intro to dna structure- inquiry modeling

INTRO TO DNA STRUCTURE- INQUIRY MODELING

BELLWORK

1. What is the circled object called?

2. What is the function (job) of the circled object?

3. Describe TWO ways that the structure of the circled object help it perform its function? (Hint: How does the shape, size, texture, etc. help it perform its job?)

STRUCTURE IS RELATED TO FUNCTION!

SOME FUNCTIONS ARE OBVIOUS

…BUT SOME ARE NOT SO OBVIOUS!

Fennec Fox

Sahara Desert (in Africa)

Arctic Fox

Near the North Pole (parts of Alaska, Canada, Russia, etc.)

LARGE-EARED DESERT ANIMALS

Long-eared Jerboa (deserts in Asia)

Jack rabbit (you can find them in our

Sonoran desert!)

African Elephant

COULD YOU SEE THE ACTUAL STRUCTURE OF DNA UNDER THE MICROSCOPE?

SO IN ORDER TO FIGURE OUT DNA’S FUNCTIONS, WE NEED TO

KNOW ITS STRUCTURE

HOW DO WE DETERMINE SOMETHING’S STRUCTURE IF IT’S TOO SMALL TO SEE?

…We use MODELS!

GRAB A PAPER CUP WITH YOUR PARTNER (1) & GO FILL IT WITH A VARIETY OF MODELING MATERIALS

(3 MINUTES)

DNA is a polymer (a long, chain-like molecule)

The chain is made up of small subunits

The subunits are attached to each other by covalent (very strong) bonds

There are four different, but very similar kinds of subunits

1. Draw a labeled sketch of your model and answer the questions for part 1

INFORMATION

DNA is a polymer (a long, chain-like molecule)The chain is made up of small subunitsThe subunits are attached to each other by covalent (very strong) bondsThere are four different, but very similar kinds of subunits

DNA is made of TWO long chains of subunits

These two chains are twisted around each other to form a “double helix” (a helix is the shape a pipe cleaner would be if you wrapped it around a pencil and took it off)

The diameter of the double helix is uniform (the same) along the entire length

2. Draw a revised sketch of your model and answer the questions for part 2.

The order of the subunits on one strand of

DNA, determines the order of subunits on the other strand of DNA

3. Make a labeled sketch of the order of subunits on each chain and answer the questions for part 3.

DNA is made of TWO long chains of subunitsThese two chains are twisted around each other to form a “double helix” (a helix is the

shape a pipe cleaner would be if you wrapped it around a pencil and took it off)The diameter of the double helix is uniform (the same) along the entire length

The subunits on opposite strands bind together according to these rules of complementary pairing:

Adenine (A) only binds to Thymine (T)Guanine (G) only binds to Cytosine (C)

The bonds that hold the two strands together are hydrogen bonds, which are much weaker than covalent bonds

4. Sketch your model and label the where the A,T,G & C subunits are. Answer the Qs for part 4.

The order of the subunits on one strand of DNA, determines the order of subunits on the other strand of DNA

CLOSURE1. Summarize the structure of DNA in 12

words or less

2. What are the 2 important functions of DNA you learned about today?

3. Why couldn’t we see DNA’s structure under the microscope?