Chap. 6 Flashcards
A Tour of the Cell
Basic features of all cells
- plasma membrane
- a semifluid substance called cytosol
- Chromosomes (carry genes)
- Ribosomes (make proteins)
domains Bacteria and Archaea consist of
prokaryotic cells
Protists, fungi, animals, and plants all consist of
eukaryotic cells
Prokaryotic cells are characterized by having
- No nucleus
- DNA in an unbound region called the nucleoid
- No membrane-bound organelles
- Cytoplasmbound by the plasma membrane
Eukaryotic cells are characterized by having
- DNA in a nucleus that is bounded by a double membrane
- Membrane-bound organelles
- Cytoplasm the region between the plasma membrane and nucleus
A eukaryotic cell has internal membranes that divide the cell into compartments
the organelles
The plasma membrane
a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell
nuclear envelope
encloses the nucleus, separating it from the cytoplasm
Each chromosome contains one DNA molecule associated with proteins, called
chromatin
are complexes made of ribosomal RNA and protein
Ribosomes
Ribosomes use the information from the DNA to make
proteins
Ribosomes carry out protein synthesis in two locations:
- In the cytosol (free ribosomes)
- On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes)
the collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
Endomembrane system
The endomembrane system consists of
Nuclear envelope§Endoplasmic reticulum§Golgi apparatus§Lysosomes§Vacuoles§Plasma membrane
accounts for more than half of the total membrane in many eukaryotic cells
endoplasmic reticulum (ER) - The ER membrane is continuous with the nuclear envelope
There are two distinct regions of ER:
Smooth ER, Rough ER
Smooth ER, which lacks ribosomes
Synthesizes lipids
- Metabolizes carbohydrates
- Detoxifies drugs and poisons
- Stores calcium ions
Rough ER, whose surface is studded with ribosomes
- Has bound ribosomes, which secrete glycoproteins(proteins covalently bonded to carbohydrates)
- Distributes transport vesicles, secretory proteins surrounded by membranes
- Is a membrane factory for the cell
lysosome
a membranous sac of hydrolytic enzymes that can digest macromolecules
onsists of flattened membranous sacs called cisternae
- Modifies products of the ER
- Manufactures certain macromolecules
- Sorts and packages materials into transport vesicles
Golgi apparatus
Vacuoles
large vesicles derived from the ER and Golgi apparatus
- Vacuoles perform a variety of functions in different kinds of cells
Food vacuoles
are formed by phagocytosis
Contractile vacuoles
found in many freshwater protists, pump excess water out of cells
Central vacuoles
found in many mature plant cells, hold organic compounds and water
organelles in eukaryotic cells that serve as the site of cellular respiration, a metabolic process that uses oxygen togenerate ATP (energy)
Mitochondria
organelles found in plants and algae (photosynthetic protists), are the sites of photosynthesis. They absorb sunlight and use it to drive the synthesis of organic compounds from carbon dioxide and water.
Chloroplasts
