![Picture](/uploads/1/1/6/4/11645333/9946973.jpg)
What you should understand about protein synthesis:
b. DNA and RNA molecules have structural similarities and
differences that define function. [See also 4.A.1]
Evidence of student learning is a demonstrated understanding of each
of the following:1. Both have three components — sugar, phosphate and a
nitrogenous base — which form nucleotide units that are
connected by covalent bonds to form a linear molecule with 3'
and 5' ends, with the nitrogenous bases perpendicular to the
sugar-phosphate backbone.
2. The basic structural differences include:
i. DNA contains deoxyribose (RNA contains ribose).
ii. RNA contains uracil in lieu of thymine in DNA.
iii. DNA is usually double stranded, RNA is usually single
stranded.
iv. The two DNA strands in double-stranded DNA are
antiparallel in directionality.
3. Both DNA and RNA exhibit specific nucleotide base pairing
that is conserved through evolution: adenine pairs with
thymine or uracil (A-T or A-U) and cytosine pairs with guanine
(C-G).
i. Purines (G and A) have a double ring structure.
ii. Pyrimidines (C, T and U) have a single ring structure.
4. The sequence of the RNA bases, together with the structure of
the RNA molecule, determines RNA function.
i. mRNA carries information from the DNA to the ribosome.
ii. tRNA molecules bind specific amino acids and allow
information in the mRNA to be translated to a linear
peptide sequence.
iii. rRNA molecules are functional building blocks of
ribosomes.
iv. The role of RNAi includes regulation of gene expression at
the level of mRNA transcription.
c. Genetic information flows from a sequence of nucleotides in a gene
to a sequence of amino acids in a protein.
Evidence of student learning is a demonstrated understanding of each
of the following:
1. The enzyme RNA-polymerase reads the DNA molecule in
the 3' to 5' direction and synthesizes complementary mRNA
molecules that determine the order of amino acids in the
polypeptide.
2. In eukaryotic cells the mRNA transcript undergoes a series of
enzyme-regulated modifications.
To foster student understanding of this concept, instructors can
choose an illustrative example such as:
• Addition of a poly-A tail
• Addition of a GTP cap
• Excision of introns
3. Translation of the mRNA occurs in the cytoplasm on the
ribosome.
4. In prokaryotic organisms, transcription is coupled to
translation of the message. Translation involves energy and
many steps, including initiation, elongation and termination.
✘✘ The details and names of the enzymes and factors involved in
each of these steps are beyond the scope of the course and the AP®
Exam.
The salient features include:
i. The mRNA interacts with the rRNA of the ribosome to
initiate translation at the (start) codon.
ii. The sequence of nucleotides on the mRNA is read in triplets
called codons.
iii. Each codon encodes a specific amino acid, which can be
deduced by using a genetic code chart. Many amino acids
have more than one codon.
✘✘Memorization of the genetic code is beyond the scope of the
course and the AP Exam.
iv. tRNA brings the correct amino acid to the correct place on
the mRNA.
v. The amino acid is transferred to the growing peptide chain.
vi. The process continues along the mRNA until a “stop” codon
is reached.
vii. The process terminates by release of the newly synthesized
peptide/protein.
d. Phenotypes are determined through protein activities.
![Picture](/uploads/1/1/6/4/11645333/6238793.gif)
DNA Replication- discuss, wrap up- turn in
Genomics and its impact on society- discussion turn in outline
Sordaria investigation- crossover- 93-96- collect data, Evaluating Results;- 1-6 Due Tomorrow
Intro to protein synthesis
Genomics and its impact on society- discussion turn in outline
Sordaria investigation- crossover- 93-96- collect data, Evaluating Results;- 1-6 Due Tomorrow
Intro to protein synthesis
![Picture](/uploads/1/1/6/4/11645333/8403351.png)
http://learn.genetics.utah.edu/content/begin/dna/