Biology
Protein Synthesis
Spring 2016
Objective: to learn about the main events of protein synthesis.
Area of interaction: approaches to learning
Criteria C: Knowledge of Science
Your Task: To demonstrate your understanding of protein synthesis, and to summarize the main steps of
transcription and translation.
Vocabulary
Chromosome: rod-shaped structures made of DNA and proteins
Gene: segment of DNA that is located on a chromosome and that codes for a hereditary character (ex.
Hair color
DNA: Deoxyribonucleic acid, material that contains information that determines hereditary characteristics.
RNA: a natural polymer that is present in all living cells and that plays a role in protein synthesis
Ribosome: organelle in cell that makes proteins
Proteins: biological molecules that perform a variety of functions and build many structures
Protein Synthesis: forming proteins based on information in DNA and carried out by RNA
DNA
RNA
Protein
Amino acid: organic molecules that make up proteins, subunits of proteins
Codon: in DNA, a three-nucleotide sequence that encodes an amino acid or signifies a start signal or stop
signal.
Anticodon: a region of tRNA that consists of three bases complementary to the codon of RNA.
Transcription: the process of forming a nucleic acid by using another molecule as a template; particularly
the process of synthesizing RNA by using one strand of a DNA molecule as a template.
RNA
RNA is similar to DNA because it is a nucleic acid made of __________________.
But, RNA is different from DNA in 4 ways
1.
2.
3.
4.
Types of RNA
Cells have 3 main types of DNA:
1. Messenger RNA (mRNA):
2. Ribosomal RNA (rRNA) part of ribosomes, (RNA’s and proteins make up ribosomes)
3. Transfer RNA (tRNA):
Draw them here:
Problem: The instructions for making proteins are written in DNA,
which is in the nucleus. Because DNA is so fragile it cannot leave
the nucleus. How do we get the instructions for building a protein
from the DNA in the nucleus to the ribosomes?
What must happen:
A. DNA must be re-written in a form that can leave the nucleus (mRNA)
B. The proteins must be built at the ribosomes from the information written in mRNA
using the genetic code.
Protein synthesis has two main steps: Transcription and Translation
Part 1: Transcription: When _________is rewritten as ______so that it can ______________________.
Part 2: Translation: When ________ is converted to _____________ in the ribosome.
Part 1: Steps of transcription (3 steps)
1.
2.
3.
Initiation
Elongation
Termination
The Genetic Code
Genetic code: The process of converting mRNA to proteins using the genetic code
-3-nucleotide sequences called codons directly code for specific amino acids.
The Genetic Code (how mRNA is translated into amino acids)
Each 3 nucleotide sequence in mRNA that encodes an amino acid or a stop or start. Look at examples:
GCU->
AAU->
AUU->
Start codon: AUG. This is the ONLY start codon. This is where translation ________.
Stop codons: UAA, UAG, UGA. This is where translation ________.
How it works: Start codon -Translation- Stop codon
These codes are universal for all life. Evidence that we may all have a common ancestor.
Part 2: Steps of Translation (5)
Translation takes place at ____________ and produces ______________ from the instructions in mRNA.
-all 3 types of RNA are involved in translation mRNA, tRNA, rRNA (Know how they are)
Once the termination signal is reached, the new protein is released to the endoplasmic
reticulum to be completed
.
List all of the organelles involved in protein synthesis and their roles:
1.
2.
3.
4.