Cell Structure, Function, Microbes, and Specialisation

Vocabulary flashcards covering cell structure and organelles, plant vs animal cells, micro-organisms, cellular specialisation, tissues, organs, and levels of biological organisation.

Cell

The basic structural and functional unit of all living organisms.

Two basic types of cells

Prokaryotic cells and Eukaryotic cells

Unicellular Organism

An organism that is composed of a single cell.

Multicellular Organism

An organism composed of many cells that become specialised to carry out essential life processes efficiently.

Prokaryotic Cell

A simple single-celled organism that lacks a membrane-bound nucleus and membrane-bound organelles, with its genetic material floating in the cytoplasm in a nucleoid.

Eukaryotic Cell

A complex cell containing a distinct, membrane-bound nucleus and other membrane-bound organelles such as mitochondria and chloroplasts.

Organelles

Specialised structures found within the cytoplasm of cells that carry out one or more vital functions.

Protoplasm

The collective term referring to the cytoplasm and nucleus together within a cell.

Cell Membrane

A differentially permeable layer composed of protein and lipid around the outside of the cytoplasm that controls what enters and leaves and keeps cell contents inside the cell.

Cytoplasm

A jelly-like substance composed of about $80\%$ water and $20\%$ dissolved substances, especially protein, which supports organelles and serves as the site of many chemical reactions.

Nucleus

An organelle surrounded by a double membrane containing chromatin threads with genetic information in the form of DNA, which controls the characteristics and functioning of the cell and is essential for cell division.

Mitochondrion

A rod-shaped organelle with a smooth outer membrane and folded inner membrane containing respiratory enzymes, where aerobic respiration occurs to release energy for the cell.

Cell Wall

A freely permeable wall made of cellulose found in plant cells that supports, protects, and gives shape to the cell.

Chloroplast

A disc-shaped organelle surrounded by a double membrane containing internal membranes, chlorophyll, and photosynthetic enzymes, where photosynthesis occurs.

Vacuole (Animal Cell)

A small membrane-bound compartment containing water, food and cell waste/secretions.

Vacuole (Plant Cell)

A large membrane-bound compartment containing cell sap (a solution of sugars, mineral salts, amino acids, and waste products) that supports the cell when turgid.

Glycogen Granules

Food storage structures found in animal cells.

Starch Grains

Food storage structures found in plant cells.

Generalised Cell

Generalised Cell

Prokaryotae

The kingdom of single-celled micro-organisms that includes bacteria.

Capsule

A slimy outer covering found in some bacteria that protects the cell.

Nucleoid

A single, long, coiled loop of DNA in a bacterial cell that controls all cellular activities.

Plasmid

A small, circular piece of DNA found in bacterial cells.

Flagellum

A long, whip-like projection in a bacterial cell that aids in movement.

Generalised Bacterial Cell

A microscopic prokaryotic cell consisting of structures such as a capsule, cell wall, cell membrane, nucleoid, plasmid, cytoplasm, and flagellum.

Amoeba

A unicellular micro-organism of the kingdom Protoctista containing specialized structures like pseudopodia, food vacuoles, and a contractile vacuole.

Pseudopodium

An extension of the membrane and cytoplasm in an amoeba used to engulf food and for movement.

Food Vacuole

A structure in an amoeba that contains ingested microscopic organisms where digestion occurs.

Contractile Vacuole

A structure in an amoeba containing water that collects and removes excess water from the cytoplasm.

Cell Specialisation

The process by which cells in a multicellular organism differentiate to carry out specific functions efficiently.

Tissue

A group of specialized cells working together to carry out a particular function.

Epidermal Tissue

Plant tissue composed of sheets of flattened cells around the outside of leaves, young stems, and roots that protects plant surfaces.

Packing Tissue

Plant tissue composed of parenchyma cells with large vacuoles found inside stems and roots; fills spaces, supports non-woody plants when turgid, and stores food.

Photosynthetic Tissue

Plant tissue found mainly in leaves, composed of mesophyll cells containing chloroplasts, which makes food by photosynthesis.

Vascular Tissue

Plant tissue composed of xylem vessels and phloem sieve tubes with companion cells; transports water, mineral salts, and dissolved food while providing support.

Nerve Tissue

Animal tissue composed of nerve cells or neurones that conducts nerve impulses.

Muscle Tissue

Animal tissue composed of muscle cells that brings about movement on contraction.

Epithelial Tissue

Animal tissue composed of sheets of cells that covers and protects inner and outer surfaces of the body.

Connective Tissue

Animal tissue consisting of a variety of cells surrounded by extracellular material, including blood tissue and adipose tissue.

Adipose (fat) Tissue

A type of connective tissue composed of fat cells surrounded by extracellular material; insulates the body, serves as a food reserve, and acts as protective padding.

Areolar (loose connective) Tissue

A type of connective tissue composed of fibroblasts surrounded by a gelatinous material containing protein fibres. It holds the organs in place and attaches epithelial tissue to underlying tissues.

Blood tissue

A type of connective tissue composed of red blood cells, white blood cells and platelets surrounded by plasma that transports various substances around the body, like food and oxygen, and helps fight disease.

Organ

A structure formed from different tissues grouped together to perform one or more specific functions.

Organ System

A group of organs working together in an organized way to carry out complex biological functions within an organism.

Levels of Organisation

The structural hierarchy of multicellular organisms: cells $\rightarrow$ tissues $\rightarrow$ organs $\rightarrow$ organ systems $\rightarrow$ organism.