CELL BIOLOGY - I scored a Level 7 on my final exam using these notes.
Introduction to cells
- Ultrastructure of cells
- Membrane structure
- Membrane transport
- The origin of cells
- Cell division
Summary document of Chapter 5 Evolution and biodiversity IB Biology
IB Biology Full Course Notes + Required Drawings Units 1 - 11 & Option D
IB Human Physiology Option D - Biology HL & SL Notes for IBDP
All for this textbook (174)
Written for
Secondary school
VWO / Gymnasium
Biology
1
All documents for this subject (19)
Seller
Follow
annagakes1
Content preview
1.4 Revision notes
MEMBRANE TRANSPORT
Vesicular transport
Vesicle: small sac of membrane with fluid inside
- Spherical
- Eukaryotic cells
- Due to fluidity of membrane, vesicles can move and be deconstructed/reconstructed
Endocytosis (formation of vesicle):
- Small region of plasma membrane is pulled away and
pinched of through ATP
- Forms on inside of plasma membrane
- Contains contents from outside of cell
Vesicle transport & movement
Secretory cells
- Protein is synthesised by ribosomes in rER
- Proteins accumulate in rER
- Vesicles containing the protein bud off and go to Golgi
apparatus
- Vesicles fuse with Golgi apparatus
- Golgi apparatus processes proteins
- Vesicles bud off and go to plasma membrane where the
protein is secreted
- In a growing cell, plasma membrane area increases
- When vesicles fuse with plasma membrane, increases area
- rER ribosomes synthesises phospholipids and membrane proteins which are later infused
into plasma membrane via vesicles
, Exocytosis
- Vesicles release materials from cell by fusing with plasma
membrane
- Digestive enzymes are released from glands via exocytosis
(secretion)
- Exocytosis expels waste products (removal of excess water in
unicellular organisms – contractile vacuole)
Simple diffusion
Diffusion: net passive movement of particles from high
concentration to low concentration as a result of the random
motions of particles.
- will continue until gradients are in equilibrium
Occurs in partially permeable membranes
Particles move through phospholipid molecules in membrane
Facilitated diffusion
Passive movement of molecules across the cell membrane via the aid of a membrane protein
- Used to transfer molecules which are unable to cross membrane freely
o Large/polar molecules, ions
- Carrier proteins & channel proteins
Carrier proteins:
- Integral lipoproteins
- Chemically specific, only bind to/allow one type of molecule to pass through
- Can move molecules against concentration gradient using ATP (active transport)
- Slower rate of transport than channel proteins
Channel proteins:
- Integral lipoproteins
- Contain a pore that allows ions to move across membrane
- Ion-selective
- Only move along concentration
- Faster rate of transport than carrier proteins
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 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 annagakes1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £3.86. You're not tied to anything after your purchase.
