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MICROBIO BIOL-160 LEC > Exam Three: Part Three > Flashcards

Exam Three: Part Three Flashcards

1
Q

what are CELLS?

A
  • the BASIC BUILDING BLOCKS of life
  • give STRUCTURE, NUTRIENTS, conversion of nutrients into ENERGY–carry specialized FUNCTIONS
  • have DNA–can make copies of themselves
  • classified into two groups;
    PROKARYOTES
    EUKARYOTES
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2
Q

what is the STRUCTURE and FUNCTION of the PLASMA MEMBRANE?

A

STRUCTURE:

made up of specific PHOSPHOLIPIDS
HYDROPHOBIC TAILS + HYDROPHOBIC HEADS
- creation of a BILAYER–CELL MEMBRANE
- they help separate the INSIDE LIVING PART of the cell from the OUTSIDE ENVIRONMENT
- SEMIPERMEABLE; small molecules can move in and out (water, salt, noncharged particles etc…)

FUNCTION:
- have EMBEDDED PROTEINS within its bilayer to carry out specific FUNCTIONS
- TRANSPORT OF MOLECULES
-CELL-CELL RECOGNITION
- SENSES ENVIRONMENT

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3
Q

what is the FLUID MOSAIC MODEL?

A
  • the plasma membrane is a FLEXIBLE LAYER
  • PHOSPHOLIPDS + PROTEINS are not STATIC–move FREELY within the MEMBRANE

FUNCTIONS:
- CELL ATTACHMENT
- moves molecules within the bilayer
- allows membranes to FUSE RAPIDLY
- allows proteins to move within membrane as needed
- ensures EVEN DISTRIBUTION evenly among daughter cells

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4
Q

what affects the FLUDITY of the MEMBRANE?

A
  • TEMPERATURE
    can make the membrane too rigid or too fluid/flexible
  • CHOLESTEROL
    keeps BILAYER FLUID in various environmental conditions
    keeps PHOSPHOLIPIDS TOGETHER - don’t separate too far
  • SATURATED/UNSATURATED FATTY ACIDS
    animal cells have more saturated fatty acids
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5
Q

describe the PROTEINS within the PLASMA MEMBRANE

A

PERIPHERAL PROTEINS
- lie at the OUTER AND INNER SURFACE
- loosely asso. with the PM
- easy removal
INTEGRAL PROTEINS
- part of the PM
- only removed by DISRUPTION
known as TRANSMEMBRANE PROTEINS; if complete PENETRATION of the MEMBRANE

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6
Q

what is important about the MOVEMENT OF MATERIAL across the MEMBRANE?

A
  • helps provide NUTRIENTS for METABOLISM
  • supplies OXYGEN for RESPIRATION
  • SECRETES WASTE
  • secretes ENZYMES and other PROTEINS
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7
Q

what are the specific ways to move material across the membrane?

A

PASSIVE (NO ENERGY)
- simple diffusion
- facilitated diffusion
ACTIVE (ENERGY)
- cell uses energy (ATP) to move a substance across the membrane

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8
Q

describe SIMPLE DIFFUSION (p)

A

the MOVEMENT of MOLECULES FROM AN AREA of HIGHER CONC. to an area of LOWER CONC.
- continues till all molecules are EVENLY DISTRIBUTED–EQUILIBRIUM

  • sees SMALL MOLECULES diffuse across PM; no energy needed
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9
Q

describe FACILITATED DIFFUSION (p)

A
  • use of INTEGRAL MEMBRANE PROTEINS to function as CHANNELS that move MOLECULES across the PM
    - known as TRANSPORTERS; no energy needed
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10
Q

describe OSMOSIS (p)

A
  • the diffusion of WATER through a semi-permeable membrane from a higher concentration to a lower concentration to establish a DYNAMIC EQUILIBRIUM
  • NO ENERGY
  • helps flow WATER into the PM
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11
Q

what are the three kinds of OSMOTIC SOLUTIONS?

A
  • ISOTONIC:
    • no net movement of water
  • HYPOTONIC:
    • more solutes inside the cells so water molecules move INTO the cell, making the cell BURST
  • HYPERTONIC:
    • more solutes outside the cell, the water MOVES OUT of the cell, making the cell SHRINK
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12
Q

describe ACTIVE TRANSPORT

A
  • uses ENERGY to move substances across the PM
    • helps transport ions, amino acids, or sugars

WHY?
- allowing cells to ACCUMULATE NEEDED MATERIAL
ex. sodium and potassium pump

again sodium is already naturally entering the PM through the diffusion of nonspecific transporters

  • can sacrifice some sodium to pump greater amounts of potassium into the cell!
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13
Q

describe GROUP TRANSLOCATION

A
  • occurs only in PROKARYTOES
  • the substance coming in is CHEMICALLY ALTERED DURING TRANSPORT
    • once altered, the PM is impermeable - cannot leave the cell! 😮
      *use of ENERGY
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14
Q

describe PROKARYOTIC CELLS

A
  • NO NUCLEUS
  • everything is FLOATING around the membrane
  • DNA has NO surrounding membrane
  • all FUNCTIONS occur in their actual CYTOPLASM
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15
Q

what is a CAPSULE (GLYCOCALYX) (p)?

A

the VISCOUS GELATINOUS polymer that is secreted and is external to the cell wall of many prokaryotes

  • ORGANIZED/FIRMLY ATTACHED to cell wall
    • considered a CAPSULE
  • UNORGANIZED/LOOSELY ASSOCIATED to cell cell
    • considered a SLIME LAYER
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16
Q

what is FLAGELLA (p)?

A
  • LONG HAIR-LIKE structure that moves bacteria
  • flagella rotate CLOCKWISE OR COUNTERCLOCKWISE
    the movement of flagella
    - move into getting nutrients, disease, or getting away from threats

PARTS:
- FILAMENT external to the cell
- HOOK
- BASAL BODY in the membrane
(has a MOVEMENT SENSOR–tells direction of filament to move cc or c)

17
Q

what is BACTERIAL MOTILITY?

A
  • specific bacteria that can sense STIMULI in their environment like food or toxins
    • uses FLAGELLA to swim toward or away from stimuli
18
Q

what is TAXIS?

A
  • movement of bacteria TOWARDS or AWAY from stimuli
  • CHEMOTAXIS:
    • movement towards CHEMICALS
  • PHOTOTAXIS:
    • movement towards LIGHT
19
Q

what are AXIAL FILAMENTS, PILI, an FIMBRAIE?

A

AXIAL FILAMENTS:
flagella that are under an outer sheath + SPIRAL around the cell

PILI:
- short and small appendages
- TWITCHING motility & GLIDING motility
- twitching movement to move 😀

FIMBRIAE:
- SHORT HAIR LIKE appendages that stick to each other and surfaces, involved in forming BIOFILMS

20
Q

what is the CELL WALL? (p)

A

SEMI-RIGID structure;; helps survive various conditions of hypotonic or hypertonic solutions

  • prevents BACTERIAL CELLS FROM RUPTURING IN HYPOTONIC SOLUTIONS
  • contributes to PATHOGENESIS
  • the site of ANTIBIOTIC ACTION
  • made up of a network of MACROMOLECULES:
    called PEPTIDOGLYCAN;
  • quite UNIQUE–target of antibiotics
    PENICILLIN prevents the proper formation of the PEPTIDOGLYCAN LAYER–weakens cell wall
      has two types; Gram+ (thicker) & Gram- (thinner)
  • use of GRAM STAINS for identification
21
Q

describe CYTOPLASM + STRUCTURES (4)(p)

A

CYTOSKELETON
- has DIFFERENT FIBERS within the cytoplasm
- has similar functions to a eukaryotic cytoskeleton; cell division, growth, shape, and DNA movement

NUCLEOID
- a type of BACTERIAL CHROMOSOME—long CiRCULAR thread of DNA
- area of the cell where most condensed DNA & DNA ASSO. PROTEINS are found
- length of DNA can be a THOUSANDS TIMES greater than cell
(has PLASMIDS–small CIRCULAR DNA–
helps with the transferring of
PATHOGENESIS FACTORS + TRANSFER OF
BACTERIA)

RIBOSOMES
- PROTEIN BUILDERS of cell
- made from 2 SUBUNITS with rRNA & proteins
- 50S subunit + 30S subunit

ENDOSPORES
- created with NUTRIENTS ARE DEPLETED–specific resting cells
- RESISTANT TO UV RADIATION, lack of water, HIGH TEMPS ETC…

22
Q

how do PROKARYOTIC CELLS REPRODUCE?

A

reproduce ASEXUALLY by a process called BINARY FISSION

23
Q

describe FLAGELLA and CILIA in EUKARYOTES

A

FLAGELLA
- few LONG PROJECTIONS
- flagella moves in a WAVE LIKE MANNER
CILIA
- short and many

both made up of MICROTUBULES

24
Q

describe CELL WALL (E)

A
  • much more SIMPLER than the PROKARYTOIC CELL WALL

in ALGAE and PLANTS –CELLULOSE

on FUNGI–made up of POLYSACCHARIDE CHITIN
*both provide PROTECTION and SUPPORT

OTHERS and ANIMAL CELLS
- don’t have cell wall; have a PM covered with GLYCOCALYX
(layer of STICKY CARBS)
- strengthens the CELL SURFACE
- greater CELL-TO-CELL ATTACHMENT
- RECOGNITION

25
Q

describe PLASMA MEMBRANE + ENDOCYTOSIS (e)

A
  • quite similar in FUNCTION AND BASIC STRUCTURE
  • contains STEROLS–CHOLESTEROL

uses the process of ENDOCYTOSIS
transports material ACROSS THE MEMBRANE BY ENGULFING IT

26
Q

describe CYTOPLASM + STRUCTURES (3) (e)

A

EUKARYOTIC CYTOSKELETON
- much more COMPLEX
- made up of SMALL RODS AND CYLINDERS
- important for SHAPE, TRANSPORT, ORGANELLE ATTACHMENT, and MOVEMENT–cytoplasmic streaming

EUKARYOTIC RIBOSOMES
- known as the 80S RIBOSOME
- LARGER AND DENSER than pro. RIBOSOME
- found FREE and ATTACHED to ER
(ER ATTACHED–synthesizes proteins that are MEMBRANE PROTEINS/EXPORTEd)
(FREE–synthesizes proteins needed INSIDE the CELL)
- SYNTHESIZES PROTEINS needed INSIDE THE CELL

MEMBRANE BOUND ORGANELLES
- nucleus
- ER
- etc….

27
Q

describe NUCLEUS (e)

A

– contains ALMOST ALL hereditary material—DNA!!
- seen within the nuclear membrane/envelope
- nuclear pores

CHARACTERISTICS:
- has LINEAR DNA
HISTONES- proteins that are associated with our DNA
- help compact the DNA
- protection for DNA against damage

28
Q

what about CHROMOSOMES?

A

the NUCLEUS has MULTIPLE CHROMOSOMES

CHROMOSOMES
- DNA molecules that package tightly around HISTONES into THREADLIKE STRUCTURES
- can be HAPLOID (one copy) or DIPLOID (two copies)

29
Q

describe MITOSIS vs MEIOSIS

A

EUKARYOTES can multiply by ASEXUAL and SEXUAL REPRODUCTION (more common)

ASEXUAL REPRO.; MITOSIS
- similar to BINARY FISSION
- have MULTIPLE CHROMOSOMES that are replicated and divided between the 2 daughter cells

SEXUAL REPRO: MEIOSIS
- only happens in DIPLOID CELLS
- creates FOUR genetically distinct gametes using HOMOLOGOUS chromosomes (each has 1/2 chromosomes from the mother cell)
FERTILIZATION:
- gametes from both male and female fuse to form the ZYGOTE
- full complement of the chromosomes
- important for a greater rate of GENETIC DIVERSITY

30
Q

describe CENTROSOMES (e)

A
  • an ORGANELLE near the NUCLEUS
  • contains the CENTRIOLES
  • this is where we have the SPINDLE FIBERS develop during CELL DIVISION
31
Q

describe the ER ENDOPLASMIC RETITUCULUM (E)

A
  • ENDOPLASMIC RETICULUM:
    • an extensive network of FLATTENED MEMBRANE SACS
  • ROUGH ER:
    • continuous with NUCLEAR MEMBRANE
    • outer surface covered in RIBOSOMES
    • production and folding of and dispatch of some proteins
  • SMOOTH ER:
    • extends from the ROUGH ER + NO RIBOSOMES
    • helps SYNTHESIZE phospholipids, fats, and steroids (estrogens)
32
Q

describe the GOLGI COMPLEX (e)

A
  • made up of 3-20 CISTERNAE
    • flattened membrane vesicles
  • very FIRST STEP in the TRANSPORT OF PROTEINS made in the rough ER to other regions of the cell
  • helps with MODIFYING proteins to form GLYCOPROTEINS AND LIPOPROTEINS
33
Q

describe MITOCHONDRIA + MITOCHONDRIAL DNA

A
  • makes ATP—THE POWERHOUSE OF THE CELLLL!!
  • contains CIRCULAR DNA
  • contains 70S ribosome
  • contains machinery that aids in REPLICATION, TRANSCRIPTION, and TRANSLATION
  • can also grow and divide 🙂

MITOCHONDRIAL DNA:
- carries 37 GENES
- important for normal mitochondrial function
- the mitochondrial disease is MATERNALLY inherited

34
Q

describe CHLOROPLASTS

A
  • present within ALGAE + PLANTS
  • contains the pigment CHLOROPHYLL in THYLAKOIDS
    • has enzymes required for PHOTOSYNTHESIS
  • also contain 70S RIBOSOME, CIRCULAR DNA, and ENZYMES
    • similar to the mitochondria
35
Q

describe LYSOSOMES

A
  • made from the GOLGI COMPLEX
  • contains around 40 DIGESTIVE ENZYMES
  • breaks down WASTE AND FOOD
  • breaks down DYSFUNCTIONING ORGANELLES
  • can DIGEST BACTERIA that enter the cell
36
Q

describe VACUOLES

A
  • CAVITY in the cytoplasm of a cell that is enclosed by a MEMBRANE
  • within plants - occupies over 5%-90% of the cell

FUNCTIONS:
- temporary STORAGE
- brings food in by ENDOXYTOSIS
- stores METABOLIC WASTE AND TOXINS
- takes up WATER — rigidity of water and leaves

37
Q

what is the ENDOSYMBIOTIC THEORY?

A

states that the MITOCHONDRIA and CHLOROPLAST in eukaryotic cells were once aerobic bacteria (prokaryotes) that were ingested by a larger proto-eukaryotic cell

  • ENDOSYMBIOSIS:
    • living together with one organism inside the other
  • EVIDENCE?
    • both mitochondria and chloroplast have;
      • own CIRCULAR DNA
      • 70S ribosomes
      • can REPLICATE their DNA

MICROBIO BIOL-160 LEC (21 decks)

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