More Cellular Organelles Flashcards
What are peroxisomes?
Single membrane-bound organelles involved in fatty acid oxidation and detoxification of toxic substances.
Peroxisomes contain enzymes like peroxidase and catalase, and are important in liver and kidney cells.
What is the function of catalase in peroxisomes?
Breakdown of H₂O₂ (hydrogen peroxide) into water.
This process is crucial for detoxifying harmful byproducts of metabolism.
Where are peroxisomes found?
Present in both animal and plant cells.
In animals, they are key for detoxification and fatty acid metabolism.
What is a glyoxysome?
A specialized type of peroxisome found in plants, involved in converting fatty acids to sugars.
This process is part of the Glyoxylate cycle, aiding germinating seedlings.
What are mitochondria often referred to as?
The powerhouse of the cell.
They are essential for aerobic respiration and ATP synthesis.
What is the shape and size of mitochondria?
Usually filamentous or thread-like and oval-shaped, approximately 1.0 to 1.0 μm in diameter and about 10μm long.
Their shape can vary depending on the cell type.
What are the two membranes of mitochondria composed of?
Lipids and proteins.
The outer membrane is smooth and permeable, while the inner membrane has folds called cristae.
What is the matrix in mitochondria?
The fluid formed by the inner membrane, rich in organic matrix and enzymes.
It plays a vital role in energy production.
What are plastids?
Double membrane-bound organelles found mainly in plant and algal cells.
They originate from undifferentiated meristematic tissues.
What are the three types of plastids?
- Chloroplasts
- Chromoplasts
- Leucoplasts
Each type has distinct functions and characteristics based on the pigments they contain.
What is the primary function of chloroplasts?
Convert light energy into chemical energy through photosynthesis.
Chlorophyll in thylakoids captures sunlight, and ATP and NADPH are synthesized in the stroma.
What is the structure of chloroplasts?
Surrounded by two membranes, contains stroma and stacks of thylakoids called grana.
Thylakoids contain chlorophyll and other pigments essential for photosynthesis.
What is the cytoskeleton?
A protein filament network throughout the cytoplasm that maintains cell shape and enables movement.
It plays a crucial role in cell division and intracellular transport.
What are microfilaments?
Solid strands made of two intertwined actin chains, involved in muscle contraction and cell shape changes.
They are approximately 7 nm in diameter.
What are microtubules?
Hollow tubes made of tubulin proteins, involved in spindle fiber formation and chromosome movement.
They are about 25 nm in diameter and are essential for cell motility.
What are cilia?
Short, numerous extensions of the plasma membrane that move substances or enable locomotion.
They are about 10–25 μm long and function in coordinated movement.
What is the structure of cilia and flagella?
Both have a 9+2 arrangement of microtubules and originate from a basal body.
This structure is crucial for their movement.
What is the difference between cilia and flagella?
Cilia are shorter and numerous, while flagella are longer and usually fewer in number.
Flagella generate force perpendicular to the cell surface, while cilia move parallel to it.
What is the role of dyneins in cilia and flagella movement?
Dyneins provide the force for bending by ‘walking’ along neighboring microtubules.
This action enables the characteristic movement of cilia and flagella.
