Chapter 4 Flashcards
What is respiration?
Respiration is the exchange of gases between the atmosphere, blood and body cells of an organism; also the chemical reactions that make energy available for the cell
- all cells need oxygen, it releases energy needed for cell activity
- glucose is also needed for respiration, it’s broken down to release energy
What is the cell membrane and what does it do?
Cell membrane is a membrane that forms the external boundary of a cell. It protects the cell from the external environment and determines what enters and exits the cell
What is the fluid mosaic model and why is it called that?
Fluid mosaic model is the currently accepted model of a cell membrane structure. The model is said to be fluid as the molecules it’s made up of is continuously changing position and it’s said to be mosaic because it’s composed of many different types of molecules
What is a lipid and phospholipid?
Lipid- large organic molecule made up of fatty acids and glycerol
Phospholipid- a lipid molecule that contains a phosphate group
What is a bilayer?
Two layers that make up a single membrane
What does the cell membrane look like?
Two phospholipids on top of one another with Hydrophobic head and hydrophilic tails with one side being surrounded by cytoplasm and the other extra cellular fluid
What are channel proteins?
A protein that allows ions, water and small molecules to pass through the cell membrane
What are the 4 functions of the cell membrane?
Physical barrier-> separates cell cytoplasm from extra cellular fluid which is good as they have different compositions
Regulation of the passage of materials -> cell membrane controls movement of materials into and out of the cell
Sensitivity -> cell membrane is the first part if the cell to be affected by any changes in the extra cellular fluid
Support-> cell membrane is attached to the micro filaments of the cells cytoskeleton, thus giving support to the whole cell
What are 4 membrane proteins?
Receptor proteins
Channel proteins
Carrier proteins
Cell-identity markers
What is a differentially permeable membrane?
A membrane that permits the passage of certain substances (usually small molecules) but restricts the passage of others (usually large molecules)
What are passive and active processes?
Passive-process that occurs without any input of energy
Active- involves the expenditure of energy
What are the 3 basic processes that transport materials in and out of the cell?
- diffusion (passive)
- Carrier mediated transport (active or passive)
- Vesicular transport (active)
What is diffusion?
The movement of particles from areas of high concentration to areas of low concentration in liquid or gasses so particles are evenly distributed over the available space
What is concentration gradient?
A difference in concentration of a solution often between the inside and outside of a cell, the steeper the diffusion gradient, the faster diffusion will occur
What is osmosis and osmotic pressure?
Osmosis is the diffusion of water molecules through a differentially permeable membrane from an area of high concentration to an area of low concentration. Osmotic pressure is due to differences in concentration on either side of a differentially permeable membrane
