Heredity
What is the main advantage of sexual reproduction compared to asexual reproduction?
It increases genetic variation, which improves survival chances in changing environments.
What type of mutation involves a single nucleotide change?
Point mutation.
Name two types of pathogens.
Bacteria, viruses, fungi, protozoa, macroparasites or prions.
What is homeostasis?
The maintenance of a stable internal environment despite external changes.
What is the purpose of a control in an experiment?
To provide a baseline for comparison, ensuring only the independent variable affects the results.
Which cellular process halves the chromosome number to produce gametes?
Meiosis.
Name one example of a mutagen.
UV radiation, X-rays, asbestos, or cigarette smoke.
Who developed the postulates that link pathogens to disease?
Robert Koch.
Name one negative feedback loop in humans and draw a flow chart
Temperature regulation (sweating/shivering) or blood glucose regulation (insulin/glucagon).
Define dependent and independent variables.
Independent variable = what is changed; dependent variable = what is measured.
Name the two stages of protein synthesis and their locations in the cell.
Transcription (nucleus) and translation (ribosome in cytoplasm).
Distinguish between somatic and germ-line mutations.
Somatic mutations occur in body cells (not inherited); germ-line mutations occur in gametes and can be passed to offspring.
How do vaccines protect individuals and populations from disease?
They stimulate an immune response to build memory cells, giving individual immunity and herd immunity.
List two categories of non-infectious disease.
Genetic diseases, nutritional diseases, environmental diseases, cancer.
Why is it important to control variables in an experiment?
Controlling variables ensures the experiment is valid by making sure only the independent variable affects the dependent variable.
How does crossing over during meiosis contribute to genetic variation?
Homologous chromosomes exchange DNA segments, producing new allele combinations.
How can gene flow alter the gene pool of a population?
Migration introduces or removes alleles, increasing or decreasing genetic diversity.
Compare the adaptations of pathogens that allow them to enter or spread between hosts.
Examples: adhesion proteins (viruses), protective capsules (bacteria), spores (fungi), antigenic variation (influenza).
How does epidemiology help scientists study non-infectious diseases?
By analysing incidence, prevalence, and distribution patterns to identify causes, risk factors, and prevention strategies.
Why must experimental procedures be repeatable and replicable?
To increase reliability, validity, and reduce the influence of random error.
Analyse how both genes and environment interact to influence phenotype. Give an example.
Phenotype is the product of genotype and environmental factors (e.g., identical twins may have different heights due to nutrition).
Evaluate the benefits and risks of using recombinant DNA technology in agriculture.
Benefits: increased yield, pest/disease resistance, improved nutrition. Risks: reduced biodiversity, ethical concerns, potential ecological effects.
Evaluate one current strategy to predict and control the spread of an infectious disease.
Quarantine and vaccination programs reduce spread; effectiveness depends on compliance, coverage, and pathogen mutation rate.
Evaluate the role of lifestyle and environmental factors in the development of cancer.
Lifestyle factors (diet, smoking, alcohol, sun exposure) and environmental factors (radiation, pollutants) increase mutation risk; prevention involves modifying these risks.
Evaluate the reliability of data in a secondary source, citing two criteria.
Check if the source is peer-reviewed and whether data are consistent with other studies.