BEDH Guide Flashcards
Benefits of Sun Exposure
Provides energy to the planet, primary biological importance is the process of photosynthesis undertaken by plants. Animals then ingest plants and use them to produce essential molecules
Photosythesis
Process by which plants trap sunlight in chlorophyll and use the energy to produce sugars and oxygen from water and carbon dioxide.
Chlorophyll A & B
Pigments in the leaves of plants that absorb light in the red and blue wavelengths which can then be used to synthesize carbohydrates
UV Exposure Dose Response Curve
Burden of disease increases if sun exposure is too high or too low. If too low, Vitamin D insufficiency and Skeletal Disease. If too high, skin cancer and eye disease.
Vitamin D
Essential nutrient for calcium uptake necessary for bone and tooth formation. Low levels of Vitamin d can lead to osteoporosis, rickets, and delayed tooth development in children.
Osteoporosis
Reduced bone calcium levels result in bones that are weaker and more prone to fracture.
Rickets
Soft bones and teeth in children caused by defective mineralization due to lack of calcium. Predominately a result of inadequate Vitamin D exposure.
Health Concerns of UV Exposure
Sunburn, Skin Cancer, Cataracts, Premature Skin Aging, Sun Allergy, and Actinic Keratosis
The Ozone Layer
The layer of the atmosphere comprised of Ozone, which is vital for absorbing UV light.
UV-A
Ultraviolet wavelength which travels through the ozone layer unimpeded
UV-B
Ultraviolet wavelength mostly blocked by the ozone layer except for the longer wavelength portion
UV-C
Ultraviolet wavelength most harmful, almost entirely absorbed by the Ozone layer in the atmosphere
Ozone
Continuously regenerating O3 molecules which absorb the energy of ultraviolet light when they are broken apart.
Chlorofluorocarbon (CFC)
Type of Haloalkane. They are harmful to the ozone layer because they introduce chlorine into the atmosphere which binds with O2 in the Ozone layer and prevent it from reforming O3.
Freon
A type of chlorofluorocarbon (CFC) that is odorless, colorless, nonflammable, noncorrosive, and safe to breathe. Invented in 1931 by Dupont Chemical to replace the previously used toxic refrigerants.
Ozone Hole
Depletion of Ozone over Antarctica and more recently, the Arctic. Result of the release of Chloroflurocarbons (CFCs) into the atmosphere.
How does UV light damage DNA?
Absorbed UV energy breaks molecular bonds of pyrimidines, which then erroneously reform, creating a pyrimidine dimer. This prevents that nucleotide from functioning as an information molecule and results in a base error when replicated or transcribed.
Basal Cell Carcinoma
Affects the lowest layer of cells, common but not very deadly
Squamous Cell Carinoma
Affects upper layers of skin cells, common but not very deadly
Melanoma
Rarest and most dangerous form
Melanocyte
Cells which produce Melanin
Melanin
Protects us from UV light by absorbing part of the UV spectrum so that it can’t damage DNA in the nucleus of the cell
SPF formula
SPF “Y” = 1/”Y”th of the sunburning energy allowed through.Minutes to burn = Normal burn time x “Y”
Nucleotide Excision Repair (NER)
Mechanism of repair which is to excise (remove) the damaged part of the DNA
Xeroderma Pigmentosum (XP)
Individuals who are not good at repairing damaged DNA due to an autosomal recessive genetic abnormality. Results in sensitivity to UV radiation leading to multiple skin disorders, skin malignancies, neuro and ocular abnormalities.
Polymorphisms
Changes in protein sequence that do not destroy protein function but alter is slightly. Can confer benefit or harm depending on the nature of the mutation.
Vienna Convention on the Protocol of the Ozone Layer
1985 - scientific concerns about the ozone layer prompt governments to adopt a legal framework for action on fixing the Ozone layer
Montreal Protocol on Substances that Deplete the Ozone Layer
1987 - international negotiators adopted legally binding commitments requiring industrialized countries to reduce/eliminate ozone harming chemicals
Spina Bifida
Congenital disorder of neural tube development where there is an opening in the spinal column of the developing fetus, affecting as many as 1 in 800 infants.Types:Occulta - Vertebrae are malformed leading to opening covered by a layer of skinMeningocele - spinal fluid and the meninges protrude through vertebral openingMyelomeningocele - spinal cord exposed through the opening, partial or complete paralysisMultifactorial - genetic, environmental, folic acid insufficiency
Nutritional Deficiency Disease
Vitamin B12 deficiency is common. Water soluble, so it needs to be ingested daily. Comes from meat, fish, brewer’s yeast, dairy. Some people have genetic predisposition to not store Vitamin B12
Vitamin B12
Controls levels of homocysteine which are associated with higher risk of heart disease. Converts homocysteine into methionine. Methionine then converted into S-adenosyl-methionine and tetrahydrofolate, which is critical for DNA sythesis.