TOPIC 4 Flashcards
describe 3 different structures found within the fluid mosaic model of the cell membrane and their purpose
Glycoproteins- act as an antigen and is important for cell recognition or as receptors
Peripheral Proteins-can be enzymes and regulate transport- eg cell signaling
Integral Proteins- main transport system forming permanent pores (hydrophilic channel) or carrier proteins or active pumps involving enzymes
Identify and describe 3 types of passive transport
Diffusion- movement of particles down the con. gradient from an area of higher concentration to an area of lower concentration as a result of random movement.
Facilitated diffusion- diffusion takes place through carrier proteins
Osmosis-movement of solvent molecules down a con. gradient across a partially permeable membrane
Identify and describe 3 types of active transport mechanisms
Endocytosis-large molecules move into cells through vesicle formation
Exocytosis large molecules move out of the cell through vesicle formation
Active Transport-movement of substances across the membrane directly using ATP
Outline the process of facilitated diffusion
molecules may be too large or strongly positive/negative
these are caried across the membrane in protein carriers of matching shape
the protein carrier changes shape and the molecules are passed into the cell.
protein carriers returns to its original shape this allows more molecules to enter
Alternative definitions of osmosis
the net movement of water from an area of higher water potential to an area of lower water potential through a partially permeable membrane
the net movement of water molecules from an area of higher osmotic potential to an area of lower osmotic potential through a partially permeable membrane
define osmotic concentration
a measure of the concentration of the solutes in a solution that have an osmotic effect
define isotonic, hypertonic, and hypotonic
Isotonic-solution in which the osmotic concentration of the solutes is the same as that in the cells
Hypotonic-solution in which osmotic concentration of solutes is lower than the cells contents
Hypertonic-solution in which osmotic concentration of solutes is higher than the cells contents
define pressure potential
a measure of the inward pressure exerted by the plant cell wall on the protoplasm of a cell opposing the entry of water by osmosis. it usually has a positive value
_________ is a state when the solute potential causing water to be moves into the cell by osmosis is balanced by the force of the cell wall pressing on the protoplasm
TURGOR is a state when the solute potential causing water to be moves into the cell by osmosis is balanced by the force of the cell wall pressing on the protoplasm
When 50% of cells have had so much water has moved out by osmosis that the cell membrane begins to pull away from the cell wall and the protoplasm shrinks
Incipient plasmolysis
Water potential is
Turgor potential is
Osmotic potential is
Water potential is a measure of the potential for water to move out of a solution by osmosis
Turgor potential is a measure of the inward pressure exerted by the plant cell wall on the protoplasm of the cell as the cell contents expand and press outwards, a force which opposes the entry of water by osmosis
Osmotic potential is a measure of the potential of a solution to cause water to move into the cell across a partially permeable membrane as a result of dissolved solutes
phagocytosis is. . .
phagocytosis is the active process when a cell engulfs something large such as a bacterium and encloses it in a vesicle
Pinocytosis is the ________ process by which cells take in tiny amounts of ____________ _________ by tiny vesicles
Pinocytosis is the active process by which cells take in tiny amounts of extracellular fluid by tiny vesicles.
Outline the process carried out by sodium pumps
active transport
sodium pump actively moves potassium ions into the cell and sodium ions out
protein carrier changes shape using ATP. changes shape back to normal passively
state the factors affecting the rate of diffusion
the surface area- bigger surface area the more particles can be exchanged at the same time
concentration gradient
distance over which diffusion is taking place
effective gas exchange features
Large surface area- compensates for small surface area: volume ratio
Thin layers- minimise diffusion distances
Rich blood supply to respiratory surfaces- maintains steep concentration gradient
Moist Surfaces- as diffusion takes place with gases
Permeable surfaces- Allows free passage of respiratory gases
name 2 ways for air to enter the respiratory system
Nasal cavity-
Mouth- but misses out on cleaning and moistening effects of nasal route
epiglottis?
Flap of tissue that closes over glottis in a reflex action when food is swallowed preventing food from entering gas exchange system
Name for voice box which uses the flow of air to produce sounds
Larynx
Describe the trachea
Major airway to the bronchi, lined with cells including mucus secreting cells. Cilia on the surface of the trachea moves mucus and microorganisms away from the lungs
Incomplete rings of cartilage purpose?
prevent trachea and bronchi from collapsing but allow food to be swallowed and moved down the oesophagus
The tubes leading to the lungs similar in structure to the trachea but narrower and divide to form bronchioles are called
Left and right bronchus
__________ are small tubes that spread throughout the lungs and end in _________.
BRONCHIOLES are small tubes that spread throughout the lungs and end in ALVEOLI
The main site of gas exchange in the lungs are the
ALVEOLI
surrounds lungs and line the chest cavity
PLEURAL MEMBRANES
the _______ _________ is the space between pleural membranes usually filled with a thin layer of lubricating fluid that allows the membranes to _________ _________ with breathing movements .
the PLEURAL CAVITY is the space between pleural membranes usually filled with a thin layer of lubricating fluid that allows the membranes to Slide Easily with breathing movements .
outline what happens during inhalation
INHALATION
active- energy using process
muscles around the diaphragm contract, diaphragm is lowered and flattened
intercostal muscles between ribs also contract raising ribcage upwards and outwards
volume of chest cavity increases, this reduces pressure in the cavity
atmospheric pressure is lower in cavity and higher outside
in order to equalise pressure inside and out air moves in through the trachea
Outline what happens during exhalation
Passive process- does not require ATP
Muscles surrounding diaphragm relax so it moves up into resting domed position
intercostal muscles relax so ribs move down and in
elastic fibres of alveoli of lungs return to normal length
volume in chest cavity lower
pressure is greater than the outside
air moves out of the lungs
describe the gas exchange system in insects
SPIRACLES- found along thorax and abdomen. site of entry and exit of the respiratory gases. Sphincters can be opened or closed to control water loss
TRACHEAE-largest tubes in insect respiratory system. Carry air directly into the body. tubes are supported by spirals of chitin which make the tracheae impermeable to gases.
TRACHEOLES Trachea narrow to form tracheoles which have no chitin spirals meaning they are freely permeable to gases
Insects way of ventilating their gas exchange system
Mechanical ventilation- air actively pumped into tracheal system. spiracles open and insect makes muscular movements of the thorax. these change volume and pressure inside body drawing air in and out of tracheae and tracheoles
Collapsible tracheae/air sacs- these act as air reservoirs and increase the volume of air moved through respiratory system. movement of thorax and abdomen deflate and inflate them
describe respiration in insects
sphincters open the spiracles allowing oxygen to diffuse through down a tube called the trachea. Gas exchange does not occur here because the trachea is lined with rings of chitin which make it impermeable. these rings prevent the trachea from collapsing
oxygen diffuses across small tubes called tracheoles which are permeable.
water builds up at the bottom of tracheoles which slows down diffusion- in active insects water is removed as lactic acid builds up which lowers water potential so water moves into cells by osmosis.
describe how fish respire
- Water Intake (Inhalation Phase)
The fish lowers the floor of its buccal (mouth) cavity, increasing the volume inside.
This reduces pressure inside the mouth compared to the surrounding water.
Water flows into the mouth due to the pressure difference.
The operculum (gill cover) remains closed to prevent backflow. - Water Flow Over the Gills
The fish then closes its mouth and raises the buccal cavity floor, decreasing volume and increasing pressure.
This forces water into the pharynx and over the gill filaments.
The gill lamellae (thin folds on filaments) increase the surface area for gas exchange.
Counter current exchange occurs:
Blood in the capillaries flows opposite to the water flow.
This maintains a concentration gradient, maximizing oxygen absorption and carbon dioxide release.
- Gas Exchange at the Gills
Oxygen diffuses from high concentration in water to low concentration in blood.
Carbon dioxide diffuses from high concentration in blood to low concentration in water.
Haemoglobin in red blood cells binds to the absorbed oxygen. - Water Expulsion (Exhalation Phase)
The operculum opens, and the fish raises the floor of its buccal cavity, increasing pressure inside.
This pressure forces oxygen-depleted water out through the gill openings.
Explain the role of pressure changes in fish respiration
Lower pressure in the buccal cavity → Water enters the mouth.
Higher pressure in the buccal cavity → Water is forced over the gills.
Higher pressure in the opercular cavity → Water is expelled from the gill openings.
_____________ are folds on the gills that increase surface area . the continuous movement of water keeps them from ________ ____________.
Lamellae are folds on the gills that increase surface area . the continuous movement of water keeps them from sticking together.
where does gas exchange occur
spongy mesophyll
describe the double circulatory system
circulation involving 2 circulatory systems:
Systemic circulation- carries oxygenated blood from the heart to the cells and deoxygenated back to the heart.
Pulmonary circulation-deoxygenated blood carried to the lungs and oxygenated blood back to the heart
a single circulatory system is where the heart pumps the blood to the organs of ____ ___________ and the blood then travels on around the body before returning to the ___________.
a single circulatory system is where the heart pumps the blood to the organs of Gas Exchange and the blood then travels on around the body before returning to the Heart.
sciencey name for RBC
ERYTHROCYTES
sciencey name for WBC
LEUKOCYTES
sciencey name for platelets
THROMBOCYTES
Name 2 main types of Leucocytes
Granulocytes- granules in the cytoplasm of the cells that can take up stain and be visible under the microscope. Have a lobed nucleus.
Agranulocytes-do not have granules and have an unlobed nucleus
Identify 3 types of granulocytes
NON- SPECIFIC REPONSE
Neutrophils-engulf and digest pathogens by phagocytosis
Eosinophils-stained red by eosin stain. Allergic reaction responses and developing immunity
Basophils-produce histamines
identify 2 types of agranulocytes
SPECIGIC IMMUNO RESPONSE
Monocytes-engulf pathogens
Lymphocytes
What are platelets
Tiny fragments of large cells called megakaryocytes, involved in the clotting of blood.
difference between haemoglobin and myoglobin
Myoglobin contains only one haem group compared to the 4 of haemoglobin. Myoglobin has a higher affinity to oxygen that is not affected by partial pressure in tissues allowing it to act as an oxygen store.
define Bohr effect
name given to changes in the oxygen dissociation curve of haemoglobin that occur due to a rise in carbon dioxide levels and a reduction of the affinity of haemoglobin for oxygen
Name 2 important substances and their role in clotting
serotonin- causes smooth muscle of blood vessel to contract narrowing blood vessels cutting off the blood flow from the damaged area.
thromboplastin-enzyme that sets in process the cascade of events that leads to the formation of a clot
outline the blood clotting cascade
Vitamin K is important in the production of prothrombin.
Thromboplastin catalyses prothrombin into an enzyme called thrombin. Calcium ions need to be present in the blood at a right con.
Thrombin acts on fibrinogen (soluble protein) converting it to insoluble fibrin which forms a mesh of fibres to cover the wound.
more platelets pouring from the wound get trapped in the fibrin mesh, special proteins in platelets contract to make the clot tighter forming scab
Outline the transport of carbon dioxide
CO2 reacts with water when dissolved in the blood forming carbonic acid. this separates to form H+ and HCO3- ions.
some combines with haemoglobin molecules to form carbaminohaemoglobin.
most of CO2 is transported in the form of hydrogen carbonate ions in the cytoplasm of erythrocytes
stages of leading to atherosclerosis following the damage of the endothelium.
- Inflammatory response triggered(increase blood flow to area)
- WBC arrive this is defence
- Cholesterol accumulating
- atheroma/plaque builds up
- fibrous tissue and calcium salts build up
- Hardened plaque
- artery wall hardens and becomes less elastic
- reduced lumen size
- Increased blood pressure in arteries
- heart has to work harder because of the higher blood pressure
- Further damage to endothelium likely in other areas
–>further damage causes a clot to form which can clot the entire artery
Name 2 risk factors of atherosclerosis
High BP
Chemicals in tobacco smoke
what is an atheroma
the build-up of fatty deposits mainly LDL cholesterol which forms in the endothelium of an artery-
atheroma=plaque
identify 2 types of risk factors
modifiable- lifestyle
non-modifiable-genes/genetic tendencies
atherosclerosis can cause. . .
anginas-condition where the plaque builds up reducing blood flow to the cardiac muscle through the coronary artery. this result in pain during exercise
aneurysms-weakened bulging area of the artery wall that results from a build up behind a blockage caused by plaques
myocardial infarctions-(heart attack) takes place when atherosclerosis leads to the formation of a clot (thrombosis) that blocks the coronary artery and deprives the art muscle of oxygen so it dies. It can stop the heart from functioning
multifactorial disease?
the interplay of many different factors rather than having one simple cause
outline the non modifiable risk factors for atheorsclerosis
genes-genetic tendencies to develop hypertension or faulty cholesterol metabolism
age- as you get older blood vessels lose elasticity and narrow slightly
sex- men more likely because women are protected by oestrogen
outline the modifiable factors for atherosclerosis
smoking damages the artery linings making the build up of plaque more likely and causing arteries to narrow raising the blood pressure
regular exercise lower BP, prevents obesity, lowers blood cholesterol and reduces stress
Type 2 dia. damages lining of blood vessels increasing the risk of plaque formation
stress-causes the release of cytokines that trigger an inflammatory response in blood vessels leading to plaque formation
define intrinsic rhytmicity
the intrinsic rhythm of contraction and relaxation in the cardiac muscle making up the heart
describe the process of controlling the heartbeat
SAN has the fastest intrinsic rhythm and it sets up a wave of electrical excitation (depolarisation) causing the atria to contract
annulus fibrous region is non conducting tissue between atrium and ventricle preventing the excitation from the atrium to spread directly to the ventricle.
AVN- atrioventricular node is stimulated but delays before passing on the wave of depolarisation to the bundle of his which is group of conducting fibres in the septum
bundle of hiss splits into 2 branches that carry the excitation on into Purkyne tissue
these penetrate down the septum spreading through the tissue setting off the contraction of ventricles starting from the apex and squeezing blood out of the heart
What does SAN stand for and where is it found
Sinoatrial node- found in right atrium and acts as the hearts natural pacemaker
why is there a delay at the AVN before the bundle of His
ensures the atria have stopped contracting before the ventricles start
fluid that surrounds all the cells in the body is called _______
fluid that surrounds all the cells in the body is called Tissue fluid
Define oncotic pressure
the tendency for water to move into the capillaries by osmosis
hydrostatic pressure is the residual pressure from the heart beat that is still present as the blood enters the __________ end of the capillary beds that tends to force fluid out through the _________ ________ walls
hydrostatic pressure is the residual pressure from the heart beat that is still present as the blood enters the arterial end of the capillary beds that tends to force fluid out through the leaky capillary walls
the fluid travelling through the lymphatic system is known as _________
the fluid travelling through the lymphatic system is known as Lymph
purpose of lymph glands?
glands in the lymph system that contain lymphocytes that make antibodies
role of xylem and phloem
Phloem- tissue transporting dissolved solutes around the plant
Xylem- tissue transporting water around the plant
Name the layer of unspecialised plant cells that divide to form both the xylem and phloem
Cambium
Metaxylem?
mature xylem vessels made of lignified tissue
At the arterialend of a capillary the hydrostatic pressure is _________ than the oncotic pressure meaning tissue fluid is forced out of the capillary through the gaps between the ________ ___________
At the arterial end of a capillary the hydrostatic pressure is greater than the oncotic pressure meaning tissue fluid is forced out of the capillary through the gaps between the endothelial cells.
What substances are too large to leave the plasma in tissue fluid
Blood Cells and plasma proteins
at the venous end of the capillary the hydrostatic pressure is lower because
at the venous end of the capillary the hydrostatic pressure is lower because water has left the blood but oncotic is still quite high because of the blood cells and plasma proteins
so water moves back into the blood via osmosis
Tissue fluid not reabsorbed into the blood drains into vessels called ________ capillaries, these connect into larger lymph __________ forming the __________ system.
Tissue fluid not reabsorbed into the blood drains into vessels called lymph capillaries, these connect into larger lymph vessels forming the lymphatic system.
first xylem not fully lignified is called ______________ as it ages it is known as _______________
first xylem not fully lignified is called protoxylem as it ages it is known as metaxylem
