Cell Biology Glossary

Dividing Cell

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Many biology students often wonder about the meanings of certain biology terms and words. What is a nucleus? What are sister chromatids? What is the cytoskeleton and what does it do? The Cell Biology Glossary is a good resource for finding succinct, practical, and meaningful biology definitions for various cell biology terms. Below is a list of common cell biology terms.

Cell Biology Glossary

Anaphase - a stage in mitosis where chromosomes begin moving to opposite ends (poles) of the cell.

Animal Cells - eukaryotic cells that contain various membrane-bound organelles.

Allele - an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome.

Apoptosis - a controlled sequence of steps in which cells signal self-termination.

Asters - radial microtubule arrays found in animal cells that help to manipulate chromosomes during cell division.

Biology - the study of living organisms.

Cell - the fundamental unit of life.

Cellular Respiration - a process by which cells harvest the energy stored in food.

Cell Biology - the subdiscipline of biology that focuses on the study of the basic unit of life, the cell.

Cell Cycle - the life cycle of a dividing cell, including Interphase and the M phase or Mitotic phase (mitosis and cytokinesis).

Cell Membrane - a thin semi-permeable membrane that surrounds the cytoplasm of a cell.

Cell Theory - one of the five basic principles of biology, stating that the cell is the basic unit of life.

Centrioles - cylindrical structures that are composed of groupings of microtubules arranged in a 9 + 3 pattern.

Centromere - a region on a chromosome that joins two sister chromatids.

Chromatid - one of two identical copies of a replicated chromosome.

Chromatin - the mass of genetic material composed of DNA and proteins that condense to form chromosomes during eukaryotic cell division.

Chromosome - a long, stringy aggregate of genes that carries heredity information (DNA) and is formed from condensed chromatin.

Cilia and Flagella - protrusions from some cells that aid in cellular locomotion.

Cytokinesis - the division of the cytoplasm that produces distinct daughter cells.

Cytoplasm - all of the contents outside of the nucleus and enclosed within the cell membrane of a cell.

Cytoskeleton - a network of fibers throughout the cell's cytoplasm that helps the cell maintain its shape and gives support to the cell.

Cytosol - semi-fluid component of a cell's cytoplasm.

Daughter Cell - a cell resulting from the replication and division of a single parent cell.

Daughter Chromosome - a chromosome that results from the separation of sister chromatids during cell division.

Diploid Cell - a cell that contains two sets of chromosomes—one set of chromosomes is donated from each parent.

Endoplasmic Reticulum - a network of tubules and flattened sacs that serve a variety of functions in the cell.

Gametes - reproductive cells that unite during sexual reproduction to form a new cell called a zygote.

Gene Theory - one of the five basic principles of biology, stating that traits are inherited through gene transmission.

Genes - segments of DNA located on chromosomes that exist in alternative forms called alleles.

Golgi Complex - the cell organelle that is responsible for manufacturing, warehousing, and shipping certain cellular products.

Haploid Cell - a cell that contains one complete set of chromosomes.

Interphase - the stage in the cell cycle where a cell doubles in size and synthesizes DNA in preparation for cell division.

Lysosomes - the membranous sacs of enzymes that can digest cellular macromolecules.

Meiosis - a two-part cell division process in organisms that sexually reproduce, resulting in gametes with one-half the number of chromosomes of the parent cell.

Metaphase - the stage in cell division where chromosomes align along the metaphase plate in the center of the cell.

Microtubules - fibrous, hollow rods that function primarily to help support and shape the cell.

Mitochondria - cell organelles that convert energy into forms that are usable by the cell.

Mitosis - a phase of the cell cycle that involves the separation of nuclear chromosomes followed by cytokinesis.

Nucleus - a membrane-bound structure that contains the cell's hereditary information and controls the cell's growth and reproduction.

Organelles - tiny cellular structures, that carry out specific functions necessary for normal cellular operation.

Peroxisomes - cell structures that contain enzymes that produce hydrogen peroxide as a by-product.

Plant Cells - eukaryotic cells that contain various membrane-bound organelles. They are distinct from animal cells, containing various structures not found in animal cells.

Polar Fibers - spindle fibers that extend from the two poles of a dividing cell.

Prokaryotes - single-celled organisms that are the earliest and most primitive forms of life on earth.

Prophase - the stage in cell division where chromatin condenses into discrete chromosomes.

Ribosomes - cell organelles that are responsible for assembling proteins.

Sister Chromatids - two identical copies of a single chromosome that are connected by a centromere.

Spindle Fibers - aggregates of microtubules that move chromosomes during cell division.

Telophase - the stage in cell division when the nucleus of one cell is divided equally into two nuclei.