Eukaryotes Flashcards
Describe the eukaryote and its basic features.
- contains a membrane bound nucleus and membrane bound organelles
- single or multicellular and much larger
Why are the advantages of having many organelles?
- helps separate incompatible reactions
- increased efficiency of chemical reactions
Why does having many organelles increase efficiency of chemical reactions?
-localized, high concentrations of substrates/enzymes
-clustered pathways (product of one rxn=substrate of the next)
What structure appears in animal cells, but not plant?
lysosomes
What structure appears in plant cells, but not animal?
cell wall, vacuole, chloroplasts
What are the components of the nucleus?
- nuclear envelope
- nuclear lamina
- nucleolus
Describe the nuclear envelope and its function.
- double membrane
- pore-like openings allow passage of materials
Describe the nuclear lamina and its function.
- “nuclear cytoskeleton”
- maintains shape
The nuclear lamina can be compared to what other structure?
cytoskeleton
What is the purpose of the nucleolus?
ribosomal RNA synthesis
What is the function of ribosomes?
protein synthesis
List the characteristics of ribosomes.
- NOT an organelle
- no membrane
In free ribosomes, proteins made are used ______ the cytosol.
inside
In ribosomes bound to ER, proteins made are used ______ the cytosol.
outside
The rough ER functions in…
protein synthesis
The smooth ER functions in…
lipid synthesis or breakdown
What is the function of the lysosome?
digestion and recycling
Describe the membrane of lysosome.
single membrane containing proton pumps
What are the components of the lysosome?
acid hydrolases (catalyze hydrolysis reactions)
How is pH maintained in the lysosome?
through proton pumps (higher concentration of p+, the lower the pH)
Describe the pH of the lysosome.
acidic pH (optimal for the hydrolases)
Describe the membrane of vacuoles.
single, contains transporters for selected molecules
What are the components of a vacuole?
vary…
- carbohydrates
- pigments
- oils
- toxins
- hydrolases
What is the function of a vacuole?
-storage centers of plants and fungi
- water storage
-similar to lysosomes
- filled w/ colorful pigments
- filled with defensive chemicals
What are the components of peroxisomes?
important enzymes
- catalase: breaks down h202 which is a toxic byproduct of many rxns
- alcohol dehydrogenase (ADH)
Describe the membrane of peroxisomes.
single and contain transporters for selected macromolecules
What is the function of peroxisomes?
-oxidation of fatty acids, ethanol, or other compounds
-centers for redox rxs
What is the mitochrondria?
- powerhouse of cell
provides ATP for the cell
Describe the membrane of the mitochrondria.
-double and inner layer contains enzymes for the production of ATP (forms cristae)
- solution is inside matrix
What are the components of the mitochondria?
-enzymes that harvest energy from molecules to make ATP
-also contain its own DNA and ribosomes
What is the main function of the mitochondria?
ATP production
Chloroplasts are the sites for….
photosynthesis
Describe the membrane of a chloroplast?
-triple membrane
- contains individual thylakoids that are stacked into grana
- solution in between is stroma
What are the components of chloroplasts?
-pigments
- enzymes that use light energy to make sugars (photosynthesis)
What are the functions of a chloroplast?
production of sugars via photosynthesis
What are the functions of the cytoskeleton?
- cell shape
- structural stability
- movement of materials (organelles) within the cell
What are the 3 filaments in the cytoskeleton?
- microfilaments
- intermediate filaments
- microtubules
microfilament function
movement
intermediate filament function
structure and stability
microtubule function
tracks for the movement of organelles
Describe the membrane of the cytoskeleton.
there isn’t one
Describe the membrane of the plasma membrane.
single, contains transport and receptor proteins
What are the components of the plasma membrane?
- phospholipid bilayer with transport and receptor proteins
What is the function of the plasma membrane?
selective permeability: maintains intracellular environment
Describe the membrane of the cell wall.
there isn’t one
What are the components of the cell wall?
carbohydrate fibers running through carbohydrate or protein matrix
What is the function of the cell wall?
protection, structural support
What compose the endomembrane system?
- rough ER
- smooth ER
- lysosomes
- golgi
Describe the membrane of the golgi.
single, contains receptors for products of the rough ER
What are the components of the golgi?
stack of flattened, distinct cisternae
What is the function of the golgi?
protein, lipid, and carb processing
What is symbiogenesis?
mitochondria and chloroplasts were once free-living bacteria that were engulfed by ancestors of eukaryotes, and evolved a mutually beneficial relationship
What evidence is there for symbiogenesis?
- circular chromosomes
- small ribosomes
- grow and divide independently of cell division
