Chapter 3 and 7
Endomembrane System
A series of membranous tubules, sacs, and flattened disks that synthesize many cell components and move materials around within the cell
Provide some examples of bacterial structures that might be used as antibiotic targets and explain why.
Any structure specific to bacteria are good targets because they won't hurt the human cells. Like cell walls, because human cells lack cell walls.
Why are mitochondria and chloroplasts unable to multiply outside of a host cell?
Because during an endosymbiotic event, they were both engulfed by a host cell and converted into organelles. They need the host cell in order to code for their proteins, so they can't live outside of the cell
Explain why prokaryotes tend to survive and adapt more rapidly to extreme and dynamic environmental conditions than eukaryotes.
Because they have thicker cell walls and have the possibility of forming endospores
Why do eukaryotic cells require an endomembrane system?
It is required to transport materials that cannot be dispersed by diffusion alone
Why was the work of Snow so important in supporting the germ theory?
It proved that disease could be spread not just from the air but from contamination as well.
Explain how the ABC transporter system works.
It utilizes the energy of ATP binding and hydrolysis to transport various substrates
For gram-negative bacteria describe the location and function of: lipopolysaccharides (LPS); Porins; and Periplasm
LPS: An endotoxin in infections in the outer leaflet of the outer membrane, protects membrane Porins: On the outer membrane of the cell that acts as a channel for diffusion Periplasm: Between the cell wall and plasma membrane, a gel-like matrix
Polysaccharides
Large polymers of hundreds of monosaccharides Linked by glycosidic bonds Ex: starch, glycogen, and cellulose
What is a flagellum made of and what drives its "motor"?
Made of protein subunits Basal body is the motor for the flagellum
Describe the three major functions of the cytoplasmic membrane
1. Barrier- Keeps the inside and outside of the cell separate and protected 2. Protein- Protein channels that actively transport proteins and ions 3. Energy- Makes ATP for energy for the cell
List and draw 3 major morphologies of prokaryotic cells.
1. Coccus (round) 2. Bacillus (rod) 3. Spirillium (spiral)
Describe the three systems known for transporting substances through the membrane.
1. Simple diffusion (passive transport): movement of molecules from a high concentration to a low concentration (small molecules) 2. Facilitated diffusion: Movement of large molecules with use of protein channel 3. Active transport: Movement of molecules against concentration gradient with use of ATP
Explain why the experiments of Needham and Spallanzani yielded in different results even though they used similar methodologies.
Both boiled broths to test the theory of spontaneous generation, but Needham didn't boil his long enough. Therefore, there were still microbes in his broth, but he believed they came from spontaneous generation. While Spallanzani boiled his longer, and found that no new microbes formed in his broth unless exposed to the air.
Structure of Ribose
C5H10O5 The fourth carbon undergoes the ring-forming reaction with the carbonyl group
Heating a protein sufficiently may cause it to denature. Considering the definition of denaturation, what does this statement say about the strengths of peptide bonds in comparison to hydrogen bonds?
Denaturation: unfolding of proteins peptide bonds are stronger than hydrogen bonds and won't be denatured. Peptide bonds are strong covalent bonds with amino acids
The term "dextrose" is commonly used in medical settings when referring to the biologically relevant isomer of the monosaccharide glucose. Explain the logic of this alternative name.
Dextrose is called this because it is a different isomer of glucose, and it metabolizes differently with things
The causative agent of botulism, a deadly form of food poisoning, is an endospore-forming bacterium called Clostridium botulinim. Why might it be difficult to kill this bacterium in contaminated food?
Endospores are resistant to heat, chemicals, and radiation.
How do bacterial flagella respond to a chemical gradient of an attractant to move toward a higher concentration of the chemical?
Flagella act like propellers. Flagella respond to chemical gradients by increasing the length of runs and decreasing the length of tumbles
What evidence exists that supports the endosymbiotic theory?
Genetic sequencing and phylogenetic analysis show that mitochondria and chloroplasts have similar DNA sequences and chromosome structure to their bacterial counterparts. Also, ribosomes of mitochondria and chloroplasts resemble the ribosomes of bacteria
What existing evidence supports the theory that mitochondria are of prokaryotic origin?
Genetic sequencing shows that the ribosomes of mitochondria resemble those of bacteria.
Describe and draw the structural differences between gram-positive and gram-negative cell walls.
Gram-positive: think peptidoglycan layer, should be purple Gram-negative: thin layer or no peptidoglycan, should be pink or red
Draw the structure of a phospholipid bilayer and label the parts.
Hydrophyllic head, hydrophobic tails
What is the direction of water flow for a bacterial cell living in a hypotonic environment? How do cell walls help bacteria living in such environments?
Hypotonic environment is where the solute concentration inside the cell exceeds that outside of the cell, so the water will move by osmosis INTO the cell. Cells that have a cell wall can better withstand changes in osmotic pressure and maintain their shape.
Explain in your own words Pasteur's swan-neck flask experiment.
Pasteur's swan-neck flask experiment proved that spontaneous generation was false. When broth was in the flask and didn't touch the side with microorganisms, the broth had no signs microbes in it. When the broth did touch the side, there was growth of microorganisms. This proved spontaneous generation wrong.
What is peptidoglycan? (general chemical components and overall function)
Peptidoglycan is the major component of bacterial cell walls Gives the cell its shape Made of long chains of peptide bridges
Describe the structure of a typical phospholipid. Are these molecules polar or nonpolar?
Phospholipids are complex lipids that contain at least one phosphate group They have a hydrophilic head with phosphate and glycerol and two hydrophobic tails of fatty accids Polar head and nonpolar tails
Label the parts of the prokaryotic cell.
Photo Attached
Name at least two ways that prokaryotic flagella are different from eukaryotic flagella.
Prokaryotic: Stiff, rotating structure Eukaryotic: flexible whip composed of microtubules
Microorganisms can thrive under many different conditions, including high-temperature environments such as hot springs. To function properly, cell membranes have to be in a fluid state. How do you expect the fatty acid content (saturated versus unsaturated) of bacteria living in high-temperature environments might compare with that of bacteria living in more moderate temperatures?
Saturated fats are solid at room temperature (butter) Unsaturated fats are liquid at room temperature (olive oil) Bacteria living in moderate temps most likely have more unsaturated fats while bacteria living in high temps most likely have more saturated fats
How did the explanation of Virchow and Remak for the origin of cells differ from that of Schleiden and Schwann?
Schwann and Schleiden: cells form from crystallization Virchow and Remak: cells form from other cells, cell division
How are fimbriae and pili similar? How are the different?
Similar: Protein appendages that extend outward and interact with the environment. Both attach to surfaces Difference: Pili (long) transfer DNA while fimbriae (short) attach to cells for colonization, infectivity, and virulence
Monosaccharides
Simple carbohydrates Building blocks (monomers) for the synthesis of polymers or complex carbohydrates Ex: galactose
Isotonic solution
Solute concentrations inside and outside the cell are practically equal, no net movement of water
What is the function of an endospore and how is an endospore formed?
Structures that protect the bacterial genome in a dormant state Protect without food or water, against chemicals, extreme temps, and radiation Formed by sporulation when nutrients become depleted.
What would the results of Pasteur's swan-neck flask experiment have looked like if they supported the theory of spontaneous generation?
The broth would have signs of microorganisms without the flask breaking, and there would be no signs of microorganism on the flask, but only in the broth
Hypertonic Solution
The solute concentration outside of the cell exceeds that inside the cell, water diffuses OUT of the cell and into the external medium
What were the differences in mortality rates due to puerperal fever that Ignaz Semmelweis observed? How did he propose to reduce the occurrence of puerperal fever? Did it work?
Women with physicians and medical students mortality rate 10-20 % Women with midwives mortality rate 1% He suggested that physicians and med students wash their hands with chlorinated lime water before and after each patient, and it dropped mortality rates
Endosymbiotic Theory
The theory that mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship with eukaryotic host
Why are carbon, nitrogen, oxygen, and hydrogen the most abundant elements in living matter and, therefore, considered macronutrients?
They are essential to the function of many biochemical reactions, and essential to life
Explain how endospores provide an advantage to organisms capable of forming them. How long can endospores last (and remain viable)?
They can last for up to thousands of years They help organisms to survive, and when they become metabolically active again, endospores go through germination and go back to its vegetative state
Disaccharides
Two monosaccharides bonded by a glycosidic bond (covalent) Glycolsidic bonds form between hydroxyl groups Ex: maltose, lactose, sucrose