IB Biology Gas Exchange Flashcards

Vocabulary flashcards for reviewing gas exchange in organisms and plants.

Cellular Respiration

The process occurring in all living cells that releases energy in the form of ATP when substrate molecules such as glucose are oxidized.

Gas Exchange

The process by which gases are exchanged between living organisms and their environment, including oxygen uptake and carbon dioxide release.

Diffusion

Gas exchange takes place by this process, the rate of which is determined by the size of the respiratory surface, concentration gradient and diffusion distance.

Gas Exchange Surfaces Properties

To maximize the rate of diffusion of oxygen and carbon dioxide , gas exchange surfaces require permeability , thin tissue layer , presence of moisture and a large surface area.

Blood vessels

A dense network of these provide a large surface area for the diffusion of gases.

Continuous Blood Flow

This ensures that oxygen is constantly transported away from the gas exchange surface and carbon dioxide towards them.

Trachea

Air moves in through the nose and mouth before it is carried to the lungs through this.

Bronchi

The trachea divides to form the two of these (singular bronchus) with walls also strengthened with cartilage and a layer of smooth muscle.

Bronchioles

These branch off the two bronchi to form a network of narrow tubes.

Alveoli

These are found at the end of the bronchioles; each is surrounded by an extensive network of capillaries.

Alveoli

These provide a large surface area for gas exchange in mammalian lungs.

Surfactant

Cells of the alveolar wall secrete this substance which lowers the surface tension in the alveoli.

Ventilation

Essential for the effective exchange of gases in the lungs; it replaces older air in the lungs with fresh air.

Inspiration

The breathing-in process that causes the volume of the chest to increase and the air pressure to decrease.

Expiration

Breathing out, which occurs mostly due to the recoil of the lungs after they have been stretched by the inspiration process.

Spirometer

Apparatus used to investigate the effect of exercise on ventilation.

Tidal Volume

The volume of air inhaled and exhaled during normal breathing.

Maximum Inspiratory Level

The maximum volume of air that can enter the lungs during inspiration.

Maximum Expiratory Level

The maximum volume of air that can be exhaled during expiration.

Inspiratory Reserve Volume

The difference between the maximum inspiratory level and tidal volume.

Expiratory Reserve Volume

The difference between the maximum expiratory level and tidal volume.

Vital Capacity

The total amount of air exhaled after taking a deep breath; calculated by adding TV, IRV, and ERV.

Ventilation Rate

Determined by counting the number of inhalations or exhalations per minute.

Epidermal Tissue

Outer boundary of the leaf.

Mesophyll Tissue

The bulk of internal structure of the leaf that that make up the bulk of internal structure of the leaf Mesophyll tissue.

Vascular Tissue

This tissue transports substances between the leaf and the rest of the plant.

Stomata

Tiny pores on the lower epidermis of a leaf, surrounded by guard cells.

Guard Cells

These control the opening and closure of stomata.

Cuticle

A waxy layer covering the epidermis that forms an impermeable barrier.

Parenchyma Cells

Mesophyll tissue with cells containing chloroplasts where photosynthesis occurs.

Palisade Mesophyll

Mesophyll layer beneath the upper epidermis with many chloroplasts for maximum photosynthesis.

Spongy Mesophyll

Mesophyll layer containing large air spaces between the cells for gas exchange.

Vascular Bundles

Vascular tissue arranged in vascular bundles forming the veins in leaves.

Xylem

Transports water and mineral ions from the roots to the leaves.

Phloem

Transports the products of photosynthesis from the leaves to other parts of the plant.

Transpiration

The loss of water in the form of water vapour through the stomata.

Potometer

Equipment used to measure the rate of water uptake, representing the rate of transpiration.

Leaf Cast

Nail varnish is used to create this to examine stomata.

Stomatal Density

The number of stomata per unit of area.