Protein Synthesis. 5.1 I can explain the steps in the process of transcription, along with where...
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Unit 5 Notes Protein Synthesis
Protein Synthesis. 5.1 I can explain the steps in the process of transcription, along with where they take place (this includes the role of DNA and mRNA)
5.1 I can explain the steps in the process of transcription,
along with where they take place (this includes the role of DNA and
mRNA) 5.2 I can explain the steps in the process of translation,
along with where they take place (this includes the role of mRNA,
tRNA, ribosomes (rRNA), and amino acids) 5.3 I can list the three
different types of RNA and describe the function of each. 5.4 I can
describe at least three differences between DNA and RNA. 5.5 I can
label the following items in pictures of transcription and
translation: DNA sense strand, DNA nonsense strand, RNA polymerase,
mRNA strand, ribosome, start codon, stop codon, amino acid,
polypeptide chain (protein), tRNA, anti-codon, peptide bond 5.6 I
can describe at least three different types of mutations in DNA,
and their possible effects on the organism.
Slide 3
I can explain the steps in the process of transcription, along
with where they take place (this includes the role of DNA and
mRNA)
Slide 4
Every cell faces a fundamental problem when making proteins.
The instructions for making the proteins are in the nucleus on the
DNA. BUT The location for making proteins is outside the nucleus at
the ribosomes.
Slide 5
The first part of the solution is a process called
TRANSCRIPTION
Slide 6
First, an enzyme called RNA polymerase attaches to DNA at the
beginning of a gene. The enzyme unzips the double helix strand and
begins to read the instructions, coded in the sequence of the
letters A, T, C, and G.
Slide 7
As the enzyme reads the DNA code, it copies it by attaching
complementary RNA nucleotides. The result is a strand of mRNA
(messenger RNA) which carries the instructions for making a
protein. RNA polymerase RNA nucleotide Growing mRNA strand
Slide 8
Well, were making a copy of the DNA, and the DNA can be found
where? In the nucleus. The DNA cant leave the nucleus for two
reasons: Its too large to get through the pores, and its too
precious to send it out into the cytoplasm where digestive enzymes
could break off pieces of it.
Slide 9
it leaves the nucleus to go take the DNAs message to a ribosome
where the protein will be made. So mRNA solves the problem of
getting the information from the nucleus to the cytoplasm. Now to
make the protein!!
Slide 10
I can explain the steps in the process of translation, along
with where they take place (this includes the role of mRNA, tRNA,
ribosomes (rRNA), and amino acids)
Slide 11
Slide 12
The cell has another problem. It has to take the language of
nucleic acids (DNA/RNA) and turn it into the language of amino
acids (protein). So it needs a translator otherwise known as the
ribosome!
Slide 13
First, the mRNA threads into the ribosome, until the start
codon AUG, reaches the P site in the ribosome.
Slide 14
Next, the ribosome brings in a tRNA (transfer RNA). On one end
of the tRNA is an anti-codon that is complementary to the codon on
the mRNA. On the other end of the tRNA is an amino acid.
Slide 15
A tRNA also binds at the A site. A peptide bond forms between
the two amino acids, connecting them together. Then the tRNA in the
P site leaves (leaving behind its amino acid), and the ribosome
moves to the next codon. The process continues this way until it
reaches a stop codon.
Slide 16
Once the ribosome reaches a stop codon, everything detaches.
The protein finishes its production by folding a certain way so
that it can do its job. The ribosome will make another protein. The
mRNA gets recycled by digestive enzymes in the cytoplasm. The tRNA
will pick up more of their amino acids to help build another
protein.
Slide 17
I can list the three different types of RNA and describe the
function of each.
Slide 18
1. mRNA (messenger RNA) carries the message of the DNA from the
nucleus to the ribosome; created during transcription. 2. tRNA
(transfer RNA) transfers amino acids to the growing chain of amino
acids in the ribosome during translation. 3. rRNA (ribosomal RNA)
what ribosomes are made of.
Slide 19
I can describe at least three differences between DNA and
RNA.
Slide 20
DNA: Double-stranded Deoxyribose is the sugar G, C, A, and T
are the bases Very long RNA: Single-stranded Ribose is the sugar G,
C, A, and U are the bases Much smaller (one gene)
Slide 21
I can label the following items in pictures of transcription
and translation: DNA sense strand, DNA nonsense strand, RNA
polymerase, mRNA strand, ribosome, start codon, stop codon, amino
acid, polypeptide chain (protein), tRNA, anti-codon, peptide
bond
Slide 22
DNA nonsense strand mRNA strand DNA sense strand RNA
polymerase
I can describe at least three different types of mutations in
DNA, and their possible effects on the organism.
Slide 25
There are two main categories of mutations that we discuss:
Chromosomal mutations, which involve changes in whole genes on a
chromosome (we will look at these next unit) Gene mutations, which
involve changes in parts of genes.
Slide 26
There are two main types of gene mutations: point mutations,
and frameshift mutations. A point mutation is when one base is
switched out for another base. It only affects that one amino acid
in the sequence. A frameshift mutation is when one base is deleted
or added, which shifts all the bases after it, affecting all of the
amino acids in the sequence after the mutation.
Slide 27
Lets say the following sentence is a gene, and each word in the
sentence is a codon (even though the words have more than three
letters): Biology students are really nice people.
Slide 28
For a point mutation, one base is switched for another base.
Biology students ate really nice people. We changed the r in are to
a t. As you can see, only one word was affected. However, the whole
meaning of the sentence has changed.
Slide 29
Look at your codon chart. Is every amino acid coded for by one
codon? No! There are repeats, right? So if we changed the last base
of the codon, sometimes it would still code for the same amino
acid. If this is the case, is there any change in the protein? No
we call it a silent mutation because there was no effect on the
organism.
Slide 30
In an addition mutation, one base is repeated. So we will add
one letter twice. Biology students sar enic epeopl e. We put in an
additional s after students. Now, every word (or codon) after the
addition is affected because every base afterward is shifted down
one.
Slide 31
In a deletion mutation, one base is deleted from the sequence.
Biology studenta ren icep eople. We deleted the s at the end of
students. Now, it shifts all the bases afterward up one.
Slide 32
Effects of mutations can be minor, or severe. They can be
beneficial, harmful, or as weve seen, neutral. Its hard to discuss
which type is worse than others, because while frameshifts render
the entire protein useless and may appear worse at a glance, point
mutations can be equally devastating. Lets take a look at one such
case.