Cell Biology: Organelles, Cell Cycle, and Differentiation (Lecture Notes)

50 vocabulary flashcards covering cell structure, organelles, the cell cycle, mitosis/meiosis, tumor biology, and differentiation.

Cytosol

The gel-like fluid inside the cell; part of cytoplasm; excludes organelles.

Cytoplasm

The gel-like fluid plus all organelles inside the cell except the nucleus.

Nucleus

The cell’s control center that houses DNA and is enclosed by a nuclear envelope.

Nuclear envelope

The double phospholipid bilayer surrounding the nucleus.

Nuclear pores

Openings in the nuclear envelope that regulate traffic in and out of the nucleus.

Nucleolus

Region within the nucleus where RNA is synthesized.

DNA

The genetic blueprint containing instructions for building proteins.

RNA

Nucleic acid copied from DNA to relay genetic information for protein synthesis.

mRNA (Messenger RNA)

RNA copy of the DNA message sent from the nucleus to ribosomes to guide protein synthesis.

Ribosome

Molecular machine that reads mRNA and links amino acids to form proteins.

Rough Endoplasmic Reticulum (RER)

ER studded with ribosomes; site of protein synthesis and initial processing.

Smooth Endoplasmic Reticulum (SER)

ER without ribosomes; synthesizes lipids and carbohydrates.

Golgi apparatus

Packaging center that modifies, sorts, and ships proteins and lipids in vesicles.

Exocytosis

Vesicles fuse with the cell membrane to release contents outside the cell.

Lysosome

Organelle containing enzymes that break down waste and worn-out parts.

Autophagy

Cellular self-digestion where parts of the cell are recycled by lysosomes.

Peroxisome

Organelle that detoxifies reactive oxygen species and metabolizes fatty acids.

Free radicals

Reactive oxygen species that can damage cells if not controlled.

Mitochondrion

Powerhouse of the cell; produces most ATP through respiration.

Electron transport chain

Series of protein complexes in mitochondria driving ATP production using oxygen.

ATP

Adenosine triphosphate; the cell’s energy currency.

Cytoskeleton

Network of protein filaments that give the cell shape and mechanical support.

Microtubules

Large, hollow filaments providing structure and forming the mitotic spindle.

Centrioles

Organize the mitotic spindle during cell division.

Cilia

Hair-like projections that move substances across the cell surface.

Flagella

Tail-like structures used for propulsion of the cell.

Intermediate filaments

Filaments providing mechanical strength (keratins, collagens).

Actin (microfilaments)

Thin filaments contributing to cell shape and movement.

Chromatin

Relaxed DNA form during interphase.

Chromosome

Tightly packed DNA during cell division; visible as X-shaped structures.

Sister chromatids

Identical copies of a chromosome held at the centromere until separation.

Centromere

Region where sister chromatids are held together and attach to spindle.

Kinetochore

Protein structure at the centromere that attaches to spindle fibers.

Prophase

First mitotic phase: chromosomes condense, nuclear envelope breaks down, spindle forms.

Metaphase

Chromosomes align at the cell’s equator.

Anaphase

Sister chromatids separate and move toward opposite poles.

Telophase

Nuclear envelope reforms and chromosomes de-condense.

Cytokinesis

Division of the cytoplasm creating two daughter cells.

Interphase

Cell grows, duplicates DNA, and prepares for division; not actively dividing.

G1

First growth phase; cell increases in size.

S phase

DNA synthesis; genome replication.

G2

Second growth phase; prepares the cell for division.

G0

A non-dividing, resting state for cells not currently proliferating.

Diploid

Cells with two copies of each chromosome (2n); humans have 23 pairs.

Homologous chromosomes

Pairs of chromosomes with the same genes, one from each parent.

Meiosis

Cell division that reduces chromosome number to create haploid gametes.

Mitosis

Cell division producing two identical diploid daughter cells.

Tumor

Abnormal mass of cells; can be benign or malignant.

Oncogenesis

Development of cancer due to genetic mutations.

Differentiation

Process by which unspecialized cells become specialized cell types.

Totipotent

Zygote/early embryonic cells that can become any cell type, including extraembryonic tissues.

Pluripotent

Cells that can become many, but not all, cell types; can form all three germ layers.

Multipotent

Stem cells that can become multiple, but limited, cell lineages (e.g., hematopoietic cells).

Oligopotent

Stem cells with a few possible differentiation paths.

Unipotent

Cells that can differentiate only into one cell type.