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MICRO > CHAPTER 3 > Flashcards

CHAPTER 3 Flashcards

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?

A

by sterols, pleomorphic (existing in different shapes)

ex. mycoplasma pneumoniae

25
Q

structure of bacterial cytoplasmic membranes

A

referred to as phospholipid bilayer, has integral and peripheral proteins

26
Q

What are the functions of the cytoplasmic membrane?

A

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
Q

What are the passive processes?

A

diffusion
facilitated diffusion
osmosis

28
Q

What are the active processes?

A

active transport

group translocation

29
Q

What is diffusion?

A

high concentration to low concentration

30
Q

What is facilitated diffusion?

A

high to low concentration but requires protein carrier or channel. Can be specific or nonspecific

31
Q

What is osmosis?

A

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
Q

3 mechanisms of active transport?

A

uniport, antiport, coupled transport

33
Q

What is group translocation?

A

substance is chemically modified during transport

only in bacteria

34
Q

What is active transport?

A

ATP-dependent carrier proteins bring substances into cell

35
Q

What is cytoplasm?

A

liquid portion of cytoplasm
mostly water
contains cell’s DNA in region called nucleotide

36
Q

What are inclusions?

A

may include reserve deposits of chemicals

37
Q

What are endospores?

A

unique structure produced by some bacteria
defensive strategy against unfavorable conditions
resistant to extreme conditions such as heat, radiation, and chemicals

38
Q

What are ribosomes?

A

sites of protein synthesis

composed of polypeptides and ribosomal RNA

39
Q

What is the cytoskeleton?

A

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
Q

What is the external structure of archaea composed of?

A

glycocalyces, flagella, fimbriae and hami

41
Q

Characteristics of archaeal cell walls?

A

most have cell walls, but not composed of peptidoglycan. Instead, contain variety of specialized polysaccharides and proteins

42
Q

Characteristics of Archaeal cytoplasm

A

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
Q

External structure of eukaryotic cells

A

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
Q

Cell Walls in Eukaryotic Cells

A

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
Q

Cytoplasmic membrane in eukaryotic cells

A

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
Q

Function of lipid rafts

A

signaling and/or transport of membrane proteins

47
Q

Flagella characteristics of eukaryotes

A

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
Q

Characteristics of cilia on eukaryotes

A

shorter and more numerous than flagella

coordinated beating propels cells through environment

49
Q

Ribsome characteristics in eukaryotes

A

protein synthesis, largers than prokaryotic ribosomes, composed of 60s and 40s subunits

50
Q

cytoskeleton of eukaryotes

A

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
Q

centrioles and centrisomes in eukaryotes

A

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
Q

nucleus characteristics

A

often largest organelle in cell, contains most of cells DNA
semiliquid portion called nucleoplasm
RNA synthesized in nucleoli
surrounded by nuclear envelope

53
Q

endoplasmic reticulum characteristics

A

netlike arrangement of flattened, hollow tubules continuous with nuclear envelope
functions as transport system
smooth ER and rough ER

54
Q

golgi body characteristics

A

receives, processes, and packages large molecules for export of cell
packages molecules in secretory vesicles that fuse with cytoplasmic membrane

55
Q

lysosomes, peroxisomes, vacuoles, and vesicles

A

store and transfer chemicals within cells
may store nutrients
lysosomes contain catabolic enzymes
peroxisomes contain enzymes that degrade poisonous wastes

56
Q

mitochondria

A

have 2 membranes composed of phospholipid bilayer
produce most of cells ATP
interior matrix contains 70s ribosomes and a circular molecule of DNA

57
Q

chloroplasts

A

light-harvesting structures found in photosynthetic eukaryotes
use light energy to produce ATP

58
Q

Endosymbiotic theory

A

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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