Ch. 4 - Eukaryotic Cell Structure
What is the function of a phagosomes?
(phagocytic cells) used to engulf and kill potentially harmful organisms; formed by endocytosis
What is the function of a central vacuole?
(plant cells) store water and minerals, giving rigidity to cells
What is the function of a food vacuole?
(protozoa) allow one-celled organisms to engulf materials for energy and nutrition
What are the different types of vesicles/vacuoles? What are vesicles/vacuoles functions?
1. CENTRAL VACUOLE of plant cells stores water and minerals, giving rigidity to cells 2. FOOD VACUOLES of protozoa allow these one-celled organisms to engulf materials for energy and nutrition 3. PHAGOSOME a vacuole formed in phagocytic cells; used to engulf and kill potentially harmful organisms; forms by endocytosis
What are the three types of vacuoles
1. Central Vacuole 2. Food Vacuole 3. Phagosomes
Which types of organisms are the vesicles/vacuoles found in?
1. Central vacuole = plant cells 2. Food vacuoles = protozoa 3. Phagosome = phagocytic cells
How do flagella, cilia, and pseudopodia cause movement?
1. FLAGELLA cause movement of cell by whip-like motion 2. CILIA cause movement by synchronized whip-like motions 3. PSEUDOPODIA extensions/projections of cytoplasm and surrounding membrane of cells capable of amoeboid movement
What are the different types of motility structures in eukaryotes?
1. flagella 2. cilia 3. pseudopodia
Lines of evidence that support the endosymbiosis theory
1. mitochondria and chloroplasts similar in size and form to prokaryotes 2. circular DNA present in organelles, similar to that of prokaryotes 3. mitochondria and chloroplasts can divide by binary fission 4. 70S ribosomes present, as in prokaryotes 5. double membrane system of mitochondria and chloroplasts resembles membrane of Gram negative bacteria 6. chloroplasts resemble cyanobacteria 7. ribosomes carry out protein synthesis with process similar to prokaryotes 8. antibiotics that inhibit bacterial protein synthesis inhibit protein synthesis within mitochondria and chloroplasts 9. known instances of prokaryotic endosymbiosis within living protozoa
What size ribosomes are found in eukaryotic cells?
80s = cytoplasm, RER 70s = mitochondria, chloroplasts
How are the microtubules arranged in the flagella?
9+2 arrangement 2 in the center 9 around
How are mitochondria and chloroplasts similar?
Divide independently; contain circular DNA and 70S ribosomes
How is the organization of DNA in a eukaryotic chromosomes different from that seen in prokaryotic cells?
Eukaryotes: Prokaryotes:
How are eukaryotic flagella different from prokaryotic flagella in structure
Eukaryotic flagella: composed of microtubules of protein called tubulin associated with protein dyne in Prokaryotic flagella: composed of protein flagellin
How are eukaryotic flagella different from prokaryotic flagella with how they cause motility?
Eukaryotic flagella: whip-like motion Prokaryotic flagella: spinning-like rotor motion
In which organelles are the secretory proteins produced by rough endoplasmic reticulum transported and then modified?
Golgi apparatus
NUCLEUS location structure function
LOCATION cytoplasm STRUCTURE genetic enclosed within the double-membrane structure called nuclear envelope which consists of nuclear pores called pore complex which controls what gets into the nucleus and what gets out. FUNCTION place where DNA is organized with proteins to form chromatin
MITOCHONDRIA location structure function
LOCATION cytoplasm STRUCTURE membrane-enclosed structure with second internal, folded membrane; outer membrane surrounds structure; inner membrane is folded to form cristae within a semi-fluid matrix FUNCTION ATP generation by cellular respiration
SMOOTH ENDOPLASMIC RETICULUM (SER) location structure function
LOCATION cytoplasm STRUCTURE network of membrane tubules with no ribosomes (smooth in TEM) FUNCTION produces lipids, enzymes detoxifying drugs/toxins, storage and release of calcium ions in muscle cells
ROUGH ENDOPLASMIC RETICULUM (RER) location structure function
LOCATION cytoplasm STRUCTURE series of flattened sacs with attached ribosomes (looks grainy in TEM) FUNCTION produces secretory proteins and packages them within the membrane-enclosed vesicles and produces membrane (membrane proteins + phospholipids)
PEROXISOMES location structure function
LOCATION cytoplasm STRUCTURE small membrane-enclosed structures filled with oxidative enzymes FUNCTION - oxidation of fatty acids and detoxification of liver, produces hydrogen peroxide as a by product, also contain enzymes which breaks down hydrogen peroxide (because it's toxic) to water
LYSOSOMES location structure function
LOCATION cytoplasm (animal cells only) STRUCTURE small, membrane-closed structures fill with hydrolytic enzymes FUNCTION assist in digestion of macromolecules in cells - in protozoa and mammalian phagocytes fuse with vacuoles so contents can be digested - can also engulf other cell contents for recycling in a process called autophagy
VACUOLES location structure
LOCATION cytoplasm (plant cells only) STRUCTURE membrane-enclosed structures that store various materials
GOLGI APPARATUS location structure function
LOCATION cytoplasm near ER STRUCTURE membrane system of flattened sacs FUNCTION cis face: - receives transport vesicles produced in ER trans face: - produces vesicles filled with modified contents originally received from ER - secretory vesicles transport materials to plasma membrane
CHLOROPLAST location structure function
LOCATION cytoplasm of plant and algal cells only STRUCTURE double membrane-enclosed structure with separate, internal membranes called thylakoids occuring in stacks called grana and connecting sheets (lamellae) FUNCTION thylakoids contain the green pigment chlorophyll, which captures light energy, as well as enzymes for light-gathering phases of photosynthesis
RIBOSOMES location structure function
LOCATION free in cytoplasm surface of the rough ER, mitochondria, and on chloroplasts STRUCTURE (40S) small ribosomal subunit which reads the RNA, (60S) large subunit which joins amino acids to form a polypeptide chain. FUNCTION involved in protein synthesis
CYTOSKELETON location structure function
LOCATION throughout the cytoplasm STRUCTURE network of protein fibers forming microtubules, microfilaments and intermediate filaments FUNCTION - giving rigidity and strength to cells - amoeboid movement in some cells
How are mitochondria and chloroplasts different?
MITOCHONDRIA: single membrane-enclosed ATP present in almost all eukaryotic cells CHLOROPLASTS: double membrane-enclosed photosynthesis present in plant and algal cells
What are the components in a eukaryotic cell?
Nucleus Mitochondria Chloroplast Endoplasmic Reticulum Golgi apparatus Lysosomes Peroxisomes Vacuoles Cytoskeleton Ribosomes Cell Walls Motility structures
What are the different types of cell walls found in eukaryotic cells? In what types of organisms are they found?
Plant cell walls = cellulose; other Algal cell walls = cellulose; maybe polysac/silica Fungi cell walls = chitin; maybe cellulose
Explain the Endosymbiosis Theory
Theory that eukaryotic cells evolved by incorporation of prokaryotes within larger prokaryotic cells; prokaryotes developed into membrane-bound organelles of eukaryotic cells - mitochondria and chloroplasts
Where are pseudopodia found?
amoebae and in movement of animal white blood cells
What are algal cell walls composed of?
cellulose (may have other polysaccharides or silica)
What are plants cell walls composed of?
cellulose and other associated compounds
What are fungal cell walls composed of?
chitin, a polysaccharide of NAG), may also have cellulose
How are flagella and cilia different?
cilia is shorter and more numerous on cells that possess them and movement is synchronized
Where are cilia found in?
ciliated protozoa and in human respiratory tract
Define ENDOPLASMIC RETICULUM (ER)
complex membrane system of tubules and sacs, continuous with nuclear envelope
What is the structure of flagella in eukaryotes?
composed of microtubules of protein called ,*tubulin*, surrounded by a membrane, with associated protein dynein
motility of pseudopodia?
crawling motion caused by action of actin and myosin proteins
What is the structure of pseudopodia in eukaryotes?
extensions/projections of cytoplasm and surround membrane of cells capable of amoeboid movement
Where are ribosomes found in eukaryotic cells?
free in cytoplasm and associated with RER, mitochondria and chloroplasts
Where are cell walls present?
in plant cells, algal cells and fungi
Where are flagella found in?
protozoa, some algae, and mammalian sperm
What are the two distinct but connected regions of ER?
rough endoplasmic reticulum (RER) smooth endoplasmic reticulum (SER)
How are flagella and cilia similar?
same chemical composition and microtubule arrangement
What is the structure of cilia in eukaryotes?
same chemical composition and microtubule arrangement as in flagella
motility of cilia?
synchronized whip-like motions
How does flagella move in eukaryotes?
whip-like motion