Year 9 Science Revision

A clear question that guides the research process.

A testable prediction about the relationship between variables.

The intended outcome of an investigation.

The extent to which an investigation accurately measures what it is supposed to.

Systematic errors that can influence the results of an experiment.

A type of bias where researchers seek out evidence that confirms their existing beliefs.

A group of individuals selected for a study, not representative of the whole population.

The variable that is being changed or manipulated in an experiment.

The number of digits in a measurement that are considered reliable and contribute to its precision.

The smallest division on a measuring instrument, indicating the limit of precision. Represents the uncertainty of a single measurement.

The range within which a measurement is likely to fall, considering possible errors. It's expressed with one significant figure.

The degree of closeness of repeated measurements to each other. It reflects the consistency of the measurement process.

The degree of closeness of a measured value to the true or accepted value. It reflects how accurate the measurement is.

A measurement that is both precise and accurate. It reflects both consistency and closeness to the true value.

When two measurements overlap in their uncertainty range, indicating that they are consistent within the limits of their errors. This is a key criterion to assess the reliability of experimental data.

A concise way to express very large or very small numbers. It consists of a number between 1 and 10, multiplied by a power of 10.

The rate at which an object's velocity changes over time, often used in the context of falling objects.

A simple sugar, consisting of one sugar molecule, that can be absorbed directly into the bloodstream.

A sugar formed when two monosaccharides are joined together by a chemical reaction.

A large complex carbohydrate made up of many monosaccharide units linked together.

A graph that shows the relationship between two variables, where one variable is plotted on the x-axis and the other on the y-axis.

The slope of a line on a graph, calculated by dividing the change in y-values by the change in x-values.

The measure of how well the line of best fit represents the data points on a graph. A higher correlation coefficient means a better fit.

A process used to find the line that best represents the relationship between data points on a graph.

A chemical reaction that breaks down larger molecules into smaller ones, releasing energy.

A chemical reaction that builds larger molecules by combining smaller ones, requiring energy.

The process by which plants convert light energy into chemical energy in the form of glucose.

Reactions in photosynthesis that directly use light energy to produce ATP and NADPH.

Reactions in photosynthesis that use ATP and NADPH from light reactions to convert carbon dioxide into glucose.

Enzymes are biological catalysts that speed up chemical reactions without being consumed, but they can lose their function under extreme conditions.

A series of linked chemical reactions within a cell that are controlled by enzymes to carry out specific functions, like energy production or building molecules.

The optimal pH range where an enzyme functions at its highest rate.

Biological catalysts that speed up chemical reactions in living organisms without being consumed in the process. They are highly specific for the reactions they catalyze.

Enzymes are protein molecules with a unique 3-dimensional structure that allows them to bind to specific molecules called substrates. This binding facilitates the chemical reaction.

The activation energy required for a reaction is the minimum amount of energy needed for the reaction to start. Enzymes work by lowering this activation energy, making the reaction proceed much faster.

Each enzyme works best at a specific temperature. Increasing temperature generally speeds up the reaction, but excessive heat can denature the enzyme and destroy its activity.

Each enzyme has an optimal pH range where it functions at its highest activity. Extreme pH levels can disrupt the enzyme's structure and hinder its effectiveness.

The substance that an enzyme acts upon is known as its substrate. The enzyme's shape is specific to its substrate, creating a lock-and-key mechanism for precise interaction.

The active site of an enzyme is a specific region where the substrate binds to the enzyme. It's like a pocket on the enzyme specifically shaped to fit the substrate.

Enzymes are very sensitive to changes in the environment. Factors that can affect enzyme activity include temperature, pH, substrate concentration, and the presence of inhibitors or activators.

RNA is a single-stranded nucleic acid composed of nucleotides. Its nucleotides differ from those of DNA, with uracil replacing thymine. RNA plays a key role in protein synthesis.

The four nitrogenous bases found in RNA are adenine (A), guanine (G), cytosine (C), and uracil (U).

DNA replication is the process of making an exact copy of a cell's DNA molecule. It involves unwinding the double helix, separating the strands, and using each as a template to build a new complementary strand.

DNA replication is semi-conservative because each new DNA molecule consists of one original strand and one newly synthesized strand. This ensures that the genetic information is accurately copied.

DNA polymerase is the primary enzyme responsible for synthesizing new DNA strands during replication. It adds nucleotides to the growing chain, following base pairing rules.

Helicase is an enzyme that unwinds the DNA double helix, separating the two strands to allow replication to occur.

DNA replication involves unwinding the helix, separating the strands, using each as a template to build a new complementary strand. This process is carried out by specific enzymes such as helicase, DNA polymerase, and ligase.