09. Applied biology Flashcards
1
Q
What are aquatic organisms?
A
Fish
Molluscs
Crustaceans
Aquatic Plants
2
Q
What are some importances of aquaculture
A
Farming edible aquatic organisms is accepted as one of the best solutions for feeding the ever increasing human population.
A healthy diet, high in protein is necessary to ensure that growing population doesn’t succumb to sicknesses and diseases due to the lack of essential nutrients, Harvests from wild sources of fish, crustaceans and other aquatic species cannot keep up with the demand presented by the growing human population.
Trying to match the demand through commercial fishing would eventually result in over-fishing and the loss of those species entirely. It is accepted that while aquaculture is essential to meet the human demand for fish and fishery products, it also relieves the strain on wild species and allow them to continue to be a significant source of food for humans.
3
Q
What are the general characteristics of species that could be cultured?
A
Selected species should withstand the climate of the region in which it is cultured.
It should grow well (have a fast growth) in prevailing physical and chemical parameters of water in the area.
It should be easy to breed (breeding techniques should be available) so that sufficient number of fertilized eggs/early fry could be obtained easily.
Techniques of incubation of fertilized eggs and rearing techniques of hatchlings/ early fry should be available so that the production of sufficient number of young organisms (seed) would be easy under culture conditions
If the eggs. larvae, fry, fingerlings, juveniles and adults of the species are hardy it is easier for the hatchery manager/farmer (handling hardy species is easy)
Food and feeding habits of each developmental stage of the species should be known (easy to provide nutritionally balanced diet for each developmental stage)
It should not reproduce in grow-out ponds/tanks
If it reaches sexual maturation relatively late, it is advantageous
It should accept formulated food and grow well.
It should be an efficient converter of economical foodstuffs.
If it is accidentally released to natural water bodies there shouldn’t be adverse environmental impacts.
It should tolerate high population density and grow well
Having resistance to common diseases is advantageous
It should satisfy consumers by the taste, nutritive value, texture of flesh or appearance/body color/color patterns
4
Q
How did ornamental fishes lure and draw a great attention worldwide?
A
Through their attractive colouration
shapes
sizes of body and fins
Swimming behaviors
Ability to live under captive conditions and adaptability to live in little spaces
5
Q
Why do people keep fish in their homes?
A
Decoration
Children’s education
Enjoyment
Relaxation of elderly or health affected individuals
Prosperity and fortune of home occupants
To collect rare species and even to propagate them
6
Q
What are the species of fish commonly used in freshwater ornamental fish culture of SL
A
Guppy (Poecilia reticulata)
Black molly (Poecilia mexicana)
Swordtail (Xiphophorous helleri)
Platy (Xiphophorous maculatus)
Angelfish (Pterophyllum scalarae)
Discus (Symhysodon discus)
Siamese fighting fish (Betta splendens)
Kissing gourami (Helostoma temmincki)
Goldfish (Carassius auratus)
Koi Carp (Cyprinus carpio)
7
Q
How do aquaria vary?
A
In size, shape and design ranging from a simple bottle containing some water (ex: an empty jam bottle used to keep a Siamese fighting fish) to a multimillion liters commercial exhibit tanks
8
Q
How often must the maintenance of a home aquarium be carried out?
A
Daily, weekly, fortnightly and monthly
9
Q
Why must a home aquarium be maintained?
A
in order to maintain environmental conditions (water quality parameters) within the optimum ranges for the fish kept in an aquarium
10
Q
What activities must be performed to maintain a home aquarium?
A
Provision of correct nutrition
Maintenance of water quality within the optimum ranges contribute for the well-being
Health management of fish kept in an aquarium
11
Q
What must be performed daily to maintain a home aquarium?
A
- feed the fish with a nutritionally balanced diet following a correct feeding regime (suitable daily ration should be offered in 2 or 3 meals)
- Check on the status of health while feeding and remove the affected individuals for treating in another tank/basin
- Allowing fish to adapt for the changing intensity of light (to prevent unnecessary stress on fish)
This is done by switching on the light of the aquarium several minutes after the room lights have been on or after the day break
Switch off the light of the aquarium several minutes before the room lights are switched off or shortly before natural lights fade
12
Q
What must be performed weekly to maintain a home aquarium?
A
- fish shouldn’t be fed one day per week (not applicable for brood fish, fry and fingerlings)
13
Q
What must be performed fortnightly to maintain a home aquarium?
A
- Switch off aeration
- Rake or stir up gently the surface of the rooting medium (under-gravel filter medium)
- Scrape excess algal growth
- Allow debris to settle
- Siphon off the debris along with 20-25% of the aquarium water
- Replace the volume siphoned out with freshwater in which temperature, pH and hardness watch with conditions of the water in the aquarium
- Switch on aeration
14
Q
What must be performed monthly to maintain a home aquarium?
A
- Take out some water from the aquarium into a basin/another tank/bucket
- Collect the fish carefully using a hand net and introduce them into the basin/tank/bucket and arrange aeration to it
- Rinse rooting medium (under-gravel filter medium)
- Remove the aeration tube the air lift, scrape off any deposit (algal or calcite) from the opening and clean/scrape off air diffuser stones
- Introduce the siphoning tube under the filter plates and suck out the accumulated organic debris
- Check the terminals of light source
- Remove dead and dying leaves from plants
- Prune, thin out and tidy the plants and replace poorly grown plants
- Rearrange the filter plates and the filter medium
- Arrange the aeration and fill the aquarium halfway with clean freshwater/aged aerated tap water
- reintroduce the fish with the water and then fill the aquarium to the original level of water using aged clean freshwater.
15
Q
What can go wrong in a aquarium from time to time?
A
Equipment failure
Excessive algal growth
Poor water quality
Occurrence of diseases
16
Q
What are the indications of the aquarium receiving too much light?
A
Water turning green frequently
Green algae growing on plants on aquarium décor and on the side glasses of the aquarium
17
Q
How can you prevent the aquarium receiving too much light?
A
Reduction of intensity and/or duration of light followed by partial water exchange
18
Q
What are the indications of insufficient illumination in an aquarium?
A
Growth of brown algae as brown encrustations on plants on aquarium décor and on the side glasses of the aquarium
19
Q
What are the indications of an aquarium of having high level of oranic pollution?
A
Blue-green algal mats on plants on aquarium décor and on the side glasses of the aquarium
20
Q
What must be done to prevent the further accumulation of organic pollution in an aquarium?
A
Physical removal of algal mats followed by partial water exchange
A review of the maintenance routine with a view to prevent further accumulation of organic pollutants
21
Q
Why might organic pollutants be accumulated in an aquarium ?
A
Too much food being offered to fish
Inadequate filtration or aeration
Overstocking
22
Q
What may lead to the development of infectious diseases in ornamental fish?
A
Invasion of fish tissues by a disease causing agent (a pathogenic virus, bacterium, fungus or an obligatory/opportunistic parasite)
Multiplication of it in/on fish tissues and increasing its population
23
Q
What can be done to present infectious diseases in ornamental fish?
A
Better management practices (BMPS such as maintenance of water quality, correct stocking density of compatible fish with compatible plants, correct feeding regime) to keep the immunity of fish at a higher level
Through correct bi-security measures (to present contamination by pathogens) by quarantining new fish, plants and other aquarium décor
24
Q
What group causes bacterial fin rot and gill rot?
A
Bacteria
25
What group causes hemorrhagic septicemia?
Bacteria
26
What group causes columnaris disease?
Bacteria
27
What group causes external mycosis?
Fungi
28
What group causes fish spot disease (ich disease)
A unicellular, external, obligatory parasite
29
What group causes trichodinosis?
A unicellular, external, opportunistic parasite
30
What group of disease causes gill and skin infestation?
obligatory/opportunistic, gill flukes and skin flukes
31
What are the benefits of ornamental fish culture?
Species conservation
Production of species that are difficult to obtain from the wild
90% of freshwater ornamental fish traded globally are done under captive conditions, there is some environmental benefits or elimination of environmental damage via those breeding programs
The golden arrowana and tiger barb (puntius tetrazona) are two species conserved via ornamental fish production
Sale of fish to hobbyists
Fish can be reintroduced to habitats in which they have been eliminated
32
What are two species conserved via ornamental fish production?
The golden arrowana
tiger barb (puntius tetrazona)
33
What are the harmful impacts of ornamental fish culture?
Invasive ornamental fishes/aquatic plants that are accidentally escaped to natural environment could affect a wide range of native organisms from zooplankton to mammals across multiple levels of biological organizations ranging from the genome to the ecosystem
With imported live fish non-indigenous disease causing agents may also come in to a country.
Haphazard use of broad-spectrum antibiotic and other chemicals as preventive/therapeutic treatments and release of treated water (containing those medications) in to the natural environment may cause antibiotic resistance/resistance to chemicals used on pathogenic microorganisms including human pathogenic bacteria
34
Where can plant propagation and nursery management be done?
In fields, orchids, forests or in protected environments such as greenhouses, polytunnels or tissue culture laboratories
35
What is the main requirement of a nursery?
Providing optimum/favorable conditions for germination and seedling growth which provides healthy, vigorous, evenly grown plants leading to best transplants
36
What issues to growers face when they manage plant nurseries?
The optimum capacity of a crop could be obtained only by providing optimum environmental conditions to the nursery plants
Some issues in nursery management practices (like management of light, soil management (soil type, properties of soil and maintenances of soil) pest and disease control, water management (water quality and quantity) nursery structures and environmental controls (protected cultivation versus open air cultivation)
+ Lack of access to modern technology
+ Lack of financial incentives to further improve the nursery and cultivation facilities
+ Shortage of quality planting/propagating materials
+ Inadequate knowledge on suitable techniques and growth conditions that can be used to grow crops
37
what are some issues in nursery management practices ?
management of light
soil management (soil type, properties of soil and maintenances of soil)
pest and disease control
water management (water quality and quantity)
nursery structures and environmental controls (protected cultivation versus open air cultivation)
38
Why is the management of light a critical factor?
For rooting cuttings
Seed germination
Seedling growth as in tissue culture facilities
39
How can light be manipulated in nursery management?
By controlling quality (wave length) and duration (day length, photoperiod)
40
What factors influence soil condition?
Soil texture
Structure
Organic matter content
41
How can soil condition be improved?
Via application of fertilizer or manure into soil
42
Why is pest and disease control vital?
To get a quality product and to maintain plant health
43
How is pest and disease control achieved?
via biological, cultural, physical, chemical or combination of these as integrated pest management
44
What factors govern the rooting of cuttings and regulation of plant growth?
Water management and humidity control
45
What does the type of irrigation used depend on?
Natural conditions of the area
Soil type
Slope of the land
Water availability
The crop to be irrigated
Adequate supply of good quality water
46
What is the advantage of growing horticultural crops in various types of plant growing structures?
These structures provide a more favorable environment for plants than the open air/outdoor cultivation. In simple terms protected cultivation is growing crops under controlled environmental conditions
Protected cultivation of horticultural crops will tremendously benefit in terms of enhanced productivity
47
What is protected cultivation technology used for?
Its used to protect plants from adverse climatic conditions (wind, heavy rain, mist, etc.) by providing optimum conditions to achieve maximum yield and the best quality
48
How must protected cultivation be done?
In green houses (depends on the covering materials different structures are used such as polytunnels)
49
What is protected cultivation mainly utilized for?
To grow perishable horticultural produce such as fruits, vegetables and ornamental plants
50
What is a simple form of green house?
A structure where it is covered with material that allows light to penetrate inside and reach plants
51
How are green houses made with advanced technology?
Sophisticated modern green houses are constructed in horticulture industry, where the plants microenvironment in more precisely controlled.
52
What are the plants grown in green houses including polytunnels?
- Vegetables such as bell pepper, tomato, salad cucumber, cauliflower and lettuce
- Fruits - strawberries
- Ornamental plants - carnations, roses, orchids
53
Tissue culture is the ability to....
establish plant tissues (cells, callus and protoplasts) plant organs (embryos, shoots, roots) is aseptic, in vitro culture.
54
What is the most common benefit of tissue culture?
Cloning or mass production of genetically identical organisms
55
What is the main concept behind plant tissue culture?
Totipotent ( a single cell has the genetic programme to grow into an entire new plant )
56
Who introduced the concept of totipotent?
Matthias Schledien and Theodor Schwann who postulated the cell theory in 1838
57
What does a tissue culture medium generally consist of?
Inorganic salts
Organic substances
Water and gelling agent
58
How is the inorganic salt component in the tissue culture medium made?
Macro and micronutrients in appropriate ratios make the organic salt component
59
Name some organic substances in a tissue culture medium
Carbon energy source (usually sucrose)
Plant growth regulators (cytokinins and auxins)
vitamins
miscellaneous compounds
60
What substance is incorporated as the gelling agent?
Agar
61
What is the function of agar in the tissue culture medium?
Provides physical support for the explant and increase the aeration of the medium
62
What are the commercial media available for tissue culture?
Murashige and Skoog or MS medium
63
What are the importance of tissue culture techniques?
Rapid multiplication of clones
Mass propagation of specific clones
Genetic uniformity
Genotype modifications
Ability to produce plants in large numbers in a small space
Production of pathogen-free plants
All year around production of plants
Ability to produce plants which do not produce viable seeds
64
What are examples for tissue-cultured plants?
Anthurium ( Anthurium andreanum)
Banan
Pineapple
Dragon fruit
65
What is the most common and widely used propagation method for plants?
Seeds
66
What is a prime importance in the horticulture sector?
Producing high quality seeds
67
What kind of seeds do growers wish to have?
High quality seeds with higher percentage of germination and higher viability and free of diseases and pest damage
68
For a seed to initiate germination what conditions must be completed?
The seeds must be viable
The seed must be subjected to suitable environmental conditions
Dormancies existing should be overcome
69
What plants can be produced using seed propagation methods ( at present tissue culture is culture methods)
Anthurium and Orchid
70
How are new plants in vegetatively propagated plants?
The new plants are nearly always genetically identical to the parent
71
What are the various methods of vegetative propagation?
Separation and division
Cuttings
Layering
Grafting
72
What structures are used in the separation process in the separation and division of plants?
Separation is a process where naturally detachable structures (ex: Rhizomes, bulbs and corms) are used.
73
What occurs during division process in the separation and division of plants?
During division, the plant is cut or divided into sections with both roots and stems (ex: stolons and rooted runners)
74
Give examples for corms
Alocassia/Colocasia
Gladiolus
75
Give examples for runners
Spider plant / chlorophytum comosum
76
Give examples for stolons
Cyanodon grass species
Mentha (mint)
Stachys
77
What is one of the most important clonal regeneration techniques used in horticulture industry for ornamnetal plants and fruit trees?
Cutting propagation
78
What is a prerequisite of the cutting propagation process?
Adventitious root formation
79
What are adventitious roots?
A piece of plant from the stem, leaf root or leafy bud can generate into a fully developed plant. The roots arising from stem, lead or bud tissues are adventitious roots
80
Give examples for adventitious roots
Roses
Ficus
Dracaena s African violets
Croton
81
What is the difference between stem and leaf-bud cuttings and root and leaf cuttings?
Although stem and leaf-bud cuttings need only a new adventitious root system to be formed, for root and leaf cuttings both the new shoot and root systems need to be formed
82
Give examples for the propagation of via leaf cuttings
Begonia
African violet
Snake plant (sansvieria)
83
What happens in layering?
It is a method of vegetative propagation where stems are rooted while attached to the parent plant
84
What are the natural tendencies naturally self-layering plants have?
They have the tendency to regenerate by self-layering, forming adventitious roots from the stem where they touch the soil (ex: Strawberry and Cynodon sp.)
85
What is the advantage of layering?
Layering technique is a good way of getting a small number of plants with relative certainty because the new plant is nourished by its parent plant until roots are formed and rooted
86
Give examples for layered plants
Rose
Hibiscus
87
What occurs in grafting
Grafting involves joining two separate plants so that they later function as one healthy plant that has the best characteristics of two parent plants. A root system is provided by one plant (known as root stock or understock) and the desired top part by the other plant (known as scion)
ex: roses
During a graft union it's vital that the cambium of the scion is placed in close contact with the rootstock cambium. Initially a callus (mass of undifferentiated parenchyma cells) bridge is formed between the scion and restock in a successful graft. These callus cells originate from the scion and the rootstock.
88
What do floricultural practices found in SL include?
Cut flowers and ornamental foliage plants
89
Give examples for cut flowers
Anthurium
Orchids
90
Give examples for ornamnetal foliage plants?
Rose
Dracinia
Begonia
91
What is the function of food preservation?
Food preservation ensures that food can be preserved for a particular period. and protects the food that is available for human consumption reducing the "food loss"
prevent unnecessary wastage and contribute greatly to meet food requirement of growing human population
92
When is food preserved?
Food is preserved during some seasons over production of certain food occurs and the excess production could be preserved (using suitable methods) and stored to be used later.
93
How can food be preserved before undergoing spoilage using suitable techniques?
- eliminating avoidable losses
- making more nutritive food items from low grade raw commodity using proper processing and fortification
- diverting a portion of food materials presently being fed to animals for human consumption by way of processing
- fortifying low grade food and organic wastes and by-products into nutritive animal feed
94
How must the contamination of harvested food from damaging agents be done?
Hygienic handling
Transportation
Storage
95
What are the three basic principles of food preservation?
Preservation of entry of microorganisms into food (aseptic)
Prevention of the growth and activity of microorganisms in food
Remove or killing microorganisms in food
96
What do food preservation methods aim to do?
Prevent contamination in the first place
To remove/reduce the numbers of contaminants
97
How is the preservation of food achieved?
By the application of physical, chemical, and/or biological methods. The techniques may be applied separately or in combination
98
What factors do microorganisms need to grow?
A source of food
Water
A suitable pH
A suitable temperature
99
What must be removed by the food preservation technique?
One or several of the living conditions needed for the growth of microorganisms have to be removed by the food preservation technique
100
What is one of the oldest method of food preservation?
drying
101
How is drying performed?
Food is mostly dried in the sun and drying reduces the water activity of the food sufficiently to prevent or delay microbial growth allowing food to be kept for weeks.
102
What kinds of food are dried?
Most types of grains are dried to increase shelf life
Wheat, corn, oats, rice, rye, and barley are eft to dry to prevent spoilage
Hams are meats preserved through drying in ovens
103
What food is dried to increase shelf life?
Most grains
104
What food is left to dry to prevent spoilage?
Wheat, corn, oats, rice, rye, and barley are left to dry to prevent spoilage
105
What is an example for meat preserved through drying in ovens?
Hams
106
Why is heating food an effective way of preservation?
Because the great majority of harmful pathogens are killed at temperatures close to the boiling point of water
107
What method of food preservation is the preliminary step in many other forms of food preservation?
Especially in forms that make use of packaging, is to heat the food to temperatures sufficiently high enough to destroy pathogens. In many cases, food is actually cooked prior to their being packaged and stored.
108
What is the most common of all modern food preservation methods both commercially and domestically?
Freezing
109
How is commercial freezing done?
Its done in different types of freezers under extremely fast freezing or fast freezing (bringing the temperature of fish/meat down to a value between -18 to -30c within 15 minutes to 2 hours) to preserve the quality until distributed in order to prevent the growth and spreading of spoilage of microorganisms (the extreme cold prevents microbial growth)
Storage of food (fruits, fruit juices, vegetables, fish, meat, etc) in refrigerators at low temperatures (chilling at 4=7c) reduces the growth and activities of spoilage microorganisms, preserving food for a short period (for 10 to 14 days)
110
Name a older form of preserving raw foods?
Salting
111
Why is salting an effective way of food preservation?
Salt has an ability to suck the moisture out of food through the process of osmosis. When the food is totally dry from salting, growth of microorganisms are inhibited
112
What food is commonly preserved through salting?
Meat
113
How is dried fish prepared?
(anchovy, tuna, etc.) are first salted and then dried in the sun.
114
How is dried fish prepared?
(anchovy, tuna, etc.) are first salted and then dried in the sun.
115
Why is salt added in the salting and drying of dried fish?
Addition of salt makes the removal of water fast and the salt inhibits microbial growth on fish even though some moisture is still remaining in flesh
116
What foods is sugaring used in?
Sugar is used in syrup form to preserve fruits and in crystallized form to preserve food items like ginger and orange peel.
117
Why are some fruits glazed with a sugar syrup?
For the fruits to get a superficial, protective coating
118
Why are some fresh fruits cooked with sugar and then dried?
High sucrose concentration produces osmotic stress on microorganisms and protects the food from microbial spoilage
119
What are examples for fresh fruits that are cooked with sugar and dried?
Jam
Sugared toffees made made with ash pumpkin
120
What is smoking?
Smoking is the process that cooks, flavors, and preserves food exposing it to the smoke from burning wood.
121
Why is smoking beneficial for food preservation?
Smoke is antimicrobial and antioxidant
The aroma generated by hydrocarbons of burning wood enhances the taste, flavor and adds smokiness to the meat/fish while preserving
122
What foods are preserved by smoking?
Most often, meats and fish
123
What is the benefit of the aroma of smoking?
The aroma generated by hydrocarbons of burning wood enhances the taste, flavor and adds smokiness to the meat/fish while preserving
124
Why is using chemicals for food preservation beneficial?
Chemicals inhibit the growth and activity of microorganisms while some chemical compounds even kill the microorganisms
125
Give examples for food preservation using chemicals
Preservation of fruit juice and the production of pickles using chemicals such as sodium benzoate, EDTA, acetic acid and brine solution
126
What type of radiations are used in processing food materials?
Radiations from high energy gamma rays
X-rays
Accelerated electrons
127
What type of radiations are used in processing food materials?
Radiations from high energy gamma rays
X-rays
Accelerated electrons
128
How is processing food by radiation performed?
This involves the exposure of food to short wave radiation energy to achieve a specific purpose such as the extension of shelf life, insect disinfestation and the elimination of food borne pathogens and parasites.
129
What specific purposes does radiation achieve?
the extension of shelf life
insect disinfestation
elimination of food borne pathogens and parasites.
130
Give examples for the preservation of food through radiation
Packets of spices
Ground meat
131
What is the product quality of harvest influenced by?
When and how the harvest is done
Pre-harvest factors such as source of seed and quality that has been set during growth
132
What is the product quality at harvest lost further by?
It is lost during harvesting, handling, transporting, storage, domestic processing and distribution
133
How are postharvest losses broadly categorized as?
Weight loss due to spoilage
Quality loss
Nutritional loss
Seed viability loss
Commercial loss
134
Give examples for postharvest losses
In production of cereals (ex: paddy) fruits and vegetables
135
What may the delayed harvesting of paddy result in?
Quality loss
Nutritional loss
Seed viability loss
Weight loss
Commercial loss
136
How are the losses of delayed harvesting of paddy further increased?
Paddy fields being flooded due to heavy rains just before harvesting
137
What does paddy harvested earlier require?
More drying (drying cost)
138
What are grains with high moisture content susceptible to?
Mold growth
Insect infestation
resulting in broken grains and low milling yield with significant commercial losses.
139
Why should fruits and vegetables be harvested at the best time?
To have the maximum quality and to obtain the highest quantity
140
What occurs when fruits and vegetables are harvested too early?
The crop will not be ripe/matured enough
141
What occurs when fruits and vegetables are harvested too late?
It may spoil quickly leading to quality loss and nutritional loss, finally resulting in economical losses.
142
Why should harvesting fruits and vegetables be done without allowing physical/mechanical damage to occur?
If damages occur quality and storage life will be reduced as spoilage microorganisms will quickly invade through damaged areas
143
What negative impacts could food have during handling?
High shattering loss o paddy seed could occur which is a commercial loss
144
What must be done to avoid the high shattering loss of paddy seed?
Harvest paddy should be dried, bagged, and stored temporarily without allowing the paddy seed to absorb the moisture and greater attacks by insects and rodents
145
How must the quality of harvest fruits and vegetables be preserved during handling?
Harvested fruits and vegetables should be handled hygienically and kept in plastic cartons which could be kept in a shade temporarily.
They should be sorted to removed damaged, infested, moldy and over-ripe fruits/ over-matured vegetables
146
What is the function of sorting fruits and vegetables during handling?
sorting will reduce spoilage during transportation and storage.
147
What does poor road infrastructure along with improper and poorly maintained modes of transportation result in?
Large spillage of paddy and high contamination
148
Give reasons for high transportation losses.
Multiple movements of crop
Poor road infrastructure
Improper and poorly maintained modes of transportation
Sometimes bagged paddy is loaded and unloaded from vehicles several times before its milled. During each movement some grains are lost as spillage
149
How do transportation losses occur in bagged paddy?
Sometimes bagged paddy is loaded and unloaded from vehicles several times before its milled. During each movement some grains are lost as spillage
150
What percentage of losses occur from the handling and transportation of rice in Southeast Asia?
2-10%
151
How can transportation losses be minimized?
By using well-planned, better modes of transportation with an efficient bulk handling system
152
What must be done during the transportation of fruits/vegetables?
Fruits/vegetables arranged at the bottom of the stacked cates could be damaged by the weight of the produce kept above; use of crates that could be stacked without putting the weight on produce at the bottom would solve this issue.
Use of straw or something soft in between layers of produce within a crate will reduce the damages due to rubbing.
Rough handling of crates containing produce should be avoided to prevent possible damages to the produce.
Uncontrolled changes of temperature and excessive shaking could do great damages to the produce during transport. In tropical countries, if transportation is carried out at night time produce could be protected by high temperature of the day time.
153
What losses are considered the most critical in developing countries?
Storage Losses
154
Why are storage losses considered the most critical in developing countries?
Because maximum losses occur during storage.
155
Why are storage losses considered the most critical in developing countries?
Because maximum losses occur during storage.
156
How are grains stored after harvesting/milling?
Grains are stored for short or long periods of storage as food reverses, and as seeds for next season
157
What does poor storage infrastructure allow?
It allows rice to absorb excess moisture
Rice grains with excess moisture to be infested easily by insects pests followed by the invasion of spoilage microorganisms
rice to be attacked by rodents and other pests
158
How can losses be prevented/reduced during the storage of paddy/milled rice?
Provision of proper storage infrastructure
159
Why must the storage of fruits and vegetables should be done in properly chilled rooms?
To reduce the rate of spoilage
160
What conditions can encourage spoilage microorganisms to grow faster?
Uncontrolled changes of temperature could encourage spoilage microorganisms to grow faster spoiling the stored produce (fruits and vegetables)
161
Why do postharvest loss of food processing occur?
Early harvesting, improper handling, etc
162
How can postharvest losses that occur during domestic processing be reduced?
By following correct procedures (ex: harvesting at the right time)
Hygienic handling to prevent microbial contaminations and proper storage (to prevent attacks of insects, rodents, etc.)
163
Give examples for food that uses drying.
Paddy/rice
Other cereals
164
Give examples for food that uses drying after thermal treatment
Jack fruit
165
Give examples for food that uses pasteurization
Milk
166
Give examples for food that uses freezing
Fish and meat and temporarily stored in freezer compartments of a refrigerator
167
Give examples for food that uses chilling
fruits and vegetables
168
Give examples for food that uses salting
lime
169
Give examples for food that uses salting & drying
fish
170
Give examples for food that uses sugaring
homemade jams
171
Give examples for food that uses the use of chemicals
pickles
172
What is dengue?
Dengue is a vector borne disease which is caused by an arbovirus which is an RNA
173
Where are dengue epidemics reported?
In tropical and subtropical regions of the world
174
How is the dengue virus transmitted?
By two species of mosquitoes:
1. Aedes aegypti
2. Aedes albopictus
175
What factors is the transmission of the dengue virus dependent on?
Biotic and abiotic factors
176
What are the biotic factors that encourage the transmission of the dengue virus?
The virus, the vector and the host
177
What are the abiotic factors that encourage the transmission of the dengue virus?
temperature, humidity and rainfall
178
How is the dengue virus transmitted to humans?
its transmitted via biting of an infected female mosquito
179
Describe the nature of the humans infected with the dengue virus
The infected humans can be symptomatic as well as asymptomatic and they are the carriers and multipliers of the virus
180
Describe the nature of the Aedes mosquito
They are small to medium sized (approximately 4-7mm) and dark in colour.
They have white markings/brands on its body and the arrangement on these bands are different in the body and the legs.
They live about 2-4 weeks depending on the environmental conditions
181
What is the lifespan of an Aedes mosquito?
They live about 2-4 weeks depending on the environmental conditions
182
Describe the life cycle of an Aedes mosquito
It has 4 stages: they are eggs, larva, pupa and adults
183
Where does the adult female mosquito lay eggs?
They lay eggs singly on the inner surface of wet container above the water level, preferably clear water
184
Describe the nature of dengue mosquito eggs
Initially the laid eggs are white in colour and they become shiny black colour within few minutes from deposition of the eggs.
These eggs are smooth, long and ovoid in shape and about 1mm long
185
How long does it take for the eggs hatch to become a larvae
2 days
186
What happens if the dengue eggs are not hatched?
They can undergo dormant for a period of 6 months
187
How does the larvae rest?
The larvae rests with an angle to the water surface
188
Describe the body of a larva
The body of larva consists of three major parts: head, thorax and abdomen
189
How long does it take for a larva to become a pupa?
4-5 days
190
Describe the nature of a pupa
It is comma shaped and mobile
191
How long does it take for a pupa to become an adult mosquito?
1-2 days
192
Describe the nature of the breeding sites of dengue mosquitos
The female mosquitoes lay eggs in a wide variety of artificial and natural wet containers.
They prefer dark coloured surfaces with clear (unpolluted) water
The breeding sites can be both indoors as well as outdoors
193
What do the breeding sites of mosquitoes include?
discarded plastic containers (tins, clay pots, yoghurt and ice cream cups, bottles, cans, damaged ceramic items, coconut shells, etc.)
water storage containers such as cement tanks, barrels, etc.
discarded automobile tires and machinery parts
building structures such as roof gutters, concrete slabs, etc.
household/institutional appliances including refrigerator trays, flower cases, ornamental ponds, squatting pans of wash rooms,etc
natural breeding sites such as leaf axils, tree holes, etc.
194
Who can dengue affect?
infants, young children and adults
195
How do the symptoms of dengue start?
It starts with flu-like symptoms
Sudden onset of high onset fever (40c/ 104F) could be accompanied by any of the following symptoms (severe headaches, pain behind the eyes, muscle and joint pains, nausea, vomiting, or skin rash)
196
How long do the symptoms of dengue last?
They usually last for 2-7 days after incubation period of 4-10 days from the bite of an infected female Aedes mosquito
197
What is severe dengue (dengue hemorrhagic fever)?
It is a potentially deadly complication due to blood plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment.
198
When do the warning signs of severe dengue take place?
3-7 days after the first symptoms in conjunction with a decrease in temperature (below 38c/100F)
199
What do the warning signs of severe dengue include?
Severe abdominal pain
Persistent vomiting
Rapid breathing
Bleeding from the nose and gums
Fatigue
Enlargement of liver
Reduced no. of platelets
Restlessness
Blood in vomit
200
Why are the next 24-28 hrs of the critical stage lethal?
Here, symptoms may progress to massive bleeding, very low bp, shock, and death.
201
Why is proper medical care needed for dengue?
To avoid complications and the risk of shock and death (dengue shock syndrome)
202
What are the dengue vector controlling methods mainly aimed at?
Both immature and adult stage of the Aedes mosquito
203
What do the integrated vector management strategy include?
Environmental, chemical and biological controlling methods
204
What is the most cost effective way of controlling the dengue vector?
Eliminating its breeding sites
205
How can the removal of open source of water through environmental management be done by?
- having continuous supply to minimize the storage of water in cement tanks, barrels and other containers
- making mosquito proofing of water storage cement tanks, domestic wells and over head tanks
- construction of buildings without roof gutters
- removal of unserviceable roof gutters
- regular cleaning with scrubbing of water storage tanks, flower pots, flower vases, ant traps, refrigerator trays
- proper disposal of solid wastes
- proper storage of used tired, household and garden utensils
206
What can be used to control the vector other than environmental management practices?
Biological controlling methods
207
What are the biological controlling methods used to control the vector?
- use of fish species which feed on the larval stages of the mosquito
- the Bacillus thuringiensis israelensis (Bti) can be used to control dengue vectors by producing an endotoxin which is toxic to the larval stages of the mosquitos
- thermal fogging (a chemical method)
208
What are the fish species that could be introduced to water stooge tanks, ornamental ponds, etc. to feed on the larval stages of mosquitos?
Guppy (Poecilia reticulata)
Dandi (Rasbora daniconius)
Juvenile stages of Tilapia
209
Where can fish species be introduced to feed on the larval stages of mosquitos?
water storage tanks
ornamental ponds.
210
How is the Bacillus thuringiensis israelensis (Bti) used to control dengue vectors?
by producing an endotoxin which is toxic to the larval stages of the mosquitos
211
What method of mosquito control is a chemical method?
Thermal fogging
212
What are the limitations in vector controlling methods?
Lack of sufficient knowledge in biological controlling methods
When fish are used to control vectors,
-fish could die in the absence of food in the breeding site and due to the changes in water quality parameters such as pH of water in the breeding site
-when the domesticated water containers are filled with chlorinated water it may lead to the death of the fish
When Bti is suggested to control the vector, there could be some breeding sites that bti cannot be applied in
Chemical methods such as fogging could affect the health of both humans and animals
213
What are the limitations of using fish to control the vector?
-fish could die in the absence of food in the breeding site and due to the changes in water quality parameters such as pH of water in the breeding site
-when the domesticated water containers are filled with chlorinated water it may lead to the death of the fish
214
What are the limitations of using Bti to control the vector?
there could be some breeding sites that bti cannot be applied in
215
What are the limitations of chemical methods such as fogging in vector control?
Chemical methods such as fogging could affect the health of both humans and animals
216
What disease is one of the major leading causes of permanent and long term disability?
Filaria
217
What is filariasis?
it is a mosquito borne disease transmitted by a thread like nematode, who lives in human lymphatic system
218
What regions is filariasis endemic to?
This disease is endemic in developing countries with poor socio-economic status and is often associated with poor environment sanitation
219
What kind of disease is filaria categorized as?
A neglected tropical disease
220
What parasite causes 90% of filaria infections?
Wuchereria bancrofti
221
What parasite has the human as its exclusive host?
W. bancrofti
222
What vector transmits filaria solely in Sri Lanka?
Culex quinquefasciatus mosquito
223
Where does Culex breed?
Polluted water bodies
Blocked drains
Broken toilet pits
Husk pits
224
Describe the nature of the Culex mosquito
The culex mosquito is small to medium in size (3 to 4 mm in length) and grey-black in colour
The nervures of wings of adult mosquito are beset with brown or blackish scales and the posterior margin of the wings is fringed with bristle and scales
225
Where do female filaria mosquitos lay eggs?
They lay eggs in the form of egg rafts that float on the surface of water.
226
Describe the nature of filaria larva after hatching
Larva rests keeping its body with an angle to the water surface
227
What are the factors associated with the transmission of filaria in a community ?
- no. of infected persons (prevalence)
- density of microfilaria in blood of infected persons
- density of vector mosquitoes
- characteristics of the vector ( affects the development of larvae)
- frequency of human vector contact
228
How is the filariasis parasite introduced to human bodies?
By a bite of a female adult mosquito
229
What happens when the mosquito sucks the blood from humans?
The larval stages of the parasite falls on to the skin (do not inoculate in to the body as the other mosquito borne disease agents)
Then these larvae penetrate the skin through the bite would and enter into the human vascular system
From here, the larvae migrate to the lymphatic system.
Within one year larvae become matured in to adult worms
230
Where do adult male and female worms nest and mate in?
Lymphatic vessels
231
What do adult male and female worms produce after mating?
A large number of tiny, immature eggs which hatch into microfilaria
232
How to microfilariae migrate?
From the lymphatic system and enter the blood stream
233
Where do microfilariae live during the day and night?
They live in lungs during the day and travel to peripheral blood during the night.
234
From where do microfilaria transfer to mosquito when it takes a blood meal from a human body?
Peripheral blood
235
How long do adult filariae worms live in the lymphatic system?
5-6 years
236
How long do microfilaria live for?
1 year
237
What happens when adults worms block lymphatic vessels?
They get distorted and lymph flow does not occur smoothly.
Lymph tends to accumulate in dependent parts of the body: legs, hands, testes, penis, and breasts causes lymphedema.
238
What happens when microfilaria live in lungs?
Patients develop dry cough, wheezing, mild fever, weight loss, etc
Fluid accumulation in the scrotum manifests as hydrocele.
Presence of microfilariae in lungs manifest as occult filariasis.
239
What is occult filariasis characterized by?
High eosinophilic count with chronic cough and wheezing which worsens at night with dyspnea, chest pain, fever and weight loss
240
How does clinical manifestations of occult filariasis vary?
From asymptomatic to chronic lymphedema (elephantiasis)
241
What happens to the filarial parasite (L3 larva) after entering the human body?
It develops into an adult worm and remains silent in lymphatics for several years producing microfilaria.
These patients are asymptomatic and can only be detected through active surveillance
242
What does the presence of adult parasites in lymphatic system for a longer period give rise?
late manifestations due to the dilation of lymphatic vessels followed by their dysfunction, accumulation of fluid in tissues and increased risk of infection (lymphoedema)
243
What occurs with recurrent infections skin of oedematous?
extremities become thickened and later on give rise to warty, nodular, papillomatous appearance
244
How is lymphedema graded?
According to the state of oedema and appearance of the skin
245
What are the controlling measures of filariasis?
- personal protection from mosquito bites/ prevent mosquito bites by the use of mosquito nets, repellants, long sleeve shirts and trousers.
- elimination of breeding sites: repair broken septic tanks, cleaning drainages, prevent dumping garbage in to drains, chemical control of aquatic plants in water reservoirs
- prevent creation of breeding sites
- use of larvivores fish such as guppy, nalahandaya in water bodies
- screening healthy population with night blood films and detect people who harbor the infection but do not show any symptoms and treat them
- monitor vector mosquito population for infectivity
246
What are the limitations of controlling methods of filariasis?
Lack of sufficient knowledge among people about
the disease
the vector
method of transmission
breeding sites
controlling measures
247
What is nanotechnology?
It is an emerging science involved in designing, building and manipulating minute structures at the nanometer level. It is the creation and the use of materials and devices on the same scale as molecules and intracellular structures, typically less than 100nm in size
248
What is a nanometer?
One billionth of a meter (10-9m)
249
How do the physical and chemical properties of tiny molecules change with respect to the bigger particles?
The physical and chemical properties of tiny molecules are significantly different than bigger particles as they have a very high surface areas to volume ratio
250
Who introduced nanotechnology and when?
American physicist Richard Reynman in 1959
251
How large are living organisms built of cells?
10 micrometers
252
What is the typical size of proteins?
Typically 10 micrometers across
253
What can the size of proteins be compared to?
Its comparable with the dimensions of the smallest manmade nanoparticles
254
What does the size comparison between proteins and nanoparticles give us an idea of?
This simple size comparison gives us an idea of using nanoparticles as very small probes that would allow us to investigate the cellular machinery without introducing too much interference
255
What is a strong driving force behind the development of nanotechnology?
Understanding biological processes on the nanoscale level
256
What applications did nanotechnology become a big business with?
Applications of nanoparticles material manufacturing, energy, electronics and engineering
257
What applications of nanotechnology were of particular interest?
Applications of nanoparticles in biology and medicine
258
What is one of the most important applications of nanotechnology?
In medicine
259
What is nanomedicine?
Applications of nanotechnology for improving human health
260
What can nanotechnology be applied to in nanomedicine?
Prevention, diagnosis and treatment of dieases
261
What can nanotechnology be applied to in nanomedicine?
Prevention, diagnosis and treatment of dieases
262
What are the examples of nanoparticles in nanomedicine?
Titanium dioxide (Ti02) and silver (Ag) nanoparticles are used for the sterilization and operation theatres and surgical instruments in hospitals
Silver nano lotions are applied in theatres to prevent the entry of microbes
Nano particles are used in the production of antimicrobial coatings and nano-filters
Nano device sensors are used to monitor blood pressure, blood oxygen levels and hormone concentrations
Nano particles can unclog blocked arteries and detect and eliminate cancer cells
Several nanotechnology enabled drugs are available in the market primarily in areas of cancer treatment
Scientists have developed "smart drugs" using tiny nanoparticles such as gold particles that are introduced into the body to seek out and target special cells such as cancer cells to deliver a cargo that would destroy those that are damaged rapidly and effectively in a silent manner with very few side effects.
Spherical nanoparticles consisting of a dielectric called nano shells are used in the treatment of cancer.
Gold nano shells are used in bio imaging enhancements
In the treatment of diabetes a nano device is attached to the body which can release the required dosage of insulin at required time intervals
There has been successful application of nano-technology to the treatment and management of pain both in clinical and experimental studies like the fabrication of nano-formulated liposomes to deliver drugs for pain therapy
Viva gel is a virginally applied microbicide in development for prevention of HIV and HSV (Herpes simplex virus)
Nanocomposites are used to replace broken bones and to fill teeth as well
263
What nanoparticles are used for the sterilization and operation theatres and surgical instruments in hospitals?
Titanium dioxide (Ti02) and silver (Ag) nanoparticles
264
What are Titanium dioxide (Ti02) and silver (Ag) nanoparticles used for?
for the sterilization and operation theatres and surgical instruments in hospitals
265
Why are Titanium dioxide (Ti02) and silver (Ag) nanoparticles used for the sterilization and operation theatres and surgical instruments in hospitals?
Because these nanoparticles are able to destroy microbes
266
What is applied in theatres to prevent the entry of microbes?
Silver nano lotions
267
Why are silver nano lotions applied in theatres?
to prevent the entry of microbes
268
What is the function of Ti02 and silver nano filters?
They prevent the entrance of tiny particles such as viruses
269
Where are nano filters used?
to examine SARS patients
270
What are nano device sensors used for?
They are used to monitor blood pressure, blood oxygen levels and hormone concentrations
271
What device is used to monitor blood pressure, blood oxygen levels and hormone concentrations ?
Nano device sensors
272
What areas are several nanotechnology enabled drugs are available in the market ?
primarily in areas of cancer treatment
273
What is the advantage of scientists developing "smart drugs"?
They are introduced into the body to seek out and target special cells such as cancer cells to deliver a cargo that would destroy those that are damaged rapidly and effectively in a silent manner with very few side effects.
274
What are "smart drugs" developed by?
Using tiny nanoparticles such as gold particles
275
What are nanoshells?
They are spherical nanoparticles consisting of a dielectric core. A nanoshell is bigger than a polio virus
276
What are nanoshells used for?
They are used in the treatment of cancer
277
What are gold nano shells used for?
They are used in bio imaging enhancements as well
278
How is nanotechnology used In the treatment of diabetes?
a nano device is attached to the body which can release the required dosage of insulin at required time intervals
279
How is nano-technology successfully applied to the the treatment and management of pain both in clinical and experimental studies?
the fabrication of nano-formulated liposomes to deliver drugs for pain therapy
280
Why is viva gel a virginally applied microbicide ?
in development for prevention of HIV and HSV (Herpes simplex virus)
281
What is viva gel?
It is a product of nanotechnology which prevents the entry of HIV and HSV during sexual intercourse
282
What are nanocomposites are used for?
Nanocomposites are used to replace broken bones and to fill teeth as well
283
What are stem cells?
They are undifferentiated cells which can give rise to cells of the same type
284
How do stem cells divide?
They can divide by mitosis without a limit (or at least for the lifetime of the animal)
285
What are stem cells capable of?
They are capable of terminally differentiating into
286
Where are stem cells required?
Stem cells are required whenever there is a recurring need to replace differentiated cells that cannot themselves divide
287
What ability do stem cells have?
The stem cell itself has to be able to divide but it doesn't necessarily have to divide rapidly
288
At what rate do stem cells usually divide?
At a relatively slow rate
289
What are the two types of stem cells?
Embryonic stem cells
Adult stem cells
290
What is a zygote?
Following the fertilization of a sperm and an egg cell, the fertilized egg is called a zygote
291
How does the zygote divide?
Rapidly
292
What is the blastocyst?
In humans, in around five to seven days after fertilization, the dividing cells create an embryo consisting of a small hollow cluster of approximately 100 cells called a blastocyst
293
What is the size of a blastocyst?
It is approximately a seventh of a millimeter in diameter
294
What is the inner cell mass?
There is a small cluster of around 30 cells tucked inside the blastocyst that form a structure known as the inner cell mass
295
What cells are the source of embryonic stem cells ?
Inner cell mass
296
Why are ES cells so special?
Because they can eventually differentiate to form all of the more than 200 cell types that make up the human body
297
Why are ES cells called pluripotent?
Because they have the potential to develop into a variety of different cell types.
298
Describe the nature of human ES cells (hESCs)
Human ES cells are unspecialized cells
They have two major properties:
- ES cells cans elf-renew indefinitely to produce more stem cells
- Under the proper growth conditions, hESCs can differentiate into a variety of mature cells with specialized functions
299
What are the two major properties of hESCs
- ES cells cans elf-renew indefinitely to produce more stem cells
- Under the proper growth conditions, hESCs can differentiate into a variety of mature cells with specialized functions
300
Where are adult stem cells found?
They are found throughout the body after development
301
Where are adult stem cells present?
In many tissues
302
Why are there many adult stem cells specialized for?
For the genesis of different classes of terminally differentiated cells and hence type of stem cell serves for the renewal of one particular type of tissue
