Summary TEAS 6 Science Notes UPDATED

TEAS 6 Notes DNA (deoxynucleic acid) -Contains heredity/genetic material in humans and most other organism. -Each cell an organism has the same DNA -Most DNA is found in the nucleus of a cell (some in the mitochondria) -Information found in DNA is stored as a code mode up 4 chemical bases: Adenine, Guanine, Cytosine, Thymine A + T, G + C The sequence determines how the organism builds and maintains itself. -Each base pair attaches to a sugar molecule which then attaches to a phosphate molecule to form a nucleotide -Nucleotides form 2 long strands that spiral into a double helix -DNA can replicate or make copies of itself by splitting the “ladder” in half. -Each strand (half) serves as a pattern for duplicating bases. -Each new cell needs an exact copy of DNA from the old cell. Enzymes -Enzymes are highly selective catalysts that greatly accelerate the rate of reactions. -Most enzymes are proteins, but some catalytic RNA molecules has been found. -In enzymatic reactions, the molecules at the beginning of the process are known as substrates. During the reaction, they are turned into different molecules known as products. The enzyme will be unchanged. -Enzymes work by lowering the activation energy of a reaction, drastically reducing the reaction time. -Enzymes are highly specific for their substrates. Each enzyme will only bind with specific substrates that fit with its active site. -Enzymes can be affected by: -inhibitors: molecules that decrease enzyme activity -activators: moleculels that increase enzyme activity