Biology Final Exam Practice Quiz

The cell is the fundamental unit of life that carries out all necessary functions. Every living organism is made up of one or more cells.

Mitochondria are known as the powerhouses of the cell because they generate ATP, the cell's energy currency. The other organelles serve different functions unrelated to energy production.

Photosynthesis is the process in which plants convert light energy into chemical energy stored as sugars. This process is essential for plant growth and sustains almost all life on Earth.

Enzymes are proteins that catalyze biochemical reactions by lowering the activation energy. Their protein structure is key to their ability to bind substrates and perform specific functions.

DNA, or deoxyribonucleic acid, is the primary genetic material in nearly all living organisms. It contains the instructions for development, functioning, and reproduction.

DNA replication takes place during the S phase of the cell cycle, ensuring that each daughter cell receives a complete copy of the genome. The other phases primarily handle cell growth and division.

Ribosomes are the cellular structures where proteins are synthesized by translating messenger RNA into amino acid sequences. Their function is crucial for gene expression and cell function.

Osmosis is the movement of water through a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration. It specifically pertains to water, unlike general diffusion.

DNA is the molecule that carries genetic instructions in most living organisms. It serves as the blueprint for protein synthesis and cellular function.

Being heterozygous means having two different alleles at a gene locus, one from each parent. This variation can affect how traits are expressed in an organism.

A mutation is a change in the nucleotide sequence of a gene, which can lead to altered protein function. The other listed options do not describe changes at the genetic level.

The electron transport chain is crucial for producing ATP through oxidative phosphorylation. It transfers electrons through a series of complexes to generate the energy needed for cellular activities.

Mitosis is the process of cell division that results in two daughter cells with identical genetic material. Although cytokinesis is part of cell division, it refers only to the physical splitting of the cell.

Enzymes act as catalysts by lowering the activation energy required for reactions, thereby speeding up the process. They do not change the reaction equilibrium or permanently modify the reactants.

Precipitation is the process by which condensed water in the atmosphere falls to the ground as rain, snow, or hail. This mechanism is essential to the water cycle and differs from evaporation or transpiration.

The endosymbiotic theory suggests that mitochondria and chloroplasts were once free-living bacteria that entered into a symbiotic relationship with early eukaryotic cells. This theory is supported by the fact that these organelles have their own DNA and double membranes.

Genetic recombination shuffles alleles during meiosis, resulting in diverse genetic combinations among offspring. This increased diversity is a driving force for natural selection and adaptation in populations.

Pyruvate oxidation converts pyruvate from glycolysis into acetyl-CoA, which then enters the citric acid cycle. This step is fundamental because it bridges carbohydrate metabolism with energy production and biosynthetic processes.

The cohesion-tension theory explains that water molecules adhere to each other (cohesion) and are pulled upward through the xylem due to the negative pressure created by transpiration. This mechanism is widely accepted as the primary driver for water transport in plants.

Coevolution refers to the process in which two or more species influence each other's evolution through mutually interacting relationships. This reciprocal influence leads to specific adaptations in each species involved over time.