TOPIC 4

Question 1

describe 3 different structures found within the fluid mosaic model of the cell membrane and their purpose

Answer 1

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

Question 2

Identify and describe 3 types of passive transport

Answer 2

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

Question 3

Identify and describe 3 types of active transport mechanisms

Answer 3

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

Question 4

Outline the process of facilitated diffusion

Answer 4

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

Question 5

Alternative definitions of osmosis

Answer 5

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

Question 6

define osmotic concentration

Answer 6

a measure of the concentration of the solutes in a solution that have an osmotic effect

Question 7

define isotonic, hypertonic, and hypotonic

Answer 7

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

Question 8

define pressure potential

Answer 8

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

Question 9

_________ 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

Answer 9

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

Question 10

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

Answer 10

Incipient plasmolysis

Question 11

Water potential is
Turgor potential is
Osmotic potential is

Answer 11

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

Question 12

phagocytosis is. . .

Answer 12

phagocytosis is the active process when a cell engulfs something large such as a bacterium and encloses it in a vesicle

Question 13

Pinocytosis is the ________ process by which cells take in tiny amounts of ____________ _________ by tiny vesicles

Answer 13

Pinocytosis is the active process by which cells take in tiny amounts of extracellular fluid by tiny vesicles.

Question 14

Outline the process carried out by sodium pumps

Answer 14

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

Question 15

state the factors affecting the rate of diffusion

Answer 15

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

Question 16

effective gas exchange features

Answer 16

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

Question 17

name 2 ways for air to enter the respiratory system

Answer 17

Nasal cavity-
Mouth- but misses out on cleaning and moistening effects of nasal route

Question 18

epiglottis?

Answer 18

Flap of tissue that closes over glottis in a reflex action when food is swallowed preventing food from entering gas exchange system

Question 19

Name for voice box which uses the flow of air to produce sounds

Answer 19

Larynx

Question 20

Describe the trachea

Answer 20

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

Question 21

Incomplete rings of cartilage purpose?

Answer 21

prevent trachea and bronchi from collapsing but allow food to be swallowed and moved down the oesophagus

Question 22

The tubes leading to the lungs similar in structure to the trachea but narrower and divide to form bronchioles are called

Answer 22

Left and right bronchus

Question 23

__________ are small tubes that spread throughout the lungs and end in _________.

Answer 23

BRONCHIOLES are small tubes that spread throughout the lungs and end in ALVEOLI

Question 24

The main site of gas exchange in the lungs are the

Answer 24

ALVEOLI

Question 25

surrounds lungs and line the chest cavity

Answer 25

PLEURAL MEMBRANES

Question 26

the _______ _________ is the space between pleural membranes usually filled with a thin layer of lubricating fluid that allows the membranes to _________ _________ with breathing movements .

Answer 26

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 .

Question 27

outline what happens during inhalation

Answer 27

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

Question 28

Outline what happens during exhalation

Answer 28

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

Question 29

describe the gas exchange system in insects

Answer 29

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

Question 30

Insects way of ventilating their gas exchange system

Answer 30

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

Question 31

describe respiration in insects

Answer 31

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.

Question 32

describe how fish respire

Answer 32

1. 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. 2. 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. 3. 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. 4. 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.

Question 33

Explain the role of pressure changes in fish respiration

Answer 33

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.

Question 34

_____________ are folds on the gills that increase surface area . the continuous movement of water keeps them from ________ ____________.

Answer 34

Lamellae are folds on the gills that increase surface area . the continuous movement of water keeps them from sticking together.

Question 35

where does gas exchange occur

Answer 35

spongy mesophyll

Question 36

describe the double circulatory system

Answer 36

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

Question 37

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 ___________.

Answer 37

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.

Question 38

sciencey name for RBC

Answer 38

ERYTHROCYTES

Question 39

sciencey name for WBC

Answer 39

LEUKOCYTES

Question 40

sciencey name for platelets

Answer 40

THROMBOCYTES

Question 41

Name 2 main types of Leucocytes

Answer 41

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

Question 42

Identify 3 types of granulocytes

Answer 42

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

Question 43

identify 2 types of agranulocytes

Answer 43

SPECIGIC IMMUNO RESPONSE Monocytes-engulf pathogens Lymphocytes

Question 44

What are platelets

Answer 44

Tiny fragments of large cells called megakaryocytes, involved in the clotting of blood.

Question 45

difference between haemoglobin and myoglobin

Answer 45

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.

Question 46

define Bohr effect

Answer 46

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

Question 47

Name 2 important substances and their role in clotting

Answer 47

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

Question 48

outline the blood clotting cascade

Answer 48

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

Question 49

Outline the transport of carbon dioxide

Answer 49

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

Question 50

stages of leading to atherosclerosis following the damage of the endothelium.

Answer 50

1. Inflammatory response triggered(increase blood flow to area) 2. WBC arrive this is defence 3. Cholesterol accumulating 4. atheroma/plaque builds up 5. fibrous tissue and calcium salts build up 6. Hardened plaque 7. artery wall hardens and becomes less elastic 8. reduced lumen size 9. Increased blood pressure in arteries 10. heart has to work harder because of the higher blood pressure 11. Further damage to endothelium likely in other areas -->further damage causes a clot to form which can clot the entire artery

Question 51

Name 2 risk factors of atherosclerosis

Answer 51

High BP Chemicals in tobacco smoke

Question 52

what is an atheroma

Answer 52

the build-up of fatty deposits mainly LDL cholesterol which forms in the endothelium of an artery- atheroma=plaque

Question 53

identify 2 types of risk factors

Answer 53

modifiable- lifestyle non-modifiable-genes/genetic tendencies

Question 54

atherosclerosis can cause. . .

Answer 54

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

Question 55

multifactorial disease?

Answer 55

the interplay of many different factors rather than having one simple cause

Question 56

outline the non modifiable risk factors for atheorsclerosis

Answer 56

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

Question 57

outline the modifiable factors for atherosclerosis

Answer 57

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

Question 58

define intrinsic rhytmicity

Answer 58

the intrinsic rhythm of contraction and relaxation in the cardiac muscle making up the heart

Question 59

describe the process of controlling the heartbeat

Answer 59

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

Question 60

What does SAN stand for and where is it found

Answer 60

Sinoatrial node- found in right atrium and acts as the hearts natural pacemaker

Question 61

why is there a delay at the AVN before the bundle of His

Answer 61

ensures the atria have stopped contracting before the ventricles start

Question 62

fluid that surrounds all the cells in the body is called _______

Answer 62

fluid that surrounds all the cells in the body is called Tissue fluid

Question 63

Define oncotic pressure

Answer 63

the tendency for water to move into the capillaries by osmosis

Question 64

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

Answer 64

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

Question 65

the fluid travelling through the lymphatic system is known as _________

Answer 65

the fluid travelling through the lymphatic system is known as Lymph

Question 66

purpose of lymph glands?

Answer 66

glands in the lymph system that contain lymphocytes that make antibodies

Question 67

role of xylem and phloem

Answer 67

Phloem- tissue transporting dissolved solutes around the plant Xylem- tissue transporting water around the plant

Question 68

Name the layer of unspecialised plant cells that divide to form both the xylem and phloem

Answer 68

Cambium

Question 69

Metaxylem?

Answer 69

mature xylem vessels made of lignified tissue

Question 70

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 ________ ___________

Answer 70

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.

Question 71

What substances are too large to leave the plasma in tissue fluid

Answer 71

Blood Cells and plasma proteins

Question 72

at the venous end of the capillary the hydrostatic pressure is lower because

Answer 72

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

Question 73

Tissue fluid not reabsorbed into the blood drains into vessels called ________ capillaries, these connect into larger lymph __________ forming the __________ system.

Answer 73

Tissue fluid not reabsorbed into the blood drains into vessels called lymph capillaries, these connect into larger lymph vessels forming the lymphatic system.

Question 74

first xylem not fully lignified is called ______________ as it ages it is known as _______________

Answer 74

first xylem not fully lignified is called protoxylem as it ages it is known as metaxylem