Anat Lecture, Cells

Endoplasmic reticulum (ER)

A network of intracellular membrane-bound tunnels. Enclosed spaces are called cisternae.

Cisternae

Enclosed spaces within the endoplasmic reticulum.

Smooth endoplasmic reticulum (SER)

Site of lipid synthesis and carbohydrate metabolism; functions include synthesis, transport, and storage of lipids and detoxification of drugs/poisons.

Rough endoplasmic reticulum (RER)

Has ribosomes attached to its outer surface; synthesizes, transports, or stores proteins for secretion, incorporation into the plasma membrane, and creation of lysosomes.

Ribosome

Synthesizes proteins. Ribosomes can be free in the cytosol or fixed to the outer surface of the RER.

Golgi apparatus

Stacked cisternae whose lateral edges bulge, pinch off, and give rise to small transport and secretory vesicles. Receives proteins and lipids from the ER for modification, sorting, and packaging.

Lysosome

Vesicles generated by the Golgi apparatus; contain enzymes used to digest and remove waste products and damaged organelles within the cell.

Autophagy

Digestion and removal of waste products and damaged organelles within the cell by lysosomal enzymes.

Autolysis

When a dying cell releases lysosomal enzymes that digest the cell.

Mitochondria

Bean-shaped organelles with a double membrane; produce ATP. Cells requiring more energy have more mitochondria.

Cytoskeleton

Proteins organized in the cytosol as solid filaments or hollow tubes.

Microfilaments

One of the three main protein types of the cytoskeleton.

Intermediate filaments

One of the three main protein types of the cytoskeleton.

Microtubules

One of the three main protein types of the cytoskeleton; involved in structures such as centrioles, cilia, flagella, and spindle fibers.

Centrosome

A pair of centrioles at right angles to each other.

Centriole

Nine sets of microtubule triplets; involved in organizing microtubules and attached to chromosomes during cell division, causing chromosomal migration.

Cilia

Grouped cell projections containing cytoplasm and microtubules capable of movement; move objects across the cell surface.

Flagella

Longer, usually singular cell projections containing cytoplasm and microtubules; propel a cell.

Chromatin

Nuclear DNA unwound into fine filaments when the cell is not dividing.

Chromosome

Chromatin coils tightly to form chromosomes during cell division.

Gene

Stretches of DNA that code for proteins.

Interphase

Maintenance (resting) phase between cell divisions; normal activities and preparation for cell division occur. Cells spend most of their life in this stage.

Mitotic phase

When the cell divides.

G1 phase

Cells grow and replicate organelles and centrioles just prior to cell division.

G0

Nondividing cells, such as neurons, remain arrested in G0.

S phase

Nondividing cells, such as neurons, remain arrested in G0.

S phase

“Synthesis” phase where DNA replicates.

G2 phase

Centriole replication is completed; final stage just before mitosis.

Mitosis

Division of the nucleus/DNA.

Cytokinesis

Division of the cytoplasm and the mother cell.

Daughter cells

Two cells produced by mitotic cell division that are genetically identical to the original (mother) cell.

PMAT

The four consecutive stages of mitosis: Prophase, Metaphase, Anaphase, Telophase.

Prophase

Chromatin supercoils forming chromosomes; sister chromatids are conjoined at the centromere; spindle fibers begin to grow; nuclear envelope breaks down at the end.

Sister chromatids

Duplicate, identical chromatids conjoined at a region called the centromere.

Centromere

Region where duplicate, identical sister chromatids are conjoined; spindle fibers attach to it during metaphase.

Spindle fibers

Elongated microtubules that grow from each centriole during prophase and pull sister chromatids apart during anaphase.

Metaphase

Chromosomes line up along the equatorial plate; spindle fibers attach to the centromere of sister chromatids.

Equatorial plate

Location along which chromosomes line up during metaphase.

Mitotic spindle

Oval structure array formed by spindle fibers attaching to the centromeres of sister chromatids.

Anaphase

Spindle fibers pull sister chromatids apart to opposite ends of the dividing cell.

Telophase

A pinched area that appears during telophase and will complete the physical division of the daughter cells.