RESPIRATION
But we need to quit taxing people upon death… no taxation without
respiration ~ Stephen King
What is respiration?
• The process in which organisms exchange gases with the
environment
• Unicellular organisms use diffusion
– Diffusion involves moving molecules from areas of high
concentration to low concentration
• Larger organisms have specialized organs for respiration
• 2 types
– aerobic- uses oxygen
– anaerobic – doesn’t use oxygen
How does respiration happen at the
cellular level?
• Cells break down glucose into
CO2 and water
– Equation: C6H12O6+O2 = CO2+H2O
• Photosynthesis is the chemical
opposite of respiration
– Equation: CO2+H2O = C6H12O6+O2
• Adaptations are structures that
increase an organisms chances
surviving
ofreproducing
________ and __________.
• Examples include: lungs; gills;
trachea and spiracles; and, in
some organisms, skin
How do lungs work?
• Sponge-like elastic organs
that exchange gases between
body and air of many land
dwelling creatures
– Few marine animals have
lungs such as dolphins and
whales
• Usually in pairs in the chest
• Air moves through branched
tubes that become smaller
and smaller
• Tiniest branches of tubes end
in balloon-shaped sacs with
thin walls called alveoli
How does oxygen get to the rest of the
body?
• Alvioli are surrounded by
capillaries where blood picks
up oxygen AND blood
transfers CO2 released by the
body’s cells
– This occurs by diffusion
• Oxygen is delivered to body
by blood
• O2 and CO2 are between
avioli and blood by simple
diffusion
– This is also the method in
which the gases are
exchanged between cells and
blood
Assignment!
• Lung coloring sheet
• Due tomorrow
• Materials:
– Coloring pencils or crayons
– Worksheet
What are gills and how do they work?
• Specialized tissues containing
many blood vessels that can
take in oxygen dissolved in
water
– Used by many aquatic animals
– Covered by a flap of skin
• Fish take in water through
their mouths
• As water flows over gills
oxygen is taken in, and carbon
dioxide is removed as water
flows out of the gills
– Happens by diffusion
How well do gills
work?
• They are less efficient that
lungs
– Difficult to move water over
them
– O2 concentration in water is low
• Some aquatic animals have
special adaptations
– Mollusks and clams have gills in
their body cavity allowing them
to pump water over their gills
– Some crustaceans like lobsters
and crabs have gills on their legs
so they can walk to move water
over them
What about amphibians?
• Frogs and salamanders
spend the entire
beginnings of life in water
and depend entirely on gills
– Physically move gills to
move water over them
• As adults they live on land
and water and develop
lungs
• Many use their skin
• Some frogs also use the
lining of their mouth for
gas exchange
Do land animals use other methods?
• Some use skin only
– Thin skinned and small
– Skin must stay moist
– Ex. Earthworms secrete mucus
and live underground and
oxygen in soil diffuses through
its thin skin into capillaries;
carbon dioxide diffuses out
– Other examples of animals that
use their skin for respiration:
•
•
•
•
Amphibians
Segmented worms
Mollusks
Some arthropods (insects)
How do insects
exchange gases?
• Arthropods (insects) use a
network of tubes within
their body called trachea
• Trachea deliver oxygen
and pick up carbon
dioxide directly to tissues
• Trachea are connected to
the outside of the body
using tiny openings in the
exoskeleton called
spiracles
How do plants exchange gas?
• Plants take in carbon dioxide
and remove oxygen through
photosynthesis
• At night, plants take in oxygen
for cellular respiration
• Plants do BOTH photosynthesis
and cellular respiration
• Exchange gas through tiny
openings called stomata
– Gas moves between stomata
and cells via diffusion
– Land stomata are usually under
leaves in the epidermis
How do plants keep from drying out?
• Guard cells control the size of stomata
– Help maintain homeostasis, or balance
in the cell
• Gases exchanged are:
– Carbon dioxide - in
– Oxygen - out
– Water vapor – out
• Usually plants open stomata in the
morning
• When do you think desert plants open
theirs? Why?
• Land plants usually have stomata on the
bottom of their leaves. Where do you
think aquatic plants stomata are? Why?
– Some plants have roots adapted to take
in oxygen also
Assignment!
• Leaf anatomy coloring worksheet
• Due tomorrow
• Materials:
– Colored pencils or crayons
– Worksheet