38 Angiosperm Reproduction and Biotechnology Flashcards
(160 cards)
1
Q
What are the unique features of angiosperm reproduction?
A
Flowers, fruits and double fertilisation.
2
Q
What feature of plant reproductive cycle is not seen in animals?
A
Alternation of generations in which the plants have diploid stages and haploid states that alternate.
3
Q
What is the diploid stage of alternation of generations called?
A
The sporophyte
4
Q
What is the haploid stage of alternation of generations called?
A
The gametophye
5
Q
What can the parts of a flower be broken down into?
A
The female reproductive organs, the male reproductive organs and the supporting structures.
6
Q
What are the female reproductive organs of a plant collectively called?
A
The Carpel
7
Q
What does the carpel include?
A
The Ovary which is at the centre of the flower. A ’style’ grows up from the ovary and ends with a ‘stigma’
8
Q
What are the male reproductive organs collectively called?
A
The stamen.
9
Q
What does the stamen include?
A
Around the ovaries are multiple stamens. Each includes a ‘filament’ that holds up the ‘anther’
10
Q
What is inside each ovary?
A
One or more ovules.
11
Q
What do the supporting structure of a flower include?
A
A receptacle, sepal and petal.
12
Q
What is the petal?
A
A large, typically coloured, tissue that attracts insects.
13
Q
What are sepals?
A
Small leaflike (but not leaves) flaps at the bottom of the flower. They enclose the flower when it is still developing i.e. they form the bud.
14
Q
What are receptacles?
A
The structure at the base of the flower that connects it the stem. (similar to the petiole found in a leaf)
15
Q
What are the basic types of flowers?
A
‘Complete flowers’ and ‘incomplete flowers’.
16
Q
How do complete and incomplete flowers differ?
A
Complete flowers have all 4 basic flower organs (sepals, petals, stamens and carpel).
Incomplete flowers lack one or more of these structures.
17
Q
What can incomplete flowers further be grouped as?
A
Sterile (no-reproducitve organ), unisexual (stamen or carpel) and fertile (stamen and carpel)
18
Q
How can flowers be arranged?
A
On their own or in large groups called ‘inflorescences’
19
Q
What is an example of an inflorescence?
A
A sun flower. This is because each of those brown structures in the central disk is a separate ‘incomplete flower’
20
Q
What is the basic life cycle of angiosperms? (hint: focus on alternation of generations)
A
Male gametophyte (pollen grain) alands on the stigma. It forms a ‘pollen tube’ and thus fertilises the female gametophyte (‘embryo sac’)
This ‘fertilisation’ leads to a ‘diploid sporophyte’ (‘embryo’). A fruit develops from the embryo causing the release of seeds.
These seeds develop in to ‘mature sporophytes’ which then release ‘male gametophytes’ as pollen whilst also maintaining female gametophytes (‘embryo sac’) in the ovaries.
21
Q
What is the female gametophyte of angiosperms?
A
Embryo sac.
22
Q
What is the male gametophyte of angiosperms?
A
Pollen grains.
23
Q
What is a carpel also known as?
A
A ‘pistil’ (note that this can also refer to multiple fused carpels.)
24
Q
How are male gametophytes formed?
A
Each anther contains four ‘microsporangia’ or ‘pollen sacs.’ Each microsporangium contains diploid ‘microsporocytes’ (‘microspore mother cells’)
Each microsporocyte divides by meiosis to form 4 ‘microspore.’ Each ‘microspore’ grows by mitosis to form a pollen grain.
Each pollen grain contains a ‘generative cell’ (haploid) that will become two sperm. To also includes a ’tube cell’ that will later form the pollen tube.
25
What is the ploidy of the microsporocyte?
Diploid
26
What is the ploidy of the microspores?
Haploid
27
What is the ploidy of the 'generative cell’ in the pollen grain?
Haploid
28
What is the ploidy of the 'tube cell' in the pollen grain?
Haploid
29
What is it called when the pollen grain develops the pollen tube?
Germination i.e. “the pollen grain has germinated to form a pollen tube."
30
What is the structure of a pollen grain?
It contains a tough wall called the ’spore wall’ surrounds a ’tube cell’ and a ‘generative cell’
By the time the pollen grain has developed the ‘generative cell’ will actually be inside the ’tube cell’!
The spore wall may contain spikes i.e. in an animal pollinated species.
31
What forms the ’spore wall’ of the pollen grain?
It is composed of materials produced by the microspore and by the anther.
32
What happens when the pollen grain lands on the stigma?
It ‘germinates’ as the 'tube cell’ forms a large protuberance called a ‘pollen tube’ which grows down the style.
As the pollen tube grows down the style the generative cell which is inside the ’tube cell’ divides into two sperm cells.
As the pollen tube reaches the ovary it releases the two sperm into the ovule
33
What is the female gametophyte called?
‘Embryo sacs'
34
What is the structure of a ovule?
It consists of a ring composed of ‘megasporangium. (n). Inside this is large diploid cell called the 'megasporocyte’ (‘megaspore mother cell’).
At the base of the ovule are two ‘integuments’ which are diploid sporophytic tissue that completely surrounds the ovule except for a ‘microphyle’ at the bottom.
35
What do the ‘integuments’ of the ovule develop into?
The seed coat
36
What structure does the ovule eventually become?
A seed
37
What structure does the ovary eventually become?
The ovule.
38
What happens during female gametophyte development?
The megasporocyte (' megaspore mother cell') enlarges and undergoes meiosis, producing four haploid megaspores. Only one megaspore survives; the others degenerate.
The nucleus of the surviving megaspore divides by mitosis three times without cytokinesis, resulting in one large cell with eight haploid nuclei. The multinucleate mass is partitioned by membranes into a multicellular female gametophyte—the embryo sac.
39
What happens the the 8 haploid nuclei of the megaspore?
3 become ‘antipodal cells’, 2 become ‘polar nuclei’, 2 become ’synergies’ and 1 becomes an 'egg'
40
What is the ploidy of the ‘megasporangium’?
Diploid
41
What is the ploidy of the ‘megaporocytes’?
Diploid
42
What is the ploidy of the ‘integuments’?
Diploid
43
What is the ploidy of the ‘megaspore’?
Haploid
44
What is the ploidy of the ‘antipodal cells’?
Haploid
45
What is the ploidy of the ‘polar nuclei’?
Haploid
46
What is the ploidy of the ‘egg’ in an ovule?
Haploid
47
What is the ploidy of the ‘synergids’?
Haploid
48
What is the structure of a complete ovule?
At the bottom is has an opening called the ‘microphyle’. The ‘integuments’ completely surround the ovule except at the microphyle.
At the entrance of the microphyle is a single egg. It is surrounded by two ’synergids’: one on each side.
At the centre of the ovule is two ‘polar nuclei’.
At the far end (relative to the microphyle) of the ovule are three ‘antipodal cells'
49
What are the ’synergies’ of the ovule?
Cells that flank the egg at the microphyle. They help attract and guide the pollen tube to the embryo sac.
50
What are the ’polar nuclei’ of the ovule?
Cells at the centre of the ovule that will develop into endosperm
51
What are the ’antipodal cells’ of the ovule?
Their function has not yet been determined.
52
What are the basic “vectors" of pollination?
Wind, Bees, Moths/Butterflies, Flies, Bats and Bees.
53
What is wind pollination also known as?
‘Abiotic pollination’ as it is the only format that does not depend on 'biotic factors’ i.e. animals. (another extremely rare form of abiotic pollination by water is found in a select few species)
54
How does the shape of wind pollinated flowers help collect pollen?
They are shaped so that in the wind they generate ‘eddy currents’ that suck the pollen in.
55
What determines what type of cell each of the 8 nuclei of the megaspore will develop into?
A gradient of auxin concentration which is released from the microphyle.
56
What carries pollen in ‘abiotic pollination’?
Most commonly the wind but in a few species water carries the pollen.
57
What are some typical feature of bee-pollinated flowers?
They have bright petals that glow when seen under ultraviolet light. They often also have a sweet fragrance.
They are typically yellow or blue as red seem dull to bees.
58
There are four flowers: one red, one blue, one yellow and one grey. Predict the likely pollinator for each?
Red: Birds
Blue: Bees
Yellow: Bees or Birds
Grey: Moths
59
What are some typical feature of towers pollinated by butterflies and moths?
Butterflies and moths are both able to smell and thus the flower will likely be scented.
Moths are nocturnal so the flowers they pollinate will likely be grey. Butterflies are active in the day so will pollinate brightly coloured flowers
60
What are some typical feature of fly-pollinated flowers?
They will often have a odour like rotten meat. They may also be red like meets.
61
What is a ‘carrion’ flower?
A specific flower that is pollinated by flies and thus produces an odour like rooting meats.
62
What are some typical feature of bird pollinated flowers?
They are often red or yellow but since birds do not have a developed sense of smell they are not scented.
Many have petals that are fused to formed a long tube that the bird must insert its beak into and thus ensures it rubs against the anthers and the stigma.
At the end of the tube there is often a sweet sugary substance called nectar.
63
What is it called when two species evolve together i.e. so that they can be symbiotic?
‘Coevolution'
64
What is an example of coevolution?
Darwin observed a madagascan orchid with a long tube. He deduced that their must an organism with a tongue long enough to reach into it. This was confirmed with the observation of such as moth.
65
What is an insect’s tongue called?
Its ‘proboscis'
66
What does ‘proboscis’ refer to?
An insect’s tongue.
67
What happens when the sperm are discharged in to the ovule?
One sperm fuses with the egg to form a diploid zygote.
The 2 polar nuclei and the other sperm fuse to form a triploid (3n) ‘endosperm nucleus'
68
What does the triploid cell derived form the polar nuclei and sperm develop into?
The endosperm of the seed.
69
What is the basic purpose of the seed’s endosperm?
To store nutrients in the form of starch for the dormant seed.
70
Why is double fertilisation important?
It ensure that the polar nuclei do not fuse and produce endosperm unless sperm is present.
Therefore this avoids resources being wasted on developing endosperm for unfertilised ovules.
71
What happens in the various cells when the sperm fuses with the egg?
The cytosolic Ca2+ levels increase and a block to ‘polyspermy’ is established.
Both of these responses are also seen in animal cells.
72
Where are nutrients stored in a seed?
Originally the endosperm (thick liquid) of the embryo stores the nutrients.
But later in some species the cotyledons ("seed leaves”) swell to store nutrients.
73
What types of nutrients do seeds need?
Proteins, oils and carbohydrates.
74
What is the endosperm?
It starts as a single multinucleate ’super cell’. It then divides by ‘cytokinesis’ (not mitosis) to form empty cells called ’naked cells’ During this time the endosperm is a milky liquid.
Eventually the ’naked cells’ develop cell walls and thus the endosperm hardens.
75
What are some example of endosperm?
Coconut milk is liquid endosperm and "coconut meat” is solid endosperm
The white fluffy bit in popcorn is also endosperm.
76
What happens to the endosperm when the seeds germinate?
In grains and most other species of monocots, as well as many eudicots, the endosperm stores nutrients that can be used by the seedling after germination.
In other eudicot seeds, the food reserves of the endosperm are completely exported to the cotyledons before the seed completes its development. Therefore the mature seed lacks endosperm.
77
What happens during embryo development?
The zygote undergoes mitosis to split into a ‘basal cell’ and a ’terminal cell’ Most of the embryo will develop from the terminal cell.
The basal cell continues dividing to form a thread of cells called the 'suspensor'. As the ’suspensor’ grows it pushes the embryo deeper into the protective and nutritious tissues.
The terminal cel continues dividing and forms a ’spherical proembryo’ (early embryo) that is attached to the suspensor.
The cotyledons begin to form as on the proembryo. A eudicot has two cotyledons so is heart shaped. Monocots only have one cotyledon.
After the cotyledons appear, the embryo elongates. Between the two cotyledons (if eudicot) the "shoot apex” forms. At the opposite end of the embryo (where the suspensor attatches) the ‘root apex forms.’ The root apex and shot apex will be the apical meristems of the root and stem respectively when they develop.
78
On what side of the embryo is the ‘root apex’?
The same side as the suspensor.
79
On what side of the embryo is the ’shoot apex’?
The side opposite the shoot apex and suspensor.
80
What is the function of the ’suspensor’ of the embryo?
It anchors the embryo to the parent plant. It also transfers nutrients to the embryo from the parent plant (and endosperm if the seed has one) to the embryo.
81
How does the embryo acquire nutrients?
Through the ’suspensor’.
82
What happens just before the seed matures?
The seed is dehydrated (most water removes) so that it enters a state of 'dormancy'.
83
What happens to the seed during 'dormancy'?
Growth and metabolism essentially stop.
84
What is the structure of a mature seed?
Below where the cotyledons are attached, the 'embryonic axis' is called the ‘hypocotyl' The ‘hypocotyl' terminates in the ’radicle', or embryonic root.
The portion of the embryonic axis above where the cotyledons are attached and below the first pair of miniature leaves is the ‘epicotyl'. The ‘epicotyl', young leaves, and 'shoot apical meristem' are collectively called the ‘plumule'.
85
What are some structure of mature seeds found only in those from specific species?
Grasses, including maize and wheat (both monocots) have a specialized cotyledon called a 'scutellum' which has a large surface area and is pressed against the endosperm, from which it absorbs nutrients during germination.
The embryo of a grass seed is enclosed within two protective sheathes: a coleoptile, which covers the young shoot, and a ‘coleorhiza', which covers the young root. Both structures aid in soil penetration after germination.
86
What is the structure in grass seeds that protects the radicle as it pushes down into the soil?
The ‘coleorhiza'
87
What is the structure in grass seeds that protects the plumule as it pushes up and out of the soil?
The ‘coleoptile'
88
Why are coconuts so large?
This provides floatation and protection as they travel between islands. This also allows large amounts of endosperm which feeds the seed as it travels and as it develops on nutrient-poor sandy soils.
89
What is unique about orchid seeds in how they store nutrients?
Orchid seeds have almost no food reserves and must bond symbiotically with mycorrhizae (a fungus) prior to germination.
90
What is the purpose of seed dormancy?
To allow the seed to with until the perfect conditions are present before germinating.
91
What are some example of specific stimuli that cause seeds to break dormancy?
Mainly desert seeds germinate after only substantial rain.
Some woodland species germinate only after a forest fire as this clears space for new plants to grow.
Lettuce seeds only germinate when exposed to light and thus only when they are burred near the surface.
Some seeds only germinate if their seed coat is partially digested as they pass through an animal’s digestive tract. This aids in seed dispersal.
92
What process allows seed to germinate?
‘Imbibition’ which is the intake of water into the seed due to its low water potential.
93
What does ‘imbibition’ do to the seed?
It causes the seed to expand and thus its seed coat ruptures.
It also triggers the activation of hydrolytic enzymes which begin to breakdown the storage materials in the endosperm and cotyledon.
94
After ‘imbibition’ has ruptured the seed coat and activated hydrolytic enzymes, what happens during germination?
The radicle (embryonic root) emerges. Then the plumule (embryonic shoot) emerges.
95
Why does the radicle emerge before the plumule?
This provides water for growth by expansion.
| not for anchoring
96
How does the plumule emerge?
This differs between normal plants (eudicots and some monocots) and the few monocots, such as grass, that use coleoptiles.
97
How does the plumule emerge in plants without coleoptiles?
The hypocotyl, attaches the radicle the rest of the seed. It extends and forms a loop which pulls the cotyledon up and out of the soil.
In response the light the cotyledon straightens and opens up into the leaves inside it.
Eventually the epicotyl develops true ‘foliage leaves’ so the embryonic leaves that constitute the cotyledon drop off.
98
How does the plumule merge in plants with coleoptiles?
The coleoptile is a tough sheath that encloses and protects the embryonic shoot.
Protected by the coleoptile the shoot can simply go straight up through the soil. Eventually the shoot inside grows out through the tip of the coleoptile and sprouts leaves.
99
How does the ovary know when to develop into a fruit?
Fertilisation triggers hormonal changes. Therefore if the flower is not fertilised no fruit is produced and the flower often just drops off.
100
What happens during fruit formation?
The ovary wall thickens to form the ‘pericarp’, the thickened wall of the fruit.
As the ovary grows other parts of the flower i.e. the petals and reproductive organs wither away and are shed.
101
What are the basic types of fruits?
Simple fruit, aggregate fruit, multiple fruit and accessory fruit.
102
What is a simple fruit?
A fruit that develop from a single carpel (or several fused carpels)
103
What are some examples of simple fruit?
Peas, lemons and peanuts
104
What are aggregate fruit?
A fruit that develops from many separate carpels from the SAME flower
Each carpel grows into a little ‘fruitlet’ like the segments of a raspberry.
105
What are some examples of aggregate fruit?
Raspberry, blackberry and strawberry.
Note that those hairs seen on the surface of the raspberry are actually stigmas.
106
What is a multiple fruit?
A fruit that is formed from many carpels of MANY flowers in a ‘inflorescence’.
Each segment i.e. scale on a pineapple is a separate carpel of a different flower.
107
What are some examples of multiple fruit?
Pineapples and figs
108
What is a accessory fruit?
A fruit that develops largely from tissues other than the ovary.
109
What is an example of an accessory fruit?
Apples in which the main fleshy bit of the apple is actually the swollen ‘receptacle.'
110
What happens when a fruit ripens?
In 'dry fruits' such as soy bean pods the fruit simply dries and hardens.
In ‘fleshy fruit’ a more complex interaction of hormones is required. The ‘pulp’ of the fruit becomes softer as enzymes break down the cell walls. The color usually changes from green to red, orange, or yellow. The fruit becomes sweeter as organic acids or starch molecules are converted to sugar.
111
What are the basic methods of seed dispersal?
Dispersal by water, wind or animals.
112
What are some typical adaptations of seeds that are dispersed by water?
They are buoyant and have large reserves of food for long voyages. (and for their arrival on nutrient poor sandy soils)
They are also tough. In coconuts for example the endosperm is surrounded by a tough layer ‘endocarp’ that is in turn protected by the fibrous ‘husk.'
113
What are some typical adaptations of seeds that are dispersed by wind?
They often have wings or parachutes to control their descent and thus allow them to glide farther.
Tumble weeds have large surfaces areas to allow their seeds to be carried round the desert.
114
What are some typical adaptations of seeds that are dispersed by animals?
Some have hooks etc. to attach onto the coats of animals.
Some have tough seed coats that resist chemical digestion. This allows them to be swallowed by animals and then egested into new areas.
Some seeds attract animals such as ants or squirrels. The squirrels burry the nuts and thus is they lose them the nuts can germinate. Ants carry the seeds into their nests where they germinate.
115
Why is seed dispersal important?
It prevents competition between the parent plant and its offspring.
It also allows the offspring to colonise new niches.
116
What are the basic mechanisms of asexual reproduction in plant?
'Fragmentation', apomixis
117
In terms of plant asexual reproduction, what is ‘fragmentation'?
When a piece of a plant drops/separates of then develops into a new independent plant.
118
In terms of plant asexual reproduction, what is apomixis?
The asexual production of seeds.
Specifically a diploid cell in the ovule gives rise to the embryo, and the ovules mature into seeds
119
How can a small region of a plant develop into a full normal one?
Cambium and meristems provides a source of undifferentiated cells. Parenchyma cells throughout the plant can also specialise into specific cell types.
120
What is an example of a plant that undergoes apomixis?
Dandelions
121
What is an advantage of apomixis over other forms of plant asexual reproduction?
Unlike ‘fragmentation’ the seeds can be dispersed over a larger area to reduce competition with the parent plant.
It also allows for seed dormancy and thus a sudden population increase at the correct time.
122
What is asexual reproduction also called in plants?
Vegetative reproduction, even to describe apomixis, as the offspring typically derive form mature vegetative fragments.
123
What are some advantages of asexual reproduction in plants?
- It requires less energy i.e. no fruit production or flowers
- It is typically faster-more offspring
- Plant is genetically identical to parent-offspring extremely well adapted.
- No need for a pollinator
124
What are some disadvantages of asexual reproduction in plants?
-Limited genetic variation - more vulnerable to disease
125
What is it called when a plant self fertilises?
’Selfing'
126
When can ’selfing’ be beneficial?
In pea plants it is used to fertilise any peas left in the pod which have not been fertilised sexually.
Therefore it leads to more offspring with little additional cost.
127
How can ’selfing’ be non-beneficial?
It wastes all the elaborate structures i.e. flowers produced to reap the benefits of sexual reproduction i.e. increased variation.
128
What are the major methods of preventing ’selfing’?
’Self-incompatability’, ‘dioecious plants’, and prevention based on timing
129
What are ‘dioecious plants’?
Plant prevent self-fertilize because different individuals have either 'staminate flowers' (lacking carpels) or 'carpellate flowers' (lacking stamens)
130
How can plants prevent self-polination through prevention based on timing?
An individuals stamens would mature and disintegrate before the carpels etc.
Note that as one plant has mature anthers another plant must have mature carpels or cross-pollination would not occur as well
131
What is it called when pollination is carried between different individuals?
‘Cross-polination'
132
What is the basic principle of ’self-incompatibility’ in preventing ’selfing’?
Molecular mechanisms of the plant prevent one of its male gamete from fertilising the ova.
133
What can ’self-incomparability' be divided into?
'Gametophytic self-incompatibility' or 'sporophytic self-incompatibility'
134
What is gametophytic self-incomparability?
The S-allele in the pollen genome governs the blocking of fertilization. For example, an S1 pollen grain from an S1S2 parental sporophyte cannot fertilize eggs of an S1S2 flower but can fertilize an S2S3 flower. An S2 pollen grain cannot fertilize either flower.
Self-recognition of this kind involves the enzymatic destruction of RNA within a pollen tube. RNA-hydrolyzing enzymes are produced by the style and enter the pollen tube. If the pollen tube is a “self” type, these enzymes destroy its RNA.
135
What is sporophytic self-incomparability?
In sporophytic self-incompatibility, fertilization is blocked by S-allele gene products in tissues of the parental sporophyte that adhere to the pollen grain wall. For example, neither an S1 nor S2 pollen grain from an S1S2 parental sporophyte can fertilise eggs of an S1S2 flower or S2S3 flower, due to the S1S2 parental tissue attached to the pollen wall.
Sporophytic incompatibility involves a signal transduction pathway in epidermal cells of the stigma that prevents germination of the pollen grain.
136
How can scientists prevent self-fertilisation during experiments?
By removing the anthers or developing breeds which don’t develop them (are ‘male sterile')
137
What types of vegetative propagation are used for agriculture and research?
‘Cuttings’, ‘Grafting’ and test-tube cloning and related techniques
138
What are ‘cuttings' in the context of artificial vegetative reproduction?
A region of the shoot is cut off and treated with IAA to form a callus at the end (ball of generic cells)
Adventitious roots then form and an identical offspring has been produced.
In some plants the cuttings can be taken from the leaves and in other from tubers (i.e. potatoes)
139
What is grafting in the context of artificial vegetative reproduction?
A twig or bud from one plant can be grafted onto the roots of another plant of the same or similar species.
The plant that provides the root system is called the 'stock'; the twig grafted onto the stock is referred to as the ‘scion.'
140
What does ‘in vitro’ mean?
“In glass” i.e. outside the body so in a test tube etc.
141
What is the opposite of ‘in vitro’?
“In vivo” which is in the body.
142
How does in vitro propagation of plants often work?
Undifferentiated cells are grown in cell medium and, with the correct hormone and nutrient cocktail, become a new plant.
143
What does ’transgenic’ refer to?
An organism which contains the genes of another species.
144
What are ‘protoplasts’?
Cell that have had their cell walls removed by enzymes such as cellulase and pectinase
145
Where do the pectinases and cellulases used in prop last formation derived?
Fungi which perform extracellular digestion and thus freely release these hormones.
146
How can protoplasts be used in research?
Two haploid protoplasts i.e. gametes can be forced together to form a diploid offspring.
Since the protoplasts can be from different species this allows novel hybrids to be produced.
147
Given that the rate of mutation is slow, how can new alleles be quickly formed?
The rate of mutation can be increased by treating seeds (or animals) with mutagenic chemicals or radiation.
148
What developmental abnormality is typical of ‘hybridisation’?
Often the embryo will form normally but the endosperm will not develop.
To rescue to the embryo it can be removed and cultured in vitro as the seed would not develop with out endosperm.
149
What does ‘hybridisation’ refer to?
The crossing of two distinct species.
150
What is the formation of offspring form parents of different offspring called?
Hybridisation.
151
What is an example of a hybridised plant with parents from species outside the same genus?
Triticale which is a cross between wheat and rye.
152
What is the binomial name for wheat?
Triticum aestivum
153
What is the advantage of genetic engineering over traditional methods i.e. artificial selection?
It allows genes to be transplanted from diverse species i.e. putting a yeast gene in a plant.
154
What are the primary limiting factors of human food production?
Water and Land
155
What typical features of GM crops allow them to increase human food production?
- The ability to grow on less fertile soil
- Reduced water need
- Pest and cold/heat resistance
etc.
156
What is a specific example of a GM crop that is already positively impacted human lives?
‘Golden rice’ which is a form of rice that has genes from daffodils. These provide the beta-carotene the body can convert to Vitamin A to prevent blindness in humans.
157
What is it called when genes are transplanted between species?
Transgeneis
158
What are some potential dangers of transgenic plants?
- Plants with genes for herbicide immunity could breed with weeds to produce herbicide resistant strains of weeds.
- Could be allergen producing
- The transgenic plant could spread and by the primary strand of that species. An unknown weakness i.e. poor cold resistance could then lead to mass crop
159
What is ‘fumonisin’?
A fungal toxin found in many wheat products, even beer
160
How can transgene escape be minimised?
- Make the plants male sterile so that they do not produce pollen which can travel long distance.
- Trigger apomixis so that no pollen is produced while preventing the need for manual pollination
- Encode the genes in chloroplast DNA as this is passed on exclusively from the mother.
- Causes the petals to not open so that the plant self-polinates with little chance of pollen escaping.
