Free HESI Biology Questions and Answers 1 — Questions and Answers
Question 1: What is the primary function of the mitochondria in a cell?
- Protein synthesis
- Genetic information storage
- Energy production (Correct answer)
- Cell division
Correct answer: Energy production
The primary function of the mitochondria in a cell is energy production. Often called the 'powerhouses' of the cell, mitochondria generate most of the chemical energy needed to power the cell's biochemical reactions. They achieve this through cellular respiration, converting nutrients into adenosine triphosphate (ATP), which is the main energy currency used by the cell for various functions.
Question 2: Which organ system is primarily responsible for transporting nutrients and oxygen?
- Digestive system
- Respiratory system
- Circulatory system (Correct answer)
- Excretory system
Correct answer: Circulatory system
The circulatory system, composed of the heart, blood vessels, and blood, is specifically designed to transport essential substances throughout the body. Its primary role is to deliver oxygen and nutrients to all cells and remove metabolic waste products like carbon dioxide, ensuring proper cellular function.
Question 3: Which macromolecule is responsible for storing genetic information?
- Carbohydrates
- Proteins
- Lipids
- Nucleic acids (Correct answer)
Correct answer: Nucleic acids
Nucleic acids, specifically DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are the macromolecules responsible for carrying genetic information. DNA stores the complete hereditary instructions for an organism's development and function, while RNA plays a crucial role in expressing these instructions to build proteins.
Question 4: What part of the cell regulates what enters and leaves the cell?
- Nucleus
- Cytoplasm
- Cell wall
- Cell membrane (Correct answer)
Correct answer: Cell membrane
The cell membrane, also known as the plasma membrane, acts as a selectively permeable barrier that encloses the cell's contents. Its critical function is to control which substances can enter and exit the cell, thereby maintaining the cell's internal environment and facilitating communication with its surroundings.
Question 5: Which organelle is responsible for protein synthesis?
- Golgi apparatus
- Ribosome (Correct answer)
- Lysosome
- Mitochondrion
Correct answer: Ribosome
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 assemble amino acids into specific protein chains, which then fold into functional proteins.
Question 6: What process do plants use to make their own food?
- Respiration
- Fermentation
- Photosynthesis (Correct answer)
- Digestion
Correct answer: Photosynthesis
Photosynthesis is the fundamental process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. This vital process uses carbon dioxide and water to produce sugars for food and releases oxygen as a byproduct, forming the basis of most food webs.
Question 7: Which of the following is a characteristic of prokaryotic cells?
- Have a nucleus
- Contain mitochondria
- Lack membrane-bound organelles (Correct answer)
- Are multicellular
Correct answer: Lack membrane-bound organelles
Prokaryotic cells, such as bacteria and archaea, are characterized by their simpler cellular organization compared to eukaryotic cells. A key distinguishing feature is their lack of a true nucleus and other membrane-bound organelles like mitochondria or the Golgi apparatus; their genetic material is typically found in a nucleoid region.
Question 8: Which term describes the maintenance of a stable internal environment?
- Equilibrium
- Metabolism
- Homeostasis (Correct answer)
- Diffusion
Correct answer: Homeostasis
Homeostasis refers to an organism's ability to maintain a stable internal environment despite external fluctuations. This dynamic equilibrium is crucial for survival and involves various regulatory mechanisms that control physiological factors like body temperature, pH, and blood glucose levels within narrow limits.
Question 9: What is the role of enzymes in biological reactions?
- Slow down reactions
- Provide energy for reactions
- Act as catalysts (Correct answer)
- Break down DNA
Correct answer: Act as catalysts
Enzymes are biological catalysts, meaning they significantly speed up the rate of biochemical reactions without being consumed in the process. They achieve this by lowering the activation energy required for a reaction to occur, making metabolic processes efficient and viable at physiological temperatures.
Free HESI Biology Questions and Answers 1
What is the primary function of the mitochondria in a cell?