Our Questions about DNA?

1
Our Questions about DNA?

• What does DNA look like?
• How is DNA made?
• How do we know DNA has the instructions to make
  proteins?
• How does DNA instruct the cell to make proteins?

• WHAT DETERMINES THE ORDER OF AMINO ACIDS IN A
  PROTEIN???

2
Do the cells in your eye and your tongue have the
same functions?
Do the cells in your eye and your tongue have the
same proteins?
3
Do the cells in your eye and your tongue have the
same DNA?
4
Humans have 46 chromosomes- where are they?

• Do all cells have DNA?
• Do all cells have the same DNA?

5
When doing DNA identification (think CSI) does it
matter which cells you use to get the
sample?Cheek cells?Red Blood cells?Hair
follicle cells?
6
What changes occur to a salmon when it spawns?
Do the salmons proteins change when it spawns?
7
Does a salmons DNA change when it spawns?
8
Does the DNA in your body change as you go
through puberty?
9
Does the DNA in your body change as you go
through puberty?
10
Writing assignment

• Do different cells in your body have different
  DNA?
• What makes you think that?
• Does the DNA in your cells change as you develop
  from a baby to an adult?
• What makes you think that?

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What have we learned?

• Proteins determine most characteristics of a cell
  and organism
• Information stored in DNA determines which
  proteins can be made by a cell
• The environment influences which proteins are
  made by a cell

12
Some things we will learn

• Where is protein made in a cell?
• How does the information stored in DNA determine
  which proteins can be made in a cell?
• How is protein made in a cell?
• How does the environment influence which proteins
  are made in cell?

13
Where is protein made in a cell?
14
DNA does not leave the nucleus of eukaryotic
cells... but proteins are made outside of the
nucleus by ribosomes
Elodea leaf cell
human cheek cell
mitochondria
chloroplasts
vacuole
nucleus
(DNA here)
(DNA here)
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DNA does not leave the nucleus of eukaryotic
cells... but proteins are made outside of the
nucleus by ribosomes
ribosomes
(proteins made here)
(proteins made here)
nucleus
(DNA here)
(DNA here)
16
DNA and ribosomes are at different locations in a
prokaryoic cell.
E. coli bacteria cell
ribosomes
(proteins made here)
DNA
17

• Add ribosomes to the diagrams you have been
  keeping in your notebook
• Plant cell- elodea leaf cell
• Animal cell- human cheek cell
• Prokaryote- E. coli bacterium
• Ribosomes make protein but are not in the same
  location as DNA in a cell. Discuss ideas with
  your classmates about how the proteins could be
  made according to the DNA information.

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Information flow from DNA to trait
Observed trait
DNA
protein
Made by ribosomes outside of nucleus
Stored in nucleus
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messenger RNA

• mRNA transfers information from the DNA in the
  nucleus to the ribosomes.
• Ribosomes build proteins according to the mRNA
  information received.

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Information flow from DNA to trait
messenger RNA
Observed trait
DNA
protein
Made by ribosomes outside of nucleus
Stored in nucleus
21
DNA information ? mRNA information
messenger RNA
DNA

• Transcription is the process used to convert DNA
  information into mRNA information.
• Note DNA does not become RNA the information in
  DNA is copied as RNA