Biology IGCSE Flashcards

Flashcards on cell structure, biological molecules, plant nutrition, diseases and immunity, respiration, and other topics.

Cytoplasm

A jelly-like material within the cell in which reactions occur.

Cell membrane

A thin membrane that surrounds the cell, controls entry and exit of substances.

Nucleus

Contains genetic material in the form of DNA which codes for proteins and is the site of DNA replication.

Ribosomes

The site of protein synthesis.

Mitochondria

Site of respiration, provides energy for the cell to function.

Vacuole

A fluid-filled sac containing mineral salts, sugars, amino acids, waste substances and pigments which colour the cell and attract pollinating insects.

Chloroplasts

The site of photosynthesis, which converts light energy to glucose.

Cell wall

Gives the cell structure and prevents bursting; made of cellulose.

Cilia

Hair-like projections that move together to transport mucus, dust, and bacteria upwards to the throat.

Root hair cells

Adapted to have a large surface area to speed up the rate of osmosis and mineral ion uptake in plants.

Palisade mesophyll cells

Where photosynthesis occurs; tall and closely packed to efficiently absorb light and contain lots of chloroplasts.

Neurones

Adapted to rapidly transmit electrical impulses and are myelinated for insulation.

Red blood cells

Contain haemoglobin to carry oxygen and have a biconcave shape to increase surface area for rapid diffusion.

Sperm cells

Gametes containing lots of mitochondria, a tail for movement, and digestive enzymes to penetrate the egg cell membrane.

Egg cells

Gametes with nutrients in their cytoplasm and a membrane that changes after fertilisation to prevent more sperm from entering.

Cell

The basic building block of all living organisms.

Tissue

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

Organ

A group of tissues working together to carry out a specific function.

Organ system

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

Carbohydrates

Molecules made up of many sugar molecules, containing carbon, hydrogen and oxygen atoms.

Cellulose

Used for structure and makes up plant cell walls.

Starch and Glycogen

Stored in cells and used in respiration to provide energy for the organism.

Fats and oils

Made up of glycerol and fatty acids, containing carbon, hydrogen and oxygen, and have roles in insulation and energy.

Proteins

Made up of nitrogen, carbon, hydrogen, oxygen and sulphur, which make up amino acids that bind together to make this.

DNA

Composed of two strands coiled around each other to form a double helix, with a sugar backbone and bases attached.

Photosynthesis

A metabolic reaction occurring in plants in which light energy converts raw materials into carbohydrates.

Nitrate ions

Used in the plant to build amino acids, proteins and enzymes.

Magnesium ions

Used to make chlorophyll.

Stomata

Located on the lower side of the leaf, allow carbon dioxide in and water vapour and oxygen out of the leaf by diffusion.

Xylem

Transport water through plants from the roots in transpiration.

Phloem

Used to transport sugars and food nutrients in translocation.

Transpiration

Loss of water vapour from the leaves due to evaporation.

Translocation

Occurs in the phloem vessels and involves the transport of amino acids and sucrose from sources to sinks.

Pathogen

An organism that causes disease.

Active transport

The movement of molecules against a concentration gradient using energy from respiration.