I have a COLD!

When we learned about the immune system we learned that the body has many defense mechanisms in order to protect itself. For example mucus! Mucus coats your body cavities that are exposed to the environment like your GI tract, respiratory tract, and reproductive tract. This mucus can help trap particles, fight pathogens, and moisten the air that we take in. But I have a cold and I want to know why my nose doesn’t stop running! Well basically my airways are inflamed. Woooo! So like I mentioned before mucus helps fight off pathogens, like the common cold. Your immune system activates the inflammation when it detects a pathogen, and it increases its mucus production. Even though I have to use a tissue every 4 seconds, and my nose turns bright red this mucus is helping my body fight the cold. GO MUCUS!!!!

But I think I am going to go take some cold medicine : )

Storing Protein for Growth!!

We all know that our bodies require certain amounts of proteins. Certain animals like the Adelie penguin from Antarctica molt or grow new feathers yearly. Their feathers are like puffy winter coats that help them sustain a constant body temperature. So when they don’t have this insulation they cannot go into the freezing ocean to feed or swim, they must remain on land. So how do they survive the time period of about the 20 days it takes for them to restore their feathers? Before the penguin molts it amplifies its muscle mass (A JACKED PENGUIN : D ). Then during those 20 days where the feathers are growing back the penguin survives by breaking down the extra muscle protein. This extra protein provides the penguin with the amino acids it needs to grow new feathers. What an awesome adaptation!

A cool picture of a molting King Penguin : http://www.galenfrysinger.com/penguins.htm

Tropisms!!!!!!

WOOOO!!! Let's discuss TROPISMS! First, let's define what the word means.

Tropism- The growth of a biological organism, usually plants, in response to environmental stimulus. A definition never really hits it on the nail, so we'll discuss three types of tropisms.

1. Phototropism (no, there is no "h" in the word) is a plant's response to light. When the shoots grow towards the light, it's called positive phototropism. When the shoots grow away from the light, it's called negative phototropism. When the apical meristems on all sides of the plant absorb equal amounts of light the plant grows evenly; however, when light is only absorbed by apical meristems on one side of the plant, it will grow towards the light.

http://www.yksd.com/distanceedcourses/Courses09/Biology/lessons/FourthQuarter/Chapter13/13-1/images/II17phototropism1.gif

2. Geotropism is a plant's response to gravity, the roots always grow down through the soil from the seed no matter how you plant it.

http://www.omegagarden.com/images/photos/geotropism.jpg

In this image you will see 3 types of Geotropism.

• The first seed, which is planted sideways shows Transversal Geotropism, where the root extends sideways and pushes down through the soil due to gravity.
• The second seed, which is planted upside down shows Negative Geotropism, where the root pushes up and then pushes back down into the soil due to gravity.
• The third seed is planted normally, it shows Positive Geotropism, where the root grows straight down and pushes through the soil due to gravity once again.

3. Thigmotropism is the plant's response to touch or contact.

http://www.alphadictionary.com/images/flytrap.gif

I thought this image was a very good example of thigmotropism. As you can see, once the insect makes contact with the plant, the plant traps the insect for some good old NUTRITION!
That's really as simple as it gets. Some other plants use thigmotropism to protect themselves from predators who feed on their surfaces by closing their leaves.

Success!

Plant Growth

One of the things that seems most interesting when it comes to plant growth is indeterminate growth! Unlike humans, plants are able to start, speed up, or completely stop growth depending on weather. If the weather is not suitable for the plant to grow in, a certain plant hormone called Abscisic Acid will slow down growth. This hormone is more abundant during times of stress (like harsh weather). It makes sure that the seed doesn't germinate (develop) at the wrong time, and protects growing plants by suspending growth temporarily.

Plants have other hormones that are involved in growth as well. Cytokinins for example stimulate cell division and influences organ development. This hormone however, has no effect if used independently; it needs to be used with Auxin (another hormone) to be effective and activate growth. The amount of Cytokinins and Auxin determines whether the roots and shoots develop.

Auxin is a growth hormone that elongates the cells of a plant; it breaks down cell walls to make them more flexible for stretching and elongation. When Ethylene (a plant gas that makes fruits age faster and more ripe) works with auxin, it inhibits elongation of roots, stems, and leaves; meaning growth is slowed down. However, when one apple is rotting, for example, it will release Ethylene, exposing the gas to the environment and other apples. The other apples will therefore age faster, become more ripe, and eventually rot as well.

Lastly, the Gibberlin hormone promotes growth in embryo's of seeds and helps break their dormancy at the appropriate time. BASICALLY, these hormones can either speed up, slow down, stop growth or break dormancy of seeds and plants. Imagine if humans had these hormones!!!!!!!! I would love to speed up the next two months and get over with the AP exams !!! The stress!!!!! Hope this blog was informative! :D

Overview Of Cytokinins

The cytokinin hormones promote cell division (cytokinesis) and tissue growth (organogenesis or organ development). This depends on the presence of auxins (another plant hormone) to determine the level of their activity. Without auxin cytokinins do not function. When the ratio of cytokinins to auxins is relatively high, stem and leaf growth is stimulated. When, on the other hand, the ratio of cytokinins to auxins is relatively low, root growth is stimulated instead. The balance between these hormones makes sure that the plant invests in both root and shoot growth, so that neither becomes too large or small for the other. Cytokinins are also involved in the development of cholorplats, fruits, and flowers. Also, they have been shown to delay senescence (aging), especially in leaves, which is one reason that florists use cytokinins on freshly cut flowers. Coconut milk has a high level of cytokinin present and a little trick to keep your plant's alive longer is to spray coconut milk on them. This is a way florists use the cytokinins on their plants to delay their aging process. Try it out sometime and see how much longer your flowers stay alive. :-)

Plants Are Metropolises. Organic, Green Metropolises.

It's no mystery that in terms of overall structure, what separates plant cells from the cells of other organisms is the cell wall. Knowing that, it's also no mystery that those walls play huge parts in plant cell function and differentiation. Such is so for the 'chyma cells. While parenchymas happen to be the seeming structurally blandest and yet the most functionally flexible with their thin primary walls and lack of secondary walls, their smaller counterparts, elongating collenchyma and lignin-secured sclerenchyma have thick cell walls perfect for their rolls as support cells. The other half of the spectrum belongs to cells that are essentially advanced delivery shoots. Thick-walled tracheids and vessels are tubes that are dead at maturity, and use "end walls" to transport water. Their cousins, or whatever you'd call them, ribosome and nucleus-lacking sieve-tubes, use similar "end walls" to transport various nutrients such as sugar. Just imagine what life would be like if our cities cleaned themselves, protected themselves, repaired themselves, and transported materials themselves like plants do.

Hormones

I made a new post. Easier to say that than to post it here.

Transport of Water

Water is essential in a plant. There are two pathways water can take to move toward the center of the roots. One pathway is symplast. Water in this pathway moves from the cytoplasm through the plasmodesmata to the cytoplasm of the next cell. Another pathway is apoplast. This is when water moves through intracellular spaces from one cell to another without entering the cells. However, when the water reaches the endodermis in the apoplast pathway it can no longer continue into the vascular cylinder. It can only do this by traveling through the symplast pathway. This occurs because of casparian strip. This strip is made of suberin walls which blocks the apoplast pathway.

Sugar Transport in Plants!

The pressure flow theory! The pressure flow theory is the mechanism by which sugars are transported through the phloem from the leaves (sources) to the roots (sinks). Leaves are called the sources because the sugars are made there and the roots are called the sinks because the sugars are stored there. At the sources, sugar molecules are transported into the sieve-elements (phloem cells) through active transport (the movement of a substance across a biological membrane against its concentration gradient with the help of energy input). Water flows the sugar molecules into the sieve elements through osmosis (since water passively diffuses into areas of higher solute concentration). This water creates tugor pressure (the force directed against a cell wall after the entering of water and swelling of a walled cell due to osmosis). This forces the sugars as well as fluids down the phloem tubes toward the sinks. When at the sinks, the sugars are actively removed from the phloem therefore creating the water to flow osmotically. This is so that the conditions of high water potential and low tugor pressure, which causes the pressure flow process, which enables and creates the transport of sugars throughout the plant so that the sugars can be used for the plant's metabolism. I hope this helped everyone better understand the pressure flow theory and the transport of sugar in plants !

Photosynthetic Chasms of Wonderment

I recalled the day of class when Ms. Aber asked us to discuss what adjustments would have to be made and what would be the mental repercussions of switching bodies with plants. Then I asked myself, what if we didn't switch bodies with plants, but by various mechanisms of karma--probably the same ones which made it possible for plants to have conscious thought--we switched lifestyles with plants? What if plants were physically permitted to move about even with the fragility of their limbs under their weight, and we had to stay in one place our entire lives? Would you be able to process the concept of plants simply walking and/or sliding to springs and fountains and literally just soak their roots in them for a bit? Would you or they ever get used to the idea of trees running from giraffes? How would they know where to go? Eyelessness! Would we begin to leave our self-induced evolutionary stasis and find new limbs selected for us? Or, being masters of adaptation, would human beings just change the direction of technology to adjust to the new condition? Or...would we become......EXTINCT!

Opening And Closing of the Stomata

At first I did not fully understand the opening and closing factors of the stomata. We understand that the stoma are pores on the epidermal layer of leaves, where gas exchange occurs. This gas exchange is where the plant takes in carbon dioxide and releases water and oxygen. We must now understand how these pores open and close and the contributing factors. The kidney shaped guard cells are the cells that physically open and close the stomata. When Potassium ions (K+) diffuse into the guard cells from the surrounding cells, this sends a signal to open the stomata. This is due to the concentration gradient that is formed by the K+ when there are less free water molecules inside the guard cells. (We know water flows from areas of high concentration to low). The opposite happens in order to close the stomata. This time the K+ diffuse out of the guard cells, again forming a concentration gradient in the opposite direction. What was stomata with me? :D This concept is easy now!!