1. Notes: Life of a Cell
Part 1: Understanding the
Chromosome

2. I. Understanding DNA as a Chromosome
5 Key Points
A. Found in the
NUCLEUS of the cell

3. I. Understanding DNA as a Chromosome
5 Key Points
B. Composed of 1 very large, compacted,
TIGHTLY COILED strand of DNA
1. DNA name: DEOXYRIBOSE NUCLEIC ACID
• Contains the HEREDITARY INFORMATION
for the assembly of PROTEINS in the body that
specifies cell structure and function

4. I. Understanding DNA as a Chromosome
5 Key Points
2. Built by repeating subunits or monomers
called NUCLEOTIDES: 3 parts
a. DEOXYRIBOSE SUGAR
b. PHOSPHATE GROUP
c. NITROGEN BASES (A,T,C,G)

5. I. Understanding DNA as a Chromosome
5 Key Points
Nitrogen
Draw this
and label
it!
DNA Nucleotide

6. I. Understanding DNA as a Chromosome
5 Key Points
3. GENE: a segment of DNA coding for a
specific trait

7. I. Understanding DNA as a Chromosome
5 Key Points
C. Chromosome appearance
in the cell varies
1. LOOSELY coiled: dark
mass
2. TIGHTLY coiled:
extended threadlike
strands
 Can be seen during stages
of cell division

9. I. Understanding DNA as a Chromosome
5 Key Points
D. Chromosome number - Humans
Chromosome # in
Humans
HAPLOID = 23 Chromosomes Diploid = 46 Chromosomes
-1/2 set of chromosomes -Full set of chromosomes
-Gamete: sex cells -Somatic Cell: body cells
-ex: sperm and egg Ex: skin, liver, zygote

10. HAPLOID = 23 Chromosomes
-1/2 set of chromosomes
-Gamete: sex cells
-ex: sperm and egg

11. I. Understanding DNA as a Chromosome
5 Key Points
D. Chromosome number - Humans
Chromosome # in
Humans
HAPLOID = 23 Chromosomes Diploid = 46 Chromosomes
-1/2 set of chromosomes -Full set of chromosomes
-Gamete: sex cells -Somatic Cell: body cells
-ex: sperm and egg Ex: skin, liver, zygote

12. Diploid = 46 Chromosomes
-Full set of chromosomes
-Somatic Cell: body cells
Ex: skin, liver, zygote

13. I. Understanding DNA as a Chromosome
5 Key Points
E. Chromosomes have the ability to
REPLICATE or COPY ITSELF
 Once DNA copies itself, it will contain an
identical half