Gas Exchange Flashcards
How are leaves adapted for diffusion in plants
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
Which way does gas exchange happen in insects
From end of tracheole meets muscle
Three differences between structure of gas exchange systems in insects and mammals
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
Advantage of gas exchange system to insects
Gas exchange happens directly with tissue so shorter diffusion distance
No need for circulatory system to transport gases so faster
Disadvantage of insect gas system
Limits insect size
Takes up lots of space
What happens to diaphragm inhalation
Contracts and flattens/ moves down
Explains how diaphragm lets air move in
D contracts
Increases volume of thorax
Dear eases the internal presssure
Air moves in from high to low pressure
How does oxygen in air whether blood in capillaries
Diffusion across alveoli epithelium / capillary endothelium
Substances that are interchanged in organisms
Respiratory gases
Nutrients
Excretory products
Heat
Single celled organisms
Bacteria substances can diffuse directly into the cell
Have Marge SA to V ratio
Human adaptations
Large surface area
Thin exchange surface for short diffusion path
Selectively permeable surface
Transporting system to maintain diffusion gradient
Alveoli adoptions
Large surface area
Thin walls
Network of capillaries to maintain conc gradient
Moist lining to dissolve gasses
Short diffusion pathway
Villi
One cell thick
Good blood supply for quick absorption
Adaptations of insects
Waterproof covering
Small sA;v ratio to minimize the area over which water is lost
Resiportary gasses move in and out tracheal system by
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
What causes spiracles to open
Increasing level of co2
What causes oxygen conc in trachea to fall
Used in respiration and diffuses to tissues
Oxygen is unable to enter the organism
What does sunlight do in photosynthesis
Bonds carbon dioxide and water
Leaves adapted for diffusion by having
Thin flat shape = Large surface area
Thin short pathway
Many Stomata
Xylem and phloem
Xylem transports water to leaves
Phloem transports glucose products around the leaf
Upper epidermis
Forms boundary between plants inner cells and outside = Prevents water loss
Palisade mesophyll
Many chloroplasts to absorb light
Elongated cells for max light absorption
Large SA for rapid co2 absorption
Spongy mesophyll
Large air spaces which allow for diffusion of gases
Guard cell
Attached to stoma become flaccid or turgid to close or open prevent water loss
Stoma
Allow diffusion of gases and water
Reducing water loss in cacti
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
Similarities between gas exchange of insects and plants leaf
No living cell fat from external air
Diffusing takes place in gas state
Need to avoid excessive water loss
Diffuses air through pores
Differences between gas exchange of insects and plants leaf
Insects have trachea and plants don’t
Insects have spiracles
Why Lungs are located inside the body
Air not dense enough to support and protect delicate structure
Lungs could lose lots of water and dry out
Walls of trachea and bronchus adaptations
Contain goblet cells that secrete mucus ; traps microorganism
Cilia : beta and move microorganisms along with mucus to be destroyed by stomach acid
Tidal and alveolar air
Tidal air is one that’s goin out of alveoli
Alveolar air goes in
Define ventilations
The process of breathing in and breathing out
Define inspiration
When air pressure of atm is geared than air pressure inside the lungs so air is forced into lungs i
Define expiration
When air pressure in lungs is greater than atm so air is forced out
During inspiration
RICE
Pressure of lungs decreases
Volume of thorax increases
Diaphragm contracts and flattens
Ribs up and out due to external im
Define tidal volume
Volume of air taken in at each breath when at rest
Define breathing rate
Number of breathes per minute
Define vital capacity
Max breath in and out
Define residual volume
Air left in longs after strongest exhalation
Define pulmonary ventilation rate
Total volume of air that’s moved into the lungs in a minute
Tidal volume x breathing rate
Features for gas exhange surfaces
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
How does alveoli having a network of capillaries help it
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
Red blood cells
Erythrocytes
Transport oxygen from lungs to cells
Contains haemoglobin pigment that carries oxygen
Features of RBC
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
Role of haemoglobin
Associate with oxygen when gas exchange takes place
Disassociate oxygen at cells that require it
Structure of haemoglobin
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
How does DNA lead to different affinities of haemoglobin
Different base sequence
Different amino acid sequence
Different teritary structure
