BIOA01H3 Lecture Notes - Lecture 15: Prokaryote, Heterotroph, Cell Wall

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Bioa01h3: unifying principles life on earth - lecture 15: all about bacteria and. Prokaryotes: unicellular organisms: thrive almost everywhere: remarkable diversity, appear simple in structure, have the greatest metabolic diversity, classified into two domains (bacteria, archaea, three common shapes: sphere (coccus), rod (bacillus), spiral (spirillus) Bacteria: responsible for several human disease, food production. Archaea: disappeared forty years ago, have different plasma-membrane from bacteria prokaryote. External: cell wall, cell membrane, capsule, pili, flagella, cell wall protection maintains shape (most contain peptidoglycan, polymer of modified sugars cross-linked by short polypeptides, some bacterial cell walls contain outer membrane, contains lipopolysaccharide (lps) semblance of cytoskeleton. Gram stain: classification based on reaction to gram stain procedure, difference in cell wall composition-peptidoglycan, cells stained with crystal violet (purple +) then iodine, rinsed with ethanol, counterstained with safranin (pink) Having an outer membrane; haemophilus influenza change the shape of enzymes. Layer outside of cell wall: consists of polysaccharides, protects bacteria from external environment, desiccation, antibodies.

Related Questions

nothing is missing now.you just have to tell what are expected observations.AS WE HAVE TO DO EXPERIMENT AFTER BUT FIRST WRITE THAT WHAT WILL BE EXPECTED FROM THE RESULTS?WE WILL GET PHOTOS WHEN WE PERFORM BUT THEN WE WILL COMPARE WHETHER WHAT WE EXPECTED IS WHAT WE GOT OR IS THE ACTUAL RESULT DIFFERENT.
INTRODUCTION
For acquiring food material, bacteria excrete extracellular enzymes that split larger molecules into smaller units.For example, amylase and cellulase degrade polysaccharides such as starch and cellulose into simple sugars, which are then transported into the cell for metabolic purposes. A variety of proteases degrade protein molecules such as gelatin and casein into amino acids, and lipases split fats into fatty
acids and glycerol. These physiological or biochemical characteristics are used for isolation and identification of bacteria in conjunction with other morphological and cultural methods. In this exercise, you will perform tests related to hydrolytic reactions.
Starch hydrolysisâSince many bacteria are capable of hydrolyzing starch, this test has a fairly wide application. Bacteria that hydrolyze starch produce amylases that yield molecules of maltose, glucose, and dextrins.
Casein hydrolysisâCasein is the predominant protein in milk and its presence causes milk to have its characteristic white color. Many bacteria produce proteases that degrade proteins into peptides and individual amino acids in a process called proteolysis.

MATERIALS
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Nutrient broth cultures of Bacillus subtilis, Escherichia coli andStaphylococcus epidermidis
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Starch agar culture plate
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Casein agar culture plate
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Gramâs iodin

1.Label and streak in a straight line with all the 3 cultures on the starch agar plate ANDon the casein agar plate.

2.Incubate the plates at 37oC for 24-48 hours.

Week 2 âStarch Hydrolysis

1.Add several drops of Gramâs iodine over the growth on the medium. Rotate and tilt the plate gently to spread the iodine. Iodine is a starch indicator and when it comes in contact with a medium of starch, it turns blue.

2.If starch is hydrolyzed and no longer present, the medium will have a clear zone next to the growth.

3. Take a photograph of your plate against a white background. (If you do not have a phone equipped with a camera, ask a lab mate to take a picture for you and have the picture electronically sent to you.)

Week 2 âCasein Hydrolysis

1.Examine the streaks on the casein agar plates. A clear zone adjacent to the growth is evidence of casein (protein) hydrolysis. Discussion Amongst other points, you should address in the discussion whether the observations you made were expected. (You will need to do research to answer address this issue. Make sure you include proper citations?

What is expected observation for it with reference if possible

Directions: Write out your answers in the word document and then copy and paste everything into the text box. If you do not include the question along with your answer, you will be marked down.

1. What would happen if you put pGLO directly onto an agar plate and you checked on it after letting it incubate?

a. It would glow

b. It would grow

c. Nothing

d. E.Coli would grow

2. Explain in a short sentence or two your reasoning for question 1.

3. What shape is a plasmid?

4. How is a plasmid different from human DNA? Write one difference.

5. Bacteria can share DNA through a unique method called transformation. What are the TWO requirements a bacteria cell must possess in order to share DNA with another bacteria cell?

6. Why during our experiment did we put our e.Coli with pGLO inserted in it onto agar plates with ampicillin (Amp)?

a. So that it would kill the e.Coli and serve as our control

b. To kill all the e.Coli that did not take up the pGLO

c. To create antibiotic resistant bacteria

d. To cause the e.Coli to glow

7. Yeast cells are what type of cell?

a. Bacteria

b. Eukaryotes

c. Prokaryotes

d. Archaea

8. Why would someone study yeast cells instead of human cells?

9. Do you agree or disagree with the following statement: If your cells is exposed to UV light and it causes a thymidine dimer, your cell is doomed to die.

10. Are wildtype (control) yeast immune to UV light damage?

11. BTB was a dye we used to directly measure ________

a. PH

b. Oxygen

c. Carbon Dioxide

d. Carbon

12. BTB was a dye we used to INDIRECTLY measure ________

a. PH

b. Oxygen

c. Carbon Dioxide

d. Carbon

13. What is one reason why a plant would want to close its stomata?

14. What is one function that ground tissues provides for a plant?

15. List one difference between monocots and dicots

16. Why is it important for a plant to have stomata? Write one reason why

17. What is the purpose of xylem in a plant cell?

18. Pholem is also important to plant cells, what is itâs purpose?

19. This theory explains why trees can grow to such tall heights and still provide water to their leaves.

a. Translocation

b. Transpiration

c. Cohesion-Tension

d. Vacuum

20. Fill in the blank

Pholem is considered to be a(n) _________ transport system while xylem is considered a(n) _______________transport system.

21. Apical meristems are found in these two places on a plant

a. At the site of new leaf growth and the roots closes to the top of the soil

b. Vascular tissue and ground tissue

c. Ground tissue and dermal tissue

d. The point of new growth on the stem and root

22. Fill in the blank.

Xylem moves substances _____ while phloem moves substances _____ a plant.

23. What are the two types of digestive mechanisms?

24. What is one benefit that mastication has for digestion?

25. What is an example of an organism that digests food intracellularly?

26. What is an example of an organism that digests food extracellularly?

27. Give two examples of where surface area is increased in a small space to aid in absorption within the human body

28. Name one difference between arteries and veins.

29. What is the role of capillaries in the circulatory system?

30. How are the terms âexcretionâ and âdefecationâ different?

31. What is the role of the ADH hormone?

32. What does the term âMedullaâ refer to when talking about mammalian tissue?

a. The outer edges of a tissue

b. The middle of a tissue

c. The top of a tissue

d. The bottom of a tissue

33. Fill in the blank

Mammals have a _______ circulatory system while insects have a _______ circulatory system.

34. What is one benefit a closed circulatory system provides?

35. What is hemolymph?

1) What clinical manifestation do Staphylococcus aureus and Staphylococcus epidermidis share? A) nosocomial infections B) protein A antiphagocytic factor C) hyaluronidase enzyme D) enterotoxins E) staphylokinase 2) Which of the following has been historically classified as Gram-negative bacteria but is genetically more similar to low G + C Gram-positive bacteria? A) mycoplasmas B) Mycobacterium C) Clostridium D) Propionibacterium E) Nocardia 3) What is one virulence factor that differentiates Staphylococcus aureus from other species of staphylococci? A) It has a capsule. B) It can produce coagulase. C) It produces catalase. D) It can live on the surface of the skin and in cutaneous oil glands. E) It produces lipase. 4) Over 90% of Staphylococcus aureus isolates are penicillin-resistant. Why? A) They have loosely organized polysaccharide slime layers. B) They produce coagulase. C) Cell division occurs in successively different planes, and the daughter cells remain attached to one another. D) They produce Î²-lactamase. E) They produce staphylokinase, which dissolves fibrin threads in blood clots. 5) A woman comes to the emergency department with fever and vomiting. She soon develops a red rash all over her body, and her blood pressure begins to drop. What is one possible diagnosis? A) erysipelas C) scarlet fever B) endocarditis D) toxic shock syndrome E) staphylococcal food poisoning 6) Bacteria collected from a severely inflamed wound are sent to the lab for analysis. The results come back as follows: Gram-positive cocci in irregular clusters, kinase and coagulase positive, and able to grow in the presence of most antibiotics except vancomycin. The bacteria in the wound are most likely _______ A) Enterococcus. C) Staphylococcus aureus. B) Staphylococcus epidermidis. D) methicillin-resistant Staphylococcus aureus (MRSA). E) Streptococcus pyogenes (group A streptococcus). 7) Which of the following statements about "flesh-eating" streptococci is FALSE? A) It is caused by a group A streptococcus. B) It is also known as necrotizing fasciitis because it travels along the fascia. C) It causes death in over 50% of cases. D) It is considered a common complication of pyoderma. E) It involves toxemia. 8) Streptococcus agalactiae is associated with which of the following diseases? A) neonatal bacteremia B) neonatal meningitis C) neonatal pneumonia D) both neonatal bacteremia and neonatal meningitis E) neonatal bacteremia, neonatal meningitis, and neonatal pneumonia 9) What differentiates virulent strains of Streptococcus pneumoniae from nonvirulent strains? A) the species-specific teichoic acid present in its cell wall B) the type of Lancefield antigen it produces C) the presence of a polysaccharide capsule that protects it from digestion after endocytosis D) the type of toxins it produces E) the extent of the hemolytic zone it produces when it is grown on blood agar 10) Otitis media may lead to dangerous meningitis in children due to infection with _____ A) Streptococcus agalactiae. B) Streptococcus pneumoniae. C) Streptococcus mutans. D) Enterococcus. E) Mycoplasma pneumoniae. 11) Which of the following streptococci is associated with dental caries? A) viridans streptococci B) Streptococcus pyogenes C) Streptococcus pneumoniae D) Streptococcus equisimilis E) Streptococcus arginosus 12) Anthrax, which means "charcoal" in Greek, derives its name from _____ A) the airborne endospores it produces. B) the staining properties of the bacillus under the microscope. C) the black eschars it produces on human skin. D) its ability to invade the bloodstream and produce toxemia. E) the high mortality it causes in infected individuals. 13) Which of the following bacteria produce one of the most deadly bacterial toxins known? A) Clostridium perfringens C) Clostridium tetani B) Clostridium difficile D) Clostridium botulinum E) Corynebacterium species 14) Which of the following bacteria can cause life-threatening pseudomembranous colitis? A) Clostridium difficile B) Staphylococcus aureus C) Streptococcus pyogenes D) Enterococcus species E) Clostridium botulinum 15) How does the toxin from Clostridium tetani produce its action? A) It fuses irreversibly to neuronal cytoplasmic membranes, blocking release of acetylcholine at synaptic clefts. B) The smaller polypeptide of its toxin can block the release of inhibitory neurotransmitters by inhibitory neurons in the central nervous system, causing simultaneous contraction of both muscles in an antagonistic pair. C) It is a pyrogenic toxin, which triggers a diffused rash and, later, sloughing of skin. D) It destroys tissues, including muscle and fat. E) It produces antibodies that attack the neuromuscular junctions in skeletal muscle and prevent them from relaxing. 16) Listeria virulence is directly related to its ability to ______ A) produce powerful toxins. B) form very resistant endospores. C) live within cells and thus avoid exposure to the immune system of its host. D) easily become a pathogen in humans. E) resist most antimicrobial agents. 17) The pus from an abscess in a patient's jaw contains microbes that form yellowish grainy masses and appear filamentous under the microscope. Neither antifungal medication nor a normal course of antibiotics has been effective in treating the infection. The abscess is likely the result of infection with A) Actinomyces. B) Mycobacterium. C) Nocardia. D) Propionibacterium. E) Streptococcus. 18) What is the most common disease caused by Propionibacterium? A) acne B) food poisoning C) pneumonitis D) folliculitis 19) Streptococcus pneumoniae is a leading cause of ______ A) acne. C) pharyngitis B) furuncles. D) primary atypical pneumonia. E) otitis media. 20) The soil bacterium Nocardia asteroides can establish opportunistic infections of the _____ A) skin C) central nervous system B) lungs D) cardiovascular system. E) skin, lungs, and central nervous system

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BIOA01H3 Lecture Notes - Lecture 15: Prokaryote, Heterotroph, Cell Wall

BIOA01H3 Full Course Notes

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