biol 1101 lab 7: UV light, mitosis, and melanoma

uv light

sunlight energy which is a type of electromagnetic energy (radiation)

what are the two types of electromagnetic energy?

wave-like or particle-like

what is energy of light determined by?

wavelength

what kind of relationship do wavelength and energy have?

inverse

shorter the wavelength the greater energy the wave has

larger the wavelength the less energy the wave has

what is visible light?

380-750nm

type of light seen by our eyes

what is ultraviolet light?

200-400nm

contains enough energy to damage proteins and nucleic acids

what is UVA (uv light)

400-320nm

penetrates deeper layers of our skin, can cause cancer

what is UVB (UV light)

what is UVC

290-200nm

absorbed by atmosphere’s ozone

which UV light has more energy?

UVC, however since most is absorbed by the atmospheres ozone it is UVB and UVA we must concern ourselves with

sun protection factor (SPF)

measure of how long a person who has applied a sunscreen can stay in the sun without burning

SPF 15

stay out in the sun 15 times longer

SPF 30

stay out in the sun 30 times longer

SPF 50

stay out in the sun 50 times longer

how long can i stay out in the sun for?

SPF x the amount of minutes= how long you should be able to stay out in the sun for

melanocyte

cells in the skin that produce melanin

melanin

acts as a natural sunscreen (about 2 SPF)

how does a tan build?

pigments accumulate forming a tan

melanoma

type of skin cancer that starts in your melanocyte cells

most common in people aged 25 to 29

can be bigger than a mole, with jagged edges, raised dark spots

accumulation of mutations can cause

cell cycle protooncogenes to become super active (oncogenes)

build up of mutations can cause

cell cycle tumor suppressors to become not functional

how can you get melanoma?

can be genetically predisposed meaning that you can inherit a mutation in your cell cycle genes from parents

malignant tumor

mass of abnormal cells whose growth cannot be controlled by regular mechanisms, often spreading to other parts of the body

not all tumors are cancerous:

benign tumor

cell cycle

series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells

interphase

non-dividing stage of the cell cycle

mitosis

part of cell cycle where a cell divides its chromosomes to prodcue two identical nuclei

prophase

nuclear membrane disassembles, chromosomes become visible, centrioles migrate to opposite poles

metaphase

spinal apparatus completely formed and spindle fibers attached to chromosomes, chromosomes lined up at the equator

anaphase

centromere divides allowing the sister chromatids to begin to move apart. chromosomes move to respective pole

telophase

chromosome reach poles and uncoil, nuclear envelope begins to reform

cytokinesis

part of cell cycle where a cell divides its cytosol to produce two identical daughter cells

what do plants form at equator

cell plate

what happens with animals during cytokinesis

cleavage furrow where plasms appear to pinch at equator