Download Chapter 4.1 Notes: “DNA: The Molecule of Life”

NAME: _______________________________________
PERIOD: _____
Chapter 4.1 Notes: “DNA: The Molecule of Life”
Directions: Using your journal and Gateways to Biology textbook, answer/complete the following.
1)
DNA is known as the molecule of life because it contains?
DNA contains the hereditary material of all living things; stores information for cells to properly function.
2)
The structure of DNA can be described as a(n) twisted ladder / double helix.
3)
The enzyme that links nucleotides to the open strand of DNA is DNA polymerase.
4)
The backbone of the DNA molecule is composed of phosphates and sugars.
5)
Write the nucleotide base sequence that complements the following DNA sequence:
A T G C C A T G C --------> TAC GGT ACG
6)
Why were scientists in the 1920s through the early 1940s skeptical that DNA was the molecule of life?
Scientists believed that DNA was too simple to be the molecule of life.
7)
What does a forensic scientist do? Forensic scientists study DNA in crime scenes.
8)
Explain how DNA is contained differently in a prokaryotic cell and a eukaryotic cell.
DNA is found in the nucleus of eukaryotic cells, however, it is scattered throughout the cytoplasm in
prokaryotic cells.
9)
What does DNA stand for? Deoxyribonucleic Acid
10)
What are the monomers of DNA? nucleotides
11)
What are the four nitrogen bases in DNA (write entire names)?
adenine, thymine, guanine, cytosine
12)
In DNA, the nucleotide sequence provides the genetic instructions for the sequencing amino acids
to build proteins.
13)
Who are credited for the discovery of the DNA structure? James Watson and Francis Crick
14)
The nitrogen bases of DNA are held together by hydrogen bonds.
15)
The nitrogen bases of DNA are attached to the sides of the phosphate groups by deoxyribose sugar.
16)
One side of DNA is arranged from 5’ to 3’, whereas the complementary strand is antiparallel and is
arranged from 3’ to 5’.
17)
In your body, where is the cells’ DNA located? In the nucleus of your cells.
18)
How many chromosomes does a normal human body cell contain? 46 (23 pairs)
19)
What is the base pairing rule for DNA? A = T
C=G
T=A
G=C
NAME: _______________________________________
PERIOD: _____
Chapter 4.1 Notes: “DNA: The Molecule of Life”
20)
When a gets ready to divided and reproduce, it must first make a copy of its DNA. What is the process of making
a copy of the DNA called? Replication
21)
What are the three components of a DNA nucleotide?
1) phosphate
2) sugar
3) nitrogen base
22)
Which part of the DNA molecule stores the genetic information? nitrogen bases (A,T,G,C)
23)
What makes up the “rungs” of the ladder in a double-helix? nitrogen bases (A,T,G,C)
24)
Where in the cell does DNA replication occur? nucleus
25)
Located on chromosomes, what are codes for certain proteins called? genes