DNA Day 1

DNA Day 1

Unit 8

Part 1: DNA, Genes, and Chromosomes

What is DNA? What does it stand for?

• DNA stands for deoxyribonucleic acid.

• It is the blueprint for life.

• It has the instructions for making the proteins which make up an organism.

DNA is made of smaller units called NUCLEOTIDES, which have 3 parts:

• Sugar

• Phosphate

• Nitrogen base

DNA Bases

• Adenine

• Thymine

• Cytosine

• Guanine

• These 4 bases form complimentary pairs: 

  A pairs with T, C pairs with G.

Structure of the DNA Double Helix

• 8. Hydrogen bonds

• 9. Nucleotide

• 10. Nitrogen base

• 11. Sugar

• 12. Phosphate

• 13. Base pair

Multiple Choice

What is the smaller molecule unit that makes up DNA?

• nucleotide

• fatty acid

• amino acid

• monosaccharide

Multiple Select

Select all 3 of the parts of a nucleotide.

• Sugar

• Phosphate

• Nitrogen base

• Hydrogen base

• Amino acid

Discovery of DNA & its Structure

• In 1953, two scientists named Watson and Crick discovered that DNA is made of 

  two chains of nucleotides that are joined together at the nitrogen bases by hydrogen bonds.

• By using special X-ray techniques, another scientist named Rosalind Franklin discovered that DNA is made of two strands and that the sugar & phosphate molecules make up its backbone.

• Watson & Crick put this information together with what they knew and they discovered that DNA is twisted into a shape called a double helix.

Discovery of DNA & its Structure

• The complementary nitrogen bases make up the “rungs” (steps) of the double helix “ladder” structure

Multiple Select

Select all 3 of the true statements.

• The sides/backbone of the helix is made of sugar and phosphate molecules.

• The sides/backbone of the helix is made of paired nitrogen bases.

• The rungs of the ladder are made of paired nitrogen bases.

• The rungs of the ladder are made of sugar and phosphate molecules.

• The nitrogen bases are held together by hydrogen bonds.

Chromosomes

• Found in the nucleus of eukaryotic cells.

• Chromosomes contain the genetic material of an organism.

• Chromosomes are long strands of DNA 

  and special types of proteins that are all tightly packed together.

• Chromosomes contain many genes.

Genes

• The section of DNA that carries the information to 

  make one specific protein is called a gene; 

  it is a PIECE/portion of DNA.

• One chromosome may have more than 1,000 genes on it, 

  and each gene may be made of thousands of nucleotide base pairs.

Multiple Choice

Which term is used to describe one long, continuous strand of DNA?

• chromosome

• gene

• trait

Multiple Choice

Which term is a segment of DNA that codes for a specific trait?

• chromosome

• gene

• double helix

DNA Replication

• The information on DNA can be transferred to another strand of DNA through the process of DNA Replication, which occurs during Interphase of the Cell Cycle. 

• In this process, the two strands of DNA unwind and separate by breaking the hydrogen bonds between the base pairs. 

• Then, free nucleotides start to pair with exposed bases to form complementary base pairs. The result is two molecules of DNA that are identical. Replicate this strand:

• G       C       G       A       T       A       C       T       A       C       G       A       T       T       

• __     __     __     __     __     __     __     __     __     __     __     __     __     __     

Multiple Choice

A T C G A T would be replicated into which strand?

• T A G C T A

• U A G C U A

• A T C G A T

• C G A T C

Part 2: DNA vs RNA

The Differences between DNA and RNA

• In eukaryotic cells, you typically only find DNA inside of the nucleus, while you can find RNA both inside and outside of the nucleus.

• Both DNA and RNA are types of nucleic acids, which has the monomer nucleotide.

• DNA is double-stranded; RNA is single-stranded.

• The sugar in DNA is deoxyribose and the sugar in RNA is ribose.

The Differences between DNA and RNA

• The bases in DNA are adenine, thymine, guanine, and cytosine; 

  RNA, however, has the bases adenine, uracil, guanine, and cytosine.

• In RNA, adenine will pair with uracil instead of thymine.

Types of RNA

• mRNA: Carries the DNA message from the nucleus to the ribosomes

• rRNA: part of the ribosome; creates the peptide bonds between amino acids during protein production 

• tRNA: Carries the amino acid to the ribosomes for protein production. 

Multiple Select

Which of the following 3 apply to BOTH DNA and RNA?

• Made up of nucleotides.

• Contains the base adenine.

• Contains the base thymine.

• Contains the base cytosine.

• Contains the base uracil.

Multiple Select

Which of the following 3 apply to RNA ONLY?

• Single strand of nucleotides.

• Contains the base uracil.

• Has the sugar ribose.

• Contains the base thymine.

• Cannot leave the nucleus.

Multiple Select

Which of the following 3 apply to DNA ONLY?

• Contains the sugar deoxyribose.

• Cannot leave the nucleus.

• Double-stranded.

• Contains the base adenine.

• Single-stranded.