Importance of energy transfers
An important energy transfer is the transfer of light energy into chemical
energy during the light dependent reaction in the thylakoid membrane.
Light energy is transferred to electrons in Photosystem II in the
chlorophyll. Electrons become excited and move down the electron
transfer chain via a series of redox reactions into Photosystem I, releasing
energy. This energy is transferred to protons which are actively
transported into the thylakoid space. This creates an influx of protons in
the thylakoid space and so protons diffuse down the electrochemical
gradient via ATP synthase, which catalyses the reaction between ADP and
Pi to form ATP, as the kinetic energy in the protons is transferred to form
the high energy bond. Light energy is also transferred to water for
photolysis, which breaks the bonds in water, releasing protons, oxygen,
and electrons. The electrons are used to replace the ones lost in the
chlorophyll.
The energy transfers in the light dependent reaction are significant as
they lead to the production of ATP, which is then used in the light
independent reaction. Without the energy transfer of light energy into
chemical energy, ATP is unable to be used to reduce gylcerate-3-
phosphate into triose phosphate. This means that triose phosphate is
unable to be converted into organic molecules such as lipids. Lipids are
significant as they can form phospholipids, which are in cell membranes,
forming the phospholipid bilayer. This is significant as the phospholipid
bilayer prevents lipid insoluble substances from entering the cell as the
fatty acid tails are hydrophobic.
Another important energy transfer is the heat energy transfer in
polymerase chain reactions. The heat energy is transferred to hydrolyse
the hydrogen bonds between complementary bases in two DNA nucleotide
strands. The heat energy is then transferred to the surroundings, resulting
in the cooling of the mixture to allow primers to anneal to the strands.
Heat energy is transferred once again to enable optimum conditions for
DNA polymerase, which lines up free DNA nucleotides along each
template strand by complementary base pairing and catalyses the joining
of the strands, forming phosphodiester bonds. This allows DNA fragments
to be amplified very quickly.
The heat energy transfer in PCR is essential as it enables DNA fragments
to be amplified, which is imminent in gel electrophoresis. This is where a
DNA sample is obtained, and PCR is used to make many copies of the DNA
(containing VNTRs). A fluorescent tag is added to the fragment before
they undergo gel electrophoresis, and the fragments are separated
depending on their length. This is because smaller fragments move faster
and travel further through the gel and so the DNA fragments are viewed
under UV light. The genetic fingerprint of 2 people can then be compared
in paternity tests due to the comparison of bands as if both the genetic
fingerprints have bands in the same location, they are genetically related.
An important energy transfer is the transfer of light energy into chemical
energy during the light dependent reaction in the thylakoid membrane.
Light energy is transferred to electrons in Photosystem II in the
chlorophyll. Electrons become excited and move down the electron
transfer chain via a series of redox reactions into Photosystem I, releasing
energy. This energy is transferred to protons which are actively
transported into the thylakoid space. This creates an influx of protons in
the thylakoid space and so protons diffuse down the electrochemical
gradient via ATP synthase, which catalyses the reaction between ADP and
Pi to form ATP, as the kinetic energy in the protons is transferred to form
the high energy bond. Light energy is also transferred to water for
photolysis, which breaks the bonds in water, releasing protons, oxygen,
and electrons. The electrons are used to replace the ones lost in the
chlorophyll.
The energy transfers in the light dependent reaction are significant as
they lead to the production of ATP, which is then used in the light
independent reaction. Without the energy transfer of light energy into
chemical energy, ATP is unable to be used to reduce gylcerate-3-
phosphate into triose phosphate. This means that triose phosphate is
unable to be converted into organic molecules such as lipids. Lipids are
significant as they can form phospholipids, which are in cell membranes,
forming the phospholipid bilayer. This is significant as the phospholipid
bilayer prevents lipid insoluble substances from entering the cell as the
fatty acid tails are hydrophobic.
Another important energy transfer is the heat energy transfer in
polymerase chain reactions. The heat energy is transferred to hydrolyse
the hydrogen bonds between complementary bases in two DNA nucleotide
strands. The heat energy is then transferred to the surroundings, resulting
in the cooling of the mixture to allow primers to anneal to the strands.
Heat energy is transferred once again to enable optimum conditions for
DNA polymerase, which lines up free DNA nucleotides along each
template strand by complementary base pairing and catalyses the joining
of the strands, forming phosphodiester bonds. This allows DNA fragments
to be amplified very quickly.
The heat energy transfer in PCR is essential as it enables DNA fragments
to be amplified, which is imminent in gel electrophoresis. This is where a
DNA sample is obtained, and PCR is used to make many copies of the DNA
(containing VNTRs). A fluorescent tag is added to the fragment before
they undergo gel electrophoresis, and the fragments are separated
depending on their length. This is because smaller fragments move faster
and travel further through the gel and so the DNA fragments are viewed
under UV light. The genetic fingerprint of 2 people can then be compared
in paternity tests due to the comparison of bands as if both the genetic
fingerprints have bands in the same location, they are genetically related.
