Genetics
What is the shape of DNA?
Double helix
What is the primary source of energy for most ecosystems?
The Sun
Which organ pumps blood throughout the body?
The heart
What macromolecule is the main source of energy for the body?
Carbohydrates
Name the female reproductive hormones.
Estrogen and Progesterone
what are the basic units that make up DNA?
Nucleotides
What happens to energy as it moves up a food chain?
It decreases
What gas do the lungs absorb from the air we breathe in?
Oxygen
Which macromolecule is made up of amino acids?
Proteins
Which test is used to detect the presence of proteins in a food sample, and what color change indicates a positive result?
The Biuret test, a purple or violet color shows proteins are present.
What is the type of cell division that results in gametes?
Meiosis
What term describes a group of organisms of the same species living in one area?
Population
What is the main function of the villi in the small intestine?
To increase surface area for nutrient absorption.
What is the function of enzymes in biological systems?
Enzyme activity increases with temperature until it reaches an optimum; beyond that, enzymes denature and lose function.
How does the structure of red blood cells relate to their function in oxygen transport?
They are biconcave (increasing surface area for gas exchange), lack a nucleus (more room for hemoglobin), and are flexible to move through narrow capillaries.
explain the difference between a genotype and a phenotype.
Genotype refers to the genetic makeup (alleles) while phenotype is the observable trait or expression of those genes.
Distinguish between mutualism and parasitism.
Mutualism benefits both organisms; parasitism benefits one and harms the other.
Describe how oxygen is transported in the blood.
Oxygen binds to hemoglobin in red blood cells forming oxyhemoglobin, which is transported to tissues.
Describe how temperature affects enzyme activity.
Enzyme activity increases with temperature until it reaches an optimum; beyond that, enzymes denature and lose function.
Explain how changes in one population within an ecosystem can affect at least two other populations, giving an example.
A change in one population can disrupt predator-prey or competitive relationships.
Example: If the rabbit population decreases, foxes (predators) have less food, reducing their numbers, while plants (prey of rabbits) may increase due to less grazing.
How does crossing over during meiosis contribute to genetic variation?
It exchanges segments between homologous chromosomes, creating new combinations of alleles.
Explain how deforestation can disrupt the carbon cycle.
It reduces CO₂ uptake through photosynthesis and increases atmospheric CO₂ from decomposition and burning.
Explain how the structure of an alveolus makes it efficient for gas exchange.
Thin walls, moist surface, and large surface area allow rapid diffusion of gases between air and blood.
Explain how the structure of a phospholipid contributes to its function in cell membranes.
The hydrophilic heads face water while hydrophobic tails face inward, forming a semi-permeable bilayer.
During meiosis, what would happen if homologous chromosomes failed to separate during anaphase I? state the name of this error and give an example.
This error is called nondisjunction, and it can result in gametes with an abnormal number of chromosomes, leading to disorders like Down syndrome.