Human Cells, Energy Production, and Organ Systems: Comprehensive Study Notes

Prokaryotic cells

Structurally simple cells lacking a membrane-bound nucleus, with DNA floating in the nucleoid.

Eukaryotic cells

Cells possessing a true, membrane-bound nucleus and numerous membrane-bound organelles, found in plants, animals, fungi, and protists.

Cytoplasm

The semi-fluid substance within the cell, including suspended organelles, where many metabolic pathways occur.

Nucleus

The double-membrane structure housing DNA, acting as the cell's command center.

Mitochondria

Organelles known as the 'powerhouse' that generate cellular energy (ATP) through aerobic respiration.

Ribosomes

Molecular machines that translate mRNA into polypeptide chains, existing free in the cytosol or bound to the rough ER.

Rough ER

An organelle studded with ribosomes, responsible for synthesizing proteins destined for secretion, membranes, or lysosomes.

Smooth ER

An organelle involved in lipid synthesis, detoxification, and calcium storage.

Golgi Apparatus

A stack of flattened sacs that modify, sort, and package proteins/lipids into vesicles, acting as the 'post office' of the cell.

Lysosomes

Acidic vesicles containing hydrolytic enzymes, responsible for digesting cellular debris, pathogens, and worn-out organelles.

Cellular Respiration

The process of generating cellular energy, primarily in mitochondria, through glycolysis, the Krebs cycle, and oxidative phosphorylation.

Transcription

The process where DNA is transcribed into pre-mRNA in the nucleus.

Translation

The process where ribosomes read mRNA and assemble amino acids into proteins.

Mitosis

Cell division for growth, tissue repair, and maintenance of genetic consistency, resulting in two identical daughter cells.