Exam Three: Part Three Flashcards
what are CELLS?
- 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
what is the STRUCTURE and FUNCTION of the PLASMA MEMBRANE?
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
what is the FLUID MOSAIC MODEL?
- 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
what affects the FLUDITY of the MEMBRANE?
- 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
describe the PROTEINS within the PLASMA MEMBRANE
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
what is important about the MOVEMENT OF MATERIAL across the MEMBRANE?
- helps provide NUTRIENTS for METABOLISM
- supplies OXYGEN for RESPIRATION
- SECRETES WASTE
- secretes ENZYMES and other PROTEINS
what are the specific ways to move material across the membrane?
PASSIVE (NO ENERGY)
- simple diffusion
- facilitated diffusion
ACTIVE (ENERGY)
- cell uses energy (ATP) to move a substance across the membrane
describe SIMPLE DIFFUSION (p)
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
describe FACILITATED DIFFUSION (p)
- use of INTEGRAL MEMBRANE PROTEINS to function as CHANNELS that move MOLECULES across the PM
- known as TRANSPORTERS; no energy needed
describe OSMOSIS (p)
- 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
what are the three kinds of OSMOTIC SOLUTIONS?
- 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
describe ACTIVE TRANSPORT
- 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!
describe GROUP TRANSLOCATION
- 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
- once altered, the PM is impermeable - cannot leave the cell! 😮
describe PROKARYOTIC CELLS
- NO NUCLEUS
- everything is FLOATING around the membrane
- DNA has NO surrounding membrane
- all FUNCTIONS occur in their actual CYTOPLASM
what is a CAPSULE (GLYCOCALYX) (p)?
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
what is FLAGELLA (p)?
- 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)
what is BACTERIAL MOTILITY?
- specific bacteria that can sense STIMULI in their environment like food or toxins
- uses FLAGELLA to swim toward or away from stimuli
what is TAXIS?
- movement of bacteria TOWARDS or AWAY from stimuli
- CHEMOTAXIS:
- movement towards CHEMICALS
- PHOTOTAXIS:
- movement towards LIGHT
what are AXIAL FILAMENTS, PILI, an FIMBRAIE?
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
what is the CELL WALL? (p)
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 wallhas two types; Gram+ (thicker) & Gram- (thinner)
- use of GRAM STAINS for identification
describe CYTOPLASM + STRUCTURES (4)(p)
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…
how do PROKARYOTIC CELLS REPRODUCE?
reproduce ASEXUALLY by a process called BINARY FISSION
describe FLAGELLA and CILIA in EUKARYOTES
FLAGELLA
- few LONG PROJECTIONS
- flagella moves in a WAVE LIKE MANNER
CILIA
- short and many
both made up of MICROTUBULES
describe CELL WALL (E)
- 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
