Lecture3 Peptidoglycan synthesis and Eukaryotic Cell structure Flashcards Preview

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Flashcards in Lecture3 Peptidoglycan synthesis and Eukaryotic Cell structure Deck (133):
1

Gram-postive bacteria stain ____

purple

2

Gam-negative bacteria stain ____

pink

3

Giemsa staining is due to

cell wall structure

4

What two alternating sugars for peptidoglycan backbone

- N-acetylglucosamine (NAG)

- N-acetylmuramic acid (NAM)

5

Peptidoglycan chains have alternating ___ and ____ amino acids attached to ____

D-, L-, attached to NAM

6

Peptidoglycan is joined by crosslinks between the _____

peptides

7

E. coli peptidoglycan exhibits _____ cross-linking

direct

8

Staphylococcus aureus peptidoglycan exhibits _______ linking

Peptide interbridge

9

Peptidoglycan synthesis is a complex process involving _____ derivatives

UDP

10

Peptidoglycan synthesis uses ____ to transport NAG-NAM- pentapeptide units across the cell membrane

bactoprenol

11

Function of Bacitracin

Does not allow bactroprenol carrier to lose one phosphate (bactoprenol phosphate) and move back to the cytoplasmic side of the membrane

12

The final step in peptidoglycan synthesis is _____which creates the peptide cross-links between the peptidoglycan chains

transpeptidation

13

Amino acids are added to NAM one at a time, except for the last _____ ____, which are added in the same reaction

D-alanines

14

What are the two carriers involved in peptidoglycan biosynthesis

- Bactoprenol

- Uridine diphosphate

15

A 55-carbon alcohol that attaches to NAM by a pyrophosphate group and moves peptidoglycan units through membrane

Bactoprenol

16

Bactoprenol is a ___- carbon alcohol that attaches to NAM by a _____ group

55, pyrophosphate group

17

Bactoprenol function

moves peptidoglycan units through hydrophobic membrane

18

Uridine diphosphate is an activated ______ carrier, except in the case of peptidoglycan synthesis it carries _____ or ____ instead of glucose

sugar, NAM or NAG

19

Cycloserine inhibits

Blocks formation of D-Ala-D-Ala

20

______ inhibits transpeptidation by binding to D-Ala-D-Ala

Vancomycin

21

Penicillin inhibits the ______ reaction

transpeptidation

22

_____ blocks the dephosphorylation of bactoprenol pyrophosphate

Bacitracin

23

The 8 stages of peptidoglycan synthesis

- UDP derivatives of NAM and NAG are synthesized in the cytoplasm

- Amino Acids are added sequentially to UDP-NAM to form the pentapeptide chain
- The 2 terminal D-alanines are added as a dipeptide
- No ribosomes involved

- NAM-Pentapeptide is transferred from UDP to a bactoprenol phosphate at the membrane surface

- UDP-NAG adds NAG to the NAM-pentapeptide
- Glycine interbridge, if present, is added

- The completed unit is transported across the membrane to its outer surface by the bactoprenol pyrophosphate carrier

- The peptidoglycan unit is attached to the growing end of a peptidoglycan chain

- Bactoprenol returns to inside of membrane. A phosphate is released; bactoprenol phosphate can now accept another NAM-pentapeptide

- Transpeptidation occurs

24

How does a bacterial cell add new peptidoglycan units to its existing cell wall

- Autolysis carry out limited digestion of peptidoglycan

- This provides acceptor ends for addition of new peptidoglycan units

25

are ribosomes involved in the amino acids being added sequentially to UDP-NAm to form the pentapeptide chain

No!

26

Gram-positive bacteria stain

purple

27

Gram-negative bacteria stain

pink

28

The gram staining reaction is due to

cell wall structure

29

Inventor of gram stain

Danish physician Hans christian Gram

30

The gram stain was invented in ____ and published in

1883 and published in 1884

31

Hans Christian Gram studied ____ tissue sections form patients who died of ____

lung, pneumonia

32

Han Christian Gram discovered that _____ and a solution of ___ and ____ formed a water soluble precipitate that could be removed from host tissues and some microbial cells by an alcohol rinse. Many other microbes retained the stain

Gentian (crystal) violet, iodine, and potassium iodide

33

Hans Cristian Gram did not originally use ____ in his stain

safranin

34

Gram stain primary stain is _____ in combination with ___.

- Crystal violet in combination with iodine

35

What is the function of iodine in the gram stain

it acts as a mordant to enhance crystal violet staining

36

What is the counter stain used in gram staining

Safranin

37

What is used to decolorize the gram negative bacteria

Alcohol or acetone removes crystal violet from Gram-negative cells

38

Gram-positive cell wall has a ___ ring basal body

2

39

Gram-negative cell wall has a ___ ring basal body

4

40

Gram-positive cell wall is disrupted by ____ and sensitive to ____

lysozyme, Penicillin

41

Gram-negative cell wall is _____ sensitive

Tetracycline (because it attacks the ribosomes)

42

Acid-fast cells resist decolorization with _____

acid alcohol

43

the basis for acid-fast staining is a ____ cell wall composed of ______

waxy cell wall composed of mycolic acids

44

examples of cells that stain with acid-fast stain

- Mycobacterium
- Nocardia

45

The waxy cell wall composed of mycelia acids prevents

water-soluble stains form crossing the cell wall

46

Acid-fast staining methods use ______, which is a ______ soluble stain

carbolfuchsin, lipid soluble stain

47

Acid-fast stain ,Carbolfuchsin, contains ____ to help the stain penetrate the cell wall

Phenol

48

Acid-fast cells often give ____ gram stain results, this is due to

abnormal, poor stain absorption followed by high retention

49

Acid fast staining is important for identifying bacteria in the genus _____, which can be pathogenic

Mycobacterium

50

Examples of bacteria in the genus Mycobacterium

- M. leprae
- leprosy
- M. tuberculosis
- Tuberculosis

51

Acid fast staining can be used to identify opportunistic pathogenic members of the actinomycete genus _____ and oocysts of coccidian parasites, such as _______ and _____

Norcardia, Cryptosporidium, Isospora

52

bacterial spores are _____, as well as the head of sperm, and certain eukaryotic cellular inclusions (neuronal cytoplasmic inclusion bodies and nuclear inclusion bodies)

acid fast

53

What is a common counterstain in acid fast staining

methylene blue

54

Carbolfuchsin stains what color

Red

55

Mycoplasmas lack

cell walls

56

Mycoplasmas have what in their plasma membranes

sterols

57

the cell walls of archaea can be ____ or ____

absent or pseudomurein (lack NAM and D-amino acids)

58

What two groups of eukaryotes commonly possess microbial members

- protists
- fungi

59

Prominent members of ecosystem, useful as model systems and industry, and some are major human pathogens

Eukaryotic microorgansims

60

What are the common features of Eukaryotic cells

- Membrane-delimited nuclei
- Membrane-bound organelles that perform specific functions
- Intracytoplasmic membrane complex serves as transport system
- More structurally complex and generally larger than bacterial or archaeal cells

61

The intracytoplasmic membrane complex serves as ____ system in eukaryotic cells

transport

62

Functions of plasma membrane in eukaryotic cells

- mechanical cell boundary
- selectively permeable barrier with transport system
- mediates cell-cell interactions and adhesion to surfaces
- secretion
- signal transduction

63

Functions of cytoplasm

- Composed of cytosol (liquid portion) and organelles
- location of many metabolic processes

64

Functions of Cytoskeleton

- Composed of actin filaments, intermediate filaments, and microtubules
- provides cell structures and movements

65

Functions of endoplasmic reticulum

- Transport of materials
- lipid synthesis

66

Functions of ribosomes

Protein synthesis

67

Function of golgi apparatus

- Packaging and secretion of materials for various purposes
- lysosome formation

68

Function of Mitochondria

- Energy production through use of the tricarboxylic acid cycle, electron transport, oxidative phosphorylation, and other pathways

69

Function of Chloroplasts

- Photosynthesis (trapping light energy and forming carbohydrate from CO2 and water)

70

Functions of nucleus

repository for genetic information

71

Functions of Nucleolus

- Ribosomal RNA synthesis
- Ribosome construction

72

Functions of Cell wall and pellicle

- Strengthen and give shape to the cell

73

Functions of cilia and flagella

- cell movement

74

Functions of vacuole

- Temporary storage and transport
- Digestion (food vacuoles)
- Water balance (contractile vacuole)

75

Where are free ribosomes located

-cytosol, nucleus, and mitochondria

76

Where are bound ribosomes located

on the Rough ER

77

Eukaryotic cell envelopes consist of the _____ and ____

plasma membrane and all coverings external to it

78

The plasma membrane of eukaryotic cells is a _______

lipid bilayer

79

What are the major eukaryotic membrane lipids

- phosphoglycerides
- sphingolipids
- cholesterol
all of which contribute to strength of membrane

80

The plasma membrane of bacteria and eukaryotes both have _____

phospholipids

81

The plasma membrane of eukaryotic cells have ______ which participate in a variety of cellular processes

microdomains (lipid rafts)

82

Unlike the ______ in the cell wall of Bacteria and Archaea, many eukaryotes lack or have a chemically distinct cell wall

peptidoglycan

83

Cell walls of photosynthetic algae are composed of

- cellulose
- pectin
- Silica

84

Cell walls of fungi are composed of

- Cellulose
- Chitin
- Glucan

85

____ are the most prominent external structures observed on eukaryotic cells

cilia and flagella

86

how are cilia and flagella of a eukaryotic cell different

- cilia are typically only 5 to 20 micrometers while flagella are 100 to 200 micrometers long
- their patterns of movement are usually distinctive

87

substance inside plasma and outside nucleus

Cytoplasm membrane

88

fluid portion of cytoplasm

cytosol

89

Cytoskeleton is

microfilaments, intermediate filaments, microtubules

90

movement of cytoplasm through cells

Cytoplasmic streaming

91

80S ribosomes are found where in eukaryotic cells

- membrane bound: attached to ER
- Free: in cytoplasm

92

70S ribosomes are found where in eukaryotic cells

- In chloroplasts and mitochondria

93

bacterial ribosomes are what size

70s

94

An 80S ribosome are composed of

-a dimer of 60S and 40S subunit

95

The 60 S subunit is composed of 3 rRNA molecules which are ____, _____, and _____

5S, 28S, and 5.8S rRNAs

96

The 40S subunit is composed of 1 rRNA (_____), and ____ proteins

18S rRNA and 30 proteins

97

organelle that contains chromosomes

Nucleus

98

organelle that is the transport network

ER

99

Organelle that functions in membrane formation and secretion

Golgi complex

100

Organelle that functions in digestive enzymes

Lysosome

101

Organelle that brings food into cells and provides support

Vacuole

102

Organelle that functions in cellular respiration

Mitochondrion

103

Organelle that functions in photosynthesis

Chloroplast

104

Organelle that functions in oxidation of fatty acids and destroys hydrogen peroxides

Peroxisome

105

Organelle that consists of protein fibers and centrioles

Centromere

106

_____, ____ and ____ are all thought to have evolved from bacterial cells that invaded or were ingested by early ancestors of eukaryotic cells

- Mitochondria
- Hydrogenosomes
- Chloroplasts

107

Mitochondria are very similar to extant _____

bacteria

108

Chloroplasts are very similar to extant _____

cyanobacteria

109

" the power house of the cell" are found in most eukaryotic cells

Mitochondria

110

Site of tircarboxylic acid activity

mitochondria

111

Organelle where ATP is generated by electron transport and oxidative phosphorylation

Mitochondria

112

The Mitochondria is about the same size as ___ cells

bacterial

113

Mitochondria reproduce by _____ as do bacterial cells

binary fission

114

The outer membrane of mitochondria contain ____ similar to the outer membrane of Gram-negative bacteria

porins

115

The inner membrane of mitochondria are highly fold to form ______ and is the location of enzymes and electron carriers for _____ and _____

cristae, electron transport and oxidative phosphorylation

116

The mitochondrial matrix is enclosed by ______

inner membrane

117

The mitochondrial matrix contains ribosomes (_____ the same as _____) mitochondrial DNA (may be _____ like ____ DNA)

70S, same size as bacterial ribosomes, closed circular like bacterial DNA

118

The mitochondrial matrix contains enzymes of the tricarboxylic acid cycle and enzymes involved in _____ of fatty acids

catabolism

119

Small energy conservation organelles in some anaerobic protists

Hydrogenosomes

120

Hydrogenosomes descended form common ____ ancestor

mitochondrial

121

Hydrogenosomes have a ____ membrane, ____ cristae, and usually ___ DNA

double, no, lack

122

Hydrogenosomes ATP is generated by _____ process rather than respiration

fermentation

123

What are the products of ATP production in Hydrogenosomes

CO2, H2, and acetate

124

What are plastids

cytoplasmic organelles of photosynthetic protists and plants

125

Pigment containing organelles observed in plants and algae that are the site of photosynthetic reactions

Chloroplasts

126

Chloroplasts are surrounded by ____ membrane

double

127

The stroma (matrix) of a chloroplast is within the inner membrane and contains

- DNA
- Ribosomes
- Lipid droplets
- Starch granules
- Thylakoids

128

What are Thylakoids

- flattened, membrane delimited sacs
- site of light reactions (trapping of light energy to generate ATP, NADPH, and oxygen)

129

stacks of thylakoids are called

grana

130

____ is the site of dark reactions of photosynthesis (formation of carbohydrates from water and carbon dioxide)

Stroma

131

many algal chloroplasts contain a _____, which participates in polysaccharide synthesis

pyrenoid

132

Molecular unity basic to bacterial, archaeal, and eukaryotic cells

- biochemical processes, metabolic pathways
- genetic code

133

Differences in eukaryotic cells from bacterial and archaeal

- eukaryotic nucleus (membrane-enclosed nucleus)
- larger, more complex (archaea and bacteria are about the size of mitochondria and chloroplast and have no organelles)
- meiosis, mitosis (archaea and bacteria lack both)
- complex processes (bacteria and archaea cannot perform endocytosis, intracellular digestion, directed cytoplasmic streaming, and ameboid movement)