9. sickle cell anemia is a genetic disease that affects the red blood cells. your red blood cells are typically donut shaped and have the job of carrying oxygen around your body. in people with sickle cell anemia, the blood cells become crescent-shaped and are thick and sticky. they are not as able to carry oxygen, and can even get clogged in the blood vessels blocking the flow of blood, and therefore oxygen to organs, causing pain and organ damage. sickle cell is caused by a genetic mutation that changes a single glutamic acid to valine in the 6th amino acid position. examine the codon chart provided above (for #s 3-5), and determine what mutation likely occurred to cause the change from glutamic acid (glu) to valine (val). to get you started, it is to know that a person with no sickle cell at amino acid #6 has a dna code of ctc. (4pts) normal rna: gaa or gag, normal amino acid made: glu mutated rna: mutated amino acid made:

Mutated RNA: GUU, GUC, GUA, GUG   Mutated amino acid made: VAL

lets get this bread mom

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!