Cell Structure and Physiology Flashcards

Vocabulary flashcards covering cellular compartments, plasma membrane transport, organelles, protein synthesis, gene expression, cell cycle, and mitosis.

Amphipathic

Describing a molecule, such as a phospholipid, that contains both a hydrophilic (water-attracting) head and a hydrophobic (water-repelling) tail.

Isotonic

A solution condition where net water movement in and out of the cell is equal, resulting in the cell staying the same size.

Hypotonic

A solution condition where net water movement flows into the cell, causing the cell to swell.

Hypertonic

A solution condition where net water movement flows out of the cell, causing the cell to shrink.

Active Transport

Membrane transport mechanisms that require cellular energy in the form of ATP to move substances, including pumps/ports, endocytosis, and exocytosis.

Cytosol

The liquid/fluid phase present within the cell membrane.

Cytoplasm

The cell component present inside the cell membrane, including cytosol and organelle structures.

Rough Endoplasmic Reticulum

A region of the endoplasmic reticulum studded with bound ribosomes, primarily responsible for protein synthesis.

Smooth Endoplasmic Reticulum

A region of the endoplasmic reticulum lacking ribosomes, involved in lipid synthesis and detoxification.

Golgi Apparatus

An organelle that modifies, sorts, and packages proteins into vesicles for transport to their cellular destinations.

Lysosomes

Acidic organelles ($\text{pH} \thicksim 4.5\text{--}5.0$) formed via the Golgi/endosomal pathway that contain acid hydrolases (proteases, lipases, nucleases) to digest cellular waste and worn-out organelles.

Peroxisomes

Neutral to slightly alkaline organelles arising from the ER and peroxisome division that contain oxidative enzymes (e.g., catalase) to break down fatty acids and detoxify harmful molecules like $H_2O_2$.

Mitochondria

The powerhouse of the cell that provides ATP through oxidative phosphorylation, containing its own internal ribosome and DNA components.

Chromatin

Nuclear material composed of DNA wrapped around proteins.

Chromosome

A highly condensed form of chromatin; human cells contain 46 chromosomes containing an estimated 22,000 genes.

Transcription

The initial step of gene expression occurring in the nucleus where a segment of DNA is transcribed into mRNA through initiation, elongation, and termination.

Translation

The cellular process carried out by ribosomes in which the base sequence of mRNA is decoded to synthesize a polypeptide chain of amino acids.

Interphase

The longest phase of the cell cycle during which the cell grows, performs normal functions, replicates DNA, and prepares for cell division.

$G_1$ Phase

The first gap phase of interphase where the cell grows and performs normal functions.

S Phase

The synthesis phase of interphase during which DNA replication occurs.

$G_2$ Phase

The second gap phase of interphase during which final preparations for cell division occur.

M Phase

The phase of the cell cycle comprising mitosis and cytokinesis, leading to division into two identical daughter cells.

Prophase

The first phase of mitosis where chromatin condenses into visible chromosomes, the nuclear envelope breaks down, and spindle fibers form from centrosomes.

Metaphase

The mitotic phase where chromosomes align at the equatorial plate (metaphase plate) attached to spindle fibers from opposite poles.

Anaphase

The mitotic phase where sister chromatids separate and are pulled toward opposite cell poles by spindle fibers.

Telophase

The mitotic phase where chromatids reach the poles, nuclear envelopes re-form around each set of chromosomes, and chromosomes decondense.

Cytokinesis

The division of the cytoplasm resulting in two separate daughter cells, which often overlaps with telophase.

Zellweger Spectrum

A group of peroxisomal disorders resulting from defects in peroxisome function.