Cell Biology: Cell Structure

Study Notes

Plasma membrane: semi-permeable membrane that separates the cell from its environment
- Composed of phospholipid bilayer and proteins
- Regulates movement of materials in and out of the cell
Cytoplasm: jelly-like substance inside the cell membrane
- Site of metabolic reactions and cellular activities
- Composed of water, salts, sugars, and organelles
Organelles: specialized structures within the cell
- Examples: mitochondria, ribosomes, endoplasmic reticulum, lysosomes, Golgi apparatus

Passive transport: movement of molecules across the cell membrane without energy input
- Types: diffusion, osmosis, facilitated diffusion
Active transport: movement of molecules across the cell membrane with energy input
- Types: pumping, phagocytosis, pinocytosis

Mitochondria: generate energy for the cell through cellular respiration
- Convert glucose into ATP (adenosine triphosphate)
Ribosomes: site of protein synthesis
- Read messenger RNA (mRNA) to assemble amino acids into proteins
Endoplasmic reticulum (ER): network of membranous tubules and cisternae
- Involved in protein synthesis, lipid synthesis, and detoxification
Lysosomes: contain digestive enzymes to break down and recycle cellular waste
Golgi apparatus: complex of flattened sacs and tubules
- Involved in protein modification, sorting, and secretion

Cell cycle: sequence of stages a cell undergoes from birth to division
- Interphase (G1, S, G2) and mitosis (M)
Mitosis: process of cell division resulting in two daughter cells
- Stages: prophase, metaphase, anaphase, telophase, cytokinesis

Signaling pathways: mechanisms by which cells respond to signals from their environment
- Types: hormonal, electrical, and mechanical signaling
Cell adhesion: interactions between cells and their environment
- Important for tissue structure, development, and function

Plasma membrane: a semi-permeable membrane that separates the cell from its environment, composed of a phospholipid bilayer and proteins, and regulates the movement of materials in and out of the cell.
Cytoplasm: a jelly-like substance inside the cell membrane, where metabolic reactions and cellular activities take place, and is composed of water, salts, sugars, and organelles.
Organelles: specialized structures within the cell that perform specific functions, including mitochondria, ribosomes, endoplasmic reticulum, lysosomes, and Golgi apparatus.

Passive transport: movement of molecules across the cell membrane without energy input, including diffusion, osmosis, and facilitated diffusion.
Active transport: movement of molecules across the cell membrane with energy input, including pumping, phagocytosis, and pinocytosis.

Mitochondria: generate energy for the cell through cellular respiration, converting glucose into ATP (adenosine triphosphate).
Ribosomes: the site of protein synthesis, reading messenger RNA (mRNA) to assemble amino acids into proteins.
Endoplasmic reticulum (ER): a network of membranous tubules and cisternae involved in protein synthesis, lipid synthesis, and detoxification.
Lysosomes: contain digestive enzymes to break down and recycle cellular waste.
Golgi apparatus: a complex of flattened sacs and tubules involved in protein modification, sorting, and secretion.

Cell cycle: a sequence of stages a cell undergoes from birth to division, including interphase (G1, S, G2) and mitosis (M).
Mitosis: the process of cell division resulting in two daughter cells, with stages including prophase, metaphase, anaphase, telophase, and cytokinesis.

Signaling pathways: mechanisms by which cells respond to signals from their environment, including hormonal, electrical, and mechanical signaling.
Cell adhesion: interactions between cells and their environment, important for tissue structure, development, and function.