Topic 1 - Principles Of Exchange And Transport Flashcards
What do Animal tissues obtain
Oxygen from the air
Glucose, fatty acids and amino acids from ingested food
Water
What do Animal tissues remove
Carbon dioxide and nitrogenous waste
What do Plant tissues obtain
Oxygen from the air, especially at night
Carbon dioxide from the air during the day
Inorganic ions from the soil solution
Water
What does Plant tissues remove
Either carbon dioxide or oxygen, depending on the time of day
When does exchange of substances occur
When the substances are moist and permeable
How to animals and plants prevent water loss
They possess impermeable surfaces
What is the surface area of an organism
The surface area is represented by the total number of cells in direct contact with the surrounding environment
What is the volume of an organism
The volume is the total three-dimensional space occupied by metabolically active tissues
What is the volume of an organisms determined by
It’s demand for metabolites
What is relationship of the surface area-to-volume ratio, and the size of an organism
As the organisms size increases, the surface area-to-volume ratio decreases
Why do larger organisms need specialised permeable surfaces for gaseous exchange
The small surface area is unable to supply the demand for oxygen to all parts of the body
What is gas exchange
The process by which oxygen reaches cells and carbon dioxide is removed from them
What is respiration
The release or energy from food to synthesise ATP in all living cells
What does an organism with a high metabolic rate have
A high requirement for oxygen, and therefore posses specialised, large gas exchange surfaces
When does an organism require specialised absorptive surfaces
If it’s terrestrial, large or has a high metabolic rate
Give 3 methods of Increasing the are of an absorptive surface
Evagination (outfolding) of the surface
Invagination (infolding) of the surface
Flattening of the organism
Give 5 absorptive surfaces in plants and mammal
Leaf mesophyll Root hairs Alveoli Capillaries Red Blood Cells/ Erythrocytes
What is the structure of the leaf mesophyll
The leaf is a flattened structure (its thinness ensures a short diffusion distance) with a tightly packed upper palisade mesophyll layer and a loosely packed lower spongy mesophyll layer
What is the function of the Leaf Mesophyll
The wide expanse of palisade tissue is efficient at trapping light; the loose arrangement of the spongy layer provides an air space system through the leaf and creates a huge surface for gas exchange
What is the structure of Root Hairs
Tubular extensions of the epidermal cells of the young root
What is the function of root hairs
Increase greatly the surface area of the root for the uptake of oxygen, water and ions
What is the structure of Alveoli
Small sacs, occurring in clusters and in vast numbers within the mammalian lung; in human lungs there are 700 million, proving a total surface area of 70m^2
What is the function of the Alveoli
The huge, moist surface area provides for efficient gas exchange; alveolar walls are thin, so the diffusion distance is short
What is the structure of capillaries
Small, thin-walled blood vessels, with a total length of 100000km^2 and surface area of 1000m^2 in the human body
