Practical Science Key Terms and Basic Components of Living Systems

Vocabulary flashcards generated from the practical science key terms and basic components of living systems study sheets.

Valid Measurement

A measurement that measures what it is supposed to be measuring.

Accurate Result

A result that is close to the true value.

Precise Results

Results where repeat measurements are consistent/agree closely with each other.

Repeatability

How precise repeated measurements are when they are taken by the same person, using the same equipment, under the same conditions.

Reproducibility

How precise repeated measurements are when they are taken by different people, using different equipment.

Uncertainty of a Measurement

The interval within which the true value is expected to lie.

Measurement Error

The difference between a measured value and the true value.

Random Error

Error caused by results varying around the true value in an unpredictable way.

Systematic Error

A consistent difference between the measured values and true values.

Zero Error

An error that occurs when a measuring instrument gives a false reading when the true value should be zero.

Independent Variable

The variable that is changed or selected by the investigator.

Dependent Variable

A variable that is measured every time the independent variable is changed.

Fair Test

A test in which only the independent variable is allowed to affect the dependent variable.

Control Variables

Variables that should be kept constant to avoid them affecting the dependent variable.

Magnification Formula

$$\text{magnification} = \frac{\text{size of image}}{\text{actual size of object}}$$

Staining (Microscopy)

Increases contrast between different cell components, makes them visible, and allows them to be identified before being viewed with a light microscope.

Eyepiece Graticule

A glass disc that fits on top of the eyepiece lens that is marked with a fine scale from 1 to 100.

Stage Micrometer

A microscope slide with a very accurate scale in micrometers ($\mu$) engraved on it.

Scientific Drawing

A labelled line drawing that is used to highlight particular features and does not include unnecessary detail or shading; it should always have a title and state the magnification.

Magnification

How many times larger an image is than the actual size of the object being viewed.

Resolution

The ability to see individual objects as separate entities.

Nucleus

Controls the metabolic activities of the cell as it contains genetic information in the form of DNA.

Nucleolus

Area within the nucleus that is responsible for producing ribosomes.

Mitochondria

Site of production of ATP in the final stages of cellular respiration.

Vesicles

Membranous sacs that are used to transport materials in the cell.

Lysosomes

Specialised forms of vesicles with hydrolytic enzymes that break down waste material in cells.

Cytoskeleton

Controls cell movement, movement of organelles within the cell, and provides mechanical strength to the cell.

Cytoskeletal Filaments

The three types of filaments comprising the cytoskeleton: microfilaments, microtubules, and intermediate fibres.

Flagella and Cilia

Two types of extension that protrude from some cells: flagella (whip-like protrusions) and cilia (tail-like protrusions).

Endoplasmic Reticulum (ER)

A network of membranes enclosing flattened sacs called cisternae.

Functions of ER Types

Smooth ER – lipid and carbohydrate synthesis, and storage; Rough ER – synthesis and transport of proteins.

Golgi Apparatus

Plays a part in modifying proteins and packaging them into vesicles.