Cell Biology: Levels of Organization, Cell Theory, and Cell Structure

Vocabulary flashcards covering characteristics of living things, historic and modern cell theory, levels of biological organization, organelles, and differences between prokaryotic and eukaryotic cells based on lecture notes.

MR. GRAEA

A mnemonic representing the seven characteristics of living things: Made of cells, Respond to stimuli, Grow and develop, Reproduce, Acquire materials and energy, Excrete waste, and Adapt.

Cell

The smallest unit that can carry out all life processes, often referred to by scientists as the basic building block of life.

Robert Hooke

English scientist who built an improved microscope in 1665, observed thin slices of cork, and named the structures he saw 'cells' after the Latin word for storeroom or chamber.

Matthias Schleiden

Botanist who studied plants and contributed to the cell theory in 1838 by concluding that living things are made of one or more cells.

Theodor Schwann

Zoologist who studied animals and contributed to the cell theory in 1839 by concluding that living things are made of one or more cells.

Rudolf Virchow

German physician and scientist who stated in 1855 that all cells divide and come from pre-existing cells.

Unicellular Organisms

Organisms made up of only a single cell that carries out all functions of life, such as Amoeba, Euglena, Paramecium, and bacteria.

Multicellular Organisms

Organisms made up of more than one cell where specialized cells work together to sustain life, such as humans, birds, fish, trees, and spiders.

Stimulus

Any internal or external environmental change that triggers a reaction in an organism, including light, temperature, touch, sound, gravity, or chemicals.

Response

An action taken by an organism following a stimulus to protect itself, acquire resources, or maintain homeostasis.

Adaptations

Inherited structural, behavioural, or physiological characteristics that increase an organism's chances of survival.

Eukaryote

Any organism consisting of one or more cells that contain DNA enclosed within a membrane-bound nucleus and specialized organelles, including plants, animals, fungi, and protists.

Prokaryote

A simpler organism, usually single-celled, whose DNA is suspended freely in the cytoplasm and which lacks membrane-bound organelles such as a nucleus, ER, and Golgi apparatus.

Nucleus

The control centre of the cell that contains DNA (Deoxyribonucleic acid) required for cell functioning.

Nucleolus

A structure located inside the nucleus that makes ribosomes.

Nuclear Pores

Openings on the nuclear envelope that allow materials to move in and out of the nucleus.

Cell Membrane

A protective outer structure that surrounds the cell and controls the movement of substances, such as water, into and out of the cell.

Cytoplasm

A jelly-like material containing organelles that supports internal cell structures and distributes materials like food and oxygen throughout the cell.

Rough Endoplasmic Reticulum (rER)

Endoplasmic reticulum studded with ribosomes that functions in protein synthesis and transports newly assembled proteins to the Golgi apparatus.

Smooth Endoplasmic Reticulum (sER)

Endoplasmic reticulum without ribosomes that functions in producing fats.

Golgi Apparatus

Flattened stacks of membranes that separate proteins according to destination, modify them for quality control, and package materials into vesicles for export.

Lysosomes

Organelles whose name means 'kill body' in Latin that digest food molecules, cell wastes, and worn-out cell parts.

Mitochondria

Organelles known as the powerhouse of the cell because they release energy from food.

Ribosomes

Organelles that float freely in the cytoplasm or attach to the rough ER to produce proteins.

Chloroplasts

Organelles present in green plants and some unicellular organisms that serve as the site of photosynthesis, using carbon dioxide, water, and light energy to produce sugars.

Chlorophyll

A green pigment inside chloroplasts that absorbs sunlight energy to produce glucose during photosynthesis.

Permanent Vacuole

A plant cell organelle that holds sap to keep the cell firm and turgid.

Cell Wall

A structure in plant cells and bacteria that physically protects the contents, provides structural support, and contains pores connecting cytoplasm between adjacent cells.

Starch Granules

Structures formed in plant cells when simple glucose sugars produced by photosynthesis are linked together.

Capsule

A mucous-like protective outer layer surrounding many pathogenic bacteria that shields them from host immune systems and viruses.

Flagella

Long helical tubes extending out of the cell wall of some prokaryotic cells that rotate to provide locomotion.

Cilia

Hair-like projections on cells that beat to create fluid currents or sense surroundings.