Cell Membranes, Transport, and the Mitotic Cell Cycle

A set of vocabulary flashcards covering cell transport mechanisms, membrane structure, the mitotic cell cycle, and the development of cancer based on the lecture notes.

Diffusion

The net movement of molecules or ions from a region of their higher concentration to a region of lower concentration.

Facilitated diffusion

The movement of ions and polar molecules through membranes aided by transport proteins.

Osmosis

The diffusion of water from a region of higher water potential to a region of lower water potential through a partially permeable membrane.

Protoplast

The living contents of a plant cell, including the cell surface membrane but excluding the cell wall.

Turgid

The state of a plant cell when it is fully inflated with water and the cell wall resists further expansion.

Plasmolysis

The process where a plant cell loses water to the point that the protoplast shrinks away from the cell wall.

Incipient plasmolysis

The point at which the protoplast no longer exerts any pressure on the cell wall and plasmolysis is about to occur.

Fluid mosaic model

The basic structure of a membrane, about $7\,nm$ thick, consisting of a phospholipid bilayer with proteins scattered throughout.

Cholesterol

A molecule in the cell membrane needed for maintaining membrane fluidity and stability.

Cell signaling

The means by which cells communicate with each other, often involving receptors formed by glycolipids and glycoproteins.

Active transport

The movement of ions or molecules across a membrane against the concentration gradient, requiring a carrier protein and ATP.

Endocytosis

A form of bulk transport where materials are moved into the cell by the formation of vacuoles.

Exocytosis

A form of bulk transport where materials are moved out of the cell via vacuoles.

Phagocytosis

A type of endocytosis frequently described as cell eating.

Pinocytosis

A type of endocytosis frequently described as cell drinking.

Telomeres

Protective sequences of nucleotides at the ends of chromosomes that prevent the loss of genes during DNA replication.

Telomerase

An enzyme that can replenish telomeres, often active in cancer cells to make them immortal.

Interphase

The period of the cell cycle between divisions, consisting of the $G_1$, $S$, and $G_2$ phases.

S phase

The stage of interphase during which DNA replication occurs and chromosomes are doubled.

Mitosis (M phase)

The process of nuclear division that produces two genetically identical nuclei.

Cytokinesis

The division of the cytoplasm and the whole cell following nuclear division.

Centrosome

An organelle in animal cells that acts as a microtubule organising centre ($MTOC$) to produce the spindle during mitosis.

Kinetochore

A protein structure found at the centromere of a chromatid to which microtubules attach during nuclear division.

Stem cells

Cells that retain the ability to divide and differentiate into specialized cell types.

Metastasis

The spread of cancer cells through the blood and lymphatic system to form secondary growths in other parts of the body.

Carcinogens

Factors or substances that cause mutations leading to the development of cancer, such as UV light or tobacco smoke tar.

Oncogenes

Genes that can be transformed by carcinogens to cause uncontrolled cell division and tumor growth.