Model genes, DNA, and chromosomes
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Middle School Life Science › Model genes, DNA, and chromosomes
The physical trait, "brown eyes" is best described as:
phenotype
genotype
alleles
gene
Explanation
The answer is "a phenotype."
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of the following statements is true?
A chromosome is a long section of bundled up DNA.
Genes are larger sections of DNA than chromosomes.
DNA is only a small part of our genetic code.
Chromosomes are found in specific locations on genes.
Explanation
The answer is "a chromosome is a long section of bundled up DNA." Genes are smaller sections of DNA found in specific locations on chromosomes, and DNA is the entire length of our genetic code.
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of the following genotypes is heterozygous?
Ww
WW
ww
none of these
Explanation
The answer is "Ww."
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of the numbers on this diagram is a chromosome?
2
1
3
none of these
Explanation
The answer is "2"
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of the following genotypes is homozygous recessive?
gg
RR
Ss
TTRr
Explanation
The answer is "gg" because both letters are lowercase.
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of these examples best represents an allele?
the individual letters in a genotype, B or b
both the letters in a genotype, Bb
the physical trait that the gene expresses, like brown eyes
Explanation
The answer is "the individual letters in a genotype B or b"
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of the numbers on this diagram represents DNA?
all of these
none of these
1
2
3
Explanation
The answer is "all of these."
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of the numbers on this diagram is an allele?
1
2
3
none of these
Explanation
The answer is "1"
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)
Which of the following numbers on this diagram represents a gene?
3
2
1
none of these
Explanation
The answer is "3"
DNA is the set of instructions for our physical traits. Small sections of DNA that code for a single trait are called genes. Genes can come in 2 different forms called alleles. We represent alleles with both lowercase and uppercase letters. Uppercase and lowercase letters are used to show which alleles are dominant and which are recessive. A dominant (uppercase letter) allele will overpower a recessive allele (lowercase letter).
Our genotype is our genetic code. When we are writing our genotype we show our genetic code by using two alleles because we get one from our mothers and one from our fathers. Our phenotype is our physical traits. If brown eyes are dominant to blue eyes, we will represent brown eyes with a “B” and blue eyes with a “b”. Because we have two alleles, there are 3 different ways we can write a genotype. We can write a genotype as Bb, BB, or bb.
Heterozygous means that a genotype has a dominant allele from one parent and a recessive allele from the other parent. (Bb) Homozygous dominant means that a genotype has two dominant alleles. (BB) homozygous recessive means that a genotype has two recessive alleles. (bb)