2. Chapter 11: Lesson 3 Notes

3. Genes provide ___________ for a cell to assemble ___________ that express traits such as eye color or seed shape.
directions
molecules

4. DNA is an organism’s genetic material (Deoxyribonucleic Acid)
What is DNA?
DNA is an organism’s genetic material (Deoxyribonucleic Acid)

5. What five scientists are given credit for helping discover the structure of DNA?
Rosalind Franklin
Maurice Wilkens
James Watson
Francis Crick
Erwin Chargaff

6. What is a nucleotide?
A nucleotide is a molecule made of a nitrogen base, a sugar, and a phosphate.

7. What four nitrogen bases are found in our DNA?
1. Adenine (A) 2. Cytosine (C) 3. Thymine (T) 4. Guanine (G)

8. How do our nitrogen bases always pair up?

9. What are the three steps of DNA replication?
1. DNA strand separates and nitrogen bases are exposed 2. Nucleotides move into place and form new nitrogen base pairs 3. Two identical strands of DNA are produced.

10. During DNA replication an exact copy is made!

11. Most of your DNA is JUNK. No, really! What does that mean?
97% of your DNA is Junk DNA. This means that it is NOT part of a gene.

12. How is RNA different than DNA?
DNA is double-stranded; RNA is single-stranded
RNA has the base uracil (U) instead of thymine (T)
RNA has sugar ribose instead of deoxyribose

14. The first step in making a protein is to make mRNA from DNA, which is called____________
transcription

15. Proteins are made from RNA in a process called __________.
translation

16. What are the three steps of translation?
1. tRNA carries amino acids to the ribosomes 2. rRNA helps form chemical bonds that attach one amino acid to the next 3. The first tRNA seperates from its amino acid and from the mRNA. A third tRNA brings in another amino acid *AMINO ACIDS ARE WHAT MAKE PROTEINS!! Proteins make YOU who you are!!

18. mRNA, m = ______________ tRNA, t = _______________ rRNA, r = ________________
messenger
transfer
ribosomal

19. What are the three possible results of a gene mutation?
1. Negative (Example: cancer) 2. Positive (Example: Woodpecker with long beak) 3. Neutral (Example: Different color hair)

21. On what chromosome would you find an error causing the following disorders?
a. PKU: Chromosome 12 b. Cystic fibrosis: Chromosome 7 c. Breast cancer: Chromosome 17 or 13

22. Rewrite the Visual Summary found on page 417.
DNA is a complex molecule that contains the code for an organism’s genetic information
RNA carries the codes for making proteins
An organism’s nucleotide sequence can change through the deletion, insertion, or substitution of nitrogen bases.