CH. 1 CELL STRUCTURE Flashcards
The cell is contained by the
cell membrane
The cell membrane is a
functions of the cell mambrane
- cell volume regulation- what gets in and goes out
- renal filtration
GI absorption
Oxygen delivery to cells
maintenance of resting potential
The cell membrane is composed of
lipids, proteins(water loving), and polysaccharides.
hydrophilic ______ of cell membrane
heads
lipophyllic ______ of cell membrane
tails
transmembrane proteins serve as
channels, carriers, pumps and receptors- hydrophilic molecules to move
Integral proteins serve as
enzymes
One of the primary functions of the cell membrane is to maintain
the intracellular fluid (ICF) separate from the extracellular fluid (ECF).
osmolarity of ICF is the ________ as the osmolarity of ECF
same
Another function of the cell membrane is that it
holds cells together so that they can:
– Function as an electrical unit – Transmit force
– Form a continuous barrier
__________ maintains cell shape and directs progression of substances.
The cytoskeleton
- Actin filaments
‒ allows cell contraction
- Microtubules of cytoskeleton
‒ organizes organelles
- Intermediate filaments of cytoskeleton
structural support of the cell
nucleus
- Contains genetic material protected by
two membranes.
– Nuclear DNA controls production of enzymes and membrane receptors as well as maintaining genetic control.
– It is the largest organelle.
Endoplasmic reticulum
–
Central role is synthesis of protein and steroids
smooth endoplasmic reticulum
ost abundant in cells that specialize in steroid hormone or lipoprotein production.
Rough endoplasmic reticulum
Primary function is protein synthesis.
Golgi apparatus
– Receives newly synthesized proteins and
lipids from the ER.
– As they move through the Golgi, they are
modified by enzymes that attach sugar
molecules.
When they leave the apparatus, they have
very specific destinations.- (mature)
Lysosomes and peroxisomes
Organelles that digest and breakdown
organic molecules.
Mitochondria
Converts energy to forms that can be used to drive cellular reactions.
cytosol
intracellular fluid
Sodium (Na+), calcium (Ca++), chloride (Cl-), and sodium bicarbonate (HCO3-) are all examples of charged particles that share which of the following common feature?
More abundant in extracellular fluid (ECF)
The single largest component of the animal cell membrane is:
Protein.
Which of the following is a true statement about the function of the cell membrane?
It maintains ICF (intracellular fluid) separate from ECF (extracellular fluid).
Both lysosomes and peroxisomes digest organic molecules. A primary difference between the two is that:
Peroxisomes use molecular oxygen.
Maintaining cell volume and membrane potential are important functions of the:
Cell membrane.
Protein synthesis is a process in which organelles work together to synthesize a mature protein. Which statement best describes the process by which mature functional proteins are produced?
The rough endoplasmic reticulum manufactures proteins and the Golgi apparatus modifies them with enzymes.
The cell membrane functions to:
Act as an electrical unit.
The cytoskeleton is composed of actin, filaments, microtubules and intermediate filaments. Which of the following is a true statement about the cytoskeleton?
Maintains organization of organelles.
The osmolality of ECF is:
The same as ICF.
Non-energy requiring mechanisms are
– Simple diffusion
– Facilitated diffusion
– Osmosis – water moves dependent upon solute concentration
Energy-requiring mechanisms
– Active transport
– Secondary active transport
Simple diffusion
substance is lipophilic from high to low
Spontaneous movement of solutes from an area of high concentration to an area of low concentration
– Requires no external source of energy
– Each particle moves in random motion
this is a carrier- mediated process that allows particles that are too big to go by simple diffusion to get into the cell.
Facilitated diffusion
the passive flow of water across a selectively permeable membrane down an osmotic pressure gradient.
Osmosis
Energy is used from the hydrolysis of ATP to transport energy against its concentration gradient for
Active transport
ex. NA+, K+ pump
Secondary active transport
Uses energy stored in the sodium concentration gradient to transport material against an energy gradient.
The cell membrane acts as a capacitor where
It stores electrical charges that will drive many processes.
membrane potential
exists as a negative charge
membrane potential
exists as a negative charge
resting state is
-60 to -80
Depolarization to -40 mV causes
Na+ channels to open.
A variety of physiologic mechanisms are employed to transport fluid and solutes across the cell membrane. Which one of them is described by the equation J = [D(A) (Cin – Cout)]/X?
Diffusion.
Fick’s First Law of Diffusion states that flux is decreased when _____ is increased.
Thickness of the membrane
Fick’s First Law of Diffusion states that flux is decreased when _____ is increased.
Thickness of the membrane
Membrane potential is created by the separation of charges by the cell membrane. The cell membrane gets its charge as a function of the ion:
That is drawn to the inner aspect of the membrane.
The absolute refractory period is the time during which:
No stimulus can cause a second action potential.
The pressure gradient created when there are different concentrations of a solute on either side of a membrane and the solute cannot cross the membrane is a function of:
Osmosis.
Diffusion that utilizes a carrier-mediated process to allow transport of particles that are too large to move by simple diffusion is called:
Facilitated diffusion.
When energy derived from the hydrolysis of ATP molecules is used to transport ions against the concentration gradient, this is called:
Active transport.
The upstroke of the action potential of various cell types is initiated through the:
Opening of sodium channels.
Stages of the action potential include all of the following except:
Reverse stroke.
The wave shape of the action potential can vary for different cell types. The wave shape is primarily determined by the:
Number and type of ion channels utilized.
