April Summative Assessment Flashcards
What is Holozoic nutrition
A type of nutrition where organisms ingest, digest, and absorb food (e.g., humans).
What is Photoautotrophic nutrition
Organisms that use light energy to make their own food via photosynthesis (e.g., plants, algae).
What is Saprotrophic nutrition
Decomposers that break down dead organic matter externally using enzymes (e.g., fungi, bacteria).
competitive inhibitors significance
Competitive inhibitors bind to the active site, preventing substrate binding.
Non-competitive inhibitors significance
Non-competitive inhibitors bind to an allosteric site, changing enzyme shape.
How do enzyme inhibitors link to cancer
If inhibitors disrupt cell cycle regulation, uncontrolled growth of cells by mitosis may occur. Increasing the risk of tumor formation and cancer.
Which organs secrete lipase, and what are their specific roles in lipid digestion?
•Pancreas → Secretes pancreatic lipase into the small intestine, where it hydrolyzes triglycerides into glycerol and fatty acids.
•Stomach → Secretes gastric lipase, which has a limited role in lipid digestion, primarily breaking down short-chain triglycerides.
Microscopic leaf adaptations
•Hydrophytes (water plants): Large air spaces for buoyancy and stomata on the upper surface to allow gas exchange in submerged conditions.
•Mesophytes (moderate environments): Stomata on both leaf surfaces and a normal cuticle thickness for balanced water retention and gas exchange.
•Xerophytes (dry environments): Thick cuticle, sunken stomata, and rolled leaves to reduce water loss through transpiration. Hairs ti decrease water potential gradient to reduce water loss.
What are the steps of DNA transcription?
- DNA Unwinding: The DNA helicase breaks hydrogen bonds between complementary DNA bases, causing the two strands to separate and expose the template strand.
- Base Pairing: Free RNA nucleotides in the nucleoplasm align with exposed bases on the template strand according to complementary base pairing (A-U, C-G).
- RNA Polymerase Binding: RNA polymerase binds to the template strand at the promoter region and initiates mRNA synthesis.
- Phosphodiester Bond Formation: RNA polymerase catalyzes the formation of phosphodiester bonds between adjacent nucleotides, elongating the mRNA strand.
- DNA Reannealing: Only 12 base pairs are exposed at a time; the DNA strands rejoin behind RNA polymerase, reforming the double helix.
- Termination: When RNA polymerase reaches a stop triplet, it detaches, releasing the pre-mRNA, completing transcription.
Why are introns irrelevant after translation?
Introns are removed before translation, so they don’t affect the final protein.
What is the independent variable in a potometer experiment?
Light intensity, humidity, temperature (affect transpiration).
What is the dependent variable in a potometer experiment?
Rate of water uptake.
Why is oil used in a potometer experiment?
To prevent air entry and maintain an airtight system.
What factors affect transcription?
•Transcription factors (activate or repress genes).
•Hormones (e.g., oestrogen binding to receptors).
•Chromatin structure (tightly packed chromatin reduces transcription).
What are the functions of calcium in the body?
Bone strength, muscle contraction, nerve function, blood clotting.
What are the functions of phosphate in the body?
Bone and teeth formation, ATP production, DNA/RNA structure.
How does villi structure help absorption?
•Microvilli → Increase surface area for absorption.
•Thin walls → Short diffusion distance.
•Capillaries → Transport absorbed nutrients.
•Lacteal → Absorbs fatty acids and glycerol.
