GCSE Biology Paper 2 Overview

A collection of vocabulary flashcards covering key concepts from the GCSE Biology Paper 2 lecture.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Transpiration

The process of water vapor leaving plant leaves into the atmosphere through the stomata.

Xylem

The plant tissue responsible for the transport of water and mineral ions from the roots to the rest of the plant.

Phloem

The plant tissue responsible for the translocation of sugars and nutrients throughout the plant.

Stomata

Small openings on the surface of leaves that allow for gas exchange and transpiration.

Guard Cells

Specialized cells that surround stomata and control their opening and closing to regulate gas exchange and water loss.

Homeostasis

The maintenance of stable internal conditions in an organism (e.g., blood glucose, temperature, water) despite external changes.

Hormones

Chemical messengers produced by endocrine glands that travel in the blood to target organs.

Gibberellins

Plant hormones that regulate growth and development, particularly in seed germination, flowering, and fruit size.

Auxins

Plant hormones that regulate growth by causing cell elongation, particularly in response to light (phototropism) and gravity (geotropism).

Phototropism

The growth of a plant shoot toward or away from light, mediated by the unequal distribution of auxin.

Geotropism (Gravitropism)

A plant's growth response to gravity; roots show positive geotropism while shoots show negative geotropism.

Endothermic Reaction

A reaction that requires energy input from the surroundings, such as photosynthesis.

Aerobic Respiration

The process of releasing energy from glucose using oxygen, yielding carbon dioxide, water, and a high amount of energy: C{6}H{12}O{6} + 6O{2} \rightarrow 6CO{2} + 6H{2}O.

Anaerobic Respiration

The release of energy from glucose without oxygen, yielding lactic acid in animals or ethanol and CO_{2} in yeast.

Metabolism

The sum of all chemical reactions in a cell or the body.

Central Nervous System (CNS)

The brain and spinal cord, which coordinate the body's responses.

Reflex Arc

The nerve pathway of a reflex action: Stimulus \rightarrow Receptor \rightarrow Sensory Neuron \rightarrow Relay Neuron \rightarrow Motor Neuron \rightarrow Effector \rightarrow Response.

Synapse

The functional junction or gap between two neurons where neurotransmitters diffuse to transmit signals.

The Retina

The light-sensitive inner surface of the eye, containing rods for light intensity and cones for color.

Accommodation

The process of changing the shape of the lens to focus on near or distant objects.

Myopia and Hyperopia

Myopia is short-sightedness (corrected with concave lenses); Hyperopia is long-sightedness (corrected with convex lenses).

Cerebral Cortex

The outer layer of the brain responsible for consciousness, intelligence, memory, and language.

Cerebellum

The part of the brain responsible for muscle coordination and balance.

Medulla

The part of the brain that controls unconscious activities like heartbeat and breathing.

Vasoconstriction

The narrowing of blood vessels near the skin surface to reduce heat loss when the body is cold.

Vasodilation

The widening of blood vessels near the skin surface to increase heat loss when the body is too hot.

Insulin

A hormone from the pancreas that lowers blood glucose by converting it to glycogen for storage in the liver and muscles.

Glucagon

A hormone from the pancreas that increases blood glucose by converting stored glycogen back into glucose.

Type 1 vs Type 2 Diabetes

Type 1: Pancreas produces little/no insulin (treated with injections). Type 2: Body cells no longer respond to insulin (treated with diet/exercise).

ADH (Antidiuretic Hormone)

A hormone released by the pituitary gland that increases the permeability of kidney tubules to water, reducing urine volume.

Dialysis

A mechanical process to filter waste products from the blood when kidneys fail.

Menstrual Cycle Hormones

FSH (matures egg), LH (stimulates ovulation), Oestrogen (builds lining), Progesterone (maintains lining).

DNA Structure

A polymer of two strands forming a double helix, composed of nucleotides (sugar, phosphate, and a base: A, C, G, or T).

Genome

The entire genetic material of an organism.

Meiosis

Cell division that produces four non-identical haploid gametes.

Alleles

Different versions of the same gene, categorized as dominant or recessive.

Cystic Fibrosis

An inherited disorder of cell membranes caused by a recessive allele.

Polydactyly

An inherited disorder causing extra fingers or toes, caused by a dominant allele.

Natural Selection

The process where advantageous phenotypes survive and pass on genes, leading to evolution.

Speciation

The formation of new and distinct species in the course of evolution.

Classification (Linnaean)

Kingdom, Phylum, Class, Order, Family, Genus, Species.

Three-Domain System

Developed by Carl Woese: Archaea, Bacteria, and Eukaryota.

Abiotic and Biotic Factors

Abiotic: Non-living (CO2, light, temp). Biotic: Living (predators, pathogens, competition).

Trophic Levels

The positions organisms occupy in a food chain: Producer, Primary Consumer, Secondary Consumer, Tertiary Consumer.

Biomass Transfer Efficiency

Calculated as: \frac{\text{Biomass transferred to next level}}{\text{Biomass available at previous level}} \times 100.

Carbon Cycle

The movement of carbon through photosynthesis, respiration, combustion, and decomposition.

Nitrogen Cycle

Processes including nitrogen fixation, nitrification, and denitrification to cycle nitrogen for protein synthesis.

Eutrophication

Nutrient runoff causes algae blooms, oxygen depletion, and death of aquatic life.

Global Warming

Climate change caused by increased levels of greenhouse gases (CO_{2}, methane) trapping infrared radiation.