9/9, 9/11 Class Lecture Chapter 3 Flashcards
What is the plasma membrane composed of?
lipid bilayer and proteins
Are the proteins and the bilayer still or moving
constantly moving, constantly changing
what allows the proteins to move around without damage
fluid mosaic
what does fluid mosaic mean
cell membrane recovers if damaged
What type of role does plasma membrane have in cellular activity
active, dynamic role
What does the lipid bilayer separate
intracellular fluid from extracellular fluid
abbreviation with intracellular fluid
ICF
abbreviation with extracellular fluid
ECF
What does ICF refer too
within cytoplasm
What does ECF refer to
everything outside of the cell
abbreviation for interstitial fluid
IF
what is the IF
things between and among cells, ECF that surrounds the cell
What makes up the membrane lipids
Phospholipids 75%
Glycolipids 5%
Cholesterol 20%
What are the phospholipids apart of
lipid bilayer
what makes up the phospholipids heads
phosphate
what are the phospholipid head properties
polar and hydrophilic
what does hydrophilic mean
likes water
what makes up the phospholipid tails
fatty acid
what are the phospholipid tail properties
non polar hydrophobic
what does hydrophobic mean
water-fearing
what makes up the glycolipids
Lipids with polar sugar groups on outer membrane surface
what does cholesterol do
Increases membrane stability
Gives structural integrity
Can’t live without
structurally essential
what do membrane proteins do
Allow communication with environment, with rest of body, or with things floating around, through hormones
how much of plasma membrane do membrane proteins make up
1/2
where do the membrane proteins live
Some float freely, move around
Some tethered to intracellular structures, some are connected
what are the two types of membrane proteins
integral proteins, peripheral proteins
where are the integral proteins located
Firmly inserted into membrane
what type of regions do integral proteins have
hydrophobic and hydrophilic
what do the hydro properties allow for integral proteins
allows them to have reactions
what do integral proteins function as
as transport proteins (channels and carriers), enzymes, or receptors
where are peripheral proteins located
Loosely attached to integral proteins, bonds not a strong, affected by other chemicals around them
what organelles do peripheral proteins include
filaments on intracellular surface for membrane support
the function of peripheral proteins
Function as enzymes; motor means movement proteins for shape change during cell division and muscle contraction; cell-to-cell connections
6 functions of membrane proteins
Transport Receptors for signal transduction Attachment to cytoskeleton and extracellular matrix Enzymatic activity Intercellular joining Cell-cell recognition
what are cells surrounded by
IF
what does IF contain
amino acids, sugars, fatty acids, vitamins, hormones, salts, waste products, some good, some bad, some neutral, some small enough to fit through the membrane
what does the plasma membrane allow the cell to do
Obtain from IF exactly what it needs, exactly when it is needed, allows some things in and keep some things out
Keep out what it does not need
property of the plasma membrane
selectively permeable
what does selectively permeable mean
Some molecules pass through easily; some do not
Based on size and chemical properties
Charge, polarity
what are the ways that substances cross the membrane
passive process
active process
passive process
No cellular energy (ATP-cell energy) required, don’t use or need cell energy
Substance moves down its concentration gradient from greater to lesser
Natural process no energy needed
Molecule will passively diffuse through membrane if into or out of cells
active process
Energy (ATP) required,
Occurs only in living cell membranes
Does not happen in a non living world
We get our energy from the sun
two types of passive transport
diffusion and filtration
what is diffusion
greater to lesser concentration
Collisions molecule moving around cause molecules to move down or with their concentration gradient
a specialized type of diffusion
osmosis
osmosis
diffusion of water through the membrane
where does filtration occur
usually across capillary walls
example of filtration
kidneys filter blood
how is the speed of diffusion decided
influenced by molecule size and temperature
simple diffusion
Nonpolar lipid-soluble (hydrophobic) substances diffuse directly through the phospholipid bilayer of fat-soluble molecules directly through the phospholipid bilayer
example of diffusion
oxygen, carbon dioxide, fat-soluble vitamins
what is facilitated diffusion
Certain lipophobic molecules (e.g., glucose, amino acids, and ions) transported passively for them to get in our cells they need to go through the special processes
what does facilitated diffusion do
Binding to protein carriers
Moving through water-filled channels
what is carrier-mediated facilitated diffusion
Transport specific polar molecules (e.g., sugars and amino acids) too large for channels molecule has to fit this assistor molecule
Binding of substrate causes shape change in carrier then passage across membrane as protein helps across it changes its position which changes its shape
what are transmembrane integral proteins
carriers
what is carrier-mediated facilitated diffusion limited by
number of carriers present bc they could become saturated
when are the carriers saturated in carrier meditated diffusion
when they are all engaged
what is channel-mediated diffusion
Aqueous channels formed by transmembrane proteins
Selectively transport ions or water
what are the two types of channel-mediated facilitated diffusion
leakage channels
gated channels
what are leakage channels
always open
what are gated channels
controlled by chemical or electrical signals
open and close
what is osmosis
Movement of solvent (e.g., water) across selectively permeable membrane, diffusion of water through the membrane
what does the water diffuse through in osmosis
plasma membrane
Through lipid bilayer
Through specific water channels called aquaporins (AQPs)
when does osmosis occur
Occurs when water concentration different on the two sides of a membrane
why type of process is osmosis
passive
no energy required
what is osmolarity
Measure of total concentration of solute particles, similar to density (mass per unit volume) specific particles per solute particles
when does water stop moving by osmosis
hydrostatic pressure (back pressure of water on membrane) and osmotic pressure (tendency of water to move into cell by osmosis) equalize opposing forces
what happens when solutions of different osmolarity are separated by membrane permeable to all molecules
both solutes and water cross membrane until equilibrium reached, both cross if they can, if they can fit through
what happes When solutions of different osmolarity are separated by membrane-impermeable to solutes
, osmosis occurs until equilibrium reached
what does osmosis cause cells to do
swell and shrink
what happens in osmosis when cell volume changes
disrupts cell function, especially in neurons
what is tonocity
Ability of solution to alter cell’s water volume
what is isotonic
Solution with same non-penetrating solute concentration as cytosol
what is hypertonic
Solution with higher non-penetrating solute concentration than cytosol
what is hypotonic
olution with lower non-penetrating solute concentration than cytosol
what is metabolism
biochemical reactions inside cells involving nutrients- generalized and collective term
what are the two types of metabolism reactions
anabolism and catabolism
what is anabolism
synthesis of large molecules from small ones subsets of metabolism
example of anabolism
. Amino acids to proteins, break down amino acids and turn into us
what is catabolism
hydrolysis of complex structures to simpler one’s subsets of metabolism
example of catabolism
proteins to amino acids
when does metabolism occur in our cells
throughout life
where does direct energy come from in metabolism
carbohydrates
what type of process is cellular respiration
catabolism
what is cellular respiration
how we get our energy
Catabolism of food fuels –> capture of energy to form ATP in cells
what do enzymes shift during metabolism
shift high-energy phosphate groups of ATP to other molecules (phosphorylation)
what is phosphorylation
releases the phosphate group
what do phosphorylated molecules do during metabolism
molecules activated to perform cellular functions
what are the three stages of processing nutrients
Digestion, absorption, and transport to tissues
where does cellular processing occur
cytoplasm
two processes in cellular processing
synthesis and catabolism
what is synthesized during cellular processing
Synthesis of lipids, proteins, and glycogen
what happens during catabolism of cellular processing
taking glucose and splitting it apart into pyruvic acid and acetyl CoA (co enzyme or a vitamin)
what is the name for catabolism during cellular processing
glycolysis
where does oxidative breakdown occur
mitochondria
what breaks down during oxidative breakdown
breakdown of intermediates into CO2, water, and ATP
is oxidative breakdown a small process or a long process
many steps
CO2
waste product
water
metabolically waste product
ATP
useful product
what is the goal of cellular respiration
trap chemical energy in ATP
where can energy be stored in respiration
glycogen and fats
what is glycogen
energy storage, not for immediate use
what is oxidized and for what in cellular respiration
Oxidation of food for fuel
what happens during oxidation of food for fuel
Step by step removal of pairs of hydrogen atoms (and electron pairs) from substrates –> only CO2 left
what processes occur during cellular respiration
glycolysis, Krebs cycle (citric acid cycle), oxidative phosphorylation
what type of reaction is oxidation
reduction or redox reactions
what is oxidation
gain of oxygen or loss of hydrogen atoms
what happens during the oxidation-reduction reaction
Oxidized substances lose electrons and energy
Reduced substances gain electrons and energy
Catalyzed by enzymes
what are the enzymes during oxidation redox reactions
dehydrogenases
oxidases
dehydrogenases
removal of hydrogen atoms, dehydrate
oxidases
transfer of oxygen
what enzymes require help during oxidation
vitamin B derivatives
coenzymes
what is a coenzyme
(biological term for an enzyme) act as hydrogen (or electron) acceptors
examples of Co enzymes
NAD+ and FAD
