1.
What is the primary role of mitochondria in a cell?
Correct Answer
B. Energy production (ATP synthesis)
Explanation
Mitochondria, often referred to as the powerhouse of the cell, play a crucial role in cellular energy production. They produce adenosine triphosphate (ATP) through a process called oxidative phosphorylation, which occurs in the inner mitochondrial membrane. ATP is the primary energy currency of the cell, providing the energy necessary for various cellular processes such as metabolism, cell division, and signaling.
2.
Which type of DNA is primarily inherited along maternal lineages?
Correct Answer
C. Mitochondrial DNA
Explanation
Mitochondrial DNA (mtDNA) is inherited exclusively from the mother. During fertilization, the egg contributes the majority of cellular components, including mitochondria, while sperm contributes only genetic material (nucleus). As a result, offspring inherit mtDNA solely from the mother, making it a valuable tool for tracing maternal lineages and understanding maternal ancestry.
3.
What is the significance of mitochondrial DNA mutations?
Correct Answer
C. They can cause cellular energy deficits.
Explanation
Mutations in mitochondrial DNA (mtDNA) can disrupt the normal functioning of mitochondria, leading to various cellular dysfunctions. Since mitochondria are responsible for producing ATP, mutations can impair ATP synthesis, resulting in cellular energy deficits. This can have widespread effects on cellular processes and overall organismal health, potentially leading to mitochondrial diseases such as mitochondrial myopathy, Leigh syndrome, or Leber's hereditary optic neuropathy.
4.
Which process involves tracing ancestral connections through DNA?
Correct Answer
C. Maternal lineage tracing
Explanation
Maternal lineage tracing involves tracking genetic markers passed down through the maternal lineage. This process relies on the inheritance of mitochondrial DNA (mtDNA) exclusively from the mother. By analyzing mtDNA variations across individuals, scientists can reconstruct maternal ancestry, uncovering historical migrations, population movements, and familial relationships.
5.
What is the term for the DNA found in mitochondria?
Correct Answer
C. Mitochondrial DNA
Explanation
Mitochondrial DNA (mtDNA) is a small, circular molecule of DNA found within mitochondria, the energy-producing organelles in eukaryotic cells. Unlike nuclear DNA, which is located in the cell nucleus and comprises the majority of an organism's genetic material, mtDNA is present in multiple copies within each mitochondrion.
6.
What is the primary function of mitochondrial DNA analysis?
Correct Answer
B. Tracing maternal lineages
Explanation
Mitochondrial DNA (mtDNA) analysis is primarily used to trace maternal lineages and uncover ancestral connections passed down through the maternal line. By comparing mtDNA sequences across individuals or populations, researchers can infer historical relationships, migrations, and evolutionary patterns, providing insights into human origins and genetic diversity.
7.
Which of the following is a characteristic of mitochondrial DNA?
Correct Answer
C. It contains genetic information.
Explanation
Mitochondrial DNA (mtDNA) is a unique type of genetic material found within mitochondria, the organelles responsible for energy production in eukaryotic cells. Unlike nuclear DNA, which is located in the cell nucleus and contains the majority of an organism's genetic information, mtDNA is present in multiple copies within each mitochondrion and is circular in structure. One of the primary functions of mitochondrial DNA is to encode for proteins essential for mitochondrial function. These proteins play critical roles in oxidative phosphorylation, the process by which mitochondria generate adenosine triphosphate (ATP), the primary energy currency of the cell.
8.
What is the primary source of mitochondrial DNA in offspring?
Correct Answer
B. Maternal lineage
Explanation
Offspring primarily inherit mitochondrial DNA (mtDNA) from their mother due to the way mitochondria are transmitted during fertilization. While the egg contributes the majority of cellular components, including mitochondria, the sperm contributes only genetic material (nucleus). Therefore, mitochondrial DNA from the father's sperm does not typically contribute to the offspring's mitochondrial genome.
9.
What happens if there are mutations in mitochondrial DNA?
Correct Answer
C. They can lead to mitochondrial diseases.
Explanation
Mutations in mitochondrial DNA (mtDNA) can disrupt the normal functioning of mitochondria, leading to mitochondrial dysfunction and various diseases collectively known as mitochondrial diseases. These disorders can affect tissues and organs with high energy demands, such as muscles, brain, and nervous system, causing symptoms ranging from muscle weakness and fatigue to neurological impairments and organ failure.
10.
How do mitochondrial DNA mutations impact cellular function?
Correct Answer
C. They disrupt ATP synthesis.
Explanation
Mitochondrial DNA (mtDNA) mutations can impair the function of enzymes involved in ATP synthesis, disrupting the process of oxidative phosphorylation in mitochondria. As a result, ATP production may be reduced, leading to cellular energy deficits. Since ATP is essential for powering cellular processes, including metabolism and cell signaling, disruptions in ATP synthesis can have widespread effects on cellular function and organismal health.