Chapter 4 Flashcards
Who invented the first compound microscope?
Hans and Zacharias Janssen
What did Antonie van Leeuwenhoek observe with his microscope?
Several types of living cells, including sperm.
Who discovered and named “cells” by looking at cork?
Robert Hooke
What did Robert Brown discover in plant cells?
The nucleus.
What are the three components of the cell theory?
1) All organisms are composed of one or more cells. 2) The cell is the smallest unit of life. 3) All cells arise from pre-existing cells.
What is the smallest unit of life?
The cell.
What are the three common features of all cells?
Plasma membrane, nucleus/nucleoid region, cytoplasm.
What limits the size of a cell?
The surface-to-volume ratio.
Why is the surface-to-volume ratio important?
Cells must be small for efficient exchange of materials with their environment.
What does the plasma membrane do?
It separates the cell from its environment and regulates the flow of substances in and out.
What is the difference between a nucleus and a nucleoid?
A nucleus is membrane-bound, while a nucleoid is a region where DNA is localized in prokaryotic cells.
What are the main components of the cytoplasm?
Cytoskeleton, ribosomes, membrane systems, and a semifluid substance.
What is the role of the lipid bilayer in the plasma membrane?
It forms the boundary between the inside and outside of the cell and regulates the entry and exit of substances.
What is a biofilm?
A community of microorganisms living within a shared layer of polysaccharides and glycoproteins.
What are the two domains of prokaryotic cells?
Bacteria and Archaea.
What are bacterial flagella and what do they do?
Flagella are whip-like structures that enable bacteria to move.
What are plasmids?
Small, circular DNA molecules found in some bacteria.
What is the function of ribosomes in prokaryotic cells?
They are the sites where proteins are assembled.
What is the main difference between prokaryotic and eukaryotic cells?
Eukaryotic cells have a nucleus and membrane-bound organelles, while prokaryotic cells do not.
What is the function of the nucleus in eukaryotic cells?
It contains the cell’s hereditary material and controls cell activities.
What organelles are involved in protein synthesis in eukaryotic cells?
Ribosomes, rough endoplasmic reticulum, and Golgi bodies.
What is the function of the rough endoplasmic reticulum?
It modifies and transports proteins made by the ribosomes attached to it.
What does the smooth endoplasmic reticulum do?
It synthesizes lipids and detoxifies harmful substances.
What is the role of the Golgi body?
It processes, sorts, and packages proteins and lipids for transport.
What are lysosomes and their function?
Lysosomes are vesicles that contain enzymes to break down waste, foreign particles, or worn-out cell parts.
What disease is caused by a malfunction in lysosomal enzymes?
Tay-Sachs disease.
What is the function of mitochondria?
Mitochondria produce ATP by transferring energy from carbohydrates under oxygen-rich conditions.
What is the theory of endosymbiosis?
It suggests that mitochondria and chloroplasts were once free-living prokaryotic cells engulfed by an ancestral eukaryotic cell.
What are chloroplasts and what is their role?
Chloroplasts are organelles in plant cells that perform photosynthesis.
What pigment is found in chloroplasts, and what is its function?
Chlorophyll; it captures light energy for photosynthesis.
What is the central vacuole, and where is it found?
The central vacuole is a large storage organelle in plant cells that stores nutrients and waste products.
What is the function of cell walls in plants?
They provide mechanical support and protection.
What substance in plant cell walls makes them strong and waterproof?
Lignin.
What are tight junctions in animal cells?
They are connections that seal cells together, preventing leaks between cells.
What are the three components of the cytoskeleton?
Microtubules, microfilaments, and intermediate filaments.
What is the function of microtubules?
Microtubules provide structural support and are involved in cell division and movement.
What are cilia and flagella?
They are motile structures that extend from the surface of eukaryotic cells to aid in movement.
What are pseudopods?
Temporary projections of the cell membrane used for movement and engulfing food.
What is the purpose of the nuclear envelope?
It encloses the nucleus and regulates the exchange of materials between the nucleus and cytoplasm.
What role do vesicles play in cells?
Vesicles transport materials within the cell and to the cell membrane for exocytosis.
