cell and nuclear division pt. 2

This set of flashcards contains essential vocabulary related to cell and nuclear division, including terms from genetics, cell growth, cancer, and plant biology.

Non-disjunction

The failure of chromosomes to separate and move to the appropriate poles of the cell during nuclear division.

Down Syndrome

A genetic disorder caused by an extra chromosome on chromosome #21, resulting in a total of 47 chromosomes.

Trisomy

A condition in which there is an extra copy of a chromosome.

Crossing-over

A process during meiosis where homologous chromosomes exchange DNA segments, creating genetic variation.

Chiasma

The point where crossing-over occurs between non-sister chromatids during meiosis.

Random Orientation

The random arrangement of homologous chromosomes during meiosis I that results in genetic variation among gametes.

Meristem

A region in plants composed of undifferentiated cells capable of dividing by mitosis, allowing for growth.

Apical Meristem

The region at the tips of roots and stems responsible for primary growth in plants.

Lateral Meristem

Meristems located in the vascular bundles that contribute to secondary growth, increasing the girth of stems.

Zygote

The fertilized egg formed from the union of sperm and egg, which divides to form an embryo.

Cell Proliferation

The increase in the number of cells through cell division, necessary for growth and tissue repair.

Cyclins

Regulatory proteins that control the cell cycle by activating cyclin-dependent kinases (CDKs).

Oncogenes

Mutated proto-oncogenes that can lead to uncontrolled cell division and cancer.

Tumor-suppressor genes

Genes that encode for proteins that inhibit cell division; their mutation can result in uncontrolled cell division.

Mitotic Index

A measure of the proportion of cells in a sample that are undergoing mitosis; used to assess tumor growth.

Metastasis

The process by which cancer cells spread from the primary tumor to other parts of the body, forming secondary tumors.

Benign Tumor

A non-cancerous growth that does not spread to other body parts.

Malignant Tumor

A cancerous growth that spreads quickly, destroying nearby tissue.