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.
Introduction to cytology
1. What is Cytology?
2. Explain how prokaryotic & eukaryotic cells
3. What is DNA?
4. Identify the parts and function of the
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.
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.
They lack a nuclear
membrane as well any
other membrane covered
organelles in their
Considered to be
Example : Bacteria & Blue-
They possess a nuclear
membrane as well as
organelles in their
Example : Plant &
is the computer or control center of the cell.
contains the genetic material of life DNA
discovered by James Watson, Francis Crick, &
Rosalind Franklin (1953).
a DNA molecule consists of nucleotides connected
A nucleotide consists of a :
1. Phosphate group
2. Deoxyribose sugar
3. Nitrogen base: 4 types
DNA consists of two nucleotide
chains connected together.
A & T always pair up, while
C & G do the same.
Your genetic code is found in groups of 3
rungs in the ladder called DNA triplets
Complete the worksheet entitled “ODE to DNA” .
Long chains of DNA form
Short sections of DNA
along a piece of chromatin
form Genes. Human
genome contains about
A gene will either produce
or influence a specific trait
in the offspring.
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.