Human Physiology - Cells

These flashcards cover key concepts and details from the Human Physiology lecture on cells, focusing on cell structure, function, and components.

What are the basic structural units of the body called?

Cells.

What are the principal parts of a cell?

Plasma membrane, nucleus, cytoplasm, organelles.

What is the function of the plasma membrane?

It separates the cell from the external environment, is selectively permeable, and is involved in communication.

What is cytoplasm composed of?

The fluid part of the cell (cytosol) and organelles.

What does the nucleus contain?

DNA and directs cell activities.

What is the fluid mosaic model?

The idea that proteins and phospholipids in the membrane move laterally, creating a fluid structure.

What substances can pass freely through the phospholipid bilayer?

Small, hydrophobic substances, gases like oxygen and carbon dioxide, and small lipid-soluble molecules.

What is the function of carrier proteins in the plasma membrane?

They transport specific substances across the membrane by changing shape.

What role do ligand receptor proteins play?

They recognize specific ligands and alter the cell's function.

What are exocytosis and its role in the cell?

It is the process through which large cellular products, like proteins, are moved out of the cell.

What is phagocytosis?

The process of engulfing large extracellular substances into the cell.

What are the differences between pinocytosis and receptor-mediated endocytosis?

Pinocytosis is nonspecific, while receptor-mediated endocytosis is specific due to receptor proteins.

What is the function of the Golgi apparatus?

It modifies, sorts, and packages proteins for secretion or delivery to other organelles.

What is the structure and function of mitochondria?

Mitochondria have an inner membrane and an outer membrane; they produce ATP, the energy currency of the cell.

How is ribosomal RNA related to ribosomes?

Ribosomes are made of ribosomal RNA and protein, and they synthesize proteins.

What is the nucleolus and its primary function?

A dense region in the nucleus that produces ribosomal RNA.

What determines the genetic code of a cell?

Chromatin, which is composed of DNA and proteins.

What is the difference between microfilaments and microtubules?

Microfilaments are thin structures primarily made of actin, while microtubules are larger and composed mainly of tubulin.

What are cilia and flagella and their functions?

Cilia are hair-like structures that move fluid across the cell surface, while flagella are longer structures that propel the cell forward.

What role do lysosomes play in the cell?

They contain digestive enzymes to break down foreign molecules and worn-out organelles.

What is the composition and function of the endoplasmic reticulum (ER)?

A system of membranous passageways involved in protein synthesis (rough ER) and lipid synthesis (smooth ER).