Cell Structure and Function Quiz

Cell Structure and Function

• Cells are the basic units of life, exhibiting a wide variety of shapes and sizes.
• All cells share fundamental characteristics, including a plasma membrane, cytoplasm, and genetic material (DNA).
• Prokaryotic cells (bacteria and archaea) lack membrane-bound organelles, while eukaryotic cells (plants, animals, fungi, and protists) possess them.

Prokaryotic Cells

• Typically smaller and simpler than eukaryotic cells.
• Lack membrane-bound organelles like mitochondria, endoplasmic reticulum, or Golgi apparatus.
• Genetic material (DNA) is located in a nucleoid region.
• Often have cell walls for structural support and protection.
• Examples include bacteria and archaea, playing crucial roles in various ecosystems and human health.

Eukaryotic Cells

• Larger and more complex than prokaryotic cells.
• Possess membrane-bound organelles, compartmentalizing cellular functions.
• Contain a nucleus housing the genetic material (DNA).
• Exhibit diverse structures and functions depending on their specific roles in organisms.

Cell Membrane

• The plasma membrane encloses the cell, separating its interior from the external environment.
• Composed primarily of a phospholipid bilayer, with embedded proteins for various functions like transport and signaling.
• Selective permeability allows the passage of specific molecules while restricting others.
• Maintains a stable internal environment essential for cell survival.

Cytoplasm

• The region inside the cell membrane, excluding the nucleus.
• Contains various organelles suspended in a fluid cytosol.
• The site of numerous metabolic activities and cellular processes.
• Cytoskeleton provides structural support and facilitates intracellular transport.

Nucleus

• The control center of the eukaryotic cell, containing the cell's genetic material (DNA).
• Enclosed by a double membrane (nuclear envelope) with pores regulating passage of molecules.
• Houses chromosomes, which carry genetic information.
• Site of DNA replication and RNA transcription.

Organelles

• Specialized structures within the cytoplasm of eukaryotic cells, performing specific functions.
• Mitochondria are the "powerhouses" of the cell, generating energy through cellular respiration.
• Endoplasmic reticulum (ER) is a network of membranes involved in protein synthesis and lipid metabolism.
• Golgi apparatus modifies, sorts, and packages proteins for secretion.
• Lysosomes contain digestive enzymes to break down waste materials and cellular debris.
• Vacuoles store water, nutrients, and waste products.
• Ribosomes synthesize proteins according to genetic instructions.
• Chloroplasts (plant cells) capture light energy for photosynthesis.
• Peroxisomes break down fatty acids and detoxify harmful substances.

Cell Division

• Mitosis and meiosis are processes of cell division.
• Mitosis is used for growth, repair, and asexual reproduction in eukaryotic cells.
• Meiosis is involved in sexual reproduction, producing gametes with half the number of chromosomes.
• Precise regulation of cell division is crucial for maintaining organismal health.

Cell Transport

• Movement of molecules across the cell membrane is essential for maintaining cellular balance.
• Passive transport (diffusion, osmosis) occurs without energy expenditure.
• Active transport requires energy to move molecules against a concentration gradient.
• Endocytosis and exocytosis are processes for transporting large molecules.

Cell Signaling

• Cells communicate with each other through signaling pathways.
• Cells receive, process, and respond to signals from their environment.
• Signaling pathways can regulate various cellular activities, such as growth, differentiation, and metabolism.