unit 3- updated Flashcards
how do you work out surface area to volume ratio
1) to work out SA, (h x w) of one face X by number of sides
2)volume is w X h X l
3) divide them
how do single celled organisms exchange susbstances
single celled organisms have a higher surface area compared to their volume. this means that substances for example oxygen can directly diffuse into or out of the cell across the cell surface membrane.
how do multicellular organisms exchange susbtances
larger organims have a lower surface area in relation to their volume which means diffsuion would be too slow, they need specialised excahnge systems for example the lungs
mass transport in animals
circulatory system, which uses blood to carry oxygen glucose hormones co2 waste antibodies
mass transport in plants
xylem and phloem
body size and heat exchange
larger organisms have a smaller sa to volume ratio meaning that it is difficult to loose heat
smaller organisms have a larger surface area to volume ratio and loose heat easily, thats why they need a higher relative metabolic rate to keep warm
heat exchange and body shape
a less compact shape means that an organim has a higher surface area to volume ratio
a more compact shape means that an organism has larger surface area relative to volume this minimises heat loss
behavioural and physcological adaptasions to aid excghange is smaller orgasmins
animals with a larger surface area to volume ratio loose water more quickly as it evaporates from its surface this is a problem for animals living in hot regions, they had adapated kidney structure to produce less urine to compensate
in colder regions they have fur to keep warm
behavioural and physiological adaptations to aid exchange in larger organisms
larger organisms have a smaller surface area in relation to their volume this means that they find it difficult to loose heat. as an adapation they have developed large flat ears to increase surface area to keep cool
examples of adaptations to increase surface area and volume in plants and animals
-villi or microvilli to increase digestion absorption
-alveoli and tracheoles for gas exchange
-thin wide leaves
-many capillaries
why cant larger organisms use diffusion
diffusion would be too slow to supply its demand
!)cells are deep within the body, there is a large distances between the cells and outside environment
2)it has a lower surface area to volume ratio, meaning substances have to diffuse from a relatively small outer surface and a larger volume
what is the role of gas exchnage
to get oxygen in the blood for respiration and to get rid of carbon dioxide (waste)
what are the intercostal muscles
between the ribs
internal and external intercostal muscles
whats ventilation
the process of inhalation or exhilation
is inspiration an active or passive process
active process req. ATP
what does antagonistic mean
the intercostal muscle is moving in opposite directions
inspiration
external intercostal muscles and diaphragms contract
the ribcage moves up and outwards
the diaphragm flattens
lung pressure decreases below atmospheric pressure
volume of thoracic activity increases
is expiration an active or passive process
passive except if its forceful
expiration
internal intercostal msucels contrcat
diaphragm and external intercostal muscles relax
ribcage moves down and inwards
pressure increases above atmospheric pressure
volume in thoracic activity decreases
alveoli structure
one cell thick; alveolar epithelium
the alveolus contains a protein called elastin which allows recoil and return back to its normal shape after inhalation and exhalation