Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
24 Cards in this Set
- Front
- Back
|
What are the 5 potential mistakes that could be made in DNA replication? |
1 - Deletion 2 - Substitution 3 - Insertion 4 - Duplication 5 - Inversion |
|
|
What is a mutation? |
A change made to the base sequence of DNA. |
|
|
What does the order of DNA bases determine? |
The order of amino acids. |
|
|
When a mutation occurs, the amino acid sequence in a polypeptide chain may change, would affect would this have? |
- R groups interact differently - Polypeptide folds differently - Different primary protein structure - Final 3D shape changed - Protein function lost |
|
|
What is deletion? |
- One or more bases removed from sequence. |
|
|
What is substitution? |
- One or more bases changed to another. |
|
|
What is duplication? |
- One or more bases repeated |
|
|
What is insertion? |
- One or more bases added to sequencing. |
|
|
What is inversion? |
- A sequence of bases are reversed. |
|
|
What is cystic fibrosis? |
- Genetic disorder - Mutation in the gene that codes for CFTR protein. - CFTR protein dysfunctional |
|
|
What is the role of the CFTR protein? |
To facilitate the diffusion of Cl- (chloride ions). |
|
|
When the CFTR protein is functioning how is excess water removed from mucus? |
• Excess water detected by epithelial cell membrane. • ENaC facilitates diffusion of Na+ ions through apical membrane, Na+ then pumped into tissue fluid. • Creates electrochemical gradient. • Cl- diffuses down the gradient (not through CFTR - CFTR closed). • Na+ and Cl- make NaCl (A salt). • The high salt concentration in the tissue fluid draws water out of mucus by osmosis. |
|
|
When the CFTR protein is functioning, What occurs when there is too little water in the mucus? |
• Cl-, in the tissue fluid, is pumped into the cell across the basal membrane. • Cl- then diffuses through the CFTR channel into the mucus. • This creates an electrochemical gradient. • Na+ diffuses down the gradient into the mucus. • The Na+ and Cl- make NaCl. • The elevated salt concentration in the mucus draws water out of the tissue fluid and out of the cell by osmosis into the mucus. |
|
|
Why is regulation of water content in the mucus affected in someone with cystic fibrosis? |
• The CFTR protein in someone with cystic fibrosis is non-functional or non-existent, So Cl- cannot diffuse into the mucus. • Due to this the ENaC is always open, And Na+ is always being removed from the mucus and being pumped into the tissue fluid. • This creates a constant electrochemical gradient so Cl- is always diffusing into the tissue fluid. • This creates high NaCl concentrations in the tissue fluid causing water to move by osmosis out of the mucus and into the tissue fluid. • This makes the mucus very sticky and harder to move out of the airways. |
|
|
What affects does cystic fibrosis have on the respiratory system? |
• Lung infections • Reduced gas exchange • Anaerobic respiration |
|
|
How does cystic fibrosis cause lung infections? |
• Mucus in the lungs traps microorganisms, It is usually transported away by cillia. • Someone with CF has abnormally thick mucus that can't be transported away leaving the trapped microorganisms to reproduce still in the lungs. |
|
|
Why does someone with cystic fibrosis have reduced gas exchange? |
The movement of air from the bronchioles to the alveoli is reduced as the thicker mucus makes the diffusion pathway longer. |
|
|
Why is anaerobic respiration more likely in someone with cystic fibrosis? |
Due to reduced gas exchanged, less oxygen is being transported around the body causing shortness of breath and muscle aches due to a build up of lactic acid. |
|
|
How does cystic fibrosis affect the reproductive system in men? |
The tubes connecting the testicles to the penis can become blocked, So the sperm produced cannot properly reach the penis. |
|
|
How does cystic fibrosis affect the reproductive systems of women? |
Thickened cervical mucus can prevent sperm reaching the egg, at the very least the sperms mobility is reduced, making fertilisation more unlikely. |
|
|
What affects can cystic fibrosis have on the digestive sustem? |
• Reduced nutrient absorbtion • Blockage of the pancreatic duct • Cyst formation in pancreas |
|
|
What are the affects of having a blocked pancreatic duct? |
• Digestive enzymes produced in the pancreas are prevented from reaching the small intestine. • This reduces it's ability to digest food. |
|
|
What affect can pancreatic cysts have? |
• Inhibits production of emzymes - incomplete breakdown of proteins, lipids and carbohydrates can lead to malabsorbtion syndrome. • Less insulin produced - fluctuations of blood sugar levels. |
|
|
Why are less nutrients absorbed in someone with cystic fibrosis? |
• The mucus that lines the small intestines is thicker so enzymes can't be secreted and food can't be properly digested. |
