GCSE Biology Paper 1 Revision

Comprehensive vocabulary flashcards covering key definitions, processes, cellular structures, and organ systems for GCSE Biology Paper 1.

Magnification

The ratio calculated by dividing the size of the image by the actual size of the object: $\text{Magnification} = \frac{\text{Image size}}{\text{Object size}}$.

Eukaryotic Cells

Cells that contain a nucleus where their DNA is stored, such as plant and animal cells.

Prokaryotic Cells

Cells that lack a nucleus to contain their genetic material, such as bacteria.

Cell Membrane

A partially, semi-, or selectively permeable barrier that keeps cell contents inside while regulating which substances pass through.

Cell Wall

A rigid outer layer made of cellulose in plant cells that provides structural support; bacteria also possess a cell wall, though not made of cellulose.

Cytoplasm

The fluid liquid component of a cell where most chemical reactions take place.

Mitochondria

The subcellular organelles that serve as the site of cellular respiration, releasing energy needed for cellular function.

Ribosomes

The subcellular sites of protein synthesis where amino acids are assembled into proteins.

Chloroplasts

Organelles found in plant cells containing chlorophyll, acting as the site of photosynthesis.

Permanent Vacuole

A fluid-filled compartment found in plant cells used for the storage of cell sap.

Binary Fission

The method of asexual cell division by which bacteria multiply.

Aseptic Technique

Procedures used during culturing, such as sterilizing equipment and working near a flame, to ensure unwanted microorganisms do not contaminate the culture.

Diploid Cells

Body cells that have two sets of chromosomes, which equates to 23 pairs in human nuclei.

Haploid Cells

Sex cells (gametes, such as sperm and egg cells) containing half the standard number of chromosomes, having only 23 single chromosomes.

Mitosis

The cell duplication process for growth and repair where duplicated chromosomes are pulled to opposite poles of the cell to yield two identical daughter cells.

Stem Cells

Undifferentiated cells capable of specializing into various cell types, found in human embryos, plant meristems, and adult bone marrow.

Diffusion

The passive movement of particles down a concentration gradient from an area of higher concentration to an area of lower concentration.

Osmosis

The movement of water across a semi- or selectively permeable membrane from an area of higher water concentration to lower water concentration.

Active Transport

The movement of particles against a concentration gradient through carrier proteins in a membrane, requiring cellular energy input.

Tissue

A group of interconnected, similar cells working together to perform a specific function.

Bile

A fluid produced by the liver and stored in the gallbladder that neutralizes stomach acid and emulsifies lipids into small droplets to increase surface area.

Enzymes

Biological catalysts that accelerate chemical reactions by binding specific substrates to their active sites via a lock-and-key mechanism.

Amylase

A carbohydrase enzyme that catalyzes the breakdown of starch into maltose and eventually glucose.

Proteases

Enzymes that break down proteins into their constituent amino acids.

Lipases

Enzymes that break down lipids (fats) into glycerol and fatty acids.

Denatured

The state of an enzyme whose active site has changed shape due to excessive temperature or extreme pH, preventing the substrate from fitting.

Benedict's Solution

A semi-quantitative chemical reagent that turns from blue to green, orange, or brick red in the presence of reducing sugars.

Biuret Reagent

A chemical testing solution that turns from blue to purple in the presence of proteins.

Double Circulatory System

A circulatory system where blood passes through the heart twice on each complete circuit around the body.

Arteries

Blood vessels that carry blood away from the heart under high pressure, characterized by thick muscular walls and a narrow lumen.

Veins

Blood vessels that transport blood toward the heart under lower pressure, featuring thinner walls, larger lumens, and valves to prevent backflow.

Capillaries

Microscopic blood vessels with walls only one cell thick, facilitating the rapid diffusion of substances between the bloodstream and body tissues.

Coronary Heart Disease (CHD)

A cardiovascular condition caused by the buildup of fatty deposits in the coronary arteries, restricting blood and oxygen flow to heart muscle.

Stents

Small expandable tubes inserted into narrowed blood vessels to keep them open and restore blood flow.

Statins

Medications that lower blood cholesterol levels, reducing the rate at which fatty deposits build up in arteries.

Non-Communicable Disease

A disease that cannot be transmitted between individuals and arises from internal factors, such as coronary heart disease, diabetes, or cancer.

Carcinogen

Any agent or chemical substance that increases the risk of developing cancer, such as tar found in cigarette smoke.

Benign Tumours

Non-cancerous growths of cells that remain localized in one area and do not invade or spread to other parts of the body.

Malignant Tumours

Cancerous growths of cells that invade neighboring tissues and spread through the body.

Body Mass Index (BMI)

A standardized metric used to assess whether an individual's weight is healthy in proportion to their height.

Transpiration

The unidirectional process of water uptake by roots, movement upward through xylem vessels, and evaporation through leaves.

Translocation

The bidirectional transport of sugars, food, and sap throughout a plant via phloem vessels.

Chlorosis

The yellowing of plant leaves resulting from insufficient chlorophyll production, commonly caused by a deficiency in magnesium ions.

Stomata

Pores primarily located on the lower epidermis of leaves, flanked by guard cells, that open and close to control gas exchange and water loss.

Pathogens

Microorganisms that enter the body, reproduce, and cause communicable diseases, including viruses, bacteria, fungi, and protists.

Protists

Single-celled parasitic microorganisms that can cause diseases such as malaria.

Lymphocytes

White blood cells that produce specific antibodies against pathogen antigens and antitoxins to neutralize microbial poisons.

Phagocytes

White blood cells that engulf, ingest, and destroy pathogens, particularly after antibodies cause them to clump together.

Vaccine

A preparation containing a dead or inert form of a pathogen introduced to stimulate antibody production and generate immunity without causing disease.

Antibiotics

Medicines, such as penicillin, designed to treat infections by killing bacteria without harming body cells or targeting viruses.

Double-Blind Trial

A clinical testing method where neither the patients nor the doctors analyzing results know who received the real drug and who received a placebo.

Hybridoma Cell

A cell created by fusing an antibody-producing mouse lymphocyte with a tumour cell, cloned to synthesize large quantities of monoclonal antibodies.

Limiting Factor

An environmental condition, such as light intensity, carbon dioxide concentration, or temperature, that directly restricts the rate of photosynthesis when in short supply.

Aerobic Respiration

The breakdown of glucose in the presence of oxygen within the mitochondria to release cellular energy, water, and carbon dioxide.

Anaerobic Respiration

The incomplete breakdown of glucose without oxygen, yielding lactic acid in animals or ethanol and carbon dioxide in plants and yeast.

Oxygen Debt

The volume of extra oxygen required after vigorous exercise to transport and break down accumulated lactic acid in the liver back into glucose.

Fermentation

Anaerobic respiration in plant and yeast cells that converts glucose into ethanol and carbon dioxide, utilized in baking and alcoholic beverage production.

Metabolism

The sum of all chemical reactions occurring within a single cell or an entire organism.