topic 3 Flashcards
(115 cards)
1
Q
What is the relationship between surface area and volume in biological units?
A
As the size increases, surface area grows more slowly than volume.
2
Q
What are exchange surfaces?
A
Surfaces across which substances are transferred, often with a large surface area:volume ratio, thinness, and selectivity.
3
Q
What is a concentration gradient?
A
The difference in concentration of a substance inside and outside a cell.
4
Q
What are tracheae?
A
A large internal network of tubes in insects supported by rings.
5
Q
What are tracheoles?
A
Tubes extending from tracheae throughout insect body tissues for gas exchange.
6
Q
What are spiracles?
A
Tiny pores that allow gas and water vapor exchange in insects.
7
Q
Where are gills located in fish?
A
Within the body, behind the head.
8
Q
What are gill filaments?
A
Stacked structures that make up the gills of a fish.
9
Q
What are gill lamellae?
A
Structures at right angles to gill filaments that increase surface area.
10
Q
What does countercurrent flow refer to?
A
The opposite flow of water and blood across gill lamellae that maintains a diffusion gradient.
11
Q
What are stomata?
A
Minute pores mainly on leaves for gas exchange and water vapor release.
12
Q
What is the function of guard cells?
A
Control the opening and closing of stomata.
13
Q
What is spongy mesophyll?
A
Leaf tissue with large air spaces for gas exchange.
14
Q
What is a xerophyte?
A
Plants adapted to limit water loss due to restricted water supply.
15
Q
What are lungs?
A
Lobe structures with bronchioles and alveoli for gas exchange.
16
Q
What is ventilation?
A
The process of moving air in and out of the lungs.
17
Q
What is the trachea?
A
A flexible airway supported by cartilage rings.
18
Q
What are bronchi?
A
Divisions of the trachea leading to each lung.
19
Q
What are bronchioles?
A
Branching subdivisions of bronchi with muscular walls.
20
Q
What are alveoli?
A
Minute air sacs at the end of bronchioles for gas exchange.
21
Q
What happens during inspiration?
A
External intercostal muscles contract, increasing thoracic volume.
22
Q
What occurs during expiration?
A
Mostly passive; muscles relax, decreasing thoracic volume.
23
Q
What is the diaphragm?
A
A muscle sheet separating the thorax from the abdomen.
24
Q
What is the rib cage?
A
Bony frame formed by ribs around the chest.
25
What are intercostal muscles?
Muscles between ribs; external for inspiration, internal for expiration.
26
What is an enzyme?
A protein that acts as a catalyst, lowering activation energy.
27
What is absorption in digestion?
Movement of digested food molecules into blood or lymph.
28
What is the function of the oesophagus?
Muscular tube carrying food from mouth to stomach.
29
What is the stomach's role?
Store and digest food, especially proteins.
30
What is the ileum?
Long muscular tube where further digestion and absorption occur.
31
What does the large intestine do?
Absorbs water.
32
What is the rectum?
Final section of intestines where faeces is stored.
33
What do salivary glands do?
Produce saliva containing salivary amylase to hydrolyse starch.
34
What is the pancreas?
Gland producing pancreatic juice containing digestive enzymes.
35
What is hydrolysis?
The splitting of molecules by adding water.
36
What are carbohydrases?
Digestive enzymes that hydrolyse carbohydrates to monosaccharides.
37
What are lipases?
Digestive enzymes that hydrolyse lipids into glycerol and fatty acids.
38
What are proteases?
Digestive enzymes that hydrolyse proteins into amino acids.
39
What is salivary amylase?
Enzyme that starts hydrolysing starch in the mouth.
40
What is pancreatic amylase?
Enzyme that continues starch hydrolysis in the small intestine.
41
What is maltase?
Membrane-bound disaccharidase breaking down maltose into glucose.
42
What is a membrane-bound disaccharidase?
Enzyme part of cell-surface membranes, e.g., maltase.
43
What is sucrase?
Membrane-bound disaccharidase breaking down sucrose into glucose and fructose.
44
What is lactase?
Membrane-bound disaccharidase breaking down lactose into glucose and galactose.
45
What are bile salts?
Produced by the liver, they emulsify lipids into micelles.
46
What is emulsification?
Process of breaking lipids into micelles to increase surface area.
47
What are micelles?
Tiny structures formed by bile salts and lipids for absorption.
48
What are chylomicrons?
Structures formed from triglycerides, cholesterol, and lipoproteins for lipid transport.
49
What are lacteals?
Lymphatic capillaries in villi where chylomicrons enter the bloodstream.
50
What is exocytosis?
Outward bulk transport of materials through cell membranes.
51
What are endopeptidases?
Proteases that hydrolyse peptide bonds in the central region of proteins.
52
What are exopeptidases?
Proteases that hydrolyse peptide bonds at the ends of peptide molecules.
53
What are dipeptidases?
Membrane-bound proteases that hydrolyse dipeptides.
54
What is the lumen?
The cavity of the intestines.
55
What are villi?
Folded projections of the ileum wall that increase surface area.
56
What are microvilli?
Tiny projections from the cell-surface membrane of some animal cells.
57
What are haemoglobins?
Protein molecules with a quaternary structure that bind oxygen.
58
What is oxygen loading?
The process of haemoglobin binding with oxygen in the lungs.
59
What is oxygen unloading?
The process of haemoglobin releasing oxygen in the tissues.
60
What does high affinity for oxygen mean?
Haemoglobin takes up oxygen easily but releases it less easily.
61
What does low affinity for oxygen mean?
Haemoglobin takes up oxygen less easily but releases it more easily.
62
What is the oxygen dissociation curve?
Graph showing the relationship between haemoglobin saturation and partial pressure of oxygen.
63
What is positive cooperativity?
Binding of one oxygen molecule makes binding of subsequent molecules easier.
64
What is partial pressure?
The pressure contributed by a gas in a mixture.
65
What is the Bohr Shift?
Increased carbon dioxide concentration enhances oxygen release from haemoglobin.
66
What is a transport system?
System to move materials between cells and exchange surfaces.
67
What is the circulatory system?
Contains a pump, vessels, and a medium for transport in the body.
68
What is a double circulatory system?
Blood passes twice through the heart for each complete circuit.
69
What is the heart?
Muscular organ with four chambers for pumping blood.
70
What are atria?
Upper chambers of the heart that collect blood.
71
What are ventricles?
Lower chambers of the heart that pump blood out.
72
What is the vena cava?
Vein bringing deoxygenated blood to the right atrium.
73
What is the pulmonary artery?
Artery carrying deoxygenated blood to the lungs.
74
What is the pulmonary vein?
Vein bringing oxygenated blood from the lungs to the left atrium.
75
What is the aorta?
Artery carrying oxygenated blood to the body.
76
What are atrioventricular valves?
Valves preventing backflow of blood into the atria.
77
What are semilunar valves?
Valves preventing backflow of blood into ventricles.
78
What is the coronary artery?
Vessels supplying the heart muscle with oxygenated blood.
79
What is myocardial infarction?
Blockage of coronary arteries leading to a heart attack.
80
What is diastole?
Stage when the heart is relaxed and fills with blood.
81
What is atrial systole?
Stage when atrial walls contract to push blood into ventricles.
82
What is ventricular systole?
Stage when ventricles contract to pump blood out of the heart.
83
What occurs during atrial systole?
Atrial walls contract, forcing blood into the ventricles from the atria
## Footnote
Ventricle walls remain relaxed during this phase.
84
What happens during ventricular systole?
Ventricle walls contract, increasing blood pressure and closing atrioventricular valves
## Footnote
Semilunar valves open as pressure exceeds that in the aorta and pulmonary artery.
85
Define heart rate.
The rate at which the heart beats in beats per minute.
86
What is stroke volume?
The volume of blood pumped out at each beat, measured in dm3.
87
What is cardiac output?
The volume of blood pumped by one ventricle of the heart in one minute, measured in dm3min-1.
88
What is the function of arteries?
Carry blood away from the heart into arterioles
## Footnote
They have thicker muscular and elastic layers than veins.
89
What are arterioles?
Smaller arteries that control blood flow from arteries to capillaries.
90
Describe capillaries.
Tiny vessels linking arterioles to veins, with extremely thin walls and numerous branches.
91
What is the function of veins?
Carry blood from capillaries back to the heart
## Footnote
They contain valves to prevent backflow.
92
What is the purpose of valves in veins?
Ensure blood flows in one direction towards the heart.
93
What is the lumen of a blood vessel?
The central cavity through which blood flows.
94
What does the tough fibrous outer layer of blood vessels do?
Resists pressure changes from within and outside the vessels.
95
What is the role of the elastic layer in blood vessels?
Helps maintain blood pressure by stretching and recoiling.
96
What is the muscle layer in blood vessels responsible for?
Controlling the flow of blood by contracting.
97
Define endothelium.
Thin inner lining of blood vessels that reduces friction.
98
What is plasma?
Yellow liquid in blood vessels carrying blood cells and dissolved substances.
99
What is tissue fluid?
Watery liquid supplying substances to tissues and receiving waste materials.
100
What is ultrafiltration?
Filtration under pressure at the arterial end, forcing small molecules out of capillaries.
101
What is the lymphatic system?
A system of vessels that drain tissue fluid back into the bloodstream.
102
What are xylem vessels?
Hollow thick-walled tubes that transport water through flowering plants.
103
What is transpiration?
The evaporation of water from leaves, pulling water through xylem vessels.
104
What are stomata?
Tiny pores controlled by guard cells, allowing water vapor to diffuse.
105
Define cohesion in the context of water molecules.
Attraction between molecules of the same type, such as hydrogen bonds in water.
106
What is transpiration pull?
The mechanism pulling a column of water up the xylem due to transpiration.
107
What does the cohesion-tension theory explain?
The movement of water up the xylem through transpiration pull and cohesion.
108
What is a potometer?
An apparatus to measure the rate of water loss in a plant.
109
What is phloem?
Tissue that transports biological molecules in flowering plants.
110
Define translocation.
The process of transporting organic molecules and minerals in a plant.
111
What are sieve tube elements?
Living tubular cells in phloem that transport solutes.
112
What is the role of companion cells?
Control solute movement and provide ATP for sieve tube elements.
113
Define mass-flow theory.
Bulk movement of substances through channels in a specified time.
114
What is ringing in plant physiology?
An experiment removing outer layers of a stem to observe sugar accumulation above the ring.
115
What is a tracer in plant studies?
Radioactive isotopes used to trace the movement of substances in plants.
