NCEA Level 2 Biology Genetics All Answers Correct
1. What is adenine?
- Answer: Adenine is a nitrogenous base found in both DNA and RNA. In DNA, it pairs with thymine,
while in RNA, it pairs with uracil.
2. Define alleles.
- Answer: Alleles are different versions of a gene. For example, the alleles for height can be tall or
short.
3. What is cytosine's role in nucleic acid?
- Answer: Cytosine is a base present in both DNA and RNA, where it pairs with guanine in DNA.
4. Describe DNA.
- Answer: DNA, or deoxyribonucleic acid, is the molecule that contains the genetic instructions
essential for an organism's functioning. It consists of a five-carbon sugar (deoxyribose), four nitrogenous
bases (adenine, thymine, cytosine, and guanine), and is structured as a double helix with a phosphate
backbone. The bases are held together by hydrogen bonds.
5. Explain what is meant by a dominant trait.
- Answer: A dominant trait is one that is more prominently expressed compared to a recessive trait
and is denoted by uppercase letters in the genotype, such as TT or Tt, where T represents the tall trait.
6. What is the double helix structure?
- Answer: The double helix is the shape of a DNA molecule, formed by two entwined strands that
create a spring-like configuration, stabilized by hydrogen bonds between the bases.
7. What defines a gene?
- Answer: A gene is a segment of DNA that encodes for a protein, subsequently determining a specific
trait based on the sequence of its nucleotide bases.
, 8. What is meant by genotype?
- Answer: Genotype refers to the genetic composition of an organism (e.g., TT or Tt), which includes all
the possible combinations of genes related to a particular trait.
9. How does guanine function in nucleic acids?
- Answer: Guanine is a base found in both DNA and RNA and it pairs with cytosine in DNA.
10. What does heterozygous mean?
- Answer: The term heterozygous refers to an organism that has two differing alleles for a specific
trait, such as Tt for the tall trait.
11. Define homozygous.
- Answer: Homozygous denotes an organism that possesses two identical alleles for a given trait, for
instance, TT for the tall trait.
12. What is meiosis?
- Answer: Meiosis is the type of cell division that produces gametes (reproductive cells) in organisms,
occurring in the gonads (testes and ovaries). In this process, the chromosome number is halved,
resulting in haploid cells (n). The resulting daughter cells exhibit genetic diversity due to crossing over
and random segregation.
13. What is the role of mitosis?
- Answer: Mitosis is the process of cell division in which a nucleus divides to produce two nuclei, each
containing the same number of chromosomes. This process is crucial for growth and tissue repair in the
body's somatic cells.
14. Explain a monohybrid cross.
- Answer: A monohybrid cross examines the inheritance of a single trait, such as crossing a TT plant
with a tt plant, resulting in heterozygous offspring (Tt).
15. What does phenotype refer to?
1. What is adenine?
- Answer: Adenine is a nitrogenous base found in both DNA and RNA. In DNA, it pairs with thymine,
while in RNA, it pairs with uracil.
2. Define alleles.
- Answer: Alleles are different versions of a gene. For example, the alleles for height can be tall or
short.
3. What is cytosine's role in nucleic acid?
- Answer: Cytosine is a base present in both DNA and RNA, where it pairs with guanine in DNA.
4. Describe DNA.
- Answer: DNA, or deoxyribonucleic acid, is the molecule that contains the genetic instructions
essential for an organism's functioning. It consists of a five-carbon sugar (deoxyribose), four nitrogenous
bases (adenine, thymine, cytosine, and guanine), and is structured as a double helix with a phosphate
backbone. The bases are held together by hydrogen bonds.
5. Explain what is meant by a dominant trait.
- Answer: A dominant trait is one that is more prominently expressed compared to a recessive trait
and is denoted by uppercase letters in the genotype, such as TT or Tt, where T represents the tall trait.
6. What is the double helix structure?
- Answer: The double helix is the shape of a DNA molecule, formed by two entwined strands that
create a spring-like configuration, stabilized by hydrogen bonds between the bases.
7. What defines a gene?
- Answer: A gene is a segment of DNA that encodes for a protein, subsequently determining a specific
trait based on the sequence of its nucleotide bases.
, 8. What is meant by genotype?
- Answer: Genotype refers to the genetic composition of an organism (e.g., TT or Tt), which includes all
the possible combinations of genes related to a particular trait.
9. How does guanine function in nucleic acids?
- Answer: Guanine is a base found in both DNA and RNA and it pairs with cytosine in DNA.
10. What does heterozygous mean?
- Answer: The term heterozygous refers to an organism that has two differing alleles for a specific
trait, such as Tt for the tall trait.
11. Define homozygous.
- Answer: Homozygous denotes an organism that possesses two identical alleles for a given trait, for
instance, TT for the tall trait.
12. What is meiosis?
- Answer: Meiosis is the type of cell division that produces gametes (reproductive cells) in organisms,
occurring in the gonads (testes and ovaries). In this process, the chromosome number is halved,
resulting in haploid cells (n). The resulting daughter cells exhibit genetic diversity due to crossing over
and random segregation.
13. What is the role of mitosis?
- Answer: Mitosis is the process of cell division in which a nucleus divides to produce two nuclei, each
containing the same number of chromosomes. This process is crucial for growth and tissue repair in the
body's somatic cells.
14. Explain a monohybrid cross.
- Answer: A monohybrid cross examines the inheritance of a single trait, such as crossing a TT plant
with a tt plant, resulting in heterozygous offspring (Tt).
15. What does phenotype refer to?
