CIE Biology IGCSE: Topics 1–5 Comprehensive Review

Vocabulary practice flashcards covering characteristics of living organisms, cell structure and organisation, movement in and out of cells, biological molecules, and enzyme function for CIE Biology IGCSE.

Movement

An action by an organism or part of an organism causing a change of position or place; animals move to find food or escape predators, whilst plants move their leaves to catch sunlight.

Respiration

A series of chemical reactions that occurs in cells, leading to the breakdown of nutrient molecules to release energy for metabolism.

Sensitivity

The ability of living organisms to detect changes in their internal or external environments and respond to these changes.

Growth

A permanent increase in size of an organism, which can be measured through dry mass, cell size, or number of cells.

Reproduction

The processes that make more of the same kind of organism.

Excretion

The removal of waste products of metabolism, toxic materials, and substances in excess of requirements (including carbon dioxide from respiration) from an organism.

Nutrition

The taking in of materials for energy, growth, and development; animals require organic compounds, ions, and water, whereas plants take in light, carbon dioxide, water, and ions.

Species

A group of organisms that can reproduce to produce fertile offspring.

Binomial Naming System

A system of naming species using two Latin words: the first denotes the genus, and the second denotes the species (for example, Homo sapiens).

Arthropods

Invertebrates lacking a backbone that are identified by their exoskeleton and segmented body; includes myriapods, insects, arachnids, and crustaceans.

Eukaryotic Cells

Cells that contain a nucleus and membrane-bound organelles such as mitochondria and rough endoplasmic reticulum (for example, plant and animal cells).

Prokaryotes

Single-celled organisms, such as bacteria, that lack a nucleus, membrane-bound organelles, and a rough endoplasmic reticulum.

Actual Size Formula

The microscopy equation used to determine specimen size: $\text{Actual size} = \frac{\text{Image size}}{\text{Magnification}}$.

Rough Endoplasmic Reticulum (RER)

A cellular structure surrounding the nucleus that is studded with ribosomes, serving as the site of protein synthesis.

Tissue

A group of similar cells working together to carry out a particular process.

Organ System

A group of related organs working together to carry out functions in the body.

Ciliated Cells

Specialised cells lining the trachea that have hair-like projections called cilia which move together to transport mucus, dust, and bacteria upwards to the throat.

Xylem Vessels

Specialised transport vessels formed from hollowed-out dead cells with ends removed; they feature thick cell walls for structural strength and are thin to allow capillary action during transpiration.

Palisade Mesophyll Cells

Tall, closely packed photosynthetic cells positioned at the top of a leaf that contain numerous chloroplasts to efficiently absorb light energy.

Red Blood Cells

Specialised cells containing haemoglobin with a biconcave shape that increases surface area for rapid diffusion; they lack a nucleus to allow more space for oxygen and have a thin membrane to reduce diffusion distance.

Diffusion

The net movement of particles from an area of high concentration to an area of low concentration down the concentration gradient, as a result of their random movement driven by kinetic energy.

Osmosis

The net movement of water molecules through a partially permeable membrane from a region of higher water potential to a region of lower water potential.

Turgor Pressure

The pressure exerted on the cell wall by the cell membrane pushing against it as a result of water entering the plant cell via osmosis.

Flaccid

The state of a cell when water leaves via osmosis, causing it to shrink while the cell membrane remains attached to the cell wall.

Plasmolysis

The condition occurring in plant cells when excessive water loss via osmosis causes the cell membrane to peel away from the cell wall.

Active Transport

The movement of molecules through a cell membrane from regions of low concentration to regions of higher concentration against a concentration gradient, using energy from respiration and carrier proteins.

Carrier Proteins

Proteins embedded in the cell membrane that bind specific molecules on the low-concentration side and change shape using respiratory energy to release them on the high-concentration side.

Cellulose

A structural carbohydrate polymer composed of long chains of glucose molecules that forms plant cell walls.

Glycogen

A carbohydrate polymer formed by chains of glucose molecules that functions as the energy storage molecule in animals.

Iodine Test

A chemical test for starch in which the addition of iodine solution results in a colour change to blue-black if starch is present.

Benedict’s Test

A chemical test where a sample is mixed with copper sulphate-containing blue Benedict's solution and heated to $80^\circ\text{C}$; reducing sugars reduce $Cu^{2+}$ ions to form an insoluble brick-red copper (I) oxide.

Biuret Test

A chemical test for proteins where equal amounts of sodium hydroxide solution and dilute copper(II) sulphate solution turn purple if protein is present (or remain blue if absent).

Emulsion Test

A chemical test for fats and oils where the sample is dissolved in ethanol, mixed with water, and gently shaken; a cloudy white emulsion indicates the presence of lipids.

DCPIP Test

A biochemical test for vitamin C where the addition of the sample causes blue DCPIP solution to turn colourless.

Catalyst

A substance that speeds up the rate of a chemical reaction without being used up or permanently changed.

Enzyme

A biological catalyst made of protein that accelerates metabolic chemical reactions in living organisms without being consumed.

Active Site

A specific sequence of amino acids with a complementary three-dimensional shape on an enzyme that binds specifically to its substrate.

Enzyme-Substrate Complex

The temporary complex formed when a substrate enters and binds to the complementary active site of an enzyme.

Denaturation

A structural change in an enzyme where extreme pH values or temperatures above the optimum alter the shape of the active site, preventing substrate binding and enzyme-substrate complex formation.