Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The seven characteristics of living organisms (MRS GREN): Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.
Respiration is the chemical reaction in cells that breaks down nutrient molecules and releases energy for metabolism: .
Excretion is the removal from organisms of the waste products of metabolism (chemical reactions in cells including respiration), toxic materials, and substances in excess of requirements.
The Binomial System: An internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and the species (e.g., ).
Classification is traditionally based on morphology and anatomy, but modern classification uses DNA base sequences to determine evolutionary relationships. Organisms which share a more recent ancestor have DNA base sequences that are more similar.
The Five Kingdoms: Prokaryotic (bacteria), Protoctists (e.g., ), Fungi (e.g., mushrooms, yeast), Plants, and Animals.
Main features of Arthropods: Segmented bodies, exoskeleton, and jointed legs. This group includes Insects, Crustaceans, Arachnids, and Myriapods.
Ferns and Flowering Plants: Ferns produce spores, while flowering plants reproduce via seeds. Flowering plants are divided into Monocotyledons (one cotyledon, parallel veins) and Dicotyledons (two cotyledons, reticulate/net-like veins).
Viruses are not classified in the five-kingdom system as they are not considered 'living'; they consist of genetic material (DNA or RNA) surrounded by a protein coat ().
📐Formulae
💡Examples
Problem 1:
An image of a plant cell in a textbook measures in length. If the actual length of the cell is , calculate the magnification used.
Solution:
Explanation:
Using the formula , we substitute the values: . Ensure both measurements are in the same units before dividing.
Problem 2:
Identify the group of vertebrates that possess hair or fur, have a diaphragm, and provide milk for their young.
Solution:
Mammals
Explanation:
Mammals are distinguished from other vertebrates (fish, amphibians, reptiles, and birds) by the presence of mammary glands, hair/fur, and a diaphragm used for ventilation of the lungs.
Problem 3:
A scientist compares the DNA of three species. Species A has the sequence , Species B has , and Species C has . Which two species are more closely related?
Solution:
Species A and Species B
Explanation:
Species A and B differ by only one base pair, whereas Species C differs significantly from both. Similarity in DNA sequences indicates a more recent common ancestor.