Plant Bio 2: Developing Better Food Flashcards
What are the major human nutritional deficiencies?
Fe 20-40%
Vitamin A 10%
Iodine
Zinc
What has the highest source of vitamin A?
Beef liver
What is the absorption and transportation of vitamin A like?
Fat soluble vitamin
Absorbed and transported with lipids
Where is vitamin A stored?
In the liver
What is b-carotene?
Pro-vitamin A
What does B-carotene Di oxygenase become?
2x retinal molecules
Retinol
Retinoic acid
What is a major role of vitamin A?
Part of the visual pigment rhodopsin
What are forms of vitamin A also involved in?
Gene expression
Maintenance of epithelial tissue
Regulation of growth and differentiation cells- including some cells of the immune system
As part of rhodopsin, what does retinal bind to?
The protein opsin
In regulation of gene expression, what does retinoic acid bind to?
Protein receptor
What does retinoic acid (RA) binding to DNA receptors (transcription factors) lead to?
Modification of gene expressions
RA involved in early embryonic development
What are the symptoms of vitamin A deficiency?
Dry cornea and eventual blindness (xerophthalmia) Night blindness (insufficient retinal for rhodopsin formation) Impaired immune function
How many people affected by vitamin A deficiency?
750 million
What are vulnerable groups for different vitamin A deficiencies?
Children from 6 months to 6 years
Pregnant women
Lactating women
What countries have highest vitamin A deficiencies?
Developing countries; Africa, Asia, western pacific
39
How many children develop xerophthalmia?
5-10 million
What changes GGPP (geranylgeranyl-PP) to phypotene + 2 pyrophosphates?
Phytoene synthase (PSY)
What changes phytoene + 2 pyrophosphates to c-carotene?
Phytoene desatorase
What changes c-carotene to lycopene?
Zeta carotene desaturase
Carotene isomerase
What changes lycopene to b-carotene (pro-vitamin A) and a-carotene?
Lycopene cyclase (LCY)
Where does the carotenoid pathway occur?
In chloroplasts
Which enzyme is rice endosperm?
Lycopene cyclase (LCY)
What is gene 1 in golden rice?
PSY daffodil
What is gene 2 in golden rice?
Gene from bacteria erwinia=
carotene desaturase 1 CRT 1
What is the ingo potrykus idea?
To increase the b-carotene content in rice grain (endosperm) because it’s a staple food source, by using genetic engineering, or a reconstitution of carotenoid pathway in rice endosperm
Genetic engineering process?
DNA -transcription RNA -translation Protein Trait
How do you add genes into a plant genome?
Hijack a natural process: eg agrobacterium tumefaciens (a natural genetic engineer)
What is transferred from Ti plasmid on the bacterium to the plant genome?
Everything between the LB and the RB on the T-DNA (transfer DNA)
What’s in the left border sequence?
Promoter; glutelin
ATG; coding sequence; PSY
Terminator poly-A tail
What’s in the middle gene 1 sequence?
Glutelin
Choloroplast targeting signal
CRT 1
What’s in the third gene for golden rice?
355 (promoter)
Encode for resistance to antibiotic or herbicide
Example of possible encodings?
Kanamycin
Hygromycin
What is a 355 gene do?
Expresss gene everywhere aka a constitutive expression
What are the results of the golden rice experiment?
Increased levels of b-carotene
Didn’t have high enough levels of carotene to supply provitamin needs
What did the second golden rice use?
PSY gene from maize
Limitations of golden rice?
Not enough to meet daily recommended amounts (GR2)
People also require zinc and other elements in their diet
Limitations from culture and tradition
