Biology: Characteristics of Living Organisms and Cell Structures

These flashcards cover key concepts and vocabulary related to the characteristics of living organisms, cell structure, biological processes, and ecological cycles.

MRS GREN

A mnemonic for the characteristics of living organisms: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

Chloroplast

An organelle found in plant cells that conducts photosynthesis, converting solar energy into chemical energy.

Cell Wall

A rigid outer layer of plant cells that provides support and protection.

Mitochondria

Organelles that are the powerhouse of the cell, where energy production occurs through respiration.

Ribosomes

Cellular structures that synthesize proteins by translating messenger RNA.

Vacuole

A storage organelle in cells, larger in plant cells, used for storing nutrients and waste products.

Diffusion

The process of movement from an area of higher concentration to an area of lower concentration, requiring no energy.

Osmosis

The movement of water across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Active Transport

The movement of molecules across a membrane from a region of lower concentration to a region of higher concentration, requiring energy.

Photosynthesis

The process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight.

Cellular Respiration

The metabolic process in which cells convert sugar into energy, producing carbon dioxide and water as byproducts.

Nitrogen Fixation

The conversion of atmospheric nitrogen (N₂) into a usable form (ammonium, NH₄) by bacteria.

Food Chain

A linear sequence of organisms through which nutrients and energy pass as one organism eats another.

Cell Differentiation

The process by which a less specialized cell becomes a more specialized cell type.

Specialized Cells

Cells that have developed specific structures and functions to perform particular tasks within an organism.

Bacteria

Single-celled microorganisms that can be beneficial or pathogenic; an example of a microbe.

Virus

A microscopic entity that requires a host cell to replicate and is not classified as fully living.