Diversity of Cells

Researchers discovered viruses by studying a plant disease. A virus is a genome enclosed in a protective coat. Viruses can reproduce only within a host cell. Phages reproduce using lytic or lysogenic cycles. Animal viruses are diverse in their modes of infection adn replication. Plant viruses are serious agricultural pests. Viroids and prions are infectious agents even simpler than viruses. Viruses may have evolved form other mobile genetic elements. The short generation span of bacteria helps them adapt to changin environments. genetic recombination produces new bacterial strains. The control of gene expression enables individual bacteria to adjust their metabolism to environmental change. Bacteria and archae are the two main branches of prokaryote evolution. Nearly all prokaryotes have a cell wall external to the plasma membrane. Many prokaryotes are motile. The cellular and genomic organization of prokaryotes is fundamentallly different form that of eukaryotes. populations of prokaryotes grow and adapt rapidly. Prokaryotes can be grouped into four categories according to how they obtain energy and carbon. Photosynthesis evolved early in prokaryotic life. Moleculer systematics is leading to a phylogenic classification of prokaryotes. researchers are identifying a great diversity or archae in extreme environments andin the oceans. Prokaryotes are indispensible links in the recycling of chmical elementsin the ecosystems. many prokaryotes are symbiotic. Pathogenic prokaryotes cause many human diseases. Humans use prokaryotes in research adn technology. Systemists have split protists into many kingdoms. Protists are the most diverse of all eukaryotes. Endomembranes contributed to larger, more complex cells. Mitorchondria and plastids evolved from endosymbiotic bacteria. the eukaryotic cell is a chimera of prokaryotic ancestors. secondary endosymbiosis increased the diversity of algae. Absorptive nutrition enable fungi to live as decomposers and symbionts. extensive surface area and rapid growth adapt fungi for absorptive nutrition. Fungi disperse and reproduce by releasing spores that are produced either sexually or asexually. many fungi have a heterokaryotic stage. ecosystems depend on fungi as decomposers and symbionts. Some fungi are pathogens. Fungi are commercially important. They colonize land with plants. Fungi and animals evolved from a common protistan ancestor.

Cellular Metabolism

Cellular respiration and fermentation are catabolic, energy yielding pathways. Cells recycle the ATP they use for work. Redox reactions release energy when electrons move closer to electronegative atoms. Electron "falls" from organic molecules to oxygen during cellular respiration. the "fall" of electrons during respiration is a stepwise, via NAD+ and an electron transport chain. Respiration involve glycolysis, the krebs cycle, and electron transport. Glycolysis harvests chemical energy by oxidizing glucose to pyruvate. The krebs cycle completes the energyyielding oxidation of organic molecules. the inner mitochondrial membrane couples electron transport to ATP synthesis. Cellular respiration generates many ATP molecules for each sugar molecule it oxidizes. Fermentation enables some cells to produce ATP without the help of oxygen. Glycolysis and the Krebs cycle connect to many other metabolic pathways. Feedback mechanisms control cellular respiration. Plants and other autotrophs are the producers of the biosphere. Chloroplasts are the sites of photosynthesis in plants. evidence that chloroplasts split water molecules enabled researchers to track atoms through photosynthesis. the light reactions and the calvin cycle cooperate in converting light energy to the chemical energy of food. The light reactions convert solar energy to the chemical energy of ATP and NADPH. the calvin cycle uses ATP and NADPH to convert Carbondioxide to sugar. Alternative mechanisms of carbon fixation have evolved in hot arid climates. Photosynthesis is the biosphere's metabolic foundation

Photosynthesis v. Cellular Respiration

Photosynthesis and Cellular respiration both use a H+ gradient to initiate ATP production. They also both use chemiosmosis and potential energy from the H+ gradient. Furthermore, both photosynthesis and cellular respiration convert energy to usable energy as well as making ATP. Additionally, they both use an Electron Transport Chain and some sort of final acceptor molecule. Lastly, they both use oxidation reactions and reduction reactions.

Differences of photosynthesis and cellular respiration are that photosynthesis used NADPH while cellular respiration uses NADH. Photosynthesis doesn't have FADH2 like cellular respiration does and photosynthesis is only in plants while cellular respiration is in both plants and animals. Photosynthesis needs light to work while cellular respiration does not. Cellular respiration happens in or near the mitochondria while photosynthesis happens in the chloroplast.   Cellular respiration is an exergonic reaction while photosynthesis is an endergonic reaction. Cellular respiration's products are Carbon dioxide and water while photosynthesis's products are glucose and oxygen.


references:
google images
bio book
http://www.worsleyschool.net/science/files/photosynthesis/page.html
http://www.buzzle.com/articles/photosynthesis-and-cellular-respiration.html
http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/psn_primer.html

C3, C4, and CAM

c3 plants have their stomata open during the day. Their photosynthesis occurs within and throughout their leaves. c3 is more efficient than c4 adn CAM plants because c3 plants requires less energy. Most of the plants that we encounter at c3 plants. Carbon dioxide was firts incorporated into three-carbon component


c4 plants also have their stomata open during the day. Although c3 plants are mroe efficient, c4 plants are faster than c3 plants under high light intensity and temperatures. Furthermore, c4 plants have better water efficiency. carbon dioxide first incorporated into four-carbon compound. An example of a c4 plant would be corn.


CAM plants or Crassulacean Acid Metabolism plants, on the other hand, have their stomata open during the night due to the fact that evaporation rates are lower during the night time. If the conditions are too extreme during the night, their stomata may close during that time period as well. CAM plants have better water efficiency than c3 plants under arid conditions and the carbon dioxide was first stored in the form of acid before use. An example of a Crassulacean Acid Metabolism plant would be cacti.


References:
google images
The Biology book
http://hyperphysics.phy-astr.gsu.edu/hbase/biology/phoc.html
http://www.biologie.uni-hamburg.de/b-online/e24/24b.htm
http://wc.pima.edu/Bfiero/tucsonecology/plants/plants_photosynthesis.htm

Macromolecules

1. Carbohydrates

sugar, the smallest carbohydrates, serve as fuel and carbon sources. Polysaccharides, the polymers of sugars, have storage and structural roles.
Made of carbon, bydrogen, and oxygen


Monosaccharides and Disaccharides
Ex. Glucose, Ribose, Maltose, Lactose, Sucrose
Structure: can exist as a carbon chain, or a ring. the ring form is more stable and more prevalent at equilibrium. Disaccharides are made of two monosaccharides joined by a glycosodic linkage (an oxygen atom holding two rings together)
Function: Glucose is the principle molecule used for energy production during cellular respiration


Polysaccharides
Ex. Cellulose, Starch, Glycogen, Chitin
Sturcture: Chains of monosaccharides joined by glycosodic linkages (one oxygen atom joins 2 rings)
Function: Cellulose and chitin are structural; starch and glycogen are means of storing glucose for long periods


2. Lipids

fats store large amounts of energy

phospholipids are major components of cell membranes

steroids include cholesterol and certain hormones

made of carbon, hydrogen, and oxygen

triglycerides

structure:1 glycerol molecule joined to 3 fatty acid molecules

function: used for insulation adn long-term energy storage

phospholipids

structure: 1 glycerol molecule joined to 2 fatty acid molecules and a phosphate group

function: primary component of cell membranes

steroids

Ex.: cholesterol, estradiol, testosterone

structure: 4 interlinked carbon rings with functional groups attached

function: hormonal functioning; some help control the fluidity of cell membranes

3. Nucleic Acids

 

nucleic acids store and transmit hereditary information

a nucliec acid strand is a polymer of nucleotides

inheritance is based on replication of the DNA double helix

we can use DNA and proteins as tape measures of evolution

made of carbon, hydrogen, oxygen, nitrogen, and phosphorus

DNA

structure: made of repeating units of 4 nucleotides. A nucleotide is made of a phosphate group, a pentose sugar (deoxyribose, and one of four nitrogenous bases ( adenine, cytosine, guanine, thymine) double stranded helix

function: stores genetic information

RNA

structure: made of repeating unit of 4 nucleotides. the pentose sugar is ribose rather than deoxyribe. the 3 bases are adenine, uracil, guanine, and cytosine. single-stranded

function: transfer genetic information to ribosomes for protein synthesis, carries amino acids into place, and holds ribosomal subunits together.

4. Proteins

a polypeptide is a polymer of amino acids connected in a specific sequence

a protein's function depends on its specific conformation

made of carbon, hydrogen, oxygen, and nitrogen

structure: polymers of repeating units of 20 kinds of amino acid. Amino acids are structurally similar except for one side chain that varies from acid to acid. adjacent amino acids are joined by peptide bonds. one or more polypeptide may be joined to form a protein 

function: structure, enzymes, packaging, cell to cell communication, cell recognition, immune response


Reference:
http://biomodel.uah.es/en/model3/index.htm
the Biology book 6th edition
google images

Biochemistry Unit Wordle

In the context of biochemistry, it begins from chemical elements and compounds. Life requires about 25 chemical compounds. Atomic structure determines the behavior of an element. Atoms combine by chemical bonding to form molecules. Weak chemical bonds play important roles in the chemistry of life. A molecule's biological function is related to its shape. Chemical reactions make and break chemical bonds. The polarity of water molecules results in hydrogen bonding. organisms depend on the cohesion of water molecules water moderates temperatures on Earth. Oceans and lakes don't freeze because ice floats. Water is the solvent of life. Organisms are sensitive to pH. Acid precipitation threatens the fitness of the environment. Organic chemistry is the study of carbon compounds. Carbon atoms are the most versatile building blocks of molecules. Variation in the carbon skeletons contributes to the diversity of organic molecules. Functional groups comtribute to the molecular diversity of life. 

Ecology Unit Wordle

When the word ECOLOGY comes up, I think of the ecosystem and biomes and the behavior of animals which all come together to become ecology. The different biomes and their specific characteristics causes the organisms in the area to behave a certain way. Between organisms, there is competition for food, shelter, water, etc. all of which creates their niche. These terms then relate to the organization and structure of the community. There are aquatic and terrestrial biomes and aquatic biomes occupy the largest part of the biosphere. Factors that affect the distribution of organisms are abiotic and biotic factors. Behavior has both proximate and ultimate causes which results from both genes and environmental factors. Social behavior creates competition.