chapter 12 exam questions Flashcards
antibiotic resistant bacteria is becoming an increasing problem. describe how a sulfonamide-resistant population of bacteria could develop. (4)
- mutations
- resistant bacteria survive
- produced resistant offspring
- happens over many generations
Drugs, such as antibiotics are often first discovered in the natural environment. explain why it may become increasingly difficult to discover new drugs in the future (2)
- global warming/climate change
- habitats destroyed
- new drugs come from plants/animals/fungi
name the parasite that causes malaria (1)
plasmodium
name the vector for the malarial parasite (1)
female
name a human cell in which the malarial parasite reproduces (1)
red blood cells
describe the actions of B lymphocytes in the immune response (8)
- humoral response (1)
- has antigen receptor (1) specifically matched to just one (1)
- clonal selection (1) activates specific B lymphocyte by macrophages (1)
- clonal expansion (1) by mitosis (1) B cells differentiate (1)
suggest why adults who have survived malaria may lose their immunity when they leave malarial area. (2)
- no repeat infections
- no further exposure
- limited life for memory cells
state 3 biological reasons why it has not been possible to produce an effective vaccine for malaria (3)
- different strains of malaria
- different antigens due to mutations
- parasite concealed in cells
describe 2 ways resistance to erythromycin may arise in population S. pyogenes (4)
- gene mutation, change in DNA
- acquiring R plasmid, from same or different species
what is meant by the word artificial in the term active artificial immunity? (1)
antigens injected
describe how an effective vaccine can produce active immunity to a disease (4)
- injection of weakened disease
- produces antibodies and memory cells
- activates immune response
- memory cells remain in the body
state 2 reasons why measles has been more difficult to eradicate than smallpox (2)
- not all/enough of the population has been vaccinated
- people need boosters for measles
state how antibodies to measles come to be present in children at birth (1)
across the placenta
state the types of cell that produces antibodies (1)
plasma cells
what is the difference between vaccination and immunisation?
vaccination and involves injection of antigens and immunisation is the process of developing immunity
young mammals recieve antibodies in their mother’s milk. this is an example of which type of immunity?
natural passive immunity
what best describes the type of immunity by the flu vaccination?
active and artificial
which statement A to D correctly describes a process that provides artificial active immunity? (1)
A an injection of active antibodies for tetanus
B antigens for polio given in a sugar cube
C antibodies provided in milk from a breast-feeding mother
D antigens recieved on flu viruses via water droplets in the air
B
autoimmune diseases are often treated with a course of antibody injection, what immunity arises from this treatment? (1)
passive artificial immunity
an individual bitten by a rabid dog can be treated by an injection of human rabies antibodies, what immunity arises from this treatment? (1)
passive artificial immunity
which of the following strategies is a chemical defence against pathogen infection? (1)
A callose deposits at sieve tube ends that prevent pathogen movement in phloem
B hydrolytic enzymes such as chitase found between cellss
C stomata can be closed by guard cells if pathogens are detected
D cell walls can be thickened by lignin, making cell entry very difficult for pathogens
B
a person is bitten by a venomous snake, the immediate treatment is to inject them with appropriate antibodies. what immunity type is this? (1)
artificial passive
identify one similarity in the way malaria is transmitted compared with the way dutch elm disease is spread (1)
vectors
explain why the response to the subsequent infection is much bigger than the response to vaccination (3)
vaccination involves clonal selection and clonal expansion and the antigens are already present
