Cell Structure and Types Quiz

Study Notes

Cells are the basic structural and functional units of all known living organisms.
They are surrounded by a cell membrane, which regulates the passage of substances into and out of the cell.
Some cells contain a nucleus, which houses genetic material (DNA).
The cytoplasm is the jelly-like substance that fills the cell, hosting numerous organelles.

Prokaryotic cells: Lack a nucleus and membrane-bound organelles. Represented by bacteria and archaea.
Eukaryotic cells: Possess a nucleus and membrane-bound organelles. Examples include animal and plant cells.
Specialized cells: Different types of cells perform different functions in multicellular organisms (e.g., nerve cells, muscle cells, blood cells).

The cell membrane is a selectively permeable barrier.
It's a phospholipid bilayer containing embedded proteins.
It controls the movement of molecules in and out of the cell.
Cholesterol and carbohydrates are also components, influencing membrane fluidity and cell signaling.
It has receptor proteins for hormones and other signaling molecules.

The cytoplasm is a jelly-like substance filling the cell.
It suspends organelles and provides a medium for biochemical reactions.
Cytosol is the liquid component of the cytoplasm.
Cell movement like amoeboid motion depends on cytoskeletal components in the cytoplasm.
Various metabolic pathways occur in the cytoplasm, like glycolysis.

Nucleus: Contains the cell's DNA, directing cellular activities through gene expression.
Mitochondria: The "powerhouses" of the cell, responsible for energy production (ATP) via cellular respiration.
Endoplasmic reticulum (ER): A network of membranes involved in protein and lipid synthesis.
Golgi apparatus: Processes and packages proteins and lipids for secretion or use within the cell.
Ribosomes: Sites of protein synthesis, either free-floating or attached to the ER.
Lysosomes: Contain enzymes to break down waste materials and cellular debris.
Vacuoles: Fluid-filled sacs involved in storage and transport; large in plant cells.
Chloroplasts: Found in plant cells, responsible for photosynthesis.
Cytoskeleton: Supports the cell, aids in movement (e.g., cilia, flagella), and shapes the cell.

Cell division: Mitosis (somatic cells) and meiosis (sex cells) are processes for cell reproduction.
Diffusion: Movement of substances from high to low concentration.
Osmosis: Movement of water across a selectively permeable membrane.
Active transport: Movement of substances against a concentration gradient; requiring energy.

Plant cells have a cell wall, chloroplasts, and a large central vacuole, absent in animal cells.
Animal cells usually have centrioles, which are involved in cell division.

Cells communicate with each other via signaling pathways, involving various molecules.
Hormones, neurotransmitters, and other signaling molecules relay information.
Cell-to-cell contact is a fundamental aspect of communication in multicellular organisms.

Stem cells have the potential to differentiate into various specialized cell types.
During development, cells undergo differentiation to form different tissues and organs.
This process is regulated genetically and environmentally.