Y12 Exchange Flashcards
1
Q
Adaption of large organisms for exchange
A
Develop specialised exchange organs like lungs or gills to increase surface area without significantly increasing volume
2
Q
Small animals and metabolic rate
A
Due to large surface area to volume ratio, they lose heat quickly and need a relatively high metabolic rate to maintain body temperature
3
Q
Body shape and heat conservation
A
Compact body shapes help conserve heat by minimising the surface area to volume ratio
4
Q
Relationship between size and SA:V ratio
A
As the size of an organism increases, its surface area to volume ratio decreases
5
Q
Substances organisms need to excrete
A
Carbon dioxide and urea as waste products
6
Q
Metabolic rate and body temperature
A
Organisms need to maintain a constant body temperature, with heat being exchanged based on metabolic activity and environmental conditions
7
Q
Large organisms and SA:V ratio
A
Large organisms like polar bears have a small surface area to volume ratio, making it more difficult to exchange substances but helping them conserve heat
8
Q
Essential substances organisms need to take in
A
Oxygen for aerobic respiration, nutrients such as glucose and amino acids
9
Q
Surface area to volume ratio (SA:V)
A
The amount of surface area per unit volume of an object or collection of objects. Generally, the larger an object is, the smaller its surface area to volume ratio
10
Q
Heat loss relationship
A
The rate of heat loss from an animal depends on its surface area - higher SA:V ratio leads to greater heat loss
11
Q
Cold environment adaptions
A
Animals develop compact shape with smaller surface area to volume ratio to reduce heat loss
12
Q
Multicellular organisms and diffusion limitations
A
Cannot obtain sufficient oxygen and nutrients by diffusion alone due to large distances between cells and the outside environment, and small surface area to volume ratio
13
Q
Small organisms and SA:V ratio
A
Small organisms like mice have a large surface area to volume ratio, allowing for efficient substance exchange but causing faster heat loss
14
Q
Diffusion pathway
A
The distance substances must travel through diffusion to reach cells within an organism
15
Q
Single-celled organisms and diffusion
A
Can obtain sufficient substances through diffusion across their cell surface membrane due to short diffusion pathway and large surface area to volume ratio
16
Q
Metabolic activity and heat
A
Cellular metabolic activity releases heat which must be either conserved or lost depending on the environment conditions
17
Q
Specialised exchange organs
A
Structures like lungs or gills that evolved to increase surface area for exchange without significantly increasing body volume
18
Q
Hot environment adaptions
A
Animals develop less compact or flattened shape with larger. Surface area to volume ratio to increase heat loss
19
Q
Flatworm adaption
A
Has a flattened body shape that provides a short diffusion pathway and increased surface area for efficient gas exchange
20
Q
Tubifex worm adaption
A
Small thin animals with no specialised gas exchange system that can survive through direct diffusion due to their body shape
21
Q
Surface Area in Tracheal System
A
Increased by numerous tracheoles, allowing for more efficient gas exchange but also increasing potential water loss
22
Q
Features of Exchange surfaces
A
Characteristics that include:
-Large surface area
-Thin exchange surface
-Steep concentration gradient to ensure efficient substance movement
23
Q
Gas Exchange Compromise
A
Balance between the need for efficient gas exchange and the need to limit water loss in insects
24
Q
Respiratory Gas Movement
A
Occurs through both diffusion along concentration gradients and mass transport through abdominal pumping
25
Spiracles
Tiny pores on an insect’s body surface through which gases enter and leave the abdomen. These can open and close to help control gas exchange.
26
DIffusion pathway
Distance gases must travel to reach respiring tissues, kept short in insects through the extensive network of tracheoles
27
Abdominal Pumping
Rhythmic contractions of abdominal muscles in larger insects that squeeze the trachea to enable mass movements of air in and out of the tracheal system
28
Diffusion Gradient Movement
Process where respiratory gases move into and out of the tracheal system due to concentration differences between the inside of tracheoles and external environment
29
Water loss prevention in insects
Adaptions including:
-Waterproof body covering
-Tiny hairs around spiracles
-Ability to close spiracles
30
Single-celled Organism Exchange
Process where substances like glucose and oxygen can diffuse directly across the cell surface membrane due to short diffusion pathway
31
Gas exchange efficiency
Enhanced by:
-Short diffusion pathways
-Large surface area of tracheoles
-The ability to control gas exchange through spiracle opening and closing
32
Water-filled Tracheoles
The end of tracheoles normally contain water which can move into cells during intense activity when lactate production lowers cell water potential
33
Water Conservation Adaptions
Features including:
-Closable spiracles
-Waterproof covering
-Tiny protective hairs that help insects prevent excessive water loss
34
Oxygen Delivery System
Network of Tracheae and Tracheoles that brings oxygen directly to respiring tissues, creating a short diffusion pathway
35
Tracheae
Internal tubes in insects that are supported by strengthened rings to prevent collapse. They connect spiracles to tracheoles and form part of the gas exchange system.
36
Osmosis in Gas Exchange
Process where water moves from tracheoles into cells during intense activity due to lower water potential caused by lactate production
37
Mass transport
Movement of gases in larger insects achieved through abdominal pumping, causing more efficient air movement in and out of the tracheal system
38
Anaerobic Respiration in Insects
Process occurring during intense activity that produces lactate, which affects water movement from tracheoles into cells
39
Tracheoles
Small, dead-end tubes that branch from tracheae. They extend throughout body tissues to bring oxygen directly to respiring cells providing a short diffusion pathway.
40
Carbon Dioxide Exchange
Process where CO2 produced during respiration creates a concentration gradient, allowing it to diffuse out of the insect through the tracheal system
41
Concurrent Flow
Less efficient alternative to counter-current flow where blood and water flow in the same direction, resulting in equilibrium being reached partway along lamellae
42
Gills
Specialised exchange surfaces in fish located on each side of the head under the operculum, used to obtain oxygen from water. They consist of usually four gill arches, each supporting many gill filaments.
43
Operculum
A protective structure that covers the gills on each side of a fish’s head
44
Water Oxygen Content
Water contains approximately one-thirtieth the amount of oxygen compared to air, making it challenging for fish to obtain sufficient oxygen
45
Amoebic Gill Disease (AGD)
Disease caused by parasites living on fish gills, causing the lamellae to become thicker and fused together, reducing gas exchange efficiency
46
Counter-Current Principle
System in fish gills where blood flows through the lamellae in one direction while water flows across the gills in opposite direction, maximising oxygen uptake efficiency up to 80% of available oxygen
47
Gill Filaments
Structures attached to gill arches that increased the surface area for gas exchange in fish
48
Fish Ventilation
Process where water enters through the mouth, flows over the gills, and exits from under the operculum in one direction only
49
Gill arch
Bony structure that supports many gill filaments in fish respiratory system
50
Gill Lamellae
Small projections on Gill filaments that further increase surface area for gas exchange and have good blood supply with thin surface layer of cells for short diffusion pathway
51
Diffusion Gradient
The difference in oxygen concentration between water and blood that allows continuous oxygen transfer across gill surfaces
52
Xylem
Cells that transport water and mineral ions from the roots to other parts of the plant
53
Gas Exchange Surface in Plants
The surface of the mesophyll cells in the leaves where gas exchange occurs
54
Guard Cells
Cells found on each side of the stomata that control their opening and closing by becoming turgid or flaccid
55
Palisade Mesophyll Cells
Column-Shaped cells in leaves that contain many chloroplasts
56
Dicotyledonous Plants
Flowering plants that have two embryonic seed leaves, including many herbaceous plants, trees and shrubs
57
Stomata
Pores in leaves that open to allow gases to pass in and out of the leaf. The singular form is stoma
58
Phloem
Cells that transport organic substances such as sugars and amino acids around a plant
59
Flaccid Guard Cells
The state of guard cells when they lose water and collapse, causing stomata to close
60
Sunken Stomata
A xerophytic adaption where stomata are located in pits to reduce water loss by trapping water molecules
61
Curled Leaves
A xerophytic adaption where leaves curl inward, placing stomata on the inside to reduce water loss by trapping water molecules
62
Xerophytes
Plants that are specifically adapted to living in dry environments
63
Upper Epidermis
Transparent cells that let light through to reach the photosynthetic cells below
64
Plant Gas Exchange Process
The movement of gases into and out of leaves by diffusion through open stomata, driven by concentration gradients
65
Lower Epidermis
The layer of cells on the lower side of the leaf where most stomata are typically located
66
Waxy Cuticle
A protective layer on leaves that prevents evaporation of water from the leaf surface
67
Vascular Bundle
The leaf vein that contains xylem and phloem
68
Stomatal Density
A measure of the number of stomata per unit area of a leaf, typically measured in stomata per mm^2
69
Spongy Mesophyll Cells
Irregularly shaped cells surrounded by air spaces which let gases diffuse through the leaf
70
Leaf hairs
A xerophytic adaption that traps water molecules around the leaf to reduce the water diffusion gradient
71
Turgid Guard Cells
The state of guard cells when they absorb water and expand, causing stomata to open
72
Red Blood Cell Adaption
Red blood cells move slowly through pulmonary capillaries and become flattened against capillary walls to allow more time for diffusion
73
Trachea Structure
The trachea is held open by cartilage ring, allowing air flow while maintaining flexibility to blend
74
Gas exchange System Components
The human gas exchange system consists of lungs, alveoli, bronchioles, bronchi and trachea
75
Surfactant
A substance made phospholipids that reduces surface tension of water in alveoli, preventing walls from sticking together and reducing breathing effort
76
Surface Area Adaption
Lungs contain millions of alveoli to provide a very large total surface area for efficient gas exchange
77
Capillary Network
Alveoli are covered by a network of capillaries that allow for efficient gas exchange between air and blood
78
Alveoli Function
Alveoli are specialised structures in the lungs where oxygen diffuses across the alveolar epithelium and capillary endothelium into the blood
79
Gas Exchange Need in Large Mammals
Large Mammals need high volumes of oxygen absorption and carbon dioxide removal due to their large volume of living cells and need to maintain high body temperature
80
Concentration gradient
Constant ventilation of lungs and blood circulation maintains a steep concentration gradient for oxygen and carbon dioxide between alveoli and blood
81
Diffusion pathway
The epithelium of alveoli and pulmonary capillaries are only one cell thick, creating short diffusion pathway for gases
82
Active vs Passive Breathing
-Inspiration is active and requires energy for muscle contraction
-Normal expiration is passive and does not require muscle contraction
83
Pulmonary Ventilation Rate (PVR)
A measure of how much air moves into the lungs in one minute, calculated by multiplying tidal volume by breathing rate
84
Intercostal Muscles
Two sets of muscles (external and internal) that work antagonistically – as one contracts, the other relaxes to help with breathing movement
85
Elastin
Elastic protein found in alveoli walls that help them recoil and return to their normal shape during exhalation
86
Diaphragm Movement During Expiration
The diaphragm relaxes and curves upwards (domes up), decreasing thoracic cavity volume
87
Pressure Gradient
The difference in air pressure that causes air movement during breathing – air moves from areas of high pressure to areas of low pressure
88
Spirometry
A simple test using a spirometer to help diagnose and monitor lung conditions by measuring various aspects of breathing
89
Expiration
Passive breathing process were external intercostal muscles relax, ribcage moves down and inwards, and diaphragm relaxes and curves upward, decreasing thorax volume and pushing air out
90
Gas Exchange Pathway
The route air takes into the body:
Trachea, bronchi, bronchioles, alveoli, and blood capillary
91
Forced Vital Capacity (FVC)
The maximum volume of air possible to breathe forcefully out of the lungs after a really deep breath in
92
Forced Expiration
Process where intercostal muscles contract to pull ribcage further down and inwards, decreasing thorax volume more than in normal expiration
93
Diaphragm Movement During Inspiration
The diaphragm contracts and flattens, moving downward to increase thoracic cavity volume
94
Positive Correlation
When a change in one variable is accompanied by a constant multiplier change in the other variable
95
Risk Factor
A factor that increases the probability that someone will suffer from a disease
96
Forced Expiratory Volume (FEV)
The maximum volume of air that can be breathed out in one second
97
Inspiration
Active breathing process where external intercostal muscles contract, rib cage moves up and out, and diaphragm contracts and flattens, increasing thorax volume and decreasing pressure to draw air in
98
Tidal Volume
The volume of air in each breath
99
Ventilation
The process of breathing air in (inspiration) and out (expiration) of the lungs. Air moves down a pressure gradient caused by changed in volume of the thorax
100
Negative Correlation
When an increase in one variable is accompanied by a decrease in another variable
101
Physical Digestion
The process where large food molecules are broken down into smaller pieces by the teeth to increase surface area for chemical digestion
102
Rectum
Where faeces are stored before being removed via the anus through egestion
103
Maltase
Membrane-bound enzyme that breaks down maltose into glucose molecules
104
Pancreas
Produces many digestive enzymes which are secreted through the pancreatic duct into the small intestine
105
Liver and Gallbladder
Liver secretes bile which in stored in gallbladder. Bile has high pH to neutralise stomach acid and emulsify lipids
106
Membrane-bound dissacharidases
Enzymes (maltase, sucrase, lactase) attached to the cell membranes of epithelial cells lining the ileum that break down disaccharides
107
Maltose
A disaccharide formed by condensation of two glucose molecules
108
Sucrose
A disaccharide formed by condensation of glucose and fructose molecules
109
Hydrolysis
The process of breaking down large insoluble molecules into smaller soluble molecules using water
110
Ileum
Last past of the small intestine where final digestion occurs and main site of absorption of food molecules. Contains membrane-bound maltase, sucrase and lactase enzymes
111
Chemical Digestion
The process where large food molecules are broken down during hydrolysis reactions into smaller molecules which can be absorbed from gut into blood
112
Lactose
A disaccharide formed by condensation of glucose and galactose molecules
113
Amalase
Enzyme produces in salivary glads and pancreas that breaks down starch into molecules
114
Oesophagus
Muscular tube that connects the mouth to the stomach
115
Duodenum
First part of the small intestine where almost all digestion takes place
116
Monosaccharides
The basic monomers from which larger carbohydrates are made, including galactose and fructose
117
Salivary Glands
Produces saliva containing water to dissolve substances, mucus for lubrication, and amylase enzyme
118
Stomach
Organ where food is stored for up to a few hours, contains stomach acid to kill bacteria and some protease enzymes
119
Disaccharides
Formed by the condensation of two monosaccharides joined by glycosidic bonds
120
Disaccharides
Formed by the condensation of two monosaccharides joined by glycosidic bonds
121
Large Intestine
Where water is absorbed to form semi-solid faeces
122
Membrane-bound Dipeptidases
Enzymes located on the cell surface membrane of epithelial cells in the small intestine that specifically break down dipeptides into individual amino acids
123
Polypeptide
A chain formed when amino acids join together through peptide bonds
124
Exopeptidases
Enzymes that hydrolyse peptide bonds at the ends of proteins, removing a single amino acid from the end
125
Proteases (peptidases)
Enzymes that catalyse the hydrolysis of peptide bonds between amino acids during protein digestion
126
Pepsin
An endopeptidase enzyme released into the stomach that workers in acidic conditions
127
Co-transport mechanism
A method of moving molecules across cell membranes where sodium ions and another molecule (like amino acids) are transported together through specific protein channels
128
Protein Digestion
The process of breaking down proteins into amino acids through the combined action of proteases different proteases including endopeptidases, exopeptidases and membrane-bound dipeptidases
129
Bile
A substance produced by the liver and stored in the gallbladder that emulsifies lipids in the small intestine by breaking large lipid droplets into smaller ones, increasing surface area for lipase action
130
Golgi Apparatus
The cellular organelle responsible for packaging triglycerides with cholesterol and proteins to form chylomicrons
131
Golgi Apparatus
The cellular organelle responsible for packaging triglycerides with cholesterol and proteins to form chylomicrons
132
Smooth Endoplasmic Reticulum
The cellular organelle where monoglycerides are reformed into triglycerides after absorption into epithelium cells, and packaged into chylyomicrons
133
Lipid absorption process
Monoglycerides and fatty acids pass through epithelium cell membranes by simple diffusion, are reformed into triglycerides in SER
134
Lacteals
Structures in the villi that absorb chylomicrons, which then move through the lymphatic system and eventually into the bloodstream
135
Lipase
Enzyme produced in the pancreas that catalyse the breakdown of lipids by hydrolysing ester bonds in the small intestine
136
Ester Bonds
Bonds formed in triglycerides through condensation reaction between glycerol and fatty acids (RCOOH)
137
Ester bonds
Chemical bonds formed between glycerol and fatty acids in triglyceride molecules during condensation reactions
138
Lipid digestion
Lipids are broken down into monoglycerides and fatty acids when ester bonds between them are hydrolysed, catalysed by lipase enzymes from the pancrease
139
Chylomicrons
Structures formed when triglycerides are packaged with cholesterol and proteins in the Golgi apparatus
140
Micelles
Tiny structures formed when monoglycerides and fatty acids associated with bile salts after lipid digestion
141
Lipase
Enzyme produced in the pancreas that catalyses the breakdown of lipids in the small intestine
142
Lacteals
Structures in the villi that absorb chylomicrons, which then move through the lymphatic system into the bloodstream
143
Simple diffusion in lipid absorption
Process by which monoglycerides and fatty acids pass across cell membranes of epithelium cells because they are lipid-soluble
144
Emulsification
Process where bile causes larger lipid droplets to form smaller droplets, increasing surface area for enzyme action
145
Function of bile
Produced by liver and stored in gallbladder, bile emulsifies lipid by breaking large lipid droplets into smaller ones, creating larger surface area for lipase to work on
146
Exocytosis
Process by which chylomicrons are exported from epithelial cells into lacteals
