capillaries to maintain conc gradient
Moist lining to dissolve gasses
Short diffusion pathway

Question 13

Villi

Answer 13

One cell thick
Good blood supply for quick absorption

Question 14

Adaptations of insects

Answer 14

Waterproof covering
Small sA;v ratio to minimize the area over which water is lost

Question 15

Resiportary gasses move in and out tracheal system by

Answer 15

Down a diffusion gradient : oxygen used up and conc towards end of tracheoled falls creating diffusion gradient and causing oxygen to diffuse into cells
Ventilation : movement of muscles in insects can create mass movement of air in and out of trachea

Question 16

What causes spiracles to open

Answer 16

Increasing level of co2

Question 17

What causes oxygen conc in trachea to fall

Answer 17

Used in respiration and diffuses to tissues
Oxygen is unable to enter the organism

Question 18

What does sunlight do in photosynthesis

Answer 18

Bonds carbon dioxide and water

Question 19

Leaves adapted for diffusion by having

Answer 19

Thin flat shape = Large surface area
Thin short pathway
Many Stomata

Question 20

Xylem and phloem

Answer 20

Xylem transports water to leaves
Phloem transports glucose products around the leaf

Question 21

Upper epidermis

Answer 21

Forms boundary between plants inner cells and outside = Prevents water loss

Question 22

Palisade mesophyll

Answer 22

Many chloroplasts to absorb light
Elongated cells for max light absorption
Large SA for rapid co2 absorption

Question 23

Spongy mesophyll

Answer 23

Large air spaces which allow for diffusion of gases

Question 24

Guard cell

Answer 24

Attached to stoma become flaccid or turgid to close or open prevent water loss

Question 25

Stoma

Answer 25

Allow diffusion of gases and water

Question 26

Reducing water loss in cacti

Answer 26

Fleshy stem to store water Thick waxy cuticle to reduce water loss Roots very deep or shallow to catch surface water SA to volume ration is low due to round shape

Question 27

Similarities between gas exchange of insects and plants leaf

Answer 27

No living cell fat from external air Diffusing takes place in gas state Need to avoid excessive water loss Diffuses air through pores

Question 28

Differences between gas exchange of insects and plants leaf

Answer 28

Insects have trachea and plants don’t Insects have spiracles

Question 29

Why Lungs are located inside the body

Answer 29

Air not dense enough to support and protect delicate structure Lungs could lose lots of water and dry out

Question 30

Walls of trachea and bronchus adaptations

Answer 30

Contain goblet cells that secrete mucus ; traps microorganism Cilia : beta and move microorganisms along with mucus to be destroyed by stomach acid

Question 31

Tidal and alveolar air

Answer 31

Tidal air is one that’s goin out of alveoli Alveolar air goes in

Question 32

Define ventilations

Answer 32

The process of breathing in and breathing out

Question 33

Define inspiration

Answer 33

When air pressure of atm is geared than air pressure inside the lungs so air is forced into lungs i

Question 34

Define expiration

Answer 34

When air pressure in lungs is greater than atm so air is forced out

Question 35

During inspiration

Answer 35

RICE Pressure of lungs decreases Volume of thorax increases Diaphragm contracts and flattens Ribs up and out due to external im

Question 36

Define tidal volume

Answer 36

Volume of air taken in at each breath when at rest

Question 37

Define breathing rate

Answer 37

Number of breathes per minute

Question 38

Define vital capacity

Answer 38

Max breath in and out

Question 39

Define residual volume

Answer 39

Air left in longs after strongest exhalation

Question 40

Define pulmonary ventilation rate

Answer 40

Total volume of air that’s moved into the lungs in a minute Tidal volume x breathing rate

Question 41

Features for gas exhange surfaces

Answer 41

Large SA to V ration to speed up rate of exchange Very thin to keep diffusion pathway short Partially selective membrane Movement of environmental medium and internal medium to maintain diffusion gradient

Question 42

How does alveoli having a network of capillaries help it

Answer 42

Greater conc gradient = more rapid diffusion Pumping of blood through capillaries removes oxygen as it diffuses from alveoli into blood Supply of new co2 diffuses out of blood to maintain conc gradient

Question 43

Red blood cells

Answer 43

Erythrocytes Transport oxygen from lungs to cells Contains haemoglobin pigment that carries oxygen

Question 44

Features of RBC

Answer 44

Hameoglobin pigment combined with oxygen No nucleus so more space for haemoglobin Biconcave disc shape to create large SA Large SA to volume ration so oxygen always close to surface Diameter bugger than capillary slowing it down to allow maximum diffusion when passing

Question 45

Role of haemoglobin

Answer 45

Associate with oxygen when gas exchange takes place Disassociate oxygen at cells that require it

Question 46

Structure of haemoglobin

Answer 46

Globular protein consisting of 4 polypepeitde chains Each polypeptide associated with haemoglobin group contains Fe2+ Each Fe2+ can bind to one O2 molecule 4x02 in each haemoglobin

Question 47

How does DNA lead to different affinities of haemoglobin

Answer 47

Different base sequence Different amino acid sequence Different teritary structure