Unit 4 Lesson: DNA

Unit 4 Lesson: DNA

Code for Life

Is a NUCLEIC ACID - biomolecule

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​Recall:

The “NA” in DNA & RNA stands for nucleic acids.

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Deoxyribonucleic Acid: molecule that stores genetic information.

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DNA consists of 2 strands held together by hydrogen bonds.

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In 1953, Watson & Crick identified DNA’s structure.

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​Each strand is made of repeating units called nucleotides.

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​A nucleotide has 3 parts:

1. Phosphate ​

2. Sugar

3. Base​

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​DNA Structure

The alternating sugars and phosphates are called the backbone. They make up the sides of the ladder.

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Nitrogen bases:

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Adenine

Thymine

Cytosine

Guanine​

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​DNA structure - base pairing

Pairing Laws:

A pairs with T

C pairs with G

Apples in Trees.

Cars in Garages.

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​(The way in which the bases are arranged “spells out” genetic instructions.)

DNA Replication: Process of copying DNA during S phase of interphase.

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Step 1: The enzyme DNA helicase “unzips” the two DNA strands.

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Step 2: The enzyme DNA polymerase matches nucleotides together.

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Step 3: The enzyme DNA ligase reconnects the two strands of DNA.

​DNA is found in all cells.

In eukaryotic cells, DNA is in the nucleus.​

In prokaryotic cells, DNA is in the cytoplasm.

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Multiple Choice

Why is the DNA of prokaryotes found in the cytoplasm?

• Because they have a nucleus.

• Because they do not have a nucleus.

• They have a lot of cytoplasm.

• The DNA likes the cytoplasm.

Multiple Choice

Which base pairs with Cytosine (C)

• Adenine (A)

• Thymine (T)

• Cytosine (C)

• Guanine (G)

Multiple Choice

Which base pairs with Adenine (A)

• Adenine (A)

• Thymine (T)

• Cytosine (C)

• Guanine (G)

Multiple Choice

What is the complementary DNA strand to the strand of DNA below?

C G T A A G C

• CGTAAGC

• CGAATGC

• GCATTCG

• ATVSUVY

Multiple Choice

During which part of the Cell Cycle does the cell replicate its DNA?

• Replication of DNA occurs during prophase of mitosis

• Replication of DNA occurs during S phase of mitosis

• Replication of DNA occurs during G1 of interphase

• Replication of DNA occurs during S phase of interphase

Multiple Choice

What is an enzyme?

• A lipid that provides insulation and emergency food storage.

• A protein that builds the bodies muscles, hair, skin, nails, tendons, and ligaments.

• A carbohydrate that provides energy.

• A special protein that catalyzes, or speeds up, chemical reactions in the body.

Multiple Choice

Based on the names of the enzymes you have seen (helicase, primase, polymerase, ligase), how do you think you can tell if something is an enzyme?

• It ends in -ose

• It has a fancy name

• It ends in -ase

• It has a simple name

Multiple Choice

Who gives more chromosomes and therefore more DNA to a baby?

• Dad, because dad gives 75%

• Mom, because mom gives 75%

• Neither, both give 50%

• None, because both give 0%

Multiple Choice

Which biomolecule carries the instructions for life?

• Proteins

• Carbohydrates

• Lipids

• Nucleic Acids

Multiple Choice

Which one of the following is not a part of the nucleotide?

• Nitrogenous base.

• Large protein molecule.

• Deoxyribose.

• Phosphate group.