IB_Biology_2025_Flashcards
(38 cards)
What are the key properties of water that support life?
Cohesion, adhesion, high specific heat, solvent properties—these allow water to transport substances and maintain stable environments.
What is the structure of DNA and how does it relate to its function?
DNA is a double helix with complementary base pairing, enabling replication and encoding genetic information.
How did cells originate according to current scientific theories?
Abiogenesis theory suggests life originated from non-living matter under early Earth conditions.
What are the main components of a prokaryotic cell?
Cell wall, plasma membrane, cytoplasm, ribosomes, and nucleoid region.
What distinguishes viruses from living cells?
Viruses lack cellular structure, can’t reproduce independently, and are considered obligate parasites.
How are organisms classified using binomial nomenclature?
By genus and species, e.g., Homo sapiens; based on hierarchical classification systems.
What evidence supports the theory of evolution?
Fossil records, homologous structures, and molecular biology support shared ancestry.
Why is biodiversity conservation important?
It maintains ecosystem services, genetic resources, and ecological balance.
What is the role of lipids in cell membranes?
Lipids form the bilayer structure, provide flexibility, and regulate passage of substances.
How does protein structure determine function?
Primary to quaternary structure determines shape and function (e.g., enzymes, antibodies).
What is the fluid mosaic model of membranes?
Describes a dynamic bilayer with embedded proteins—allows selective permeability.
Why is compartmentalization important in eukaryotic cells?
Compartmentalization allows for specialization and efficient metabolic processes.
How do specialized cells arise from stem cells?
Through gene expression regulated by internal and external signals.
What adaptations facilitate gas exchange in alveoli?
Thin walls, moist surfaces, and a large surface area optimize diffusion of gases.
What is the role of xylem and phloem in plants?
Xylem transports water/minerals; phloem transports sugars (translocation).
How do muscles contract at the molecular level?
Actin and myosin filaments slide past each other, powered by ATP.
How do organisms adapt to different environmental conditions?
Via structural, behavioral, or physiological traits suited to environment.
What is an ecological niche?
A species’ role in its ecosystem, including resource use and interactions.
How do enzymes lower activation energy?
By stabilizing the transition state and lowering the energy barrier.
What are the stages of aerobic cellular respiration?
Glycolysis, link reaction, Krebs cycle, and oxidative phosphorylation.
What are the light-dependent reactions in photosynthesis?
Convert light energy into chemical energy (ATP and NADPH).
How do hormones function as chemical messengers?
Hormones bind to receptors and trigger specific responses.
What is the role of the synapse in neural transmission?
A synapse transmits signals via neurotransmitters between neurons.
How do organ systems work together to maintain homeostasis?
E.g., respiratory and circulatory systems coordinate gas exchange.
