DNA and Protein Synthesis Worksheet - Amazon S3



DNA and Protein Synthesis Worksheet

This worksheet accompanies DNA Summary

and Genes and Protein Synthesis Summary.

1. Answer the following questions about DNA.

a) Label the image using the words in the box below.

b) Fill in the missing words in the text using the words in the box below.

Chromosomes are found in the nucleus of cells and are made up of long molecules of tightly coiled …………………. These molecules carry coded information that controls ………………… and the characteristics of the organism. A ………………… is a small section of a DNA molecule. DNA has a ………………… structure that is formed by two strands that are coiled together. These strands of the DNA molecule are linked by ………………… which are held together by weak hydrogen bonds. The four bases of DNA are adenine (A), thymine (T), cytosine (C) and guanine (G). These ………………… always pair up in the same way – A with T, and C with G. The sequence of these bases along a DNA molecule is what forms the ………………….

2. DNA controls the function of cells by controlling the production of proteins. Answer the following questions about proteins.

a) Explain how the structure of a protein is determined by the order of base pairs in a DNA molecule. Include the following terms: amino acids, triplet, sequence, base code.

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b) Different proteins are made of different sequences of amino acids joined together to form polypeptide chains. Each protein consists of one or more polypeptide chains. The number and sequence of amino acids in a protein determine its shape and biological functions. Name two functions of proteins.

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c) Name two specific proteins.

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3. Fill in the gaps in the table below to complete the process of protein synthesis.

|Stages in the process |What happens |

|Stage 1 |A section of ………………… containing the gene unwinds and the two strands separate. |

|Stage 2 – ………………………........... |A molecule of RNA is produced, containing a copy of the genetic information. |

|Stage 3 – mRNA moves out of the nucleus |The new RNA molecule called ………………… RNA (mRNA) leaves the nucleus and enters the cytoplasm. |

|Stage 4 |The mRNA attaches to a ribosome in the cytoplasm. |

| |The ribosome ……………...... the sequence of codons in |

| |the mRNA. |

|Stage 5 – ……………………………… |As the mRNA passes through the ribosome, the correct amino acid is added to the growing chain by |

| |tRNA. Amino acids link up to form a polypeptide. |

|Stage 6 – Modification of the protein. |A completed polypeptide chain is released into the cytoplasm. Several ………………… combine to form a |

| |protein. |

4. Draw a diagram to show the process of transcription. Label your diagram using the following terms: molecule of RNA, exposed bases, DNA strands, nucleus.

5. Gene mutations are caused by errors that occur during DNA replication. Gene mutations can prevent the production of the protein that the gene normally codes for.

a) Describe what a gene mutation is.

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b) When do gene mutations occur?

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c) Give an example of a mutagenic agent that could interfere with DNA replication and cause a gene mutation.

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double helix bases genetic code DNA

gene base pairs cell activity

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DNA double helix chromosome base pairs gene

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