Question
Related Reading
Read about genetic variation and how an organism’s DNA determines its traits. If anything you read helps you answer the Guiding Question, record it as an observation.
1
Fill in the blanks to complete the sentences. Not all answer choices will be used.
Short segments of our DNA provide the instructions for thousands of
, like hair color and the shape of our eyes. These segments of DNA are called
.
chromosomes
genes
mutations
traits
2
Use the diagram to fill in the blanks and complete the sentences. Not all answer choices will be used.
This diagram represents the nucleus of an imaginary organism’s cell. If this organism reproduces, it will pass
chromosomes on to each of its offspring.
7
14
28
3
Identify two sources of genetic variation among offspring that have the same parents.
A
Mutations and threadlike structures
B
Mutations and random assortment
C
Blood type and chromosome pairs
D
Chromosome pairs and infection
4
Like humans, elephants reproduce sexually. This means that all elephant offspring have two parents. Unlike humans, elephants have 56 chromosomes in each body cell. Given this information, what must be true?
A
By random chance, each elephant will inherit 56 chromosomes from one parent and 0 from the other
B
Elephant siblings will have much more in common with each other than human siblings do
C
Each elephant inherits 28 chromosomes from its mother and 28 chromosomes from its father
D
The genes on elephant chromosomes are longer and more complex than human genes
5
How does random assortment affect the inheritance of traits?
A
It creates unpredictability and variety
B
It guaruntees a predictable pattern of inheritance
C
It prevents the occurrence of mutations
D
It results in identical copies of chromosomes

Make an observation!
You will need strong observations to answer the Guiding Question later on.


In some families, siblings look so similar that it can be hard to tell them apart. In other families, siblings don’t look much alike at all. If siblings in a family share parents, why don’t they all look the same?
The answer lies inside the nucleus of each of our cells. There, you’ll find a complete set of chromosomes. In humans, each body cell contains a total of 46 chromosomes: 23 inherited from the mother and 23 inherited from the father.
Chromosomes are threadlike structures made of tightly wound DNA. DNA, or deoxyribonucleic acid, is a spiral-shaped molecule that contains all of a person’s genome—all of their genetic information. Think of DNA as the instructions for how an organism will develop, survive, and reproduce.
Our DNA contains short segments called genes. Humans have genes that determine tens of thousands of traits, including hair texture, blood type, eye color, the shape of our ears, and how our bodies respond to infection.
Although siblings inherit genes from the same parents, they are not genetically identical. One source of genetic differences, or variation, is mutation. Mutations are random changes in DNA. If there are mutations in one or both parents’ reproductive cells, they can be passed onto offspring. The majority of mutations are harmless.
Another source of genetic variation is called random assortment. We inherit two copies of every chromosome, one from each parent. Long before we were born, each of our parents inherited two copies of every chromosome, one from each of their parents, and so on.
Let’s consider a single pair of chromosomes. Each of us inherits one copy of Chromosome 1 from our mother and one copy of Chromosome 1 from our father. Recall that each parent also has two copies of the chromosome. So, when you inherit Chromosome 1 from your father, is it the copy he inherited from his father or the copy he inherited from his mother?
The answer: It’s random! While your father might pass on his mother’s copy of Chromosome 1 to you, he might pass on his father’s copy of Chromosome 1 to your sibling. This all occurs by chance. With 23 pairs of chromosomes, that’s a lot of variation!
Read about genetic variation and how an organism’s DNA determines its traits. If anything you read helps you answer the Guiding Question, record it as an observation.
1
Fill in the blanks to complete the sentences. Not all answer choices will be used.
Short segments of our DNA provide the instructions for thousands of
, like hair color and the shape of our eyes. These segments of DNA are called
.
chromosomes
genes
mutations
traits
2
Use the diagram to fill in the blanks and complete the sentences. Not all answer choices will be used.
This diagram represents the nucleus of an imaginary organism’s cell. If this organism reproduces, it will pass
chromosomes on to each of its offspring.
7
14
28
3
Identify two sources of genetic variation among offspring that have the same parents.
A
Mutations and threadlike structures
B
Mutations and random assortment
C
Blood type and chromosome pairs
D
Chromosome pairs and infection
4
Like humans, elephants reproduce sexually. This means that all elephant offspring have two parents. Unlike humans, elephants have 56 chromosomes in each body cell. Given this information, what must be true?
A
By random chance, each elephant will inherit 56 chromosomes from one parent and 0 from the other
B
Elephant siblings will have much more in common with each other than human siblings do
C
Each elephant inherits 28 chromosomes from its mother and 28 chromosomes from its father
D
The genes on elephant chromosomes are longer and more complex than human genes
5
How does random assortment affect the inheritance of traits?
A
It creates unpredictability and variety
B
It guaruntees a predictable pattern of inheritance
C
It prevents the occurrence of mutations
D
It results in identical copies of chromosomes

Make an observation!
You will need strong observations to answer the Guiding Question later on.


In some families, siblings look so similar that it can be hard to tell them apart. In other families, siblings don’t look much alike at all. If siblings in a family share parents, why don’t they all look the same?
The answer lies inside the nucleus of each of our cells. There, you’ll find a complete set of chromosomes. In humans, each body cell contains a total of 46 chromosomes: 23 inherited from the mother and 23 inherited from the father.
Chromosomes are threadlike structures made of tightly wound DNA. DNA, or deoxyribonucleic acid, is a spiral-shaped molecule that contains all of a person’s genome—all of their genetic information. Think of DNA as the instructions for how an organism will develop, survive, and reproduce.
Our DNA contains short segments called genes. Humans have genes that determine tens of thousands of traits, including hair texture, blood type, eye color, the shape of our ears, and how our bodies respond to infection.
Although siblings inherit genes from the same parents, they are not genetically identical. One source of genetic differences, or variation, is mutation. Mutations are random changes in DNA. If there are mutations in one or both parents’ reproductive cells, they can be passed onto offspring. The majority of mutations are harmless.
Another source of genetic variation is called random assortment. We inherit two copies of every chromosome, one from each parent. Long before we were born, each of our parents inherited two copies of every chromosome, one from each of their parents, and so on.
Let’s consider a single pair of chromosomes. Each of us inherits one copy of Chromosome 1 from our mother and one copy of Chromosome 1 from our father. Recall that each parent also has two copies of the chromosome. So, when you inherit Chromosome 1 from your father, is it the copy he inherited from his father or the copy he inherited from his mother?
The answer: It’s random! While your father might pass on his mother’s copy of Chromosome 1 to you, he might pass on his father’s copy of Chromosome 1 to your sibling. This all occurs by chance. With 23 pairs of chromosomes, that’s a lot of variation!
Answers
GPT-4o mini
Based on the reading you provided, here are the answers to the questions:
1. **Fill in the blanks to complete the sentences:**
Short segments of our **DNA** provide the instructions for thousands of **traits**, like hair color and the shape of our eyes. These segments of DNA are called **genes**.
2. **Use the diagram to fill in the blanks and complete the sentences:**
This diagram represents the nucleus of an imaginary organism’s cell. If this organism reproduces, it will pass **28** chromosomes on to each of its offspring.
3. **Identify two sources of genetic variation among offspring that have the same parents:**
B. **Mutations and random assortment.**
4. **Like humans, elephants reproduce sexually. This means that all elephant offspring have two parents. Unlike humans, elephants have 56 chromosomes in each body cell. Given this information, what must be true?**
C. **Each elephant inherits 28 chromosomes from its mother and 28 chromosomes from its father.**
5. **How does random assortment affect the inheritance of traits?**
A. **It creates unpredictability and variety.**
### Observations:
- Siblings do not always look the same because they inherit different combinations of genes from their parents.
- Genetic variation occurs due to mutations in DNA and the random assortment of chromosomes during reproduction.
- Each parent contributes one copy of each chromosome, leading to a mix of traits in offspring, which explains the differences seen between siblings who share the same parents.
1. **Fill in the blanks to complete the sentences:**
Short segments of our **DNA** provide the instructions for thousands of **traits**, like hair color and the shape of our eyes. These segments of DNA are called **genes**.
2. **Use the diagram to fill in the blanks and complete the sentences:**
This diagram represents the nucleus of an imaginary organism’s cell. If this organism reproduces, it will pass **28** chromosomes on to each of its offspring.
3. **Identify two sources of genetic variation among offspring that have the same parents:**
B. **Mutations and random assortment.**
4. **Like humans, elephants reproduce sexually. This means that all elephant offspring have two parents. Unlike humans, elephants have 56 chromosomes in each body cell. Given this information, what must be true?**
C. **Each elephant inherits 28 chromosomes from its mother and 28 chromosomes from its father.**
5. **How does random assortment affect the inheritance of traits?**
A. **It creates unpredictability and variety.**
### Observations:
- Siblings do not always look the same because they inherit different combinations of genes from their parents.
- Genetic variation occurs due to mutations in DNA and the random assortment of chromosomes during reproduction.
- Each parent contributes one copy of each chromosome, leading to a mix of traits in offspring, which explains the differences seen between siblings who share the same parents.