(a) Eukaryotic flagella and cilia are composed of a 9+2 array of microtubules, as seen in this transmission electron micrograph cross-section. (b) The sliding of these microtubules relative to each other causes a flagellum to bend. (c) An illustration of
Trichomonas vaginalis , a flagellated protozoan parasite that causes vaginitis. (d) Many protozoans, like this
Paramecium , have numerous cilia that aid in locomotion as well as in feeding. Note the mouth opening shown here. (credit d: modification of work by University of Vermont/National Institutes of Health)
Explain how the cellular envelope of eukaryotic cells compares to that of prokaryotic cells.
Explain the difference between eukaryotic and prokaryotic flagella.
Resolution
Since amoxicillin has not resolved Barbara’s case of pneumonia, the PA prescribes another antibiotic, azithromycin, which targets bacterial ribosomes rather than peptidoglycan. After taking the azithromycin as directed, Barbara’s symptoms resolve and she finally begins to feel like herself again. Presuming no drug resistance to amoxicillin was involved, and given the effectiveness of azithromycin, the causative agent of Barbara’s pneumonia is most likely
Mycoplasma pneumoniae . Even though this bacterium is a prokaryotic cell, it is not inhibited by amoxicillin because it does not have a cell wall and, therefore, does not make peptidoglycan.
Eukaryotic cells are defined by the presence of a
nucleus containing the DNA genome and bound by a
nuclear membrane (or
nuclear envelope ) composed of two lipid bilayers that regulate transport of materials into and out of the nucleus through nuclear pores.
Eukaryotic cell morphologies vary greatly and may be maintained by various structures, including the cytoskeleton, the cell membrane, and/or the cell wall
The
nucleolus , located in the nucleus of eukaryotic cells, is the site of ribosomal synthesis and the first stages of ribosome assembly.
Eukaryotic cells contain
80S ribosomes in the rough endoplasmic reticulum (
membrane bound-ribosomes ) and cytoplasm (
free ribosomes ). They contain 70s ribosomes in mitochondria and chloroplasts.
Eukaryotic cells have evolved an
endomembrane system, containing membrane-bound organelles involved in transport. These include vesicles, the endoplasmic reticulum, and the Golgi apparatus.
The
smooth endoplasmic reticulum plays a role in lipid biosynthesis, carbohydrate metabolism, and detoxification of toxic compounds. The
rough endoplasmic reticulum contains membrane-bound 80S ribosomes that synthesize proteins destined for the cell membrane
The
Golgi apparatus processes proteins and lipids, typically through the addition of sugar molecules, producing glycoproteins or glycolipids, components of the plasma membrane that are used in cell-to-cell communication.
Lysosomes contain digestive enzymes that break down small particles ingested by
endocytosis , large particles or cells ingested by
phagocytosis , and damaged intracellular components.
The
cytoskeleton , composed of
microfilaments ,
intermediate filaments , and
microtubules , provides structural support in eukaryotic cells and serves as a network for transport of intracellular materials.
Centrosomes are microtubule-organizing centers important in the formation of the mitotic spindle in mitosis.
Mitochondria are the site of cellular respiration. They have two membranes: an outer membrane and an inner membrane with cristae. The mitochondrial matrix, within the inner membrane, contains the mitochondrial DNA, 70S ribosomes, and metabolic enzymes.
The plasma membrane of eukaryotic cells is structurally similar to that found in prokaryotic cells, and membrane components move according to the fluid mosaic model. However, eukaryotic membranes contain sterols, which alter membrane fluidity, as well as glycoproteins and glycolipids, which help the cell recognize other cells and infectious particles.
In addition to active transport and passive transport, eukaryotic cell membranes can take material into the cell via
endocytosis , or expel matter from the cell via
exocytosis.
Cells of fungi, algae, plants, and some protists have a
cell wall, whereas cells of animals and some protozoans have a sticky
extracellular matrix that provides structural support and mediates cellular signaling.
Eukaryotic flagella are structurally distinct from prokaryotic flagella but serve a similar purpose (locomotion).
Cilia are structurally similar to eukaryotic flagella, but shorter; they may be used for locomotion, feeding, or movement of extracellular particles.
True/false
Mitochondria in eukaryotic cells contain ribosomes that are structurally similar to those found in prokaryotic cells.
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
