The most astonishing thing about life is… Every single living thing on the face of the earth is made of the same 20 amino acids organized and directed by variations of the same molecule, DNA.
Life Science CONTENT STANDARD C: Asa result of their activities in grades 9-12, all students should develop understanding of 1. The cell 2. Molecular basis of heredity 3. Biological evolution
THE CELLCells store and use information to guide their functions.The genetic information stored in DNA is used to direct the synthesis of the thousands of proteins that each cell requires.
If just one of the 10 to 100 trillion cells in your body were thesize of a baseball park, the average bacterium would be the sizeof a pitcher’s mound, and the average virus would be the size ofa baseball.
THE CELLCell functions are regulated. Regulation occurs:through changes in the activity of the functions performed by proteinsthrough the selective expression of individual genes.This regulation allows cells to respond to their environment and to control and coordinate cell growth and division.
DNA model alone can be used to show (or to allow for thediscovery of) all the features of DNA that are important ingrades 5-12: That DNA is made up of four different nucleotides
The nucleotide parts: sugar, phosphate, and base
DNA model alone can be used to show (orto allow for the discovery of) That the double helical structure: derives from the shapes and bonding of the nucleotides , and occurs only when two DNA chains join base to base and are antiparallel QuickTime™ and a decompressor are needed to see this picture.
Replication of DNAby strand separationand laying down ofnew nucleotides alongthe separated strands.
DNA model alone can be used to show (orto allow for the discovery of) … The weak bonds that form between complementary bases The strong bonds that form between the sugar and phosphate molecules in the DNA backbone That the helices unzip readily due to the weak bonds between complementary bases while the strands remain intact due to the strong bonds of the backbone. The Energetics of bond breaking and bond formation
DNA model can be used to show (or to allow for the discovery of)…Transcription ofDNA messageinto an RNAcopy (mRNA or messengerRNA)
Its coding function - how sequences of nucleotidescan act as a code for sequences of amino acids inprotein moleculesEach combination of threenucleotides (A G C or U)is the code for a particularamino acid.Either UUU, or UUC,is the code for the topleft amino acid, phenyl-alanine
SCALEIt can be used to dramatize scale: e.g. if all the DNA in only one human cell were stretched out in one long strand it would be about 1 meter long. If the same amount were represented by the model and similarly stretched out, it would be about 149,668 km (or 93,000 miles) long.
The antiparallel directionality of thecomplementary DNA strands QuickTime™ and a decompressor are needed to see this picture.
Mutation - how information is encoded in DNAmolecules and how it is modified by mutation: how itslanguage changes – evolves – over the generations
The model can be used to demonstrate or elicitseveral of the Basic Science Process Skills Grades 5-8 OBSERVING USING SPACE-TIME RELATIONSHIPS Symmetry, mirroring, describe directions, spatial arrangements MEASURING Estimation of size, scale COMMUNICATING PREDICTING Based on observations measurements and inferences about relationships INFERRING
THE INTEGRATED PROCESSES FORMULATING HYPOTHESES DEFINING OPERATIONALLY EXPERIMENTING