Cell Structure and Types Quiz

Cell Structure

• Cells are the fundamental units of all living organisms.
• Cells vary in shape and size according to their specific function.
• A cell's basic structure includes a plasma membrane, cytoplasm, and a nucleus (in eukaryotic cells).
• The plasma membrane controls the passage of materials into and out of the cell.
• Cytoplasm is the gel-like substance within the cell, containing organelles.
• Organelles are specialized structures performing specific functions.

Types of Cells

• Cells are classified as prokaryotic or eukaryotic.
• Prokaryotic cells are simpler and smaller than eukaryotic cells.
• Prokaryotes lack a nucleus and membrane-bound organelles.
• Bacteria and archaea are examples of prokaryotic cells.
• Eukaryotic cells are more complex and larger than prokaryotic cells.
• Eukaryotic cells have a nucleus and membrane-bound organelles (mitochondria, endoplasmic reticulum, Golgi apparatus).
• Animal cells and plant cells are examples of eukaryotic cells.

Prokaryotic Cell Structure

• Prokaryotic cells have a cell wall for structural support and protection.
• The cell wall surrounds the plasma membrane.
• Some prokaryotes have a capsule outside the cell wall, aiding in protection and adhesion.
• Prokaryotes have a singular, circular chromosome in a region called the nucleoid.

Eukaryotic Cell Structure

• Eukaryotic cells contain a nucleus that stores genetic material (DNA).
• The nucleus is enclosed by a nuclear membrane (nuclear envelope).
• The nuclear envelope is a double membrane with nuclear pores, vital for molecule transport.
• Cytoplasm fills the space between the nucleus and the cell membrane.

Cell Organelles

• Mitochondria are energy-generating organelles (ATP synthesis) through cellular respiration.
• Mitochondria contain their own DNA.
• The endoplasmic reticulum (ER) is a membrane network for protein and lipid synthesis.
• Rough ER, studded with ribosomes, is crucial for protein synthesis.
• Smooth ER, lacking ribosomes, is involved in lipid synthesis and detoxification.
• The Golgi apparatus modifies, sorts, and packages proteins and lipids.
• Lysosomes contain enzymes for breaking down waste and cellular debris.
• Ribosomes synthesize proteins; some are free in the cytoplasm, others bound to rough ER.
• Vacuoles are storage compartments, with plant cells often having a large central vacuole.

Cell Membrane

• The cell membrane is a phospholipid bilayer with embedded proteins.
• The phospholipid bilayer is selectively permeable, allowing specific substance passage.
• The cell membrane regulates the entry and exit of substances.
• Membrane proteins perform various roles (channels, pumps, receptors).

Cell Wall

• Plant cells, fungi, algae, and some bacteria have rigid cell walls.
• The cell wall provides structural support and protection.
• Plant cell walls are primarily composed of cellulose.