what do genes look like?. 1. where are genes located? genes are located on our chromosomes....

What do genes look like?

1. Where are genes located?

• Genes are located on our chromosomes.

• Chromosomes are different sizes.

• There are hundreds of genes on the shorter chromosomes and thousands of genes on the larger chromosomes!

• It is estimated that the human species has over 25,000 different genes.

2. What are chromosomes made up of?

• Chromosomes are made of DNA (deoxyribonucleic acid) and proteins.

• The DNA is wrapped around the proteins.

3. Which type of material makes up your genes?

• Deoxyribose sugar

• Phosphate group

• Nitrogenous Base

4. What two things must genes be able to do?

1. Give instructions for building and maintaining cells.

2. Be able to copy themselves to prepare for cell division.

5. What are the building blocks of DNA?

• DNA is a nucleic acid.

• Nucleic acids are organic molecules made of subunits or building blocks called nucleotides.

• There are four different types of nucleotides, each with a different nitrogenous base…

The Adenine Nucleotide

A

The Thymine Nucleotide

T

The Guanine Nucleotide

G

The Cytosine Nucleotide

C

The Four different letters used to represent these nucleotides are A, T, G & C.

7. What are Chargaff’s Rules?

• Chargaff is the name of the scientist who discovered what we call the base pair rule.

The amount of A = the amount of T because they always pair together.

The amount of G = the amount of C because they always pair together.

8. How did Rosalind Franklin contribute to the discovery of

what DNA looks like?Rosalind Franklin was a female scientist who was the first to take x-ray photographs of a DNA molecule in 1952.

9. What did Watson and Crick do?

James Watson and Francis Crick studied the pictures of the DNA molecule and were the first to build a model of DNA seen here.

10. How did Watson and Crick describe the shape of DNA?

Double

Helix

Use to answer 11 & 12

Use to answer 13 &14

15. What is the complimentary strand?

A T C C G A T T

T A G G C T A A