3-6 Marks (mixed topic) Flashcards
(16 cards)
TMV causes plants to produce less chlorophyll. Explain why plants with TMV have stunted growth
(4 marks)
With less chlorophyll, rate of photosynthesis decreases. This slows down production of glucose so less protein is produced and less energy is released for growth
Plant A grows in damp conditions and it does not have guard cells. Explain why it cannot survive in dry areas
Stomata will always be open without guard cells so the plant will constantly lose water vapour through leaves, photosynthesis cannot happen
Normal body temperature is 37 degrees celsius. Referring to enzymes, why can a temperature of 40+ degrees celsius be life threatening?
Above body temperature, enzymes denature. This stops them from working and catalysing the life processes needed for survival.
How does a vaccine make someone immune?
(5 marks)
Vaccines contain a dead or weakened form of a pathogen. In the blood, lymphocytes are stimulated and produce antibodies complimentary to the antigens of the pathogen. Memory lymphocytes stay in the blood and speed up immune response in the future as antibodies will be produced more rapidly
Describe how clinical trials should be carried out, and what each phase tests for (6 marks)
In phase 1, drug tested in low doses on healthy volunteers to check side effects and dosage. In phase 2, a double blind trial conducted with ill patients, neither doctor nor patient know if a placebo or drug has been used. Tests for efficacy
How can mABs and fluorescent dye be used to see pathogens through a microscope?
Fluorescent dye binded to mABs. Then, mABs bind to the pathogen, fluorescent dye (seen through microscope) reveals pathogen location
How can an increased rate of phagocytosis help an ill patient?
Phagocytes engulf and digest bacteria faster which decreases pathogens’ damage to cells, tissues and organs
Why are lymphocytes fused with tumour cells to form hybridomas?
Extracted lymphocytes can produce antibodies but cannot replicate. Tumour cells cannot produce antibodies but can replicate rapidly. Hybridomas can do both
Explain, step by step, how hybridomas are produced
A mouse is injected with a specific pathogen. The mouse’s immune system responds, producing lymphocytes with complimentary antibodies. The lymphocyte is removed and then fused with a tumour/cancer cell
Explain how increased wind can affect rate of transpiration in a plant
Increases rate of transpiration because water molecules are blown off leaves, causing a high concentration gradient between inside and outside of the leaf. This causes water to be pulled into the plant via root hair cell
Explain how high humidity affects rate of transpiration in a plant
Decreases rate of transpiration because high humidity results in a low concentration gradient between inside and outside of the leaf so less water is pulled into the plant via root hair cell
Explain how high temperature affects rate of transpiration in a plant
Increases rate of transpiration because water particles have more kinetic energy so they move through the plant faster and evaporate at a greater rate. This causes a high concentration gradient between inside and outside of the leaf so more water is pulled into the plant via root hair cell
Explain how high light intensity affects rate of transpiration in a plant
Increases rate of transpiration because stomata open to allow more carbon dioxide to enter, resulting in water diffusing out of stomata. This causes a high concentration gradient between inside and outside of the leaf so more water is pulled in via root hair cell
Explain why heart rate and breathing rate increases during exercise
(6 marks)
Heart rate increases to increase blood flow to muscles, so more oxygen and glucose is provided for respiration. This also removes carbon dioxide from muscles faster.
Breathing rate increases to supply more oxygen for respiration, providing more energy
Bacteria X causes infections in hospital patients. A new strain of bacteria X has evolved, can only be killed by one antibiotic. Explain the advice doctors should be given to prevent the spread of the new strain. (6 marks)
Do not prescribe antibiotic for mild infections because they will get better due to normal immune system response. If prescribed antibiotic, ensure patient has finished course because any bacteria left may develop resistance, survive and reproduce. Do not prescribe antibiotic for viral infections because antibiotics do not kill viruses. Isolate ill patients with the new strain to prevent other patients getting the resistant infection.
A small animal called an axolotl lives in water, it has gills. Explain why an axolotl may die in water with a low concentration of oxygen (4 marks)
Low concentration gradient of oxygen between gills and water, less oxygen diffused into gills, decreasing rate of aerobic respiration in cells. Axolotl has muscle fatigue so it cannot move
