Educational worksheet on DNA, chromosomes, and genes with questions and a diagram.
Diagram illustrating DNA, chromosomes, and genes, showing a cell nucleus with chromosomes and a DNA double helix with genes labeled.
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Step-by-step solution for: Solved DNA, Chromosomes & Genes 1. How many genes do we | Chegg.com
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Show Answer Key & Explanations
Step-by-step solution for: Solved DNA, Chromosomes & Genes 1. How many genes do we | Chegg.com
Let's solve the worksheet step by step and provide explanations for each answer.
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- Answer: Approximately 20,000–25,000 genes.
- Explanation: The human genome contains about 20,000–25,000 protein-coding genes. These genes are responsible for producing proteins that carry out various functions in the body.
---
- Answer: Genome.
- Explanation: The genome refers to the complete set of genetic material (DNA) present in an organism. It includes all the genes and non-coding DNA sequences.
---
- Answer: A chromosome is a thread-like structure made up of DNA and proteins (primarily histones) that carries genetic information.
- Explanation: Chromosomes are found in the nucleus of cells and organize the long strands of DNA into compact structures. Each chromosome contains many genes.
---
- Answer: Humans have 46 chromosomes (23 pairs). They are found in the nucleus of cells.
- Explanation: Humans have 23 pairs of chromosomes, totaling 46 chromosomes. One set of 23 comes from the mother, and the other set comes from the father. These chromosomes are located in the nucleus of every cell (except red blood cells, which lack a nucleus).
---
- Answer: DNA is longer.
- Explanation: DNA is a very long molecule that is tightly coiled and packaged into chromosomes. If you were to stretch out the DNA in a single human cell, it would be about 2 meters long! However, when coiled into chromosomes, it fits inside the tiny nucleus of a cell.
---
- Answer: DNA fits by being tightly coiled around proteins called histones, forming a structure called chromatin. During cell division, chromatin condenses further into visible chromosomes.
- Explanation: To fit the long DNA strands into the small nucleus, DNA wraps around histone proteins to form a structure called nucleosomes. These nucleosomes then coil further to form chromatin. During cell division, chromatin condenses even more to form the visible X-shaped chromosomes.
---
- Answer: A gene is a segment of DNA that codes for a specific protein or RNA molecule. Genes are the basic units of heredity.
- Explanation: Genes contain the instructions needed to build proteins, which perform most of the work in cells. Some genes also produce RNA molecules that have regulatory roles.
---
- Answer: Sequences of genes carry the information needed for building proteins and regulating cellular processes.
- Explanation: Genes contain the code for amino acids, which are the building blocks of proteins. Proteins are essential for nearly all biological functions, including structural support, enzyme activity, and signaling.
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- Answer: About 99.9%.
- Explanation: Despite individual differences, humans share approximately 99.9% of their DNA sequence. The remaining 0.1% accounts for variations in traits such as appearance, susceptibility to diseases, and other characteristics.
---
- Answer: Environment and lifestyle factors.
- Explanation: While genetics play a significant role in determining traits, environmental factors (e.g., diet, exposure to toxins, climate) and lifestyle choices (e.g., exercise, smoking) can also influence how traits are expressed. This interaction is often referred to as "nature vs. nurture."
---
- Answer: Gregor Mendel.
- Explanation: Gregor Mendel, an Austrian monk, is known as the "father of genetics" because of his pioneering work on pea plants in the mid-19th century. He discovered the basic principles of inheritance, now known as Mendelian genetics.
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1. Approximately 20,000–25,000 genes.
2. Genome.
3. A chromosome is a thread-like structure made up of DNA and proteins that carries genetic information.
4. Humans have 46 chromosomes (23 pairs); they are found in the nucleus of cells.
5. DNA is longer.
6. DNA fits by being tightly coiled around proteins called histones, forming chromatin.
7. A gene is a segment of DNA that codes for a specific protein or RNA molecule.
8. Building proteins and regulating cellular processes.
9. About 99.9%.
10. Environment and lifestyle factors.
11. Gregor Mendel.
Final Answer Boxed:
\boxed{
\begin{array}{l}
1. \text{Approximately 20,000–25,000 genes.} \\
2. \text{Genome.} \\
3. \text{A chromosome is a thread-like structure made up of DNA and proteins that carries genetic information.} \\
4. \text{Humans have 46 chromosomes (23 pairs); they are found in the nucleus of cells.} \\
5. \text{DNA is longer.} \\
6. \text{DNA fits by being tightly coiled around proteins called histones, forming chromatin.} \\
7. \text{A gene is a segment of DNA that codes for a specific protein or RNA molecule.} \\
8. \text{Building proteins and regulating cellular processes.} \\
9. \text{About 99.9%.} \\
10. \text{Environment and lifestyle factors.} \\
11. \text{Gregor Mendel.}
\end{array}
}
---
1. How many genes do we have?
- Answer: Approximately 20,000–25,000 genes.
- Explanation: The human genome contains about 20,000–25,000 protein-coding genes. These genes are responsible for producing proteins that carry out various functions in the body.
---
2. This complete set of genes is called the _______
- Answer: Genome.
- Explanation: The genome refers to the complete set of genetic material (DNA) present in an organism. It includes all the genes and non-coding DNA sequences.
---
3. What is a chromosome?
- Answer: A chromosome is a thread-like structure made up of DNA and proteins (primarily histones) that carries genetic information.
- Explanation: Chromosomes are found in the nucleus of cells and organize the long strands of DNA into compact structures. Each chromosome contains many genes.
---
4. How many chromosomes do humans have? And where are they found?
- Answer: Humans have 46 chromosomes (23 pairs). They are found in the nucleus of cells.
- Explanation: Humans have 23 pairs of chromosomes, totaling 46 chromosomes. One set of 23 comes from the mother, and the other set comes from the father. These chromosomes are located in the nucleus of every cell (except red blood cells, which lack a nucleus).
---
5. Which is longer... DNA or a chromosome?
- Answer: DNA is longer.
- Explanation: DNA is a very long molecule that is tightly coiled and packaged into chromosomes. If you were to stretch out the DNA in a single human cell, it would be about 2 meters long! However, when coiled into chromosomes, it fits inside the tiny nucleus of a cell.
---
6. How does DNA fit?
- Answer: DNA fits by being tightly coiled around proteins called histones, forming a structure called chromatin. During cell division, chromatin condenses further into visible chromosomes.
- Explanation: To fit the long DNA strands into the small nucleus, DNA wraps around histone proteins to form a structure called nucleosomes. These nucleosomes then coil further to form chromatin. During cell division, chromatin condenses even more to form the visible X-shaped chromosomes.
---
7. What is a gene?
- Answer: A gene is a segment of DNA that codes for a specific protein or RNA molecule. Genes are the basic units of heredity.
- Explanation: Genes contain the instructions needed to build proteins, which perform most of the work in cells. Some genes also produce RNA molecules that have regulatory roles.
---
8. Sequences of genes carry the information needed for _______
- Answer: Sequences of genes carry the information needed for building proteins and regulating cellular processes.
- Explanation: Genes contain the code for amino acids, which are the building blocks of proteins. Proteins are essential for nearly all biological functions, including structural support, enzyme activity, and signaling.
---
9. What percentage of your DNA is identical to everyone else's?
- Answer: About 99.9%.
- Explanation: Despite individual differences, humans share approximately 99.9% of their DNA sequence. The remaining 0.1% accounts for variations in traits such as appearance, susceptibility to diseases, and other characteristics.
---
10. Besides genetics, what else influences our traits?
- Answer: Environment and lifestyle factors.
- Explanation: While genetics play a significant role in determining traits, environmental factors (e.g., diet, exposure to toxins, climate) and lifestyle choices (e.g., exercise, smoking) can also influence how traits are expressed. This interaction is often referred to as "nature vs. nurture."
---
11. The father of Genetics is _______
- Answer: Gregor Mendel.
- Explanation: Gregor Mendel, an Austrian monk, is known as the "father of genetics" because of his pioneering work on pea plants in the mid-19th century. He discovered the basic principles of inheritance, now known as Mendelian genetics.
---
Final Answer Summary:
1. Approximately 20,000–25,000 genes.
2. Genome.
3. A chromosome is a thread-like structure made up of DNA and proteins that carries genetic information.
4. Humans have 46 chromosomes (23 pairs); they are found in the nucleus of cells.
5. DNA is longer.
6. DNA fits by being tightly coiled around proteins called histones, forming chromatin.
7. A gene is a segment of DNA that codes for a specific protein or RNA molecule.
8. Building proteins and regulating cellular processes.
9. About 99.9%.
10. Environment and lifestyle factors.
11. Gregor Mendel.
Final Answer Boxed:
\boxed{
\begin{array}{l}
1. \text{Approximately 20,000–25,000 genes.} \\
2. \text{Genome.} \\
3. \text{A chromosome is a thread-like structure made up of DNA and proteins that carries genetic information.} \\
4. \text{Humans have 46 chromosomes (23 pairs); they are found in the nucleus of cells.} \\
5. \text{DNA is longer.} \\
6. \text{DNA fits by being tightly coiled around proteins called histones, forming chromatin.} \\
7. \text{A gene is a segment of DNA that codes for a specific protein or RNA molecule.} \\
8. \text{Building proteins and regulating cellular processes.} \\
9. \text{About 99.9%.} \\
10. \text{Environment and lifestyle factors.} \\
11. \text{Gregor Mendel.}
\end{array}
}
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