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what are the basic features of all cells?
- -plasma membrane
- -semifluid substance called cytosol
- -chromosomes (carry geneS)
- -ribosomes (make proteins)
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prokaryotic cells are characterized by having:
- -no nucleus
- -DNA in an unbound region called the nucleoid
- -no membrane-bound organelles
- -cytoplasm bound by the plasma membrane
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eukaryotic cells are characterized by having:
- -DNA in a nucleus that is bounded by a membranous nuclear envelope
- -membrane-bound organelles
- -cytoplasm in the region between the plasma membrane and nucleus
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what is the function of the nucleolus?
rRNA synthesis
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what are the components of the endomembrane system?
nuclear envelope, ER, golgi apparatus, lysosomes, vacuoles, plasma membrane
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functions of smooth ER
- -synthesizes lipids
- -metabolizes carbohydrates
- -detoxifies poison
- -stores calcium
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functions of the rough ER
- -has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates)
- -distributes transport vesicles
- -is a membrane factory for the cell
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what are the functions of the golgi apparatus?
to modify products of the ER, to manufacture certain macromolecules, and to sort and package materials into transport vesicles
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what is autophagy?
using lysosomal enzymes to recycle the cell's own organelles and macromolecules
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what is a food vacuole?
some types of cells can engulf another cell by phagocytosis;this forms a food vacuole. A lysosome fuses with the food vacuole to digest the molecules
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what are the three kinds of vacuoles?
food vacuoles, contractile vacuoles, and central vacuoles
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what are contractile vacuoles?
they are found in many freshwater protists, pump excess water out of cells
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what are central vacuoleS?
found in many mature plants, hold organic compounds and water
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what are the four special features of mitochondria and chloroplasts?
- 1. they are not part of the endomembrane system
- 2. They have a double membrane
- 3. They have proteins made by free ribosomes
- 4. they contain their own DNA
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what is the internal structure of the mitochondria?
they have a smooth outer membrane and an inner membrane folded into cristae. The inner membrane creates two compartments: intermembrane space and mitochondrial matrix.
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chloroplasts are a member of a family of organelles called _____
plastids
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chloroplast structure includes:
thylakoids, membranous sacs, stacked to form granum
stroma, the internal fluid
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what are peroxisomes?
are specialized metabolic compartments bounded by a single membrane. They use oxygen to break down different types of molecules. Peroxisomes produce hydrogen peroxide and convert it to water
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what is the cytoskeleton?
the cytoskeleton is a network of fibers extending throughout the cytoplasm. It organizes the cell's structure and activities, anchoring many organelles
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describe microtubules
they are hollow rods about 25 nm in diameter and about 200 nm to 25 microns long. Their functions include:
- Shaping the cell
- Guiding movement of organelles
- Separating chromosomes during cell division
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