Biology 1B - Agriculture Flashcards
1
Q
what factors contribute to the food security problem
A
- increase in world population (10 billion by 2050) crop production not increasing enough
- large amounts of food wate ( over a billion tones per year) mostly from households
- loss of allelic diversity (crop breeding)
2
Q
what type of food to humans ned the most
A
carbohydrates
bread, rice, potatoes etc
3
Q
what type of food is in most critical supply
A
fresh foods (more nutritional value than processed food and less carbon footprint)
4
Q
what is a possible but not ideal solution for food security problem
A
immediate food processing
lasts longer but less fresh and nutritional
5
Q
what problems can arise from lack of food
A
acute hunger - severe short term hunger
chronic hunger - long term insufficient access to food
hidden hunger - deficiency’s in essential nutrients
can lead to disease and death or fatigue, anxiety, depression etc.
6
Q
what factors can cause hunger
A
war, disease, natural disaster (acute, chronic)
poverty (in the UK) - hidden hunger
7
Q
what needs to be done to achieve food security
A
expand - land used to grow crops (marginal land - land with limited ability to grow crops)
increase yield & nutritional value
grow food more efficiently ( grow right crop in right place at right time)
manage distribution/ resources
minimise food waste
8
Q
what areas of plant science could help achieve food security
A
breeding genetics
plant stress tolerance
plat development
plant physiology
plant metabolism
9
Q
what major crop has the most production (and runners up)
A
sugarcane (only 15% of sugar cane weight is sugar)
maize
wheat
rice
potatoes
10
Q
what crops have the highest yield of direct human consumption
A
rice
wheat
potato
maize
11
Q
what is maize mostly used for
A
animal feed, industrial purposes, biofuel
only sweetcorn is used for human consumption (15% of maise)
12
Q
what did sugar cane impact historically
A
driver of colonialism and slavery
13
Q
what are spring wheat and winter wheat used for
A
spring - bread making
winter - feed and distillery
14
Q
why is wheat a good/ popular crop
A
nutritional value (high)
storage (more than 10 years shelf life)
baking qualities (The protein gluten has viscoelastic and adhesive properties. Cross-links during kneading)
15
Q
describe the two ways of producing rice
A
transitional wet rice cultivation (paddy fields) - Work intensive, Natural weed control, Natural fertilization
dryland cultivation - Easy sowing and harvest, Needs herbicides, Needs fertilizer
16
Q
what are important aspects of crop improvement to focus on in the future
A
pathogens and pests
sustainability (nutrient and water use efficiency)
climate change resilience (heat waves, flooding etc.)
17
Q
what has been lost due to plant breeding
A
allelic diversity
variation in genetic alleles which is important or evolution, disease resistance, genetic health etc.
loss due to selection by farmers and climate
18
Q
what are limitations to expanding land to grow crops
A
will have climate impacts
needs water
requires different crops
(instead could use current land better)
19
Q
how could current land space be used more effectively for vital crops
A
Move non-food crops into marginal land or oceans e.g. biofuels
20
Q
what is abiotic stress
A
environmental factors that negatively impact the growth
21
Q
what are the three pillars of improving food security
A
expand
intensify
be smart
22
Q
what is marginal land
A
land that has limitations making it less suitable for agricultural use
23
Q
what are limiting factors of marginal land
A
cold
hot
dry
saline
nutrient poor
polluted
24
Q
what can cause good land to become marginal land
A
over-use, salinization, pollution, climate change.
25
how does intensive agriculture lead to secondary salinity
irrigation water contains salt even if fresh water is used
a lot of it evaporates leaving salt behind
most of our crops do not grow in soil with high salt concentration so secondary salinity prevents further agriculture
26
how could salinity problems be addressed by creating salt resistant crops
overexpression of tonoplast Na+/H+ antiporter gene NHX1
NHX1 transports toxic substances to vacuole in exchange for H+ protons
overexpression of NHX1 improves plant growth in salt
27
what are hyalocytes
pants that naturally thrive in saline environments
28
what factor causes the greatest yield gap
abiotic stress
need create stress tolerant plants to increase yield
29
what is a key focus of Increasing CO2 assimilation and stress resistance in crops (increasing yield)
plant leaf stomata
30
what happens to plants when they experience water deficit
- production of stress hormone ABA
- perceived by ABA receptions and induces protection response
- stomata loses in leaves
- leads to reduced water loss but also reduced CO2 uptake and overheating
31
what are ABA-insensitive mutants
plants that show reduced sensitivity to ABA, that regulates various stress responses
leads to reduced stomatal closure
32
what is a strategy to improving plants stress tolerance
plants usually detect early warning signs of stress
could program plants to not respond to these signals and keep growing
33
what are the advantages and disadvantages to these less responsive plants
provides Less protection but Continued growth and Development could increase yield
Risk of death
Better yield under transient, moderate drought stress
- Will not survive long-term stress
- Require management
(breeding strategies need to be scenario driven)
34
how can trehalose contribute to drought recovery and stress resistance in plants
trehalose is a sugar that help plants regulate water balance
in rice you can overexpress two genes responsible for trehalose biosynthesis
enhancing plants ability to deal with drought and stress tolerance
35
how can ABA-inducible promoters contribute to drought recovery and stress resistance in plants
ensures that stress-resistance traits are activated only during drought conditions
avoiding yield loss under well-watered conditions
leads to better recovery from drought
36
Quantitative genetics
studies plant traits controlled by multiple genes and influenced by environmental factors
quantitative traits—such as height, yield, and disease resistance—show continuous variation rather than distinct categories.
37
what is Phenotyping, ‘phenomics
measuring and analysing an organism's physical and biochemical traits, such as plant height, yield, disease resistance, or drought tolerance. It helps scientists connect these observable traits to underlying genetic and environmental factors.
38
what are biotic factors
disease, pests, weeds
39
what pathogens affect plants
bacteria
viruses
fungi
40
how much crop loss is plant pathogenic bacteria responsible for
over 5%
41
what types of crops do bacterial diseases affect
potatoes, cereals, oilseed crops and very
vegetable and fruit trees
42
what are current solutions to bacterial diseases in plants and there downsides
introduction of genes conferring resistance - suitable resistance genes for breeding are not often available
the use of chemicals e.g. copper sprays - adverse environmental impacts
43
what is pseudomonas syrinae
one of the most widespread and damaging bacterial pathogens in crops
affects tomato, pepper, olive etc.
44
what are some bacterial diseases caused by pseudomonas syrinae
Bacterial blight- soybean
olive knot disease
Bacterial spot - peach
45
how are plant viruses typically transmitted
by vectors
46
where in the world to plant viruses affect crops the most
Africa and parts of Asia
47
what is an example of plants affected by plant viruses
cassava and sweet potato
areas of east and west Africa
virus diseases result in 25-50% yield loss
48
what is Phytophthora infestans
fungal like organism responsible for the potato famine 1840s
thrives in moist cool conditions
big problem in parts of the world that cant afford fungicides
49
what are two strategies utilised by plant pathogens
nectotrophs - grow inside dead tissues and secrete cell derogating enzymes that kill host cells, utilise nutrients used for cell growth
biotrophs - grow in living tissues and communicate with living host cells, utilise nutrients for cell growth or develop feeding structures to extract nutrients.
50
what defence mechanisms do plants use against plant pathogens
- structural barriers
- toxic substances that limit infection to particular pathogens
- recognise pathogen and activate defence mechanisms that prevent spread or localize infection (inherited ability called innate immunity)
51
what are two branches of plant immune systems (innate immunity)
1) Basal - proteins on outside of plasma membrane that recognise macro molecules that are associated with pathogens (contain PAMPS)
2) gene-for-gene - act largely within cell using proteins encoded by resistance genes (R-genes), recognise pathogen specific effector molecules (averulence genes, needed for pathogen to invade plant) and activate defence responses
complementary pairs of dominant genes must be present in the host and pathogen
52
what are PAMPS
Pathogen-Associated Molecular Patterns
molecular signatures found in microbes that trigger immune responses in plants
critical for microbes function (exposed molecules e.g. flagella) and recognised by host cell as "non self"
53
what is systemic acquired resistance (SAR)
defence system
elicited most strongly by gene for gene responses
plants with acquired resistance show reduced susceptibility to infection to virulent or avirulent pathogens
54
what are some responses to infection in resistant plants
- synthesis of PR proteins, include proteins with likely anti pathogen properties
- synthesis of cell wall structural proteins to strengthen cell walls
- synthesis of specific anti fungal, bacterial, or viral compounds
55
what is a problem with breeding resistance genes into crops
after a few years of genetic drift in the pathogen or emergence of new pathogens results in loss of resistance
56
what is conventional resistance
use of genetic manipulation methods to introduce to introduce existing resistance genes into species they dontt naturally occur in
57
what is novel resistance
use of genetic manipulation to introduce genes that limit pathogen spread via mechanisms other than conventional resistance
58
what is an example of novel resistance
Pathogen derived resistance to a virus (components of a virus are introduced into a host plant)
Constitutive expression of the major structural protein of Papaya Ringspot Virus (gene is always active), protects against infection by PRSV.
59
how does climate change affect the environment
increased temperature (drier summers)
more extreme rainfall (more flooding)
60
how does irregular heat stress affect plant growth
reduced photosynthesis
slower growth
impaired germination (due to stress)
61
what types of photosynthesis limit water loss from plants and how
C4
CAM
limits photorespiration
62
what is photorespiration
process that limits damaging products of light reactions that build up in the absence of the Calvin cycle
it limits photosynthesis by competing for
on hot dry days plants close their stomata to conserve water, reducing the supply of CO2 from the atmosphere
RuBisCo adds )2 instead of CO2 into the Calvin cycle so the plant looses carbon
(doesn't help plant conserve water as energy extensive and inefficient)
63
what strategies could be used to improve stress tolerance in plants
- selective breeding to optimize desired characteristics
e.g. artesian hybrids help corn plant to manage water
- GM plants
64
what temperature range do C3 plants have
have the broadest temp range
but lower than that allowed by C4 photosynthesis
65
what temperature range to CAM plants have
fix carbon at night, contributing to lower optimal temperatures (lower range)
66
how to high temperatures inhibit photosynthesis
crucial enzymes in photosynthesis (RuBisCo) can become denatured
increased photorespiration
67
why is cotton more heat resistant than other crops
differences in RuBisCo protein sequence
but lower RuBisCo activity in optimal conditions
68
what is RCA
RuBisCo Activase
uses ATP to activate RuBisCo
69
how can engineering RCA improve stress resistance in wheat
RCA is temp sensitive
two isoforms are expressed in wheat
substitution of a single amino acid allows a new protein with intermediate characteristics that triggers photosynthesis more effectively at higher temperatures
70
how is global warming changing crop distribution
will change where we can grow crops e.g. coffee usually grown across south America, Africa and SE Asia, will comes to hot in these places
maize and wheat cropping is moving north over time, has positive (could limit irrigation need) and negative affects(some regions will become unsuitable to grow crops)
71
how can Bt Toxins be used in GM to protect plants from pests
- gram negative bacteria bacillus thuringiensis produce crystalline proteins called BT toxins
- BT toxins show species specific toxicity to insect larvae
- genes encoding BT toxin can be inserted into plants using agrobacterium etc.
- plants become toxic to target insect larvae
- specificity means the transgenic plants aren't toxic to beneficial insects such as bees
72
what crops can use BT toxin method
maize in USA (over 70%)
cotton in USA (90%)
cotton in India (over 90%)
73
what are downsides of insecticides
expensive and have environmental and health implications
(use has been reduced by 50% by BT plants)
74
what plant diseases does BT transgenic plants protect against
European cornborer (damage inside plant so difficult to see and predict)
cotton bollworm
75
why is improving oil quality a major objective of plant breeders
- Brassicaceae and other oil producing plants naturally contain large amounts of very long chain monounsaturated fatty acids
- these have been shown to cause heart disease
76
how are plants modified to produce improved oils
erucic acid levels in brassica napus (oil seed rape/canola) have been reduced by mutagenesis and conventional breeding
genetic engineering
77
what is "golden rice"
- millions of infants a year prematurely loose their site as a result of low vitamin A diets
- particularly in areas where rice is a staple food
- the aleurone cell layer on rice contains high vitamin A but is removed for storage
- biotechnologists engineered golden rice with high levels of carotenoids in the rice endosperm
78
what are some plant derived proteins (PDPs)
avidin
trypsin
lysozyme
lactoferrin
79
what are some medical applications of plant derived proteins
medical treatments - play a role in cancer therapies, including treatments for Non-Hodgkin’s Lymphoma, breast cancer, and colorectal cancer (Avicidin). Interferons, which help regulate the immune system, are produced via plant-based methods for antiviral treatments.
vaccines - PDPs are used to develop vaccines against Ebola, Foot & Mouth Disease, Rabies, and Bovine Papilloma Virus
drugs - anti-HIV drugs, anti-malaria drugs
80
what are monoclonal antibodies
B-lymphocytes from mice can be immortalized generating clonal lines
genes from suitable monoclonal cells can be cloned and expressed in plants
81
how are monoclonal antibodies used for treatment of human health problems
- ZMapp (growing future of plant made medicines)
- treatment for Ebola
- comprises a mixture of three monoclonal antibodies against the virus "spike protein"
- the humanized antibodies were generated as mouse monoclonals, genes fort the light and heavy chains were cloned and expressed in Nicotiana benthamiana
82
what are the benefits of producing anti-cancer drugs in plants
- many new anti cancer drugs based on monoclonal antibodies are in development
- monoclonal antibodies are produced in transgenic plants in glasshouses (cheap, no contamination)
- much cheaper than using mammalian cell lines
- production in plants is scalable (suitable for large amounts of protein or small amounts for rare conditions)
83
what controls plant behaviour
circadian rhythms/biological clocks (molecular time keeping mechanisms)
84
what aspects of plant biology do circadian rhythms control
molecular biology
physiology - stomatal opening
growth - hypocotyl elongation clock
development - flowering
85
what impacts circadian rhythms
environmental imputes (red light, blue light, sugars produced by photosynthesis, temperature fluctuations)
86
what circadian oscillator
transcription-translations feedback loop
regulate gene expression and protein production in cells
(protein encoded by gene A activates gene B, protein encoded by gene B represses gene A)
feedback loop results in rhythms of transcript abundance of the two genes
87
what techniques are used to measure circadian rhythms in plants
destructive methods - obtains RNA or protein, inconvenient, a lot of plant material required, opportunity for human error, sometimes essential to measure rhythms of transcripts, proteins etc
non invasive and automated methods
88
how do plant circadian rhythms work
different clock components are expressed at different times
single mutations can break the clock
the clock is conserved amongst plants
plants use photoperiod as a signal to sense seasonal changes
circadian rhythms have slowed during domestication
89
how can winter barley be improved using circadian dependant traits
- changing flowering time
- barley is a long day plant and requires day lengths in excess of a critical minimum to flower (photoperiod sensitive)
- flowers in early spring and harvest occurs before heat of summer
- modify to make barley less dependent on day length, allowing it to flower earlier in regions with shorter daylight hours.
90
how do plants know when to flower
photoperiod sensitive plants induce flowering under either long or short days (plants day plants e.g. wheat/short day plants e.g. rice)
flowering time is highly regulated and centres on flowering locus t (FT)
activation occurs when expression and light coincide
91
what is flowering locus t (FT)
gene that regulates flowering time in plants
