SACE Stage 2 Biology flashcards
SACE Stage 2 Biology · Build recall with a focused review session.
33 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Semi-conservative replication
- Each new DNA molecule contains one original parental strand and one newly synthesised complementary strand, so genetic information is copied accurately during cell division.
- Codon
- A sequence of three mRNA bases that specifies one amino acid or a stop signal during translation at the ribosome.
- Enzyme active site
- The specific region of an enzyme where substrate binds; its shape is complementary to the substrate and is altered by denaturation from heat or pH change.
- Negative feedback
- A homeostatic mechanism in which a detected deviation from the set point triggers an effector response that counteracts the change and restores the variable.
- Natural selection
- Heritable variation within a population combined with differential reproductive success changes allele frequencies across generations as favourable traits become more common.
- Glycolysis
- The first stage of cellular respiration in the cytosol, splitting one glucose into two pyruvate molecules and yielding a net gain of two ATP.
- Calvin cycle
- The light-independent stage of photosynthesis in which ATP and NADPH from the light reactions are used to fix carbon dioxide into carbohydrate.
- Fluid mosaic model
- The description of membranes as a phospholipid bilayer with embedded and peripheral proteins able to move laterally, giving selective permeability.
- Independent assortment
- Alleles of genes on different chromosomes are distributed to gametes independently of one another during meiosis, producing new allele combinations.
- Test cross
- A cross of an individual of unknown genotype with a homozygous recessive individual; offspring ratios reveal whether the unknown was homozygous or heterozygous.
- Provisional knowledge
- The principle that scientific claims are accepted only as far as current evidence supports them and may be revised when new reliable evidence emerges.
- Peer review
- Independent expert evaluation of a manuscript's methods, analysis and conclusions before publication, intended to filter unsupported or flawed claims.
- Falsifiability
- A property of a scientific hypothesis meaning that some conceivable observation could count as evidence against it; unfalsifiable claims are not testable.
- Correlation versus causation
- Two variables changing together does not prove one causes the other; confounding factors or reverse causation may explain the association.
- Informed consent
- Participants in research voluntarily agree after being told the purpose, procedures, risks and their right to withdraw without penalty.
- Publication bias
- The tendency for studies with positive or statistically significant results to be published more readily, distorting the evidence base available for review.
- Scientific consensus
- Agreement among researchers arising from convergence of independent lines of evidence, not from the authority of a single individual or institution.
- Hazard versus risk
- A hazard is a potential source of harm; risk combines the likelihood and severity of harm occurring under specified exposure conditions.
- Controlled variable
- A factor deliberately kept constant across treatment groups so that observed differences in the dependent variable can be attributed to the independent variable.
- Control group
- A comparison group that receives no treatment or a placebo, allowing the effect of the experimental treatment to be isolated from other influences.
- Validity
- The extent to which an investigation and its measurements actually test the stated hypothesis, free from confounding variables and systematic error.
- Reliability
- The consistency of repeated measurements or trials; it is improved by replication, careful technique and consistent procedures.
- Accuracy versus precision
- Accuracy is closeness of a measurement to the true value; precision is closeness of repeated measurements to each other, regardless of the true value.
- Random versus systematic error
- Random error scatters measurements unpredictably around the true value and is reduced by averaging; systematic error shifts all measurements in one direction.
- Extrapolation
- Predicting values outside the range of the independent variable actually tested, which is unsupported because the relationship may change beyond that range.
- Risk assessment
- A documented process identifying hazards, estimating likelihood and severity of harm, and specifying controls to reduce risk before practical work.
- Total magnification
- The product of eyepiece magnification and objective magnification; field of view diameter decreases in inverse proportion as total magnification increases.
- Benedict's test
- A test for reducing sugars in which heating the sample with Benedict's solution produces a colour change from blue to green, yellow or brick-red precipitate.
- Serial dilution
- Repeated dilution of a sample by a constant factor, producing a series of known concentrations used to build standard curves or plate counts.
- Standard curve
- A graph of known concentrations against measured absorbance or another signal, used to determine the concentration of an unknown sample.
- Aseptic technique
- Procedures such as flaming loops, working near a flame and autoclaving waste that prevent contamination of cultures and exposure of the worker.
- Potometer
- An apparatus measuring water uptake or bubble movement along a capillary as an estimate of transpiration rate under controlled environmental conditions.
- Initial rate of reaction
- The rate measured over the early linear phase of a reaction before substrate depletion or product accumulation slows the change.