Chapter 3: The Cell Flashcards
Theory of Endosymbiosis
The theory that eukaryotic cells emerged when chloroplasts and mitochondria took residence inside larger cells.
Modern Cell Theory
Theory that all cells arise from preexisting cells.
All cells have…
a plasma membrane, cytosol, and DNA of some sort.
Prokaryotic Cells
Simple cells with no nucleus or organelles, like bacteria.
These types of cells have a nucleic region (where the DNA is located) instead of an enclosed nucleus.
Eukaryotic cells
Have a nucleus bound by a double membrane, as well as organelles.
Surface Area to Volume
Surface area increases slower than volume (look at the formulas for surface area and volume for different shapes).
Thus, the surface area limits the amount of stuff that can enter and exit the cell.
Nucleolus
Located within the nucleus, and controls ribosome and rRNA synthesis.
Ribosomes
Can be bound (on the rough ER) or free floating within the cytoplasm, and takes part in protein synthesis.
Peroxisomes
Found in both plants and animals. and contain “catalase,” which converse peroxide (H2O2) into water. Can also detoxify alcohols in the liver.
Endomembrane System
Regulates protein traffic and metabolic functions. Includes the golgi apparatus, ER, vacuole, vesicles, lysosomes, nuclear envelope, lysosomes, and the plasma membrane.
Nucleus
Has a selectively permeable “nuclear envelope” with pores that separates the stuff inside the nucleus from the cytoplasm.
Endoplasmic Reticulum
Rough ER: protein synthesis, and covered in ribosomes.
Smooth ER: steroid hormone synthesis, stores Ca2+ ions, and detoxifies drugs and poison from the body.
Golgi Apparatus
The mail man of the endomembrane system. It packages and processes substances, which is then secreted to other parts of the cell for export.
Lysosomes
Sacs of hydrolytic enzymes that plays a major role in intercellular digestion. The enzymes also play a role in apoptosis, or cell suicide.
Mitochondria
Site of cellular respiration, and present in both plants and animals. Mitochondria have a double membrane and cristae, which contain their own DNA.
Vacuoles
Large vesicles used for storage.
Plants have a “central vacuole,” protists have a “contractile vacuole” to pump out excess water, and food vacuoles play a major part in phagocytosis.
Chloroplast
Only present in plants, and absorb light to synthesize sugar for the plant. Chloroplasts have a double membrane and thylakoids to function in photosynthesis.
Cytoskeleton Function
- Maintain cell shape.
- Protection.
- Anchors them to the plasma membrane.
- Involved in the flow of cytoplasm.
Composed of microfilaments and microtubules.
Microtubules
Make up the cilia, flagella, spindle fibers, etc. Often assists in structures that require movement.
Microfilaments
Help maintain the shape of the cell using actin filaments.