National 5 Biology Unit 1: Cell Biology Flashcards

Vocabulary flashcards covering cell structure, organelles, cell types, staining, microscope calculation, diffusion, osmosis, and transport across cell membranes.

Total magnification formula

$$\text{Total magnification} = \text{eyepiece lens magnification} \times \text{objective lens magnification}$$

Iodine

A dye used to stain plant cells, such as onion epidermal cells, before viewing under a microscope.

Methylene blue

A dye used to stain animal cells, such as human cheek cells, before viewing under a microscope.

Nucleus

The part of the cell that controls activities of the cell.

Cytoplasm

The fluid region of the cell that serves as the site of chemical reactions.

Cell membrane

Structure consisting of phospholipids and proteins that controls the entrance and exit of materials.

Cell wall

Outer layer that provides shape and support to the cell; present in plant, fungal, and bacterial cells.

Cellulose

The material that makes up plant cell walls.

Vacuole

Organelle that contains cell sap and provides support to the cell.

Chloroplast

Green structure found in plant cell cytoplasm that is the site of photosynthesis.

Mitochondria

Organelles with two membranes (inner membrane folded) that are the main site of energy production inside cells.

Ribosomes

Small organelles attached to internal membranes or free in cytoplasm that are responsible for the synthesis of proteins.

Plasmids

Small circles of DNA found in bacterial cells.

Single circular chromosome

The genetic material structure present in bacterial cells instead of a discrete nucleus.

Diffusion

The passive movement of molecules down a concentration gradient from a region of high concentration to a region of lower concentration.

Passive process

A process that does not require cellular energy (such as diffusion or osmosis).

Osmosis

The movement of water through a selectively permeable membrane from a higher water concentration to a lower water concentration.

Selectively permeable membrane

A membrane that allows small molecules to pass through, but not large molecules.

Visking tubing

An artificial selectively permeable membrane used in experiments.

Turgid

The state of a plant cell when water enters by osmosis, causing the cytoplasm and vacuole to swell against the cell wall.

Plasmolysis

The process in which a plant cell loses water by osmosis in a concentrated solution, causing the membrane to pull away from the cell wall and the cytoplasm/vacuole to shrink.

Active transport

The movement of ions and molecules against the concentration gradient, requiring energy.

Channel proteins

Proteins located in the cell membrane that form channels involved in the transport of ions and molecules into and out of cells.