Exam Qs Flashcards
Explain the function of a reflex arc? (2 marks)
Responds to danger to protect the body from harm.
The computer program started with blue squares that turned into yellow squares.
Describe how the scientist could compare the reaction times of these students when they respond to red squares turning into yellow squares.
Measure their reaction times using red squares, keep everything else the same. Repeat measurements.
State two ways that communicable diseases are different from non-communicable diseases.
Can be passed on from person to person.
Caused by pathogens.
Explain one way that the spread of TB can be reduced or prevented.
Washing your hands regularly because it is spread by coughing and sneezing.
Give two precautions needed to prevent contamination of the agar jelly plate.
Keep the lid on at all possible times.
Use sterile equipment.
Describe two processes that occur in cells during prophase.
Chromatids condense.
Nuclear membrane breaks down.
Describe how to adjust the microscope to view the slide at a magnification of *400.
Use the *40 objective lens and use the *10 eyepiece lens.
Discuss the benefits and risks of using stem cell therapy to treat arthritis.
Can repair the damaged cells in joint.
Stem cells can become specialised.
New cells do not function correctly.
Stem cells continue to divide.
Describe how cancer develops in the liver.
Mutations in the DNA.
Cell division is uncontrolled.
Explain how to genetically modify a bacterial cell to produce Chymosin.
Plasmid is cut with restriction enzymes. Sticky ends are complementary. Ligase is used to connect the chymosin gene and the plasmid.
One gene can have several different alleles.
Explain why these alleles can produce proteins with different structures.
Alleles have different DNA mutations which code for a different amino acid. Protein folds with a different structure.
Explain why monoclonal antibodies, used to detect blood group A, would not react with the blood of a person with blood group B.
The shape of the antibody is complementary to the A antigen. The B antigen has a different shape therefore it will only bind to the A antigen.
How can mutations lead to human evolution?
Most mutations do not affect the phenotype.
But if a mutation creates a new phenotype that is better adapted to environmental changes, the mutation is likely to spread.
Malaria is spread by vectors, such as mosquitos. How can one stop malaria from spreading?
By preventing mosquitos from breeding and using mosquitos to avoid being bitten.
