Nucleic Acids and so on....

Nucleic Acids

Nucleic acids form from polymers of nucleotides, molecules composed of a phosphate group, a five-carbon sugar, and a nitrogenous base. Five different nitrogenous bases exist:

Adenine
Guanine
Cytosine
Thymine ( only in DNA)
Uracil ( only in RNA)
DNA and RNA are nucleic acids that function in protein synthesis and the storage and transmission of genetic information.

Proteins

Proteins consist of one or more polypeptides, polymers of amino acids folded into complex three-dimensional shapes. An amino acid is a small molecule made up of a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a functional group labeled “R.” Twenty different amino acids exist, each formed with a different R group. Polypeptides form when amino acids bond together in long chains. The twenty different amino acids can produce a diverse range of proteins, including enzymes, hormones, cell receptors, antibodies, transport proteins, storage proteins, motor proteins, and structural proteins, which perform a wide range of vital tasks in organisms.

All proteins have either three or four structural levels:

Primary structure refers to the sequence of amino acids that form the polypeptides.
Hydrogen bonds in single groups in a polypeptide chain result in a folded region referred to as the secondary structure. Secondary structures include helices (coils) and sheets (pleated folds).
The tertiary structure describes the folding of an entire polypeptide chain. Interactions between the R groups of the polypeptide chain determine the overall shape of the tertiary structure.
Interaction between two or more polypeptides forms the quaternary structure. Since some proteins consist of a single polypeptide, not all proteins exhibit quaternary structure


Protein Structure
Carbohydrates


Carbohydrates include both monosaccharides (also called simple sugars or simple carbohydrates) and polysaccharides (also called complex carbohydrates). Monosaccharides and polysaccharides perform different functions in organisms:

Monosaccharides, which include glucose, fructose, and lactose, provide cells with energy.
Polysaccharides, which include glycogen, starch, and cellulose, store energy and provide structural support to an organism.
Lipids

Unlike the other macromolecules, lipids are not composed of repeated monomers and therefore are not true polymers. Lipids exhibit a range of structural diversity, but all are nonpolar and therefore insoluble in water. Lipids include the following molecules:

Fats: store energy for future use in biological functions
Phospholipids: make up the cell membrane
Steroids: act as chemical messengers in an organism

Water/ H2O

Water is the most abundant molecule present in all living organisms. All chemical reactions within an organism take place in the presence of water. Several characteristics unique to water contribute to its vital importance in the processes of life, such as its properties as a solvent and tendency to form ions.

Water as a Solvent

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Solvents dissolve other molecules, called solutes, to form solutions, which are homogeneous mixtures of molecules. The hydrogen bonds that hold water molecules make water a versatile solvent that can form solutions with polar (hydrophilic) molecules. Water cannot form solutions with nonpolar (hydrophobic) molecules.


Water Ionization

Occasionally, water molecules spontaneously ionize, or break apart, into hydroxide ion (OH-) and hydrogen ion (H+), as illustrated in the following chemical equation.


The pH scale, which ranges from 0 to 14, expresses the relative concentrations of OH- and H+ in a solution. The pH value determines whether a solution is acidic, basic, or neutral:

Neutral solutions have equal concentrations of OH- and H+ and a pH of 7.
Acidic solutions have a greater concentration of H+ and a pH of less than 7.
Basic solutions have a greater concentration of OH- and a pH of greater than 7.
Acids lower the pH of solutions, while bases raise the pH. Buffers are substances that reduce the effect of acids and bases on the pH of a solution.

Calculating pH

The pH of a given solution expresses the negative logarithm of the hydrogen ion concentration, as represented in the following equation.

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pH = -log[H+]

For example, the [H+] of wine equals 10-3. Because the negative logarithm (represented by the exponent in this equation) is three, wine pH = 3 and is therefore acidic.

The scientific method

The Scientific Method

Biologists, like all scientists, conduct their research using the scientific method. The scientific method is a standardized way of making observations, gathering data, forming theories, testing predictions, and interpreting results.

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Researchers make observations to describe and measure biological states and behaviors. After observing certain events repeatedly, researchers come up with a theory that explains these observations. A theory is an explanation that organizes separate

pieces of information in a coherent way. Researchers generally develop a theory only after they have collected a great deal of evidence and make sure that their research results can be reproduced by others.

Biological research, like research in other fields, must meet certain criteria to be considered scientific. Research must be:

Replicable
Falsifiable
Precise
Parsimonious
Replicable

Research is replicable when others can repeat it and get the same results. When biologists report what they have found through their research, they also describe in detail how they made their discoveries. This way, other biologists can repeat the research to see if they can replicate the findings.

After biologists conduct their research and make sure it’s replicable, they develop a theory and translate the theory into a precise hypothesis. A hypothesis is a testable or observable prediction of what will happen given a certain set of conditions. If further tests or observations do not confirm the hypothesis, the biologist revises or rejects the original theory.

Falsifiable

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A good theory or hypothesis must also be falsifiable, which means that it must be stated in a way that makes it possible to reject it. In other words, other researchers have to be able to prove a theory or hypothesis wrong. Theories and hypotheses need to be falsifiable because all researchers can succumb to the confirmation bias. Researchers who display confirmation bias look for and accept evidence that supports what they want to believe and ignore or reject evidence that refutes their beliefs.

Precise

By stating hypotheses precisely, researchers ensure that they can replicate their own and others’ research. To make hypotheses more precise, researchers state exactly how their research has been conducted.

Parsimonious

The principle of parsimony, also called Occam’s razor, maintains that researchers should apply the simplest explanation possible to any set of observations. For instance, biologists try to explain results by using well-accepted theories instead of elaborate new hypotheses. Parsimony prevents researchers from inventing and pursuing outlandish theories.

Essential life functions

Transport: refers to processes which cause heat Energy, or particles, or something else, to flow out of the plasma and cease being confined. Diffusion partly determines the rate of transport. Energy losses from a plasma due to transport processes are a central problem in fusion energy research.
Excretion:
something excreted;esp:useless,superfluous,or harmful material(as urea)that is eliminated from the body and that differs from a secretion in not being produced to perform a useful function.
Regulation: how organisms control body processes- hormones, nervous system
Respiration: Respiration can occur with or without oxygen, aerobic ( with oxygen) and anaerobic ( without oxygen) respiration respectively.
Nutrition: how oranisms break down and absorb foods.
Synthesis: how organisms build neccessary molecules.
Reproduction: Sexual versus asexual, eggs, seeds, spores, placental, types of fertilization
Growth and Developement: metamorphosis, developement in egg or in uterus, growth from seed or spore.

Who lives on planet Earth?

What is an animal? evolved from colonial, flagelleted protist, starting in the precambrian sea.
Symmetry: There are two basic designs, radio symmetry and bilateral symmetry. Radio symmetry is like a starfish that has a single disk that radiates out into extra appendages. Bilateral symmetry is like a human where if you cut it down the middle it would be exactly the same on both sides.

Animals are multicellular, heterotrophic( does not make its own food), eukaryotes.
They ingest and have unique tissues
They lack cell walls that provide structual supports for plants and fungi.
Diploid stage usually dominates their life cycle.
All animals reproduce sexually and some can also reproduce asexually.
Phylum Chordata: must have gill slits, mucsles, notochord, adn a post anal tail