Summary
Summary Energy and respiration
- Course
- Institution
Biology A level revision notes on energy and respiration
[Show more]
Seller
Follow
mollybuckwald
Reviews received
Content preview
Energy and respirationWork in all living organisms requires energy and includes:
The synthesis of complex from simpler ones (anabolic ones), such as the
synthesis of polysaccharides from monosaccharides, lipids from glycerol and
fatty acids, polypeptides from amino acids and nucleic acids from nucleotides
The active transport of substances against the diffusion gradient, such as the
sodium potassium pump
Mechanical work such as muscle contraction and other cellular movement like
cilia and flagella
In a few organisms, bioluminescence and electrical discharge
Mammals use thermal energy that is released from metabolic reactions to
maintain body temperature
ATP is a suitable energy currency as it is readily hydrolysed to release large amounts
of energy. It is also small and water-soluble, which allows it to be easily transported
round the cell. Any excess energy is converted into thermal energy.
Short-term energy storage molecules – glucose and sucrose
Long-term energy storage molecules – glycogen, starch and triglycerides
(Store chemical potential energy)
Synthesis of ATP
Generated by using electrical potential energy:
Transfer of electrons by electron carriers in mitochondria and chloroplasts
Phospholipid membranes in mitochondria and chloroplasts are impermeable to
protons, so there is a difference in proton gradient
Protons are then allowed to flow down the gradient (by facilitated diffusion)
through a protein that spans the bilayer
Part of this protein synthesises ATP and is called ATP synthase
The transfer of 3 protons allows the production of 1 ATP molecule
This is called CHEMIOSMOSIS
Generated in glycolysis and link reaction
Role of ATP in active transport
Active transport is the movement of molecules or ions across a partially permeable
membrane against a concentration gradient. Energy is needed, ATP, to counteract the
tendency of the particles to move by diffusion down the gradient.
The sodium-potassium pump is a protein that spans the cell membrane and has
binding sites for sodium ions and for ATP on the inner side, and for potassium ions on
the outer side. The protein acts as an ATPase and catalyses the hydrolysis of ADP to
ATP and inorganic phosphate, releasing energy to drive the pump. Changes in the
shape of the protein move sodium and potassium ions across the membrane in
opposite directions. For every ATP, 2 potassium ions move into the cell and 3 sodium
out of the cell. This creates a negative gradient inside the cell.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller mollybuckwald. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $8.42. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
73918 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now