Purpose and Structure of DNA

Unit 3 Lesson 4

Deconstruct the structure and
components of DNA.

❏ Identify the components and the

repeating pattern found in the backbone
of a DNA molecule.

❏ Construct a model of the DNA structure

DNA LOCATION

●DNA never ever leaves

the nucleus (in eukaryotic
cells)

●DNA is the master copy

of the directions a cell
needs to live so it needs
to be protected

LG #1: Explore & Interact:

FUNCTIONS OF DNA

DNA is the master code for life. It is a large molecule that
functions to store and transmit genetic information to direct
life. Included in this information is the ability to:

➔ direct its own synthesis or replication including differentiation (used in mitosis/meiosis)

➔ code for protein synthesis to create other molecules needed by the cell.

LG #1: Explore & Interact:

DNA STRUCTURE

● Ladders have two parts:
1) The sides of the ladder (or backbone)
2) The rungs (or steps of the ladder)

●The double-stranded structure of DNA

makes a double helix, or twisted ladder.

LG #1: Explore & Interact:

● In DNA, the sides of the ladder are
made from the sugar and phosphate
groups of different nucleotides attached
together. (See the dark and light green parts of the picture.)

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STRUCTURE OF DNA

➔Nucleotides connect together to form
the "ladder rungs"
These are called BASE PAIRS

➔Two nitrogen bases form hydrogen bonds to hold the two side of the ladder together.
(See the dotted lines in the picture.)

➔This bond is very weak and can be broken we needed, but will easily for back (think of magnets)

LG #1: Explore & Interact:

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GENES

●Gene = segment of DNA that codes for a protein,

which in turn codes for a
trait (hair color, eye
color..etc),
A gene is a small part of DNA.

LG #1: Explore & Interact:

Labeling

Label the parts of the DNA structure

Drag labels to their correct position on the image

Hydrogen Bond

Sugar-Phosphate Backbone

Base Pair

Nitrogen Base