1. Objectives:
1. What is Cytology?
2. Explain how prokaryotic & eukaryotic cells
differ.
3. What is DNA?
4. Identify the parts and function of the
Nucleus.
2. It is the study of the structure and function of cells.
The cell is the basic structural and functional unit of
life so therefore cytology is the fundamental most
important topic in all of biology.
3.
4. Cytoplasm : area of space outside the nucleus;
contains the organelles & cytosol.
Organelles : are tiny structures in the cytoplasm
which perform various jobs for the cell.
Cytosol : is the fluid part of the cytoplasm.
5. They lack a nuclear
membrane as well any
other membrane covered
organelles in their
cytoplasm.
Considered to be
“Primitive Cells”
Example : Bacteria & Blue-
Green Algae
6. They possess a nuclear
membrane as well as
membrane bound
organelles in their
cytoplasm.
Example : Plant &
Animal Cells
7. is the computer or control center of the cell.
contains the genetic material of life DNA
(Deoxyribonucleic acid).
discovered by James Watson, Francis Crick, &
Rosalind Franklin (1953).
a DNA molecule consists of nucleotides connected
together.
8. A nucleotide consists of a :
1. Phosphate group
2. Deoxyribose sugar
3. Nitrogen base: 4 types
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
DNA consists of two nucleotide
chains connected together.
A & T always pair up, while
C & G do the same.
14. Long chains of DNA form
Chromatin.
Short sections of DNA
along a piece of chromatin
form Genes. Human
genome contains about
30,000 genes!
A gene will either produce
or influence a specific trait
in the offspring.
16. Nucleolus / Nucleoli (plural) : a dark spherical
structure that is the site of ribosome formation.
Ribosomes and other important chemical messages
leave the nucleus through the Nuclear Pores. The
membrane around the nucleus is called the Nuclear
Membrane or Envelope.
Notas do Editor
DNA is a double helix in which two strands are wound around each other. Each strand is made up of a chain of nucleotides. The two strands are held together by hydrogen bonds between adenine and thymine and between guanine and cytosine.
Identify 5 prime (exposed phosphate) and 3 prime (no exposed phosphate)
Eukaryotic chromosomes contain DNA wrapped around proteins called histones. The strands of nucleosomes are tightly coiled and supercoiled to form chromosomes.