GCSE Biology Paper 1H (June 2024) - Key Vocabulary

Comprehensive practice flashcards defining key biological concepts, tissue structures, metabolic processes, and experimental terminology from the GCSE Biology Higher Tier Paper 1 examination.

Coronary Arteries

The specific blood vessels supplying oxygenated blood to the heart muscle that are narrowed or blocked in coronary heart disease.

Chest Compressions

An emergency technique of applying downward pressure on the sternum to compress the heart and manually push blood around the body to deliver oxygen to vital organs.

Statin

A class of medicinal drug prescribed to reduce the level of cholesterol in the blood, lowering the risk of coronary heart disease.

Stent

A wire-mesh tube surgically inserted into a narrowed artery to keep it open, restoring blood flow and delivering oxygen and glucose to heart tissue.

Cystic Fibrosis (CF)

An inherited recessive genetic disorder caused by a faulty gene located in the cell nucleus on a chromosome, affecting the lungs, pancreas, and small intestine.

Lipase

A pancreatic digestive enzyme that catalyses the breakdown of lipids (fats) into fatty acids and glycerol.

Protease

A digestive enzyme produced by the pancreas that breaks down dietary proteins into soluble amino acids.

Amylase

A carbohydrase enzyme found in saliva and pancreatic secretions that hydrolyses starch into simpler sugars such as maltose and glucose.

Alveolar Adaptations for Gas Exchange

Structural specialisations of the alveoli including a large surface area, thin walls that are one cell thick, and an extensive capillary network ensuring an efficient blood supply.

Hypoxia / Reduced Blood Oxygenation Effects

A deficit of oxygen in the blood that lowers the rate of aerobic respiration, releasing less energy and causing muscle fatigue from anaerobic respiration and lactic acid buildup.

Iodine Test

A qualitative food test used to detect starch, turning from yellow/orange/brown to blue-black, black, or dark blue in the presence of starch.

Benedict's Test

A chemical test for reducing sugars that requires heating the sample with reagent to at least $60\,^\circ\text{C}$, yielding a color change from blue to green, yellow, orange, brown, or brick red.

Palisade Mesophyll

The upper photosynthetic leaf tissue composed of columnar cells packed with the highest density of chloroplasts to absorb sunlight efficiently.

Spongy Mesophyll

Leaf tissue containing loosely arranged cells with large intercellular air spaces that facilitate the diffusion of carbon dioxide and oxygen.

Meristem Tissue

Undifferentiated plant tissue found in shoot and root tips containing stem cells that retain the ability to divide and differentiate throughout the plant's life.

Lignin

A rigid polymer deposited in the cellulose cell walls of xylem vessels that waterproofs and mechanically strengthens the transport tissue.

Translocation

The active, energy-requiring transport of dissolved sugars (such as sucrose) through the phloem tissue from sources to sinks throughout a plant.

Companion Cell

A specialised plant cell adjacent to phloem sieve tube elements containing abundant mitochondria that perform aerobic respiration to supply energy for active transport of sugars.

Phloem Sieve Tube Specialisation

The structural differentiation of unspecialised plant cells into phloem cells involving the loss of nuclei, cytoplasm, and organelles, and the formation of perforated end walls (sieve plates).

Osmosis

The diffusion of water molecules from a more dilute solution to a more concentrated solution across a partially permeable membrane.

Concentration Gradient in Osmosis

The difference in solute concentration between two regions; a steeper gradient (such as $1.0\,\text{mol/dm}^3$ versus $0.6\,\text{mol/dm}^3$ salt solution) increases the net rate of water loss from cells.

Antibiotic

A medicinal drug, such as penicillin, that treats bacterial infections by killing pathogenic bacteria or preventing their reproduction without harming host cells.

Zone of Inhibition

The clear area on an agar plate around an antibiotic-impregnated disc where bacterial growth has been inhibited or killed.

Antibiotic Resistance

The evolved ability of a bacterial strain to survive exposure to one or more antibiotics that were previously effective, rendering diseases more difficult or impossible to cure.

Chlorosis

The yellowing of plant leaves caused by a lack of chlorophyll, typically triggered by a deficiency of mineral ions such as magnesium ($\text{Mg}^{2+}$).

Limiting Factor (Photosynthesis)

An environmental condition (light intensity, carbon dioxide concentration, or temperature) that is in shortest supply and directly restricts the rate of photosynthesis.

Inverse Square Law (Light)

The mathematical relationship where the intensity of light is inversely proportional to the square of the distance from the source: $\text{light intensity} \propto \frac{1}{\text{distance}^2}$.

Preclinical Testing

Early drug testing carried out in a laboratory on computers, isolated cells, live tissues, and animals before administering the drug to humans in clinical trials.

Spindle Fibres

Microtubule structures that attach to replicated chromosomes during mitosis to pull chromatids toward opposite poles of the dividing cell.

Magnification Formula

The mathematical equation relating the size of a magnified image to the actual size of the specimen: $\text{magnification} = \frac{\text{image size}}{\text{real size}}$.