DNA - The Double Helix - Key

Original Document: DNA - The Double Helix


1.  Why is the nucleus called the "control center" of the cell?________________because it tells the cell what to do_______________
2.  What is a gene? _________
section of DNA, codes for a trait_____________
3.  Where in the cell are chromosomes located? ____
4.  DNA can be found in what organelles? ____
mitochondria, chloroplasts_
5.  What two scientists established the structure of DNA? ___
Watson & Crick_____
6.  Replication is called “semi-conservative” because half of the original strand is ____
7.   What are the sides of the DNA ladder made of? _______
sugar and phosphates__________________________
8. What three parts make up a single nucleotide: _____
sugar, phosphate, base______________________________
9.  What are the 4 bases that make up the rungs of the DNA ladder? _____
A, T, G, C__________________
10.  What sugar is found in DNA? ___
deoxyribose_____________ In RNA? ____ribose_____________
11.  How do the bases bond together?   A  bonds with  _
T____      G  bonds with  ___C____
12.  Why is RNA necessary to act as a messenger?  ____
DNA does not leave nucleus, pores too small_________________________
13.  Proteins are made where in the cell? _________
14. How is RNA different from DNA? (list 3 things) ____
uracil, ribose, single strand_________________________________
15. The process of copying DNA is called _____
16. What is the shape of DNA?   ___
double helix (twisted ladder)_______________________
17. How do some cells become brain cells and others become skin cells, when the DNA in ALL the cells is exactly the same.  In other words, if the instructions are exactly the same, how does one cell become a brain cell and another a skin cell? only some genes are turned on

18.  Why is DNA called the "Blueprint of Life"? it contains the instructions for building an organism