Describe how a nephron works. How is this similar to counter currents or hydrostatic skeletons?

     The nephron is the basic unit of the kidney. It is a long thin tube that is closed at one end, and has two twisted regions inter spaced with a long hairpin loop, and ends in a long straight portion that is surrounded by capillaries. The parts of a nephron are the bowman's capsule, proximal convoluted tubule or proximal tubule, loop of henle, distal convoluted tubule, and collecting duct. The bowman's capsule is the closed end at the beginning of the nephron. The proximal tubule is the twisted region located right after the Bowman's capsule. The loop of the Henle is a long hairpin loop after the proximal tubule and extends from the cortex down to the medulla and goes back. The distal tubule is the other twisted portion of the nephron after the loop of henle. The collecting duct is a long straight portion after the distal tubule that is open and extends from the cortex to the medulla. Every part of the nephron has different cells with different properties. In the nephron, about 20 percent of the blood gets filtered under pressure through the walla of the glomerular capillaries and Bowman's capsule. The filtrate has water, ions,glucose and small proteins. Inside the nephron is the lumen where small molecules such as ions, glucose and amino acids get absorbed from the filtrate. The transporters grab only one or two small molecules from the filtrate.

     In hydrostatic skeletons, pressure of fluid and the action of the surrounding circular and muscles are used to change an organisms shape and produce movement. This is very similar to kidney filtration. Inside the nephron about 20 percent of blood is filtered under pressure through the walls of the glomerular capillaries and Bowman's capsule. The higher the concentrations of the substance in blood, the greater the amount filtered or the greater the filtration rate, the more substances gets filtered.

Blog 3 Starfish

     The starfish is in the phylum Echinodermata, it has 5-rayed symmetry, mostly, radial, and sometimes bilateral. The first echinoderms did not have any radial symmetry showing hat this characteristic was acquired later in the group's evolution. a number of echinoderms are distinguished from other phyla because they have radial or occasionally bilateral symmetry. There are five planes of symmetry. The body of an echinoderm has three layers. The epidermis is the outer layer, and it is a single layer of cells which covers the entire animal. The middle layer is thick and is called the dermis. It is composed of connective tissue and the exoskeleton. The exoskeleton has three different forms; a set of closely joined plates with individual movement, a set of separately free moving small pieces  called ossicles, and a collection of widely separated microscopic ossicles lying in the dermis. The third layer is a single layer of cells that are ciliated. This layer encloses the animal's coelom separating the animals guts from its skin. The starfish has a poor defined open circulatory system. They reproduce normally sexual and gonochoristic. A starfish may eat over a dozen oysters or young clams a day. Echinoderms are filter feeders, substrate eaters, or carnivores. In the Crinoidea the gut in U-shaped and the mouth and anus on the same surface. In others it is straight- through gut with the mouth and anus on opposite sides of the body. The nerves that are running all over the body are in connection with those of the sub-epidermal nerve net. They also use tube feet as organs of respiration.

Crinoidea

 

 

 

 

Ophiocistioidea

Astroidea

Echinoiudea

Holothuoidea

Source: http://www.earthlife.net/inverts/echinodermata.html

Genome Chapter 1 Summary- Life

In this chapter the author refers the word as RNA, not DNA. DNA is an analogous to written languages and its own alphabet. Then the history of life is talked about starting with RNA because it became before DNA. RNA is is unstable so it was possible for it to come up with DNA through a trial and error process because RNA was faster, more accurate, and more reliable. Then LUCA is introduced as a bacterium living in a hot marine environment, but is now more of a protozoan because bacteria would have had to drop the extra RNA in order to reproduce more quickly. The history of life is basically written in the genome.

Source: http://tchefty.edublogs.org/files/2011/06/DNA-versus-RNA-1zyhmjx.gif

Describe double fertilization.

     Double fertilization is a process when a diploid zygote and a triploid endosperm form in flowering plants. Fertilization takes place between sperm cells and two cells within the ovule. The megaspore in the ovule is diploid and undergoes meiosis to produce four haploid megaspores. The surviving megaspore undergoes three rounds of mitosis to produce eight haploid nuclei. the eight nuclei share the same cytoplasm before cytoplasmic divisions start, this is called the embryo sac.

      In the embryo sac, cell walls form between the nuclei. Three cells form opposite the micropyle opening of the ovule and another three from near the micropyle. Two are called synergids and the other an egg. The polar nuclei (two nuclei) remain together in one large central cell. The egg, single cell, and two polar nuclei be in the process of double fertilization. But first the sperm travels to the cells by a pollen grain landing on the stigma, beginning to germinate, and sending a long pollen tube through the style and ovary. A haploid cell travels down the pollen tube, behind the tube nucleus, and divides by mitosis to produce two haploid sperm cells.

     The pollen tube reaches the micropyle of the ovule and gets into one of the synergids by digesting itself, releasing the sperm cells. The synergid degenerates and a sperm cell fertilizes the egg cell producing a diploid zygote. The other sperm cell fuses with polar nuclei fertilizing them to produce a triploid cell. The zygote will develop into an embryo, and the triploid cell into an endosperm. This will serve as the embryo's food supply.

source: http://bcs.whfreeman.com/thelifewire/content/chp39/3902001.html

EXTRA CREDIT BLOG

What topics really confused you?
The chemistry parts were confusing because I wasn't very good in chemistry in the first place. Because I was already confused about the topic I didn't understand much about this lesson.

What topics do you feel very clear on?
Photosynthesis and cellular respiration because those are the ones that I've learned the most about in other classes too. So some of the material we learned was familiar to me and I didn't feel totally lost.

What lab/ activity was your favorite? Why?
My favorite lab of the semester was the transpiration lab mostly because it was my groups lab and we all knew what to do. I felt really prepared for this lab and I understood the steps of the lab. I also felt like it was pretty easy to understand the steps everything was clear on what to do.

What lab/activity was your least favorite? Why?
My least favorite was the Kool- Aid lab. When doing the lab I was always confused if I was doing the process right because there were many chemicals to deal with. The syringe was difficult to deal with because they were broken or we were not used to using them at all.

If you could change something about the class to make it better, for instance the type of homework (not the amount) what would it be and why?
I would change the simulations that we do online because they were confusing at times and I didn't feel like I got anything out of them. The labs are actually helpful because I remember things that I have put in my blogs, but the simulations don't help me retain any material we learn in class.