SNC 2D Biology: Cell Division, Mitosis, and Specialized Tissues

Comprehensive vocabulary flashcards covering the cell cycle, mitosis stages, cell differentiation, plant tissues, animal tissues, and cancer development from SNC 2D Biology.

Cell Theory

The biological principle stating that: 1) all living organisms are made of one or more cells, 2) the cell is the basic organizational unit of life, and 3) all cells come from pre-existing cells.

Hierarchy of Cell Organization

The structural levels of organization in multicellular organisms: Cell $\rightarrow$ Tissue $\rightarrow$ Organ $\rightarrow$ Organ Systems.

Cell Division

The process by which a parent cell divides into two daughter cells; used for reproduction in single-celled organisms, and for growth, repair/healing, and replacement of old or lost cells in multicellular organisms.

Interphase

The phase comprising approximately $90\%$ of the cell cycle, divided into three stages: $G_1$ phase, $S$ phase, and $G_2$ phase.

$G_1$ Phase

The stage of interphase where the cell grows and conducts regular metabolic activities, such as taking in oxygen and nutrients and removing waste.

$S$ Phase

The synthesis stage of interphase during which DNA replication occurs and uncoiled chromatin duplicates from $46$ to $92$ chromatids.

Chromatin

Uncoiled genetic information located within the nucleus of a cell that condenses into chromosomes at the end of interphase.

Sister Chromatids

Duplicated chromosomes that are held together by a centromere.

Centromere

The central structure that joins duplicated sister chromatids together.

$G_2$ Phase

The final stage of interphase where the cell continues to grow, doubles all other organelles (such as mitochondria and ribosomes), and prepares for cell division.

Mitosis

The division of the cell nucleus, consisting of four distinct stages: Prophase, Metaphase, Anaphase, and Telophase (PMAT).

Prophase

The first stage of mitosis during which the nucleolus and nuclear membrane disappear, centrioles move to opposite poles, and spindle fibres form and attach to each side of the centromere.

Metaphase

The second stage of mitosis in which spindle fibres align the sister chromatids along the middle (equator) of the cell.

Anaphase

The third stage of mitosis where spindle fibres contract, pulling sister chromatids apart toward opposite poles of the cell.

Telophase

The final stage of mitosis where complete sets of chromosomes arrive at opposite poles, spindle fibres disappear, a nucleolus and nuclear membrane re-form for each nucleus, and chromosomes uncoil back to chromatin.

Cytokinesis

A separate process from mitosis involving the physical division of cell material, including cytoplasm and organelles, into two daughter cells.

Cleavage Furrow

The structure formed during cytokinesis in animal cells when the cell membrane pinches inward to divide the cell in two.

Cell Plate

The structure that develops across the middle of a plant cell during cytokinesis, which subsequently leads to the formation of a new cell wall.

Cell Cycle Checkpoints

Three critical points in the cell cycle where specialized proteins check cell growth; they halt the cycle if nutrients are lacking ($G_1$), DNA hasn't replicated ($S$), or DNA is damaged.

Apoptosis

Programmed or intentional cell death triggered when a cell does not receive the signal to proceed or has irreparable damage.

Cell Lifespans

The specific survival duration of distinct cell types: skin cells ($20\text{ days}$), stomach lining cells ($2\text{ days}$), red blood cells ($120\text{ days}$), and brain cells ($30\text{ to }50\text{ years}$).

Stem Cells

Unspecialized cells capable of replicating themselves or differentiating into various specialized cell types.

Totipotent Stem Cells

Early embryonic stem cells (present from conception to day $5$) capable of developing into any cell type in the body.

Pluripotent Stem Cells

Embryonic stem cells present from day $5$ until birth that can differentiate into many, but not all, cell types.

Adult Stem Cells

Stem cells present late in development and after birth that can only produce specific types of cells (e.g., skin stem cells producing only skin repair cells).

Cell Differentiation

A developmental stage in a living organism during which specialized cells form.

Cell Specialization

The biological process in which cells develop from similar cells into cells with specific structures and functions in a multicellular organism.

Meristematic Cells (Meristem)

Unspecialized plant cells responsible for continuous growth by constantly producing cells that develop into specialized plant tissues.

Dermal Tissue

The outermost covering of plant organs that acts as a protective barrier and regulates the exchange of water and gases ($CO_2$ and $O_2$).

Ground Tissue

Plant tissue consisting of cells specialized for performing photosynthesis as well as cells with thick walls that provide structural support.

Vascular Bundle

Plant transport structure composed of xylem tissue (transports water and minerals upward from roots to leaves) and phloem tissue (transports sugars from leaves throughout the plant).

Xylem Cells

Dead, tubular cells arranged end to end that conduct water and minerals upward from plant roots to other parts of the plant.

Phloem Cells

Living, tubular cells joined end to end that transport sugars produced in the leaves to other parts of the plant.

Epithelial Tissue

Animal tissue lining body surfaces and internal organs; includes skin epithelia (semi-permeable barrier sheets) and columnar epithelia (columns lining the small intestine and stomach).

Muscle Tissue

Contractile animal tissue designed to shorten and lengthen for movement; categorized into skeletal muscle (voluntary movement), smooth muscle (slow, sustained movement in organ walls), and cardiac muscle (contracts as a unit in the heart).

Nervous Tissue

Tissue composed of neurons possessing large nuclei and long, finger-like projections that rapidly send and receive signals to and from the brain and spinal cord.

Connective Tissue

Tissue providing strength, support, and protection; includes bone (surrounded by calcium), adipose tissue (fat cells for insulation and energy), and blood tissue (red blood cells for oxygen transport and white blood cells for defense).

Tumor

A build-up or mass of abnormal cells formed when mutated cells bypass cell cycle checkpoints and divide uncontrollably at an accelerated rate.

Metastasis

The biological process in which cancer cells break away from an initial site and spread to other parts of the body.

Carcinogens

Environmental factors that induce cancerous mutations in cellular DNA, such as asbestos, tobacco, and UV radiation.