IBDP Biology A2.2 Cell Structure

70S Ribosome

A type of ribosome found in prokaryotic cells, composed of 50S and 30S subunits.

80S Ribosome

A type of ribosome found in eukaryotic cells, composed of 60S and 40S subunits.

Animal

Multicellular, eukaryotic organisms that are heterotrophic and typically have specialized tissues.

Aseptate Fungal Hyphae

Fungal filaments that lack septa, allowing for continuous cytoplasmic flow.

Capsule

A protective layer surrounding some bacteria, providing defense against phagocytosis.

Deductive Reasoning

A logical process where conclusions are drawn from general principles or premises.

Cell Specialization

The process by which generic cells evolve to perform specific functions.

Cell Theory

The scientific theory that all living organisms are composed of cells, and cells are the basic unit of life.

Cell Wall

A rigid outer layer found in plant cells, fungi, and bacteria that provides structural support.

Centriole

A cylindrical organelle involved in cell division, found in animal cells.

Chlamydomonas

A genus of green algae that are unicellular and often used in research.

Chloroplast

An organelle found in plant cells that conducts photosynthesis.

Chromosome

A structure made of DNA and proteins that contains genetic information.

Cilia

Short, hair-like structures on the surface of some cells that aid in movement.

Cryogenic Electron Microscopy

A technique for imaging frozen samples at very low temperatures using electron microscopy.

Cytoplasm

The gel-like substance within a cell, excluding the nucleus, where organelles are suspended.

Cytoskeleton

A network of fibers that helps maintain cell shape and aids in movement.

Differentiation

The process by which cells become specialized in structure and function.

Deoxyribonucleic Acid (DNA)

The molecule that carries genetic information in living organisms.

Electron Microscope

A type of microscope that uses electrons to create high-resolution images of specimens.

Endosymbiosis

A theory that explains the origin of eukaryotic cells from prokaryotic organisms through symbiotic relationships.

Eukaryote

An organism whose cells have a nucleus enclosed within membranes.

Excretion

The process of removing waste products from the body.

Eyepiece Graticule

A scale or measuring device placed in the eyepiece of a microscope.

Field of View

The extent of the observable area seen through a microscope.

Flagellum

A long, whip-like structure that enables some cells to swim.

Freeze-Fracture

A technique used to study the structure of cell membranes by freezing and fracturing them.

Fungus/Fungi

A kingdom of usually multicellular organisms that absorb nutrients from their environment.

Gene Expression

The process by which information from a gene is used to synthesize a functional gene product.

Golgi Apparatus

An organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery.

Gram Positive

Bacteria that retain the crystal violet stain used in the Gram staining procedure.

Growth

The increase in size or number of cells in an organism.

Histone

A type of protein that helps package and order DNA into structural units called nucleosomes.

Homeostasis

The ability of an organism to maintain a stable internal environment despite external changes.

Immunofluorescence

A technique used to visualize the location of proteins or antigens in cells using fluorescently labeled antibodies.

Inductive Reasoning

A logical process where generalizations are made based on specific observations.

Light Microscope

An optical instrument that uses visible light to magnify images of small samples.

Lysosome

An organelle that contains digestive enzymes to break down waste materials and cellular debris.

Magnification

The process of enlarging the appearance of an object using lenses.

Metabolism

The set of life-sustaining chemical reactions that occur in living organisms.

Microfilaments

The thinnest filaments of the cytoskeleton, involved in cell movement and shape.

Micrograph

A photograph taken through a microscope.

Microtubule

A component of the cytoskeleton that helps maintain cell shape and is involved in cell division.

Microvilli

Small, finger-like projections on the surface of some cells that increase surface area.

Mitochondrion

An organelle known as the powerhouse of the cell, responsible for producing energy.

Movement

The ability of an organism or cell to change position or location.

Multicellular

Organisms composed of multiple cells that work together.

Naked DNA

DNA that is not associated with histones or proteins.

Nucleoid

The region in prokaryotic cells where the genetic material is located, not enclosed by a membrane.

Nucleus

The membrane-bound organelle that contains the cell's genetic material.

Nutrition

The process by which organisms obtain and utilize food for energy and growth.

Objective Lens

The lens in a microscope closest to the specimen, responsible for magnification.

Ocular Lens

The lens in a microscope that is closest to the eye.

Organelle

Specialized structures within a cell that perform distinct processes.

Paramecium

A genus of unicellular ciliated protozoa commonly found in freshwater environments.

Phloem Sieve Tube Element

A type of cell in plants that transports sugars and nutrients.

Pili

Hair-like structures on the surface of bacteria that help with attachment to surfaces.

Plant

Multicellular, eukaryotic organisms that perform photosynthesis and have cell walls.

Plasma Membrane

The semipermeable membrane surrounding the cytoplasm of a cell.

Plasmid

A small, circular piece of DNA found in bacteria that can replicate independently.

Plastid

An organelle found in plant cells that is involved in the synthesis and storage of food.

Prokaryote

An organism whose cells lack a nucleus and other membrane-bound organelles.

Quantitative

Data or information that can be measured and expressed numerically.

Red Blood Cell

A type of blood cell that carries oxygen from the lungs to the body and carbon dioxide back to the lungs.

Reproduction

The biological process by which new individual organisms are produced.

Resolution

The ability of a microscope to distinguish between two points that are close together.

Response

The reaction of an organism to a stimulus.

Ribosome

A molecular machine that synthesizes proteins by translating messenger RNA.

Rough Endoplasmic Reticulum

A type of endoplasmic reticulum studded with ribosomes, involved in protein synthesis.

Scale

A system of measurement used to represent the size of objects in relation to one another.

Skeletal Muscle Fibre

A type of muscle cell that is striated and under voluntary control.

Smooth Endoplasmic Reticulum

A type of endoplasmic reticulum that is involved in lipid synthesis and detoxification.

Ultrastructure

The detailed structure of a biological specimen that can only be observed at high magnification.

Unicellular

Organisms composed of a single cell.

Vacuole

A membrane-bound organelle in cells that stores nutrients and waste products.

Vesicle

A small membrane-bound sac that transports materials within a cell.

Wet Mount

A method of preparing a specimen for microscopic examination by placing it in a drop of liquid.