Biology Assessment 2 – Flashcards

Organic molecules are the molecules which exist in all living things. They are life's building blocks. All things are formed from these organic molecules.

There are four categories of organic molecules: Carbohydrates, lipids, proteins and nucleic acids.

Organic molecules have four common characteristics. First, they are all carbon based, meaning they all contain carbon.

They are formed from just a few elements which join together to form small molecules which join together, or bond, to form large molecules.

The third characteristic of all organic molecules is that each is kind of organic molecule is built from a single type of building block. When these building blocks are joined together, they form a large molecule (polymer), just as bricks joined together form a wall.

For example, the building block of carbohydrates is sugar, the building block of lipids is fatty acids, the building block of protein is amino acids and the building block of nucleic acids is the nucleotide.

A polymer is a more complex molecule created by forming monomers together.

The last common characteristic of all organic molecules is that their form determines their function. That means that their shape determines how they will behave and how they will react with other molecules.

They are all carbon based. They are formed from just a few elements which join together to form small molecules which join together, or bond, to form large molecules. The third characteristic of all organic molecules is that each is kind of organic molecule is built from a single type of building block. The last common characteristic of all organic molecules is that their form determines their function. That means that their shape determines how they will behave and how they will react with other molecules. For example, the order of amino acids in a protein will determine the shape and function of the protein just as the order of words in a sentence shapes the meaning of the sentence.

They are made from carbon, hydrogen and oxygen.

Their building block a single sugar called a monosaccharide.

The building block of carbohydrates that consists of carbon rings.

Sugars (monosaccharides) consist of carbon rings.

When two monosaccharides, or sugars, combine, they form a disaccharide (di = two).

When more than two monosaccharides join together, a polysaccharide (poly = many) is formed.

The first is starch. The second is glycogen. The third is cellulose.

Starch is a carbohydrate used in food storage in plants.

Glycogen is used for food storage in animals.

Cellulose is used for structural support in plants (stems, leaves).

Potatoes, pasta and rice are rich in starch. Starches are very valuable because they provide a quick form of energy for the body.

Lipids are a class of organic molecules which includes fats and oils, and has the function of long-term storage of energy in the body.

Saturated fat, unsaturated fat

The building block of lipids is the fatty acid, which is a chain of carbons with hydrogen attached to each side.

Saturated fats have two carbons attached to each carbon (except the one at the end).

Lipids are soluble (dissolve) in oil but are insoluble (don't dissolve) in water. When mixed with water, the lipid will float on top to form a separate layer.

To test for the presence of lipids in food, the sample is placed on a piece of brown or newspaper, and then the paper is held up to the light. A test that is positive for lipids will have a oily spot that is translucent, or clear, on the paper.

Proteins are organic molecules that form muscles, transport O2 (hemoglobin), and act as hormones and enzymes. Most importantly, proteins determine how our bodies look and function.

Amino Acids

Proteins are made of amino acids combined through a dehydration link called a peptide bond.

Around 20

Amino acids consist of five separate parts. The first is a central carbon atom. Second is a carboxyl group (-COOH). Third is an amino group (-NH2). Fourth is a hydrogen. The fifth group is a variable 'R' group. The only difference in the 20 kinds of amino acids is the "R" group.

The sequence and shapes of the "R" groups control the shape and function of the protein.

DNA and RNA

DNA is the blueprint of life because it contains instructions on how to make proteins in the body.

RNA is a copy of DNA. Because DNA can't leave the cell's nucleus, and because proteins are constructed outside of the nucleus in the cytoplasm, the RNA is necessary to carry the instructions from DNA to the cytoplasm where the protein is made.

The monomer of nucleic acids is the nucleotide.

Nucleotides consist of three parts: a five-carbon sugar, a phosphate group and a nitrogen base.

The structure of DNA resembles that of a twisted ladder. This twisted ladder of DNA is called a 'double helix.'

The rails of the DNA ladder are made from alternating sugars and phosphates (sugar-phosphate-sugar-phosphate-sugar...).

The rails of the ladder are held together because the bases from one rail bond to the bases from the other rail to form rungs.

The rungs of the ladder are made of four different kinds of bases, with one base hanging off of the sugar portion of each rails. The four bases are A, T, C and G.

the bases from one rail bond to the bases from the other rail to form rungs. The bases from one side of the ladder attach to the bases hanging from the other rail.

T

First, where the sugar in DNA is deoxyribose, the sugar in RNA is ribose. Second, where DNA is a double helix, RNA has just one strand. Third, where the bases in DNA are C,G, A and T, in RNA the bases are C, G, A and U. The U in RNA takes the place of the T in DNA. Fourth, DNA cannot leave the nucleus of the cell and RNA can.

They are both formed from nucleotides. They both have backbones of sugar phosphate. They both serve to transfer genetic code.

CHNOPS - Carbon, Hydrogen, Oxygen, Phosphorous, Sulfur