Replication & Division of Nuclei & Cells

Comprehensive vocabulary flashcards covering chromosome structure, mitosis, the cell cycle, telomeres, stem cells, and tumour formation based on the CIE AS Biology curriculum.

Histones

Large positively charged globular proteins in eukaryotic cells that host DNA to organize and condense it tightly into the nucleus.

Chromatin

The tightly coiled combination of DNA and histone proteins that forms chromatids and chromosomes.

Centromere

The narrow region that joins two identical strands of DNA, known as chromatids, together.

Sister Chromatids

The two identical strands of DNA that make up the double structure of a chromosome after replication.

Telomeres

Protective structures at the ends of chromatids made of non-coding DNA with multiple repeat sequences that prevent the loss of genes during replication.

Mitosis

The process of nuclear division by which two genetically identical daughter nuclei are produced from a parent nucleus.

Meristems

The specific growing points in plants where growth by mitosis is confined.

Asexual Reproduction

The production of new individuals of a species by a single parent organism, resulting in genetically identical offspring.

Cell Cycle

The regulated sequence of events occurring between one cell division and the next, comprising interphase, nuclear division (mitosis), and cell division (cytokinesis).

Cyclins

Chemical signals that trigger the movement of a cell from one phase of the cell cycle to another.

Interphase

The phase of the cell cycle consisting of $G_1$, $S$, and $G_2$ phases, during which the cell increases in mass and replicates its DNA.

$G_1$ Phase

The first gap phase of interphase where the cell makes RNA, enzymes, and proteins required for growth.

S Phase

The synthesis phase of interphase during which DNA replication occurs to produce identical sister chromatids.

$G_2$ Phase

The second gap phase of interphase where the cell checks new DNA for errors and produces tubulin protein for microtubules.

Cytokinesis

The final stage of the cell cycle following mitosis where the whole cell divides into two daughter cells.

Stem Cell

A cell that can divide by mitosis an unlimited number of times and has the potential to remain a stem cell or differentiate into a specialized cell.

Differentiation

The process through which a stem cell develops into a specialized cell, such as a blood cell or muscle cell.

Potency

The ability of stem cells to differentiate into more specialized cell types.

Multipotent Adult Stem Cells

Stem cells found in adults that can produce an unlimited number of cells but are restricted to a limited range of cell types, such as bone marrow stem cells.

Mutation

A change in any gene; if occurring in genes controlling cell division, it can lead to cancer.

Oncogene

A mutated gene that specifically causes cancer.

Carcinogen

Any agent that may cause cancer, including UV light, tar in tobacco smoke, X-rays, and certain viruses (oncoviruses).

Benign Tumour

An irregular mass of cells that does not spread from its original site and is not considered cancerous.

Malignant Tumour

A cancerous mass of cells that invades and destroys other tissues and can spread to form secondary growths.

Metastasis

The process by which malignant tumour cells break off and travel through the blood or lymphatic system to form secondary cancers in other parts of the body.