1.3 Flashcards
What does the plasma membrane do
It surrounds the cell and controls entry and exit of materials
What describes the structure of the plasma membrane
Fluid mosaic
What does the plasma membrane consist of
Phospholipids and proteins
The head of the phospholipid is charged, which word describes it
Hydrophilic
The tail of the phospholipid is uncharged and non polar, which word describes it?
Hydrophobic
What word describes the constant change of position of the plasma membrane?
Fluid
How are the phospholipids arranged?
Bilayer
What type of functions are proteins used are for in the membrane
Active transport
Channel forming
Enzymes
Receptors
Attachment for cytoskeleton
What two types of proteins are found in the plasma membrane
Peripheral and integral
Where are integral proteins are found
Within the membrane
What type of integral proteins span the entire width of the membrane
Transmembrane
What do integral membrane proteins interact with
Hydrophobic region of phospholipids
What holds the integral membrane proteins within the phospholipid bilayer?
WDL
Hydrophobic R groups allow strong hydrophobic interactions
Where are peripheral proteins found
On the surface of the membrane
What type of R groups do peripheral proteins have on the surface
Hydrophilic
What type of bond interactions do the hydrophilic R groups on the surface are bound to the surface of membranes
Ionic and hydrogen bonds
What two small molecules have the ability to diffuse straight through the membrane
carbon dioxide and oxygen
What type of transport is facilitated diffusion
Passive
Facilitated diffusion is passive transport of substances and across the membrane through what type of proteins?
Transmembrane
What types of proteins are involved in transporting substances
Channel
Transporter
Pumps
What are channel proteins
Multi-subunit proteins to make waterfilled pores that extend across the membrane and are selective
How are ligand gated channels controlled
Binding of signal molecules
How are voltage gated channels controlled
Changes within the ion concentration
What are transporter proteins
They bind to a specific substance and has a conformational change to transfer solute across membrane (transport)
How many sides are open for a transporter
1 out of 2
What type of proteins are used by active transport
Pumps
Why use pump proteins to transfer substances in active transport
So They can transport against their concentration gradient
What are pumps
Transporter proteins with energy
What is required for active transport to take place
Metabolic energy
Why do some active transport proteins hydrolyse ATP directly
To provide energy for the conformational change to move substances across membrane
What do ATPases hydrolyse
ATP
What makes up the electrochemical gradient for a solute carrying charge
Concentration gradient and electrical potential difference
What determines the transport of the solute
Electrochemical gradient
How is a membrane potential created
Difference in electrical charge on two sides of membrane
How does the sodium potassium pump get energy? and what is maintained?
Hydrolysis of ATP and maintain ion gradients
Is sodium pumped in or out
Out
Is potassium pumped in or out
In
Explain steps of active transport
Pump has high affinity for Na ions in, phosphorylation by ATP, this changes conformation, affinity of Na ions decrease, Na ions release, K ions bind out side, dephosphorylation, conformation change , K ions into cell affinity returns
How many sodium ions are pumped out
3
How many potassium ions are pumped in
2
What accounts for a large proportion of the basal metabolic rate in many animal organisms
SODIUM POTASSIUM PUMP
What drives the active transport of glucose to in the small intestine
Sodium gradient created by the Sodium-potassium pump
What did the sodium potassium pump make in the intestinal epithelial cells
Sodium ion gradient across the plasma membrane
What does the glucose transporter do
Glucose symport transports sodium ions and glucose at the same time and in the same direction
