Biology Test Practice Test: Video 2 Answers (24 Questions) Flashcards

What is the primary function of ribosomes in a cell?

Answer: Synthesizing proteins

Ribosomes are essential cellular organelles responsible for protein synthesis, a process also known as translation. They read the genetic code carried by messenger RNA (mRNA) and use this information to accurately assemble amino acids into specific protein chains, which then perform various functions within the cell.

What is the powerhouse of the cell?

Answer: Mitochondria

Mitochondria are famously known as the 'powerhouses of the cell' because they are the primary sites for cellular respiration. During this metabolic process, mitochondria generate adenosine triphosphate (ATP), which is the main energy currency that fuels nearly all cellular activities and functions.

What process describes the movement of water across a selectively permeable membrane?

Answer: Osmosis

Osmosis is a specialized type of passive diffusion that specifically describes the net movement of water molecules across a selectively permeable membrane. This movement occurs from an area of higher water concentration (lower solute concentration) to an area of lower water concentration (higher solute concentration) to achieve equilibrium.

Which phase of the cell cycle involves DNA replication?

Answer: S phase

The S phase, or synthesis phase, is a critical stage within the interphase of the cell cycle. During this phase, the cell meticulously replicates its entire genome, ensuring that each chromosome is duplicated to form two sister chromatids. This DNA replication is essential to provide each daughter cell with a complete and identical set of genetic material after cell division.

Which molecule carries the genetic instructions in most living organisms?

Answer: DNA

Deoxyribonucleic acid (DNA) is the fundamental molecule that carries the complete genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses. It contains the blueprint for synthesizing proteins and regulating cellular activities, making it the central repository of hereditary information.

What is the function of root hairs?

Answer: To increase surface area for water and mineral absorption

Root hairs are extensions of epidermal cells that dramatically increase the surface area of roots, improving the efficiency of water and mineral absorption from the soil.

What type of vascular tissue transports water and minerals from roots to leaves?

Answer: Xylem

Xylem transports water and dissolved minerals upward from roots through the stem to leaves.

During which phase of the cell cycle does DNA replication occur in plants?

Answer: S phase

DNA replication occurs during the S (synthesis) phase of interphase, duplicating the entire genome before cell division.

Which process describes the loss of water vapor from plant leaves?

Answer: Transpiration

Transpiration is the evaporation of water from plant surfaces, primarily through stomata, and drives the transpiration stream.

What is the term for the movement of water across a semipermeable membrane from low to high solute concentration?

Answer: Osmosis

Osmosis is the passive movement of water molecules across a semipermeable membrane toward higher solute concentration.

How are traits inherited?

Answer: Through the transfer of genes from parents

Traits are inherited through the transfer of genetic material, specifically genes, from parents to their offspring. Genes are segments of DNA that carry the instructions for developing specific characteristics. During reproduction, these genes are passed down, determining an individual's inherited traits.

What is an adaptation?

Answer: A beneficial trait increasing survival and reproduction

An adaptation is a heritable trait that has evolved over time through natural selection, enhancing an organism's ability to survive and reproduce in its specific environment. These beneficial characteristics allow species to better cope with environmental challenges and exploit resources. Adaptations are crucial for the long-term survival and success of a species.

What is the basic unit of heredity?

Answer: Genes

Genes are the basic units of heredity, consisting of specific sequences of DNA that code for particular traits or functions. They are passed down from parents to offspring, carrying the instructions that determine an organism's characteristics, from physical appearance to metabolic processes. This makes genes fundamental to understanding how traits are inherited and expressed across generations.

What does genetic drift refer to?

Answer: Random changes in allele frequency

Genetic drift refers to the random fluctuations in the frequency of alleles (different forms of a gene) in a population, particularly in small populations. Unlike natural selection, which is directional, genetic drift is a chance event that can lead to the loss or fixation of certain alleles, regardless of their adaptive value. It is a significant evolutionary force, especially in isolated or small populations.

Which type of RNA carries amino acids to the ribosome during translation?

Answer: tRNA

Transfer RNA (tRNA) carries specific amino acids to the ribosome, matching anticodons to mRNA codons.

What type of relationship exists between two species where both benefit?

Answer: Mutualism

Mutualism is a type of symbiotic relationship where both interacting species benefit from their association. This reciprocal benefit can manifest in various ways, such as enhanced nutrient acquisition, protection from predators, or improved reproductive success for both organisms involved.

What term describes a species’ role in its environment?

Answer: Niche

A species' niche encompasses its entire role and position within an ecosystem, including its interactions with other species, its resource requirements, and its impact on the environment. It describes not just where a species lives (its habitat), but also what it does, how it obtains food, and how it contributes to the ecosystem's balance.

What is the primary driver of biodiversity loss today?

Answer: Habitat destruction

Habitat destruction is widely recognized as the leading cause of biodiversity loss globally. When natural habitats are converted for human uses like agriculture, urbanization, or resource extraction, species lose their homes, food sources, and breeding grounds, leading to population declines, fragmentation, and ultimately, extinctions.

Which process drives evolution by favoring individuals with advantageous traits?

Answer: Natural Selection

Natural selection is the primary mechanism of evolution, where individuals with traits better suited to their environment are more likely to survive, reproduce, and pass on those advantageous traits. Over successive generations, this differential survival and reproduction leads to an increase in the frequency of beneficial traits within a population, driving evolutionary change.

Gluconeogenesis is the metabolic pathway that synthesizes glucose from:

Answer: Non-carbohydrate precursors such as lactate and amino acids

Gluconeogenesis uses non-carbohydrate substrates like lactate, glycerol, and glucogenic amino acids to produce glucose, mainly in the liver.