2B: The Structure, growth, physiology and genetics of prokaryotes & viruses Flashcards Preview

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Flashcards in 2B: The Structure, growth, physiology and genetics of prokaryotes & viruses Deck (95):
1

What are the 4 tenets of Cell Theory?

1. All living things are composed of cells
2. The cell is the basic functional unit of life
3. All cells arise ONLY from preexisting cells
4. Cells carry genetic information in the form of DNA

2

How do viruses violate cell theory?

They do not arise from preexisting cells and they do not carry genetic information the form of DNA

3

List the 7 organelles in eukaryotic cells:
N M R
L P S
G

Nucleus, Mitochondria, Lysosome, Rough E.R., Smooth E.R., Golgi Apparatus, Peroxisome

4

What surrounds the nucleus and what is that structures function?

Nuclear envelope, it has nuclear pores that allow selective 2 way exchange of material

5

What does the nucleus contain and what is that structures function?

Nucleolus, synthesizes ribosomal RNA

6

What is the function of the nucleus? What processes occur here?

To contain and protect DNA; DNA replication, transcription and partial RNA assembly

7

What is the function of mitochondria?

Produce ATP via Krebs Cycle & Oxidative Phosphorylation

8

List the structures of the mitochondria.

Outer Membrane
Intermembrane Space
Inner Membrane
Matrix

9

What is the function of cristae?

Increase surface area available for electron transport chain

10

What enzymes are contained in the mitochondrial matrix?

Pyruvate dehydrogenase complex
Citric Acid Cycle enzymes

11

What lines the inner mitochondrial membrane?

Electron Transport Chain & ATP Synthase

12

Describe the DNA in Mitochondria.

Single circular DNA molecule that encodes rRNA, tRNA and several mitochondrial proteins

13

What is the endosymbiotic theory?

That mitochondria originated as independent unicellular organisms living within larger cell

14

What is special about the DNA of Mitochondria?

It's inherited only from the mother because the ovum supplies the organelles

15

How do mitochondria replicate?

Binary Fission

16

What process can mitochondria participate in?

Apoptosis

17

What is the function of the lysosome?

Degrades biomolecules through hydrolysis

18

What do lysosomes use to degrade molecules? When are they active?

Hydrolytic enzymes; active in only low pH environments

19

What is autophagy?

Lysosome degrades non-functional or damaged self-organelles

20

What is the Rough E.R.? What is it responsible for?

The part of the ER that contains ribosomes; it synthesizes proteins that are secreted extracellularly or plasma membrane proteins

21

What is the Smooth E.R.? What is it responsible for?

The part of the ER that lack ribosomes; responsible for lipid synthesis and detoxification of certain compounds

22

What is the function of the Golgi Apparatus?

It receives cellular products (proteins) and modifies them; sort and sends those proteins to their cellular destination; performs exocytosis

23

How does the golgi apparatus modify proteins?

Glycosylation, Phosphorylation, Sulfonation

24

What is the cis vs. trans face of the golgi?

Cis face is closer to the ER and Trans face is farthest from the ER

25

What is the function of peroxisomes?

They contain hydrogen peroxide which aid in metabolizing lipids and toxins (in the liver); phospholipid synthesis

26

What enzyme do peroxisomes contain? What does that enzyme do?

Catalase; converts H2O2 into H2O and O2

27

What is the function of the cytoskeleton? What is it composed of?

Provide structure to the cells and helps maintain cell shape; it's composed of microfilaments, microtubules and intermediate filaments

28

What are microfilaments composed of? Are they thick or thin?

Polymerized rods of actin; thin

29

What is the function of microfilaments?

Use ATP to generate force for movement; forms the cleavage furrow in cytokinesis

30

What are the kinds of actin? Which is a monomer or polymer?

Filamentous Actin (F-Actin) [polymer]
Globular Actin (G-Actin) [monomer]

31

What are microtubules composed of? Are they they thick or thin?

Hollow polymers of tubulin (alpha and beta), thick

32

What is the function of microtubules? Where are they organized?

They provide pathways for movement throughout the cell via kinesin and dynein; the centriole organizes them (9 w/ a hollow center)

33

What are some structures that are made of microtubules? What are their arrangements?

Cilia & Flagella; 9+ 2 arrangement w/ dynein arms

34

What are intermediate filaments composed of?

Filamentous proteins (such as keratin)

35

What is the function of intermediate filaments?

They are involved in cell-cell adhesion as well as maintenance of the cytoskeleton by resisting mechanical stress

36

What are the 4 tissue types?

Epithelial, Connective, Muscle and Nervous

37

Describe Epithelial Tissue

Cover the body, protect against invasion and desiccation, connected to the basement membrane

38

What is the parenchyma?

The functional part of an organ

39

What are the types of epithelial tissue? # of layers

Simple (1)
Stratified (multiple)
Pseudostratified (1 @ different heights)

40

What are the shapes of epithelial tissue?

Cuboidal (cube shaped)
Columnar (column shaped)
Squamous (flat and scalelike)

41

What is the function of connective tissue?

Supports the body and provides a framework for the epithelial cells to carry out their function

42

What is the stroma?

It is the part of a tissue or organ that has a connective and structural role

43

Describe the structure of a prokaryote.

It has no membrane bound organelles, single circular DNA in a nucleoid regions

44

What are the shapes of bacteria?

1. Cocci (sphere)
2. Bacilli (rod)
3. Spirilli (spiral)

45

Obligate Aerobes

Require O2 for Metabolism

46

Anaerobes

Do not require O2 for metabolism

47

Obligate Anaerobes

Cannot survive in the presence of O2

48

Facultative Anaerobes

Use O2 if present; utilizes anaerobic metabolism if its not present

49

Aerotolerant Anaerobes

Unable to use O2 for metabolism but aren't harmed by its presence

50

Describe prokaryotic cell structure; What are some of the structures?

They lack a nucleus and membrane bound organelles; cell wall & flagella

51

Cell Wall

Protects cell from outer environment; provides structure and controls movement in and out of the bacteria

52

Types of Cell Walls

Gram Negative
Gram Positive

53

Negative Gram Stain (Pink-Red)

Absorbs safranin counterstain but not crystal violet primary stain

54

Gram Negative Cell Wall

Thin wall of PTG (small amounts); outer membrane of phospholipids & lipopolysaccharide

55

Positive Gram Stain (Purple)

Absorbs crystal violet but not safranin counterstain

56

Gram Positive Cell Wall

Thick layer of PTG; contain lipoteichoic acid

57

Flagella

Used for taxis, composed of a filament, basal body and hook

58

Plasmids

Circular pieces of DNA that may confer particular characteristics such as antibiotic resistance

59

Bacterial Mitochondrial Subunits

30S and 50S

60

Binary Fission

Chromosome replicates while cell grows in size, the cell wall grows inward and eventually divides in two

61

Genetic Recombination Processes

Transformation, Conjugation & Transduction

62

Episomes

Plasmids that are capable of integrating into the host genome

63

Transformation

Integrates foreign genetic material into host genome

64

Conjugation

Two cells form a conjugation bridge between them allowing genetic material to transfer (unidirectional)

65

What does F+ indicate?

Donor (Male)

66

What does F- indicate?

Recipient (Female)

67

How does E. coli work?

F+ cells replicate their F factor and donate the copy to an F- cell which can donate it to other cells

68

Transduction

Requires a virus (bacteriophage); integrate genome from host cell to new cell

69

Transposons

Genetic elements capable of inserting themselves into the genome, if inserted into a coding region it can disrupt the gene

70

Stages of Bacterial Growth

Lag
Exponential
Stationary
Death

71

Lag Phase

Bacteria adapt to new environment, not much growth occurs

72

Exponential Phase

Growth increases exponentially on a linear path after they adapt to their environment

73

Stationary Phase

Reproduction slows down due to decreased resources

74

Death Phase

Number of bacteria exceed the ability of the environment to support them

75

Viruses

Obligate intracellular parasites

76

Characteristic of Viruses

Contains a head with nucleic acid inside; a tail that's used for insertion

77

Virions

Viral progeny that can be released to infect additional cells

78

Viral Genome

They determine how infection by each virus proceeds

79

Positive Sense

Genome may be directly translated to functional proteins by the ribosomes of the host cell

80

Negative Sense

Requires synthesis of an RNA strand complementary to negative sense RNA that can be used as template for protein synthesis

81

[-] RNA Viruses

Carries & encodes RNA-Dependent RNA Pol; makes complimentary copy that acts as mRNA and are translated into viral proteins

[-] -replicase-> [+] -> proteins + [-]

82

[+] RNA Viruses

Encodes RNA-Dependent RNA Pol; synthesize [-] strand which can be used to make proteins for new viruses

[+] -replicase-> [-] -replicase-> [+] -> proteins + [-]

83

Retroviruses

Encode for reverse transcriptase; enveloped ssRNA;

[+] -RT-> dsDNA -integration/transcription-> [+]

84

Self Replication Process

Attachment -> Entry -> Uncoating -> Replication -> Post-Translational Modification -> Lysis

85

Attachment

Binding to receptors on host cell

86

Entry

Penetrates the host cell wall/membrane

87

Uncoating

Viral capsid is degraded by viral enzymes

88

Replication

mRNA, Proteins and other genomic material are produced

89

Lysis

Host cell lyses due to release of viral progeny

90

Lytic Cycle

Virus maximally uses cell machinery disregarding the survival of the host cell

91

Lytic Cycle Processes

Attachment -> Penetration -> Transcription/Translation -> Degradation of host genome -> Replication of phage genome -> Assembly of new capsid -> Lysosomes destroy bacterial cell wall

92

Lysogenic Cycle

Integration into the host genome as a provirus or prophage; virus is replicated as the bacterium reproduces since its a part of the host genome; does not lyse the host cell

93

Lysogenic Cycle Processes

Prophage integrates, reproduces with bacterium, are activated due to some excision event

94

Prions

infections proteins, trigger the misfolding of other proteins and affect their solubility causes aggregates

95

Viroids

Plant pathogens, circular ssRNA, bind to plant genome and silence it