IB Bio SL - gas exchange quiz

Adaptations of gas exchange surfaces

Large surface area - increase quantity of gas particles exchanged

Thin tissue layers - reduce distance

Permeable membranes - allows diffusion

Concentration gradient - high concentration to low concentration

Exchange surfaces covered in moisture - gases can dissolve and diffuse rapidly

Diffusion

Passive transport of particles from high to low concentration

Adaptations to maintain a high concentration gradient

Dense network of capillaries

Continuous blood flow

Ventilation - O2 into alveoli, CO2 out

Ventilation

maintains concentration gradient of O2 and CO2 between air and blood

Respiration

release of ATP from organic compounds

Lungs Diagram

Trachea to bronchi (left and right), to bronchioles to alveoli

Alveoli

provide a large surface area for gas exchange

Surfactant

moisture that stops alveoli from collapsing in on itself

provides a moist surface for gas exchange

Capillaries

surround the alveoli - maintain high concentration gradients of O2 and CO2

capillaries provide continuous blood flow high in CO2 and low in O2

Inspiration

breathing in

diaphragm contracts and moves down

volume in the thorax increases, decreasing pressure in the lungs

air moves into lungs with concentration gradient (high to low pressure)

Expiration

breathing out

diaphragm moves up

volume in thorax decreases, increasing lung pressure

air moves out with concentration gradient (low to high pressure)

Tidal volume

normal breath

inspiratory reserve

additional air that can be inhaled above tidal volume

expiratory reserve

additional air that can be exhaled after a normal breath

vital capacity

volume of air that can be exhaled after the deepest possible breath

residual volume

volume of air remaining in the lungs after a maximum exhalation

Layers of a leaf

Waxy cuticle

Epidermis

Palisade mesophyll

Spongy mesophyll

Waxy cuticle

Stomata

pores that allow gas to enter and exit the cell

Transpiration

evaporation of water from the leaves of a plant through the stomata

water in mesophyll cells evaporates

Effects on transpiration

More light - more water lost

More heat - more water lost

More humid - less water lost

More wind - more water lost