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CHAPTER 3 Flashcards

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1
Q

What are the characteristics of life?

A 
growth
reproduction
responsiveness
metabolism
cellular structure
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2
Q

What are characteristics of prokaryotes?

A

lack nucleus
lack various internal structures bound with phospholipid membranes
are typically 1.0 um in diameter or smaller
composed of bacteria and archaea

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3
Q

What are characteristics of eukaryotes?

A 
have nucleus
have internal membrane-bound organelles
are typically 10-100 um in diameter
more complex structure
composed of algae, protozoa, fungi, animals, and plants
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4
Q

What are glycocalyces?

A

gelatinous, sticky substance surrounding the outside of the cell (bacterial cells)
composed of polysaccharides, polypeptides, or both

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5
Q

What are the two types of glycocalyces? Describe them.

A

Capsule- composed of organized repeating units of organic material, firmly attached to cell structure, may prevent bacteria from being recognized by host

Slime layer- loosely attached to cell surface, water-soluble, sticky layer allows prokaryotes to attach to surfaces

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6
Q

Functions of the glycocalyx?

A

protect cells from dehydration and nutrient loss
inhibit killing by WBCs by phagocytosis
attachment- formation of biofilms

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7
Q

What makes biofilms a health issue?

A

Biofilms have been shown to develop on medical device surfaces, and dispersal of single and clustered cells implies a significant risk of microbial dissemination within the host and increased risk of infection

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8
Q

What is EPS and how does it protect cells?

A

extracellular polymeric substance
cells use them to attach to themselves and the target environment
protects cells by preventing dessication, facilitates communication between cells in the biofilm, enables adherence and provides nutrients

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9
Q

3 parts in biofilm formation?

A

Attachment- cells attach to surface
Growth- sticky matrix made by biofilm encourages adhesion
Detachment- planktonic (free-floating) cells can be released from biofilm

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10
Q

Characteristics of flagella

A

responsible for movement
long structures that extend beyond cell surface
not present on all bacteria

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11
Q

Function of flagella

A

rotation propels bacterium through environment, rotation is reversible; bacteria move in response to stimuli- runs and tumbles

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12
Q

Flagellar structure

A

Filament- long, thin, helical structure
Hook- curved sheath
Basal Body- stacks of rings that anchor filament and hook to cell wall

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13
Q

Flagellar arrangements

A

monotrichous- single flagellum at one end
Lophotrichous- small bunches emerging from same site
Amphitrichous- flagella at both ends of cell
Peritrichous- flagella dispersed over surface of cell

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14
Q

Endoflagella of spirochetes chararcteristics

A

spiral tightly around cell
corkscrew motion
form axial filament that wraps around cell between cytoplasmic membrane and outer membrane

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15
Q

Characteristics of Fimbriae

A

sticky, bristle like projections
used by bacteria to adhere to one another and to substances in environment
shorter than flagella
serve an important function in biofilms

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16
Q

Characteristics of Pili

A

special type of fimbriae
longer than fimbriae but shorter than flagella
bacteria typically have only one or two per cell
transfer DNA from one cell to another (conjugation)

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17
Q

Characteristics of bacteria cell walls

A

provide structure and shape and protect cell from osmotic forces
assist some cells in attaching to other cells or in resisting antimicrobial drugs
gives bacteria characteristic shapes
composed of peptidoglycan
gram-positive or gram-negative

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18
Q

Shapes of Bacteria

A

cocci- spherical
bacilli- rod
curved shapes- vibrious, spirilla, spirochaetes

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19
Q

Peptidoglycan is a polymer of what?

A

NAG + NAM
disaccharide
joined by glycosidic bond
side chains of amino acids form peptides and link to other disaccharides to form framework of peptidoglycan on bacteria

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20
Q

Gram-Positive bacterial cell wall characteristics

A

thick layer of peptidoglycan
contain teichoic acids and lipoteichoic acids
appear PURPLE following gram staining
up to 60% mycolic acid in acid-fast bacteria helps cells survive desiccation

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21
Q

Gram-Negative bacterial cell wall characteristics

A

think layer of peptidoglycan
PINK after gram staining
bilayer membrane outside peptidoglycan contains phospholipids, proteins, and lipopolysaccharides (LPS)
may impede tx of disease

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22
Q

What is Lipid A?

A

portion of LPS and can cause fever, vasodilation, inflammation, shock, and blood clotting

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23
Q

What bacterial groups lack typical cell wall structure?

A

mycobacterium and nocardia

gram-positive cell wall structure with waxy lipid mycolic acid (cord factor)

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24
Q

How is bacteria without cell walls stabilized?

Study These Flashcards
A

by sterols, pleomorphic (existing in different shapes)

ex. mycoplasma pneumoniae

25
structure of bacterial cytoplasmic membranes
referred to as phospholipid bilayer, has integral and peripheral proteins
26
What are the functions of the cytoplasmic membrane?
energy storage harvest light energy in photosynthetic bacteria selectively permeable naturally impermeable to most substances proteins allow substances to cross membrane maintain concentration and electrical gradient passive (no ATP needed) and active (ATP needed) processes
27
What are the passive processes?
diffusion facilitated diffusion osmosis
28
What are the active processes?
active transport | group translocation
29
What is diffusion?
high concentration to low concentration
30
What is facilitated diffusion?
high to low concentration but requires protein carrier or channel. Can be specific or nonspecific
31
What is osmosis?
diffusion of free water across a semipermeable membrane from an area of high concentration to an area of low concentration until the solute concentration is equal on both sides
32
3 mechanisms of active transport?
uniport, antiport, coupled transport
33
What is group translocation?
substance is chemically modified during transport | only in bacteria
34
What is active transport?
ATP-dependent carrier proteins bring substances into cell
35
What is cytoplasm?
liquid portion of cytoplasm mostly water contains cell's DNA in region called nucleotide
36
What are inclusions?
may include reserve deposits of chemicals
37
What are endospores?
unique structure produced by some bacteria defensive strategy against unfavorable conditions resistant to extreme conditions such as heat, radiation, and chemicals
38
What are ribosomes?
sites of protein synthesis | composed of polypeptides and ribosomal RNA
39
What is the cytoskeleton?
composed of 3 or 4 types of protein fibers | can play different roles in the cell- cell division, cell shape, segregate DNA molecules, move through the environment
40
What is the external structure of archaea composed of?
glycocalyces, flagella, fimbriae and hami
41
Characteristics of archaeal cell walls?
most have cell walls, but not composed of peptidoglycan. Instead, contain variety of specialized polysaccharides and proteins
42
Characteristics of Archaeal cytoplasm
similar to bacterial cytoplasm- 70s ribosomes, fibrous cytoskeleton, circular DNA differs from bacterial cytoplasm- different ribosomal proteins, different metabolic enzymes to make RNA, genetic code more similar to eukaryotes
43
External structure of eukaryotic cells
glycocalyces- not as organized as prokaryotic capsules help anchor animal cells to each other strength cell surface provide protection against dehydration function in cell to cell recognition and communication
44
Cell Walls in Eukaryotic Cells
fungi, algae, plants, and some protozoa has cell walls composed of various polysaccharides-cellulose found in plant cells walls, fungal cells walls composed of cellulose, chitin, and glucomannan, algal walls composed of variety
45
Cytoplasmic membrane in eukaryotic cells
present in all eukaryotic cells are a fluid mosaic of phospholipids and proteins contain steroid lipids to help maintain fluidity contain regions of lipids and proteins called membrane rafts control movement into and out of cell
46
Function of lipid rafts
signaling and/or transport of membrane proteins
47
Flagella characteristics of eukaryotes
flagella structure- enclosed within cytoplasmic membrane, shaft composed of tubulin arranged to form microtubules, filaments anchored to cell by basal body, hook may be single or multiple function- undulate rhythmically
48
Characteristics of cilia on eukaryotes
shorter and more numerous than flagella | coordinated beating propels cells through environment
49
Ribsome characteristics in eukaryotes
protein synthesis, largers than prokaryotic ribosomes, composed of 60s and 40s subunits
50
cytoskeleton of eukaryotes
anchors organelles in cell extensive networks of fibers and tubules produces basic shape of cell made up of tubulin microtubules, actin microfilaments, and intermediate filamens
51
centrioles and centrisomes in eukaryotes
play role in mitosis, cytokinesis, and formation of flagella and cilia centrosome is region of cytoplasm where centrioles are found not found in all eukaryotic cells
52
nucleus characteristics
often largest organelle in cell, contains most of cells DNA semiliquid portion called nucleoplasm RNA synthesized in nucleoli surrounded by nuclear envelope
53
endoplasmic reticulum characteristics
netlike arrangement of flattened, hollow tubules continuous with nuclear envelope functions as transport system smooth ER and rough ER
54
golgi body characteristics
receives, processes, and packages large molecules for export of cell packages molecules in secretory vesicles that fuse with cytoplasmic membrane
55
lysosomes, peroxisomes, vacuoles, and vesicles
store and transfer chemicals within cells may store nutrients lysosomes contain catabolic enzymes peroxisomes contain enzymes that degrade poisonous wastes
56
mitochondria
have 2 membranes composed of phospholipid bilayer produce most of cells ATP interior matrix contains 70s ribosomes and a circular molecule of DNA
57
chloroplasts
light-harvesting structures found in photosynthetic eukaryotes use light energy to produce ATP
58
Endosymbiotic theory
proposed to explain why mitochondria and chloroplasts have 70s ribosomes, circular DNA, and two membranes eukaryotes formed from the union of small aerobic prokaryotes with larger anaerobic prokaryotes smaller prokaryotes became internal parasites

MICRO (15 decks)

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