FOB: Chapter 11

Chapter 11.1: DNA & Genes

Section 11.1

DNA: The Molecule of Heredity

Vocab:
-Nucleotide
-Nitrogenous Base
-Double Helix
-DNA Replication

​I CAN...
Determine how the structure of DNA enables it to reproduce itself accurately.

• Proteins and Enzymes are essential for life​!

• Structure of DNA contains complete instructions for manufacturing ALL proteins.

What is DNA?

• DNA is a polymer with repeating subunits called nucleotides.

• Nucleotides:

  • Simple Sugar

  • Phosphate Group

  • Nitrogenous Base

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Nucleotide Structure

• Simple Sugar = Deoxyribose

• Phosphate Group = 1 Phosphorus surrounded by 4 Oxygen atoms

• Nitrogenous Base = A (adenine), T (thymine), C (cytosine), or G (guanine)

• DNA is made of 2 chains of nucleotides held together by nitrogenous bases.

• Just as teeth of a zipper hold the two sides of the zipper together, the nitrogenous bases of the two nucleotides hold the two strands of DNA together with weak HYDROGEN BONDS.

​

Multiple Select

What is DNA?

• A type of sugar

• Instructions for proteins

• Genetic Material

• A type of protein

Multiple Choice

DNA is a polymer made up of:

• fatty acids
• nucleotides
• sugars
• amino acids

• Always equal amounts of C & G or equal amounts of A & T

• 2 strands twisted together = double helix

• Sequence forms unique genetic info

• A-T-T-G-A-C is different from

  T-A-T-A-C-G

• 6 letter word spelled two ways; same letters different meaning.

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Importance of Nucleotide Sequence

Labeling

Nucleotides are made up of:

Drag labels to their correct position on the image

Pentose (simple) Sugar

Protein

Sulfate Group

Complex Sugar

Hydrogenous Base

Nitrogenous Base

Phosphate Group

Multiple Choice

There are 4 types of nitrogenous bases, adenine, cytosine, thymine, and guanine. How do the bases pair in order to create a DNA sequence?

• Adenine pairs with thymine, and cytosine pairs with guanine
• Thymine pairs with cytosine, and adenine pairs with guanine
• Adenine pairs with guanine, and cytosine pairs with thymine
• Adenine pairs with cytosine, and thymine pairs with guanine

Fill in the Blanks

Weak

bonds hold the nitrogenous bases together to form two strands of DNA.

• A cell divides by either Mitosis or Meiosis, but FIRST it must make a copy of its chromosomes.

• DNA in the chromosomes is copied through DNA replication.

• 2 molecules are formed, each strand has 1 original strand (blue) and one newly synthesized strand (pink)

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Replication of DNA

• An enzyme breaks the hydrogen bonds between bases that hold the two DNA strands together

  • Unzipping

• As DNA unzips, free floating nucleotides attach to their base pair by H⁺ bonds.

  • Another enzyme bonds these nucleotides into a chain

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​How DNA Replicates

• Process continues until entire molecule has been unzipped and replicated.

• Each new strand is a complement of one of the original, or parent, strands.

• Result = 2 DNA molecules, each of which is identical to the original DNA molecule.

  • Genetic info can then be passed on through Mitosis or Meiosis.
    

Multiple Choice

What must happen before Mitosis or Meiosis can take place?

• Replication of DNA
• Breakdown of DNA
• Duplication of RNA
• Mutation of DNA

Fill in the Blanks

A(n)

breaks the hydrogen bonds between the bases that hold the two DNA strands together.

Multiple Choice

How are the two new complementary strands of DNA formed from the original strand of DNA?

• • free floating nucleotides attach to their base pair by H⁺ bonds

• • free floating amino acids attach to their base pair by N⁺ bonds

• • free floating phosphate groups attach to their base pair by H⁺ bonds

• • free floating sugars attach to their base pair by N⁺ bonds