TRANSCRIPTION AND TRANSLATION
WALT/L.O. 4
I can describe the process of transcription or translation.
WILF/SC for WALT 4
I will be able to understand that information within the DNA molecule is divided into segments called genes.
I will be able to learn that each gene contains the instructions for assembling a unique protein that performs a specialized function in the cell.
I will be able to summarize the two-step process of transcription and translation by which the information in a gene is used to construct a protein.
I can describe the process of transcription or translation.
WILF/SC for WALT 4
I will be able to understand that information within the DNA molecule is divided into segments called genes.
I will be able to learn that each gene contains the instructions for assembling a unique protein that performs a specialized function in the cell.
I will be able to summarize the two-step process of transcription and translation by which the information in a gene is used to construct a protein.
https://www.youtube.com/watch?v=zwibgNGe4aY
What is the role of DNA and RNA in building proteins?
•Some of the information in the DNA is copied to a separate molecule called RNA, or ribonucleic acid.
•RNA is used to build proteins.
•Like DNA, RNA has a sugar-phosphate backbone and the bases adenine (A), guanine (G), and cytosine (C).
•Instead of thymine (T), RNA contains uracil (U).
•Three types of RNA have special roles in making proteins.
•When a cell needs to make a protein, it makes an RNA copy of a section of the DNA. This is called transcription.
•In transcription, DNA is used as a template to make a complementary strand of messenger RNA (mRNA).
•The information in the mRNA is then used to build proteins. This is called translation.
•In translation, the mRNA passes through a protein assembly line within a ribosome.
What is the role of DNA and RNA in building proteins?
•Some of the information in the DNA is copied to a separate molecule called RNA, or ribonucleic acid.
•RNA is used to build proteins.
•Like DNA, RNA has a sugar-phosphate backbone and the bases adenine (A), guanine (G), and cytosine (C).
•Instead of thymine (T), RNA contains uracil (U).
•Three types of RNA have special roles in making proteins.
•When a cell needs to make a protein, it makes an RNA copy of a section of the DNA. This is called transcription.
•In transcription, DNA is used as a template to make a complementary strand of messenger RNA (mRNA).
•The information in the mRNA is then used to build proteins. This is called translation.
•In translation, the mRNA passes through a protein assembly line within a ribosome.
•A ribosome is a cell organelle made of ribosomal RNA (rRNA) and protein.
•As mRNA passes through, transfer RNA (tRNA) delivers amino acids to the ribosomes.
•The order of the bases codes for which amino acid is attached.
•The amino acids are joined together to form a protein.
•As mRNA passes through, transfer RNA (tRNA) delivers amino acids to the ribosomes.
•The order of the bases codes for which amino acid is attached.
•The amino acids are joined together to form a protein.
Reading DNA
• The information in DNA is divided into segments called genes. Each gene contains the instructions for building a particular protein. Proteins do the majority of the work in our cells and make it possible for cells to perform special jobs.
• Some of the general protein functions, e.g. enzymes catalyze (speed up) chemical reactions, transport proteins carry small molecules or ions across the cell membrane, signaling proteins carry signals from cell to cell, structural proteins give cells their different shapes, etc.
• Examples: DNA polymerase is an enzyme that makes new DNA, hemoglobin in red blood cells carries oxygen to tissues and organs, insulin hormone acts as a signaling protein to control glucose levels in the blood, α-keratin forms fibers that reinforce the structure of epithelial cells and is the major protein in hair
Activity Instructions
• Use the edible DNA models you built previously to simulate the two-step process a cell follows to build a protein, namely transcription and translation.
◦ In the first step, a cell reads the information in a gene and makes a copy (called mRNA) to send to the protein-building machinery (an enzyme called the ribosome) in the cytoplasm of the cell. The process of making an mRNA molecule from a DNA template is referred to as transcription.
◦ Note that the adenine (A) in DNA now directs the base pair uracil (U) to be inserted into the mRNA sequence.
◦ In the second step, the sequence information contained in the mRNA molecule is used by the ribosome to string together amino acids, or protein building blocks. This process is called translation. The order in which the amino acids are assembled dictates the shape and function of the protein.
• Work in groups to complete the activity. Follow the instructions in the learner handout to transcribe and translate the short gene sequence in learners’ edible DNA models.
• Use the code to find the names of the amino acids in their assembled protein.
Discussion Points
The DNA molecule has the same basic structure and function in all living things.
It carries the instructions for building and operating an organism in the form of a sequence of chemical bases each represented by the fi rst letter of its name: adenine (A), cytosine (C), guanine (G), and thymine (T).
Human cells contain forty-six DNA molecules that when tightly packaged during cell division can be visualized as forty-six chromosomes.
The sequence information in each DNA molecule is divided into segments called genes.
Each gene contains a blueprint for constructing a unique protein that has a specialized function in the cell.
Upon completion of the Human Genome Project in the year 2003, it was determined that humans have approximately 20,000 genes.
Scientists now have the enormous task of deciphering how these genes direct the development and maintenance of an organism as complex as the human body.
The human body with its different tissues and organs requires a large variety of cell types to function, yet every human cell contains the exact same set of DNA instructions. How, then, can the diversity among cells be explained?
Different cell types arise because each cell uses different combinations of genes, building only the proteins it will need to perform its special job.
To assemble a protein using the information in a gene, a cell employs the two-step process of transcription and translation.
After a cell has chosen a gene from which it will build a protein, it makes a copy of the information in the form of messenger ribonucleic acid (mRNA) to send to the protein-building machinery.
The synthesis of an mRNA molecule from a DNA template is referred to as transcription.
The structure of mRNA is very similar to DNA in that it has a sugar-phosphate backbone to which the chemical bases are attached.
However, there are some important differences: (1) mRNA is single-stranded and therefore does not form a double helix, (2) the sugar used to form the backbone is slightly different, and (3) the chemical base thymine (T) is replaced by uracil (U).
The sequence of the mRNA molecule is determined by using one strand of the DNA molecule as a template and applying the rules of base pairing.
Except, the base adenine (A) will now cause uracil (U) instead of thymine (T) to be added to the mRNA sequence. Note that the mRNA sequence is a complement of its DNA template.
Once the DNA information has been copied or transcribed, the mRNA leaves the nucleus and enters the cytoplasm where the instructions it contains are used by the cell’s protein building machinery to assemble a protein.
The process of assembling a protein from an mRNA transcript is referred to as translation.
The protein-building machinery (an enzyme called the ribosome) reads the mRNA sequence three letters at a time.
Each combination of three letters codes for a particular protein building block called an amino acid. There are twenty amino acids for the machinery to choose from.
The order in which the amino acids are assembled is different for all proteins. The amino acid sequence determines the shape of the protein, and provides the characteristics that enable it to perform a specialized function in the cell.
The three-letter codes used by the protein building machinery to assemble a protein are collectively referred to as the Universal Genetic Code.
It is universal because all living organisms use the same three-letter codes to specify the same amino acids.
Extension
Use one of the following sequences:
Sequence 1: T A C G T A T G A A A C
Sequence 2: T G G T T T A G A A T T
Delete the second nucleotide and find out what changes happen to the amino acid sequence.
Support
https://authoring.concord.org/activities/22/00ed4c34-4893-4fdf-b063-da8033a620c4
• Some of the general protein functions, e.g. enzymes catalyze (speed up) chemical reactions, transport proteins carry small molecules or ions across the cell membrane, signaling proteins carry signals from cell to cell, structural proteins give cells their different shapes, etc.
• Examples: DNA polymerase is an enzyme that makes new DNA, hemoglobin in red blood cells carries oxygen to tissues and organs, insulin hormone acts as a signaling protein to control glucose levels in the blood, α-keratin forms fibers that reinforce the structure of epithelial cells and is the major protein in hair
Activity Instructions
• Use the edible DNA models you built previously to simulate the two-step process a cell follows to build a protein, namely transcription and translation.
◦ In the first step, a cell reads the information in a gene and makes a copy (called mRNA) to send to the protein-building machinery (an enzyme called the ribosome) in the cytoplasm of the cell. The process of making an mRNA molecule from a DNA template is referred to as transcription.
◦ Note that the adenine (A) in DNA now directs the base pair uracil (U) to be inserted into the mRNA sequence.
◦ In the second step, the sequence information contained in the mRNA molecule is used by the ribosome to string together amino acids, or protein building blocks. This process is called translation. The order in which the amino acids are assembled dictates the shape and function of the protein.
• Work in groups to complete the activity. Follow the instructions in the learner handout to transcribe and translate the short gene sequence in learners’ edible DNA models.
• Use the code to find the names of the amino acids in their assembled protein.
Discussion Points
The DNA molecule has the same basic structure and function in all living things.
It carries the instructions for building and operating an organism in the form of a sequence of chemical bases each represented by the fi rst letter of its name: adenine (A), cytosine (C), guanine (G), and thymine (T).
Human cells contain forty-six DNA molecules that when tightly packaged during cell division can be visualized as forty-six chromosomes.
The sequence information in each DNA molecule is divided into segments called genes.
Each gene contains a blueprint for constructing a unique protein that has a specialized function in the cell.
Upon completion of the Human Genome Project in the year 2003, it was determined that humans have approximately 20,000 genes.
Scientists now have the enormous task of deciphering how these genes direct the development and maintenance of an organism as complex as the human body.
The human body with its different tissues and organs requires a large variety of cell types to function, yet every human cell contains the exact same set of DNA instructions. How, then, can the diversity among cells be explained?
Different cell types arise because each cell uses different combinations of genes, building only the proteins it will need to perform its special job.
To assemble a protein using the information in a gene, a cell employs the two-step process of transcription and translation.
After a cell has chosen a gene from which it will build a protein, it makes a copy of the information in the form of messenger ribonucleic acid (mRNA) to send to the protein-building machinery.
The synthesis of an mRNA molecule from a DNA template is referred to as transcription.
The structure of mRNA is very similar to DNA in that it has a sugar-phosphate backbone to which the chemical bases are attached.
However, there are some important differences: (1) mRNA is single-stranded and therefore does not form a double helix, (2) the sugar used to form the backbone is slightly different, and (3) the chemical base thymine (T) is replaced by uracil (U).
The sequence of the mRNA molecule is determined by using one strand of the DNA molecule as a template and applying the rules of base pairing.
Except, the base adenine (A) will now cause uracil (U) instead of thymine (T) to be added to the mRNA sequence. Note that the mRNA sequence is a complement of its DNA template.
Once the DNA information has been copied or transcribed, the mRNA leaves the nucleus and enters the cytoplasm where the instructions it contains are used by the cell’s protein building machinery to assemble a protein.
The process of assembling a protein from an mRNA transcript is referred to as translation.
The protein-building machinery (an enzyme called the ribosome) reads the mRNA sequence three letters at a time.
Each combination of three letters codes for a particular protein building block called an amino acid. There are twenty amino acids for the machinery to choose from.
The order in which the amino acids are assembled is different for all proteins. The amino acid sequence determines the shape of the protein, and provides the characteristics that enable it to perform a specialized function in the cell.
The three-letter codes used by the protein building machinery to assemble a protein are collectively referred to as the Universal Genetic Code.
It is universal because all living organisms use the same three-letter codes to specify the same amino acids.
Extension
Use one of the following sequences:
Sequence 1: T A C G T A T G A A A C
Sequence 2: T G G T T T A G A A T T
Delete the second nucleotide and find out what changes happen to the amino acid sequence.
Support
https://authoring.concord.org/activities/22/00ed4c34-4893-4fdf-b063-da8033a620c4
readingdna.pdf |