BIOLOGY-CELL TRANSPORT Flashcards
What is the entry and exit of molecules in the cells controlled by?
The cell surface membrane
What does the cell surface membrane surround?
The cytoplasm of the cell
How is the membrane described as
Partially permeable
What does the cell membrane consist of?
Proteins
Glycoproteins
Phospholipids
Carbohydrates
What does the phospholipid molecules form?
Double layer that are constantly moving around one another
Explain why the model for membrane structure is known as a fluid Mosiac model
The model is said to be fluid because the phospholipids are able to move
The model is said to be Mosiac because the proteins are randomly distributed. It’s called a model because it is the theory we have the most evidence for
What is the selective permeability of the cell membrane related to?
To the type and distribution of specific proteins and phospholipid molecule present in the membrane
What are intrinsic proteins?
Membrane proteins which are embedded completely or partly within the lipid bilayer of the membrane
What are extrinsic proteins?
Loosely bound proteins that are located outside the membrane
What are the hydrophobic tails attracted towards
Towards each other
Which molecules does the phospholipid bilayer allow?
Lipid soluble molecules
How does the phospholipid bilayer allow lipids soluble to pass?
By simple diffusion which prevents the passage of small polar molecules like ions
What does cholesterol do?
Decreases permeability and increases the stability of the membrane
What does more cholesterol mean?
less fluidity of the membrane
Do all types of cell have the same cholesterol?
No
What is the function of channel proteins?
They are like Pores within the membrane that only allow specific charge ions to move across the membrane by facilitated diffusion
What type of structures do proteins have?
Specific tertiary structures, so they are specific and can only transport molecules that are complementary to the shape of the channel protein
What is the function of carrier proteins?
The aid the transport of ions and large molecules, for example, glucose and amino acids, by facilitated diffusion and active transport
What do carrier proteins have?
Have a binding site at a substrate that changes shape and their specific to each substance in due to shape of binding sote
What are receptor proteins?
Cell communications
Where are enzymes embedded?
In cell membrane
What is the structure enzymes?
They have a specific active site which is complementary to its substrate, allowing them to bind and form enzyme substrate complexes
What are glycoproteins?
They’re composed of carbohydrates and proteins and are on the outer surface of the membrane and are important in cell recognition often acting as antigens
What do the immune cells detect?
The specific shapes of the glycol proteins to identify if the cells are foreign
Where are glycol proteins produced?
In the Golgi body within the cell that displays them
What do all cells have?
Glycoproteins in the surface cell membrane
What are Aquaporins
A special type of channel proteins specific to water
What happens if a cell has a lot of aquaporins
It will be permeable to water and will carry out osmosis easily
What do carrier proteins do?
Carry larger molecules through membrane
What is diffusion?
Net movement on molecules from area of high concentration to a low concentration across a partially permeable membrane
What is the function of PCT
Selective reabsorption of amino acids
What does the renal vein do?
Carry blood away from the kidney to the heart
What hormone regulates that absorption of water in collecting duct?
ADH
How does the difference in diameters help the process of ultrafiltration?
Causes high pressure due to description of aids pushing small molecules from blood into filtrate
What is the function of the loop of henle
To create a very high concentration of salts in the tissue fluid of the kidney
Give advantage of having a kidney transplant
No need for dialysis
Why does amoeba need many mitochondria?
For movement of the contractile
Why is time delay important at the AV node as the impulse spreads
To allow the atria to finish contracting, so blood goes from atria into ventricles to allow time for the valves to close before the ventricles start to contract
Explain why the student has a higher rate of oxygen consumption when cycling them when at rest
Increased muscle contraction using more ATP, so aerobic respiration in mitochondria gets rid of the lactic acid and re-oxygenates the myoglobin
What is the plasma membrane made of?
Phospholipids
Cholesterol
Protein
Carbohydrates
What are Channel proteins?
These proteins allow water to pass through the membrane
What does carrier protein do
These cause a change in shape, which allows a substance from the outside of cell move to the inside
What is a function of the bicuspid valve?
Prevents backflow of blood
From left ventricle to the left atrium
How do electrical impulses spread?
From sinoatrial node from the atria to the atrioventricular node and then a time delay happens down to the bundle of his up the purkinje fibres
How do you find percentage decrease?
Difference/original x100
How does caffeine change the cardiac output of the daphinia
Caffeine increases the cardiac output
Because heart rate is increased
Caffeine is a stimulant and binds to the receptors
Increasing the stoke volume
Explain why anyone can be given type O blood
No antigens in group O
So no binding with recipients antibodies
No clotting
What is myogenic?
When the muscle contracts on its own, without any signal from the brain, and they generate their own electrical impulses
What does the coronary artery do?
Carries blood that contains oxygen to the heart muscle
Explain how a blocked coronary artery may lead to a heart attack
Less oxygen to the heart muscles
So less respiration and less energy so part of the heart dies so the heart cannot beat
Which term describes the patient’s resting heart rate?
Tachycardia
What is the function of the vena cava
Carries deoxygenated blood from the body to the heart
Give three functions of the capillaries
Carries oxygenated blood to cell
Absorbs nutrients in the gut
Slows the blood flow so exchange can occur
