9 Cell Membrane And Transport Processes Flashcards
Active transport
Process where cells transport substances across a membrane from low to high concentration. This process consumes energy.
Adhesion protein
A membrane protein that helps link cells together
ATP
Adenosine triphosphate, a high energy compound, composed of adenine and ribose with three phosphate groups attached.
Function is to store usable energy for cellular reactions.
Carrier protein
A protein within membranes that assists other molecules to cross the membrane. They can transport specific small molecules or ions against concentration gradient using ATP
Cell membrane
Selectively permeable boundary of all living cells that maintains the contents of the salon regulates movement in an out
Channel protein
A protein that forms channels within membranes to allow the passive passage of hydrophobic substances across the membrane. They catalyse movement of specific ions down the electrochemical gradient via passive transport, a process called facilitated diffusion.
Cholesterol
A lipid embedded in cell membranes that provide stability and allows fluidity
Concentration gradient
The difference in concentration of a substance between two different regions
Contractile vacuole
The vacuole found in some freshwater unicellular organisms that maintain osmotic balance by collecting water, emptying it from the cell
Cytoplasm
All the fluid dissolved materials and organelles between the cell membrane and the nuclear membrane
Cytosol
The fluid part of cytoplasm containing highly organised fluid material and dissolve substances
Diffusion
The passive movement of particles from a high to a low concentration of that substance
Endocytosis
The movement of solids or liquids into a cell from the environment via vessel formation
Enzyme
A biological catalyst that speeds up biological reactions without undergoing any change itself. Most enzymes are proteins.
Equilibrium
Went to solutions have the same concentration of solutes, and the net movement is zero across a selectively permeable membrane
Exocytosis
The movement of solids or liquids from inside the cell to outside the cell via vessel formation
Extracellular fluid
The fluid that bass the outside of cells in multicellular organisms
Facilitated diffusion
A form of diffusion that requires a substance to be attached to a specific carrier molecule to move across a membrane
Falaccid
Floppy describes the condition of a plant cell that has lost water
Fluid mosaic model
A model which describes membranes as a double layer of lipids, a lipid bilayer with the ability to flow and change shaped like a 2-D fluid. Special protein molecules are embedded in the leopard in various patterns like a mosaic.
Hydrophilic VS hydrophobic
Hydrophilic is a substance that tends to interact with an dissolve in water, hydrophobic is a substance that avoids association with water
Hypertonic Vs hypotonic
Hypertonic is a solution with a higher solute concentration compared with another solution, hypotonic has a lower solute concentration
Ion
An atom or molecule that has an electrical charge due to losing or gaining electrons
Isotonic
Two Solution with equal solute concentrations
Net change
The amount of change after considering the movement of particles across a membrane in both directions. The result after subtracting movement in one direction from movement in the other is net change
Osmosis
Movement of water across a selectively permeable membrane from regions of low salute. Concentration to high solute concentration
Particle theory
Theory stating matter consists of tiny particles in constant motion, motion increases with higher energy
Passive process
A process WITHOUT energy input
Passive transport
Movement of molecules across the membrane WITHOUT energy input
Phagocytosis
The bulk transport of solids into cell by engulfment and formation of vessels
Pinocytosis
Bulk transport of liquids into a cell by engulfment and formation of vessels
Plasmolsis
The cytoplasm pulling away from the cell wall, because of water loss from the cell
Receptor proteins
A protein in a cell membrane that binds hormones and other signal molecules
Recognition proteins
A protein the acts as a marker on membranes
Selectively permeable
A membrane that allows some substances, but not others
Sodium potassium pump
I membrane protein that uses energy to transport, sodium ions out of and potassium ions into sell against the concentration gradient
Solute
A substance that can be dissolved in another
Solution
Mixture of a solvent and solute
Solvent
A substance in which another substance can be dissolved to create a solution
Surface area to volume ratio
The mathematical ratio of the size of the surface area, compared to the volume of an object
Tissue
A group of specialise cells working together to perform a specific function
Transport protein
A protein that carries molecules across a membrane
Turgid
Describes a salad that is tight and Richard from absorbing water
What are cell membranes made of?
Hydrophilic head made of phosphate and glycerol with a hydrophobic tail made of saturated fatty acid and unsaturated fatty acid. these create a phospholipid bilayer.
Functions of a cell membrane
- Recognition of other cells
- Transporting materials
- Providing attachment sites for enzymes and hormones
- Enabling transmission of nervous impulses (in nerve cells )
What is an amoeba?
A unicellular freshwater organism where the whole organism consist of a single cell. The amoeba can detect what is food, and what is silt in its pond
Benefits of being multicellular
The cells in multicellular organisms are more protected from swings and environmental conditions because they are surrounded by extracellular fluid compared to single celled organisms.
Who discovered cells
Robert Hooke and Anthony Van Leeuwenhoek described them in 17th century but in the 19th century scientist begin to understand them.
Hoe did scientist know cell membranes were composed of lipids?
Charles Ernest Overton demonstrated that lipid soluble substances like ether and chloroform would enter cells suggesting they were composed of lipids
What did Hugh Davson and James Danielli propose
The lipid bilayer was coated on either side with a layer of proteins. Another theory proposed by Gareth Nicolson said proteins penetrate through the phospholipid bilayer like a mosaic which better explains the physical and chemical properties. This was confirmed later with the invention of the electron microscope.
