Life Processes- Respiration in Human Beings Flashcards
is breaking down of glucose the same in all organism
The
food material taken in during the process of nutrition is used in cells to
provide energy for various life processes. Diverse organisms do this in
different ways – some use oxygen to break-down glucose completely
into carbon dioxide and water, some use other pathways that do not
involve oxygen
explain breakdown of glucose in different pathways
In all cases, the first step is the break-down of
glucose, a six-carbon molecule, into a three-carbon molecule called
pyruvate. This process takes place in the cytoplasm. Further, the
pyruvate may be converted into ethanol and carbon dioxide. This process
takes place in yeast during fermentation. Since this process takes place
in the absence of air (oxygen), it is called anaerobic respiration. Breakdown of pyruvate using oxygen takes place in the mitochondria. This
process breaks up the three-carbon pyruvate molecule to give three
molecules of carbon dioxide. The other product is water. Since this
process takes place in the presence of air (oxygen), it is called aerobic
respiration. The release of energy in this aerobic process is a lot greater
than in the anaerobic process. Sometimes, when there is a lack of oxygen
in our muscle cells, another pathway for the break-down of pyruvate is
taken. Here the pyruvate is converted into lactic acid which is also a
three-carbon molecule.This build-up of lactic acid in our muscles during
sudden activity causes cramps.
what happens to the produced energy during cellular respiration
The energy released during cellular respiration is immediately used
to synthesise a molecule called ATP which is used to fuel all other
activities in the cell. In these processes, ATP is broken down giving rise
to a fixed amount of energy which can drive the endothermic reactions
taking place in the cell.
how does gaseous exchange take [place in plants??
We
have seen that plants exchange gases through stomata, and the large
inter-cellular spaces ensure that all cells are in contact with air. Carbon
dioxide and oxygen are exchanged by diffusion here. They can go into cells, or away from them and out into the air. The direction of diffusion
depends upon the environmental conditions and the requirements of
the plant. At night, when there is no photosynthesis occurring, CO2
elimination is the major exchange activity going on. During the day,
CO2
generated during respiration is used up for photosynthesis, hence
there is no CO2
release. Instead, oxygen release is the major event at
this time.
how do aquatic animals breathe
. Terrestrial animals can breathe the oxygen in the
atmosphere, but animals that live in water need to use the oxygen
dissolved in water.Since the amount of dissolved oxygen is fairly low compared
to the amount of oxygen in the air, the rate of breathing in aquatic
organisms is much faster than that seen in terrestrial organisms.
Fishes take in water through their mouths and force it past the
gills where the dissolved oxygen is taken up by blood.
how is respiration characterised in terrestrial organisms?
Terrestrial organisms use the oxygen in the atmosphere for
respiration. This oxygen is absorbed by different organs in
different animals. All these organs have a structure that increases
the surface area which is in contact with the oxygen-rich
atmosphere. Since the exchange of oxygen and carbon dioxide
has to take place across this surface, this surface is very fine
and delicate. In order to protect this surface, it is usually placed
within the body, so there have to be passages that will take air
to this area. In addition, there is a mechanism for moving the air
in and out of this area where the oxygen is absorbed.
what is the role of thenoseand nostrils in human respiration?
air is taken into the body through
the nostrils. The air passing through the nostrils is filtered by
fine hairs that line the passage. The passage is also lined with
mucus which helps in this process.
why are there cartilage rings arund the throat
Rings of cartilage are
present in the throat. These ensure that the air-passage does
not collapse.
explain respiration in humam beings
Within the lungs, the passage divides into smaller and smaller
tubes which finally terminate in balloon-like structures which
are called alveoli (singular–alveolus). The alveoli provide a surface
where the exchange of gases can take place. The walls of the alveoli
contain an extensive network of blood-vessels. As we have seen
in earlier years, when we breathe in, we lift our ribs and flatten
our diaphragm, and the chest cavity becomes larger as a result.
Because of this, air is sucked into the lungs and fills the expanded
alveoli. The blood brings carbon dioxide from the rest of the body
for release into the alveoli, and the oxygen in the alveolar air is
taken up by blood in the alveolar blood vessels to be transported
to all the cells in the body. During the breathing cycle, when air is
taken in and let out, the lungs always contain a residual volume
of air so that there is sufficient time for oxygen to be absorbed
and for the carbon dioxide to be released.
How is oxygen and carbon dioxide transported in human beings?
When the body size of animals is large, the diffusion pressure
alone cannot take care of oxygen delivery to all parts of the body.
Instead, respiratory pigments take up oxygen from the air in the
lungs and carry it to tissues which are deficient in oxygen before
releasing it. In human beings, the respiratory pigment is
haemoglobin which has a very high affinity for oxygen. This pigment
is present in the red blood corpuscles. Carbon dioxide is more
soluble in water than oxygen is and hence is mostly transported in
the dissolved form in our blood.
