Class Notes (810,488)
Canada (494,139)
York University (33,691)
Biology (2,149)
BIOL 1000 (375)

Light and Life

5 Pages
Unlock Document

York University
BIOL 1000
Michael Gadsden

Biology 1010 Lecture 1  Light and Life o Light provides energy for life o N , H , O 2 2 2 o Must put everything into perspective (essentially must know all that’s going on around you)  EG Trees could hold bacteria to cure cancer etc. Notice all that’s around you. o What is masked? (if someone is colour-blind they see nothing) o Observe how are things are different than the background o All life depends on the sun, photosynthesis to food o Capture sunlight and use it in different ways  ATP o The energy is released when the bonds are broken o ATP  ADP + Pi(SEE SHEET 1) o Not magical radiation o Bond breaks to allow the energy to be used somewhere else o Takes up lots of space (large molecule therefore it moves things around when it is placed in certain areas) o If it binds, it moves things (due to size as well as negativity) o It is negative therefore it will attract or repel things  Pigments o As stated PIGMENTS CAPTURE LIGHT o 2 different membranes (this is talking about chloroplasts) o Chlorophyll is in the thylakoid o Beta-carotene is VITAMIN A o Lots of ring structures (ring structures are what absorbs light) o Aromatic rings because of the double bonds o Ringed carbon structures in large molecules absorb light  The light Spectrum o Wavelength is inversely proportional to energy (λ ~ 1/E ) o Violet = high energy o Red = low energy o UV light has massive effects on life o EM waves travel perpendicular to each other (One about the xy – plane, another about the xz or yz – plane) o Wave is made of the path of photons (particle of light) o Photon is equal to an electron in mass and energy and have different levels of energy o Photons are absorbed by electron orbitals of similar energy o If red, green and blue light hit a particular spot of chlorophyll :  The red will excite electrons to a slightly higher level  Blue excites it to an even higher energy level  The green is either passed through or reflected and therefore plants look green o With chlorophyll the high energy electrons get passed on and start a cascade to perform photosynthesis  “PROOF” o O 2as is a product of photosynthesis o The peak photosynthesis are occurring at 425 nm (Blue) and at 700 nm (red) o Green stimulates minimal photosynthesis  575 nm (green) stimulates a little photosynthesis in this system due to:  Experimental error  Other pigments (may use green light and release something else)  Chlorphyll will only absorb a little light at 575 nm  Light is used as a source of information o VISION! o Chlamydomonas is a unicellular eukaryote  Eyespot is a patch of proteins (etc.) and pigment s that absorb light o Photomorphogenesis is the use of light to change and grow  Proteins + pigment  a response  In some cases, changing the pattern of “gene expression” (which genes *on DNA] are used to make protein) o Rhodopsin  A protein  The light changes the structure in retinal (changes from cis to trans)  Retinal changing structure causes (de)activation of other structures  Retinal – See sheet 2  EYES! o Eyes and brain must co-evolve o Flatworm (Planaria)  Light reaches photoreceptors from one side, cup on the other  Eyespots connected to Planaria’s nervous system o Insects  Sections of the eye and the photoreceptors are multi-cellular o Higher Animal  Retina and corneal as well as the lens used to focus and things like that  This is much more advanced, used to tell where light is coming from, etc. o Flat  all the photoreceptor cells can just detect the presence of light with minimal directionality. o Eyecup  allows organisms to determine direction (essentially “where is the light coming from”)  GOING TO the light means something is photosynthetic  MOVING FROM the light means it is prey so they can hide in the dark  Most evolved eyes  best resolution o
More Less

Related notes for BIOL 1000

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.