Honors Biology EOC (Units 1-5) with
Complete Solutions
What is the role of DNA helicase in DNA replication?
✔✔ DNA helicase unwinds the DNA double helix, allowing the strands to be copied.
How does the endosymbiotic theory explain the origin of mitochondria?
✔✔ The endosymbiotic theory suggests that mitochondria originated from free-living
prokaryotic cells that were engulfed by a host cell.
Why are hydrogen bonds important in the structure of water?
✔✔ Hydrogen bonds give water its unique properties, such as cohesion, adhesion, and high
specific heat.
What is the significance of crossing over during meiosis?
✔✔ Crossing over increases genetic variation by exchanging genetic material between
homologous chromosomes.
How does a mutation in a gene affect protein synthesis?
1
,✔✔ A mutation can alter the DNA sequence, leading to the production of a different or
malfunctioning protein.
What is the importance of a concentration gradient in passive transport?
✔✔ A concentration gradient drives the movement of molecules from areas of high
concentration to low concentration without the use of energy.
How do stem cells differ from specialized cells?
✔✔ Stem cells are undifferentiated and have the potential to become any type of cell, while
specialized cells have specific functions.
What is the relationship between antigens and antibodies in the immune response?
✔✔ Antibodies recognize and bind to antigens on pathogens, marking them for destruction by
immune cells.
How does apoptosis contribute to development and homeostasis?
✔✔ Apoptosis, or programmed cell death, eliminates damaged or unnecessary cells, helping to
shape developing tissues and maintain health.
2
,What is the primary function of stomata in plant leaves?
✔✔ Stomata regulate gas exchange, allowing carbon dioxide in for photosynthesis and oxygen
and water vapor out.
What is the role of messenger RNA (mRNA) in gene expression?
✔✔ mRNA carries the genetic code from DNA to the ribosomes, where it directs protein
synthesis.
How do feedback mechanisms help maintain homeostasis in organisms?
✔✔ Feedback mechanisms, such as negative feedback loops, regulate physiological processes to
keep conditions within a stable range.
What is the function of telomeres in DNA replication?
✔✔ Telomeres protect the ends of chromosomes from deterioration or fusion with other
chromosomes during cell division.
Why is water essential for most biochemical reactions in cells?
✔✔ Water acts as a solvent, facilitating chemical reactions by allowing molecules to dissolve
and interact.
3
, How do ecosystems depend on the flow of energy through trophic levels?
✔✔ Energy flows from producers to consumers, with energy being lost at each trophic level,
maintaining the balance of the ecosystem.
What is the basic unit of life?
✔✔ The cell is the basic unit of life.
How do enzymes speed up chemical reactions?
✔✔ Enzymes lower the activation energy needed for a reaction to occur.
What is the main function of carbohydrates in the body?
✔✔ Carbohydrates provide a primary source of energy for the body.
How does DNA differ from RNA?
✔✔ DNA contains deoxyribose sugar and is double-stranded, while RNA contains ribose sugar
and is single-stranded.
4
Complete Solutions
What is the role of DNA helicase in DNA replication?
✔✔ DNA helicase unwinds the DNA double helix, allowing the strands to be copied.
How does the endosymbiotic theory explain the origin of mitochondria?
✔✔ The endosymbiotic theory suggests that mitochondria originated from free-living
prokaryotic cells that were engulfed by a host cell.
Why are hydrogen bonds important in the structure of water?
✔✔ Hydrogen bonds give water its unique properties, such as cohesion, adhesion, and high
specific heat.
What is the significance of crossing over during meiosis?
✔✔ Crossing over increases genetic variation by exchanging genetic material between
homologous chromosomes.
How does a mutation in a gene affect protein synthesis?
1
,✔✔ A mutation can alter the DNA sequence, leading to the production of a different or
malfunctioning protein.
What is the importance of a concentration gradient in passive transport?
✔✔ A concentration gradient drives the movement of molecules from areas of high
concentration to low concentration without the use of energy.
How do stem cells differ from specialized cells?
✔✔ Stem cells are undifferentiated and have the potential to become any type of cell, while
specialized cells have specific functions.
What is the relationship between antigens and antibodies in the immune response?
✔✔ Antibodies recognize and bind to antigens on pathogens, marking them for destruction by
immune cells.
How does apoptosis contribute to development and homeostasis?
✔✔ Apoptosis, or programmed cell death, eliminates damaged or unnecessary cells, helping to
shape developing tissues and maintain health.
2
,What is the primary function of stomata in plant leaves?
✔✔ Stomata regulate gas exchange, allowing carbon dioxide in for photosynthesis and oxygen
and water vapor out.
What is the role of messenger RNA (mRNA) in gene expression?
✔✔ mRNA carries the genetic code from DNA to the ribosomes, where it directs protein
synthesis.
How do feedback mechanisms help maintain homeostasis in organisms?
✔✔ Feedback mechanisms, such as negative feedback loops, regulate physiological processes to
keep conditions within a stable range.
What is the function of telomeres in DNA replication?
✔✔ Telomeres protect the ends of chromosomes from deterioration or fusion with other
chromosomes during cell division.
Why is water essential for most biochemical reactions in cells?
✔✔ Water acts as a solvent, facilitating chemical reactions by allowing molecules to dissolve
and interact.
3
, How do ecosystems depend on the flow of energy through trophic levels?
✔✔ Energy flows from producers to consumers, with energy being lost at each trophic level,
maintaining the balance of the ecosystem.
What is the basic unit of life?
✔✔ The cell is the basic unit of life.
How do enzymes speed up chemical reactions?
✔✔ Enzymes lower the activation energy needed for a reaction to occur.
What is the main function of carbohydrates in the body?
✔✔ Carbohydrates provide a primary source of energy for the body.
How does DNA differ from RNA?
✔✔ DNA contains deoxyribose sugar and is double-stranded, while RNA contains ribose sugar
and is single-stranded.
4
