Membranes Flashcards
What is the main component of the plasma membrane?
Phospholipid bilayer
Fluid mosaic made of proteins
What does the plasma membrane separate?
Intracellular fluid (ICF) from extracellular fluid (ECF).
Interstitial fluid (IF) is the same as ECF.
What happens when polar and nonpolar molecules mix?
Polar + Polar mix, Nonpolar + Nonpolar mix, Polar + Nonpolar do not mix.
Water cannot cross the cell due to the nonpolar lipid tail.
What is the function of cholesterol in the plasma membrane?
Increases membrane stability and fluidity.
Cholesterol is a crucial component for membrane function.
What are the characteristics of tight junctions?
Prevents movement of fluids and particles between cells.
Found connecting epithelial cells (skin).
What is the function of desmosomes?
Zipper-like connection holding cells together.
Provides flexibility/give between cells.
What is the role of gap junctions?
Allow small molecules to pass between cells.
Facilitates the passage of electrical signals.
What part of the phospholipid bilayer is hydrophilic in which side is hydrophobic?
Phosphate is polar and hydrophilic
Lipid tail is nonpolar and hydrophobic
What are protein islands?
Transport proteins that have hydrophilic and hydrophobic regions and can interact with lipid tales and H2O
Passive transport
Uses the concentration gradient to move from higher concentrations to lower concentrations
No energy is required
Active transport
Uses energy energy to move from areas of low concentration areas of high concentration
What are the three forms of passive transport?
Diffusion, osmosis, filtration
Explained diffusion
The movement of solute from concentration to low concentration
Explain osmosis
Movement of water from high concentration to low concentration
What is the equation for finding osmolarity?
Solute - (millimoles/volume)= osmolarity
What is Tonicity
Ability of a solution to alter cells water volume
What is osmotic pressure?
The pressure from solute that sucks water to the other side
Explained, hypotonic solutions and what happens when a cell is placed in it
Salute concentration is greater in the cell so the solute leaves cell and water enters. This causes the cell to swell and burst.
Describe isotonic solutions and what happens when cells are placed in it
Water and saw you levels are even so there will be no net movement of water.
Explain hypertonic solutions
There’s more solute in the solution than in the cell. This causes solute to move into the cell and water to leave. This causes the cell to shrink (crenation)
What is creation?
Sells shrinking due to being in a hypertonic solution
What is the net movement of ions from the sodium potassium pump?
3 NA+ ions leave and 2 K- cells come into cell
Describe facilitated diffusion
No energy needed. Transfer proteins facilitate transport.
What type of molecules can transport passively through facilitated diffusion and give an example?
Hydrophilic molecules
- Glucose
- amino acids
- ions
Describe filtration
Movement of hydrostatic pressure. Uses ATP.
If a salute is too large for channels how can I get carried across the cell?
Vesicular transport
In what cases is vesicular transport used?
Solute too large for channels, not lipids soluble solute, unable to move down the concentration gradient
What is cotransport? What is a symporter and what is a antiporter?
Cotransport- transport more than one substance at a time
Symporter- substance transported in the same direction
AntiPorter - substances transported opposite directions
Define hemostasis
Maintain stable internal conditions, despite changes in environment
Describe how the nervous system and endocrine system work together to maintain homeostasis
Nervous system= Quick reaction via nerve impulses
Endocrine system = Slow reaction via release of hormones
Describe the negative feedback loop and give an example
eliminates the stimulus
Temperature regulation, heart rate, breathing rate
Define in given example of a positive feedback loop
Enhance or exaggerate the stimulus.
Childbirth
