Unit 1 Bacterial And Intestinal Disease Flashcards
What is active transport?
Uses energy to move molecules across the plasma membrane against their concentration gradient. Carrier proteins and co-transporters involved.
Carrier proteins - same as facilitated diffusion (molecule attaches to carrier protein, protein changes shape and it’s released on the other side), the only difference is that energy is used (from ATP production) in order to move the molecule against it’s concentration gradient.
Co-transporters - type of carrier protein, they bind two molecules at a time, concentration gradient of one of the molecules is used to move the other molecule against its concentration gradient.
How are the products of digestion absorbed in the small intestine? (What are the roles of diffusion, active transport and co-transport in this process)
Stage 1 - diffusion - when carbohydrates first broken down there’s a concentration gradient between the glucose in the blood (higher) and in the small intestine (lower), so glucose moves across epithelial of cells by diffusion. Diffusion stops when equilibrium is reached.
Stage 2 - active transport - remaining glucose absorbed by active transport with sodium ions.
Sodium ions are actively transported out of small intestine epithelial cells into the blood by sodium potassium pump. Which creates concentration gradient (higher conc of sodium ions in small intestine than in lumen in epithelial cell)
Causing sodium ions to diffuse out of the small intestine into the epithelial cell via sodium-glucose co-transporter proteins.
Co-transporter carry glucose into cell with the sodium so concentration of glucose inside cell increases.
Glucose diffuses out of the cell and into the blood down its concentration gradient through a protein channel by facilitated diffusion.
What are prokaryotic cells?
Single-celled organisms, e.g bacteria.
Structure; plasmids are small loops of DNA they contain genes for things like antibiotic resistance, DNA for bacteria floats free in the cytoplasm, has a cell membrane, cells wall, and capsule which helps to protect the bacteria from attack of immune system cells. Some bacteria have a flagellum which rotates the bacteria to make it move.
How do prokaryotic cells differ from eukaryotic cells?
Prokaryotes are single-celled organisms, they are much smaller and simpler than eukaryotic cells.
What causes cholera and how does it produce symptoms?
Cholera bacteria produce a toxin when they infect the body.
The toxin causes chloride ion protein channels in the plasma membrane of small intestine epithelial cells to open.
So chloride ions move into the small intestine lumen.
This lowers the water potential of the lumen.
Therefore water moves from the blood, across the epithelial cells into the lumen by osmosis to even out concentrations.
The massive increase in water secretion into the intestine lumen leads to bad diarrhoea - body becomes extremely dehydrated.
What is oral rehydration therapy and how does it work?
It is a drink which contains large amounts of salts and sugars dissolved in water. Sodium ions are included to increase glucose absorption. The correct concentrations of the solution is important for effective treatment. ORS is a very cheap treatment and the people administering don’t require much training - good for developing countries.
How have more effective rehydration solutions been developed?
Done by clinical testing on humans to check safe and better.
How do drug trials follow a regulated set of ethical problems?
Usually involve a blind trial - where some patients are given standard ORS and others given the new ORS so they can be compared.
Some people don’t agree - as people have right to know what they have been given, however scientists argue it removes bias.
