Cell Organelles of the Central
Dogma
What Is An Organelle? (notes)
• An “organelle” is a part of the cell with a specific function
• Analogous to organs being part of the human body
(not notes)
“An organelle is to a cell
as an organ is to a human”
*Colored for your convenience
#1: The Nucleus (notes)
• Function: To organize, protect, and
transcribe DNA
• The nucleus is usually the largest
and one of the most complex organelles
Plant cells
Animal cell 
DNA (notes)
• DNA is the blueprint for how to build a living
thing (from a single cell to an entire organism)
• DNA stores its information in a code that is
made of 4 letters
• (Not notes: these letters are C, A, T, and G)
• DNA is in the form of a “double helix”
DNA Coding (not notes)
• DNA uses its two strands for replication and “proof-reading”
• Each of the two strands has a matching, but opposite, code
• C always matches with G and T always matches with A
• If the cell wants to make new DNA it splits the two strands and uses
each to make an opposite copy. It can also fix mistakes this way.
The “ribose” in “deoxyribonucleic acid”
Chemical structure of DNA
DNA Discovery (not notes)
• DNA was first isolated from cells in 1869
• Its function in inheritance was demonstrated in 1943
• In 1953 Watson and Crick published a paper on the structure and the
implications on how it would work
• Nobel Prize awarded in 1962
• One of the most important
discoveries of the 20th century
Remembering Rosalind (not notes)
• Rosalind Franklin was an X-ray
crystallographer who took the slides that
led to Watson and Crick’s discovery
• However, her name was relatively
unknown for a long time for two reasons:
• She was not directly cited in the paper that
Watson and Crick published
• By the time the Nobel Prize was given out in
1962 Rosalind Franklin had already passed
away, and the Nobel Prize must be awarded
to a living person
Rosalind Franklin and the famous Picture 51 that was the basis of Watson and Crick’s discovery
RNA (notes)
• DNA cannot leave the nucleus – it’s too precious to risk losing
• In order to get the information out of the nucleus, the cell copies the
information from DNA to a new molecule called RNA
The protein (“RNA Polymerase”) responsible for turning DNA into RNA
#2-3 Endoplasmic
Reticulum
(notes)
• The endoplasmic reticulum (ER) is a
production structure around the nucleus
• The Rough ER is responsible for turning RNA
into protein. The machine that does this is called
a ribosome.
• The Smooth ER is responsible for building fats (lipids)
Ribosomes (not notes)
• Incredibly complex mixtures of protein and nucleic acid
#4 The Golgi Apparatus (notes)
• Job: Sorting station that sends proteins
where they need to go
• (Not notes: proteins all have a “tag” on them
that tells the Golgi where they belong)
The Central Dogma (notes)
• The “Central Dogma” in biology is the idea that DNA is turned into
RNA is turned into protein
DNA
RNA
(Transcription)
Protein
(Translation)