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1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart2h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

3. Energy & Cell Processes

Genetic Code

3. Energy & Cell Processes

Genetic Code: Videos & Practice Problems

Video Lessons Practice Worksheet

Topic summary

The genetic code is a universal table that links DNA and RNA sequences to specific amino acids in proteins. It operates through a three-step process: transcription of DNA to mRNA, identifying codons in the mRNA, and translating these codons into amino acids using the genetic code. Each codon, a three-nucleotide sequence, corresponds to an amino acid, with start and stop codons marking the beginning and end of protein synthesis. Understanding this process is crucial for grasping protein synthesis and genetic expression.

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Genetic Code

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Genetic Code Video Summary

The genetic code serves as a crucial framework that illustrates how DNA and RNA dictate the sequence of amino acids in proteins. Essentially, it acts as a bridge connecting nucleic acids, such as DNA and RNA, to the amino acids that form proteins. This code is largely universal among various organisms, although some species may exhibit slight variations.

At the core of the genetic code is the concept of a codon, which is a sequence of three nucleotides found in messenger RNA (mRNA). Each codon corresponds to a specific amino acid, meaning that the genetic code can be analyzed one codon at a time to determine the amino acid it encodes. This systematic approach allows for a clear understanding of how genetic information translates into functional proteins.

In summary, the genetic code is essential for interpreting the information stored in DNA and RNA, facilitating the synthesis of proteins by specifying the order of amino acids through codons. Understanding this code is fundamental for exploring the mechanisms of genetic expression and protein synthesis.

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How to Use the Genetic Code

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How to Use the Genetic Code Video Summary

The genetic code is essential for understanding how DNA is translated into proteins, and it involves a three-step process. The first step is transcription, where the coding DNA sequence is used to create the mRNA sequence. This process involves replacing thymine (T) in the DNA with uracil (U) in the mRNA. For example, if the DNA coding strand reads TGC, the corresponding mRNA will read UGC. The mRNA sequence mirrors the coding strand, except for this substitution.

In the second step, the mRNA transcript is divided into codons, which are groups of three nucleotides. Each codon corresponds to a specific amino acid or a stop signal. The start codon, typically AUG, indicates where translation begins, while stop codons signal the end of the protein synthesis process. For instance, in an mRNA sequence, the codons might be separated visually to identify them easily, such as AUG, CAU, ACC, UGU, and UAA.

The third step involves translating these codons into their respective amino acids using the genetic code chart. Each codon is read by identifying its first, second, and third nucleotides, which correspond to specific rows and columns in the chart. For example, the codon AUG codes for methionine (Met), the start amino acid for most proteins. Continuing this process, CAU codes for histidine (His), ACC for threonine (Thr), and UGU for cysteine (Cys). The sequence ends with UAA, a stop codon that does not code for any amino acid, thus terminating the translation process.

Ultimately, the resulting polypeptide sequence from this example is methionine, histidine, threonine, and cysteine. Understanding this process is crucial for applying genetic concepts in various biological contexts, and practice with these steps will enhance comprehension of protein synthesis.

Problem

The redundancy of the genetic code is a consequence of ______.

Having more codons than amino acids.

Having four different letters (As, Cs, Gs, and Us) in the codon alphabet.

Having fewer codons than there are amino acids.

Each codon having a single amino acid.

Problem

A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed?

3′-UCA-5′.

3′-UGA-5′.

5′-TCA-3′.

3′-ACU-5′.

Problem

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is ________.

TTT.

UUA.

UUU.

AAA.

Problem

Which of the following sequences of nucleotides are possible in the template strand of DNA that would code for the polypeptide sequence Phe–Leu–Ile–Val?

5′–TTG–CTA–CAG–TAG–3′.

5′–AUG–CTG–CAG–TAT–3′.

3′–AAA–AAT–ATA–ACA–5′.

3′–AAA–GAA–TAA–CAA–5′.

Problem

What amino acid sequence will be generated, based on the following mRNA codon sequence? 5′–AUG–UCU–UCG–UUA–UCC–UUG–3′

Met-Arg-Glu-Arg-Glu-Arg.

Met-Glu-Arg-Arg-Glu-Leu.

Met-Ser-Leu-Ser-Leu-Ser.

Met-Ser-Ser-Leu-Ser-Leu.

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What is the genetic code and why is it important?

The genetic code is a universal table that links DNA and RNA sequences to specific amino acids in proteins. It is crucial because it provides the instructions for assembling proteins, which are essential for all cellular functions. The genetic code operates through a three-step process: transcription of DNA to mRNA, identifying codons in the mRNA, and translating these codons into amino acids. Each codon, a three-nucleotide sequence, corresponds to an amino acid, with start and stop codons marking the beginning and end of protein synthesis. Understanding the genetic code is fundamental for grasping how genetic information is expressed and how proteins are synthesized.

How does the genetic code translate mRNA into amino acids?

The genetic code translates mRNA into amino acids through a three-step process. First, the DNA coding sequence is transcribed into mRNA, replacing thymine (T) with uracil (U). Second, the mRNA sequence is divided into three-nucleotide codons. Each codon specifies a particular amino acid. Third, the genetic code table is used to match each codon to its corresponding amino acid. For example, the codon AUG codes for methionine, which is often the start codon. This process continues until a stop codon is reached, signaling the end of protein synthesis. This translation is essential for producing functional proteins from genetic information.

What are start and stop codons in the genetic code?

Start and stop codons are specific sequences in the genetic code that signal the beginning and end of protein synthesis. The start codon is typically AUG, which codes for the amino acid methionine. This codon marks the initiation point for translation. Stop codons, such as UAA, UAG, and UGA, do not code for any amino acids. Instead, they signal the termination of translation, indicating that the protein synthesis process should stop. These codons are crucial for ensuring that proteins are synthesized correctly and efficiently.

How universal is the genetic code across different organisms?

The genetic code is relatively universal across all organisms, meaning that the same codons generally specify the same amino acids in different species. However, there are some exceptions and variations. For example, certain organisms, such as mitochondria and some protozoa, have slight differences in their genetic codes. Despite these variations, the overall structure and function of the genetic code are remarkably consistent, allowing for a common framework for understanding genetic expression and protein synthesis across diverse life forms.

What is the role of mRNA in the genetic code?

mRNA, or messenger RNA, plays a crucial role in the genetic code by serving as the intermediary between DNA and protein synthesis. During transcription, the DNA coding sequence is transcribed into mRNA, which carries the genetic information from the nucleus to the ribosome. The mRNA sequence is then read in sets of three nucleotides, known as codons, each of which specifies a particular amino acid. This process, known as translation, uses the genetic code to assemble amino acids into a polypeptide chain, ultimately forming a functional protein. mRNA is essential for translating genetic information into proteins.