Cell Biology and the Cell Cycle Lecture Notes

Sixty vocabulary flashcards based on lecture notes covering cell types, organelles, prokaryotes, eukaryotes, the cell cycle, and stem cells.

Somatic cells

Body cells that contain two copies of the genome and are described as diploid.

Diploid

A state of having two copies of the genome, characteristic of somatic cells.

Germ cells

Sperm and egg cells that contain one copy of the genome.

Haploid

A state of having one copy of the genome, characteristic of germ cells.

Stem cells

Diploid cells that divide to give rise to differentiated cells and replicate themselves.

Self-renewal

The process by which stem cells replicate themselves to continue their lineage.

Macromolecules

The chemical constituents that compose cells, including carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Sugars and starches that provide energy and contribute to the structural integrity of the cell.

Lipids

Fats and oils that form the basis of membranes and hormones, provide insulation, and store energy.

Proteins

Molecules that enable blood clotting and form the bulk of connective tissue; some act as enzymes.

Enzymes

Proteins that catalyze biochemical reactions necessary to sustain life.

Nucleic Acids

$DNA$ and $RNA$ that translate information from past generations into proteins that define cell characteristics.

Nucleus

The genetic headquarters of the cell contained within a nuclear envelope.

Nuclear envelope

The two membrane layers that enclose the nucleus.

Nuclear pores

Openings in the nuclear envelope that allow specific molecules to move in and out of the nucleus.

Plasma membrane

A phospholipid bilayer that forms the selective structural backbone of the cell.

Phospholipids

The molecules that aggregate to form the bilayer of the plasma membrane.

Hydrophilic

The outer layer of the cell membrane that is attracted to water.

Hydrophobic

The inner region of the cell membrane that blocks the entry and exit of most water-soluble substances.

Signal transduction

A process where molecules form pathways to detect external signals and transmit them into the cell.

Cellular adhesion

A process in which the cell membrane assists cells in attaching to other cells.

Cytoskeleton

A meshwork of protein rods and tubules that provides a cell's architecture, 3D shape, and organelle positioning.

Microtubules

One of the three major types of cytoskeleton elements distinguished by protein type and diameter.

Microfilaments

One of the three major components of the cytoskeleton meshwork.

Intermediate filaments

Cytoskeleton components that help create a framework for cell strength and resistance to force.

Prokaryotes

Small living cells, such as bacteria, that lack membrane-bound organelles and a nucleus.

Flagella

External whip-like structures used by some prokaryotic cells for locomotion.

Pili

Hair-like external structures on some prokaryotic cells used for adhesion.

Cocci

Prokaryotic cells that are round in shape.

Bacilli

Prokaryotic cells that are rod-shaped.

Spirilla

Prokaryotic cells characterized by a helical or spiral shape.

Eukaryotes

Life forms consisting of cells that contain a membrane-bound nucleus and organelles.

Histones

Packaging proteins that complex with linear $DNA$ in eukaryotic chromosomes.

Plasmids

Small $DNA$ circlets found in prokaryotic cells alongside the single circular chromosome.

Nucleoid

The central open region of a prokaryotic cell where the $DNA$ is located.

$$80S$$

The size of ribosomes found in eukaryotic cells, which are larger and more complex than prokaryotic versions.

$$70S$$

The size of ribosomes found in prokaryotic cells.

Binary fission

The asexual reproduction process in prokaryotes that results in two genetically identical daughter cells.

Mitosis

The division of the nucleus in eukaryotic cells that maintains a diploid set of chromosomes.

Cytokinesis

The division of the cytoplasm that follows mitosis to produce two separate daughter cells.

Apoptosis

A form of programmed cell death where a cell is dismantled into membrane-enclosed pieces.

Cell cycle

A series of events describing the activities of a cell as it prepares to divide and then undergoes division.

Interphase

The stage of the cell cycle where a cell is not dividing but is replicating its $DNA$ and other structures.

$S$ phase

The synthesis phase of interphase during which the cell replicates its entire genome.

Centromere

The specific area where two copies of a replicated chromosome are joined.

Centrioles

Microtubule structures near the nucleus that join with proteins to form centrosomes.

Centrosomes

Paired, oblong structures that organize microtubules into the mitotic spindle.

Chromatids

The two long, identical strands of chromosomal material within a replicated chromosome.

DNA damage checkpoint

A mechanism that pauses the cell cycle to allow proteins to repair damaged genetic material.

Apoptosis checkpoint

A control point at the start of mitosis that uses survivins to ensure division occurs instead of death.

Survivins

Proteins that override cell death signals to ensure that mitosis proceeds.

Spindle assembly checkpoint

A mechanism that oversees the construction of the spindle and the binding of chromosomes to it.

Telomeres

Chromosome tips that shorten with each mitosis, functioning as a cellular clock or fuse.

Telomerase

An enzyme that prevents telomeres from shortening in certain cells, such as sperm, egg, and cancer cells.

Caspases

Enzymes activated during apoptosis that snip apart various cell components.

Progenitor cell

A cell that cannot self-renew and produces daughter cells that specialize into a restricted number of types.

Totipotent

A stem cell with the potential to give rise to every cell type, including supporting embryonic membranes.

Pluripotent

A stem cell whose daughter cells have fewer possible fates than totipotent cells.

Multipotent

A stem cell whose daughter cells have only a few developmental choices.

Meiosis

A form of cell division that produces sperm or eggs with half the somatic genetic material as $23$ single chromosomes.