Bio Mid Term 1 Study Notes.docx

This is part of a more complicated process the retina

Info icon This preview shows pages 2–4. Sign up to view the full content.

This is part of a more complicated process. The retina is composed of rod and cone cells. The cone cells are responsible for signaling the brain when light is absorbed in order to be interpreted. The retina is composed of a photoreceptor called rhodopsin. This photoreceptor contains opsin, a protein, and retinal, a non-protein. Retinal changes its shape as light is absorbed. Opsin is responsible for sending a signal to the brain in order to interpret different wavelengths of light. In order to do this, retinal must change into is cis- conformation and stimulate opsin. 3. Organisms can sense light with the use of image-forming eyes. Light is first picked up by the eye, which then sends a signal to the brain via. Photoreceptors called rhodopsin. The brain then interprets this signal and forms an image. Eyespots are not the same as eyes. This organ is found in many invertebrates and cannot form an image. Rather than forming an image, eyespots sense the general direction of light, and because it is connected with the structures involved with movement, it sends a signal whether to move towards the light positive photoaxis or away from the light, negative photaxis. 4. Colour vision is the result of retinal changing into its cis- conformation and stimulating opsin which then singals the brain as to what wavelength of light was picked up by the eye. The type of opsin that signals the brain indicates what colour this light is. If it is S opsin, for example, the brain will know the colour is red. Missing one or two opsin would cause us to not be able to see the light that that opsin is able to see. Missing one opsin would cause one to have dichromatic vision. 5. Circadian rhythms govern the body’s natural processes. It is like the body’s own biological clock. Circadian rhythms affect our sleep habits, blood pressure, hormone release, and body temperature. If these rhythms are unsynchronized, factors that depend on circadian rhythms may become out of order, which can cause problems. 6. Light can ruin our DNA. Cells and Evolution Nucleoid: irregular structure that contains DNA of prokaryotic cells; not surrounded by a nuclear membrane Nucleus: commands cellular functions; enclosed by nuclear envelope/membrane Chromosome: structure found in nucleus that contains the cell’s genetic information Plasmid: small circular double stranded piece of DNA found in bacteria o Pieces can be transferred to other bacteria for replication
Image of page 2

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Organelle: membrane-enclosed structure in a cell that has various functions Membrane: outer layer of the cell that regulates the contents that enter and exit the cell; composed of a phospholipid bilayer Cytoskeleton: function is to support the cell structurally and provide shape o Composed of filaments: primarily microtubules , intermediate filament , microfilament Microtubules: responsible for cell movement (ie. In flagella), cell structure/shape, and also cell division; composed of tubulin Contain motor proteins such as kinesin, which walks along microtubules
Image of page 3
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern