Science, Tech, Math › Science Frequently Asked Biology Questions and Answers Share Flipboard Email Print The cell nuclei contain the genetic material chromatin (red). The proteins making up the cells cytoskeleton have been stained with different colors: actin is blue and microtubules are yellow. DR Torsten Wittmann/Science Photo Library/Getty Image Science Biology Basics Cell Biology Genetics Organisms Anatomy Physiology Botany Ecology Chemistry Physics Geology Astronomy Weather & Climate By Regina Bailey Biology Expert B.A., Biology, Emory University A.S., Nursing, Chattahoochee Technical College Regina Bailey is a board-certified registered nurse, science writer and educator. Her work has been featured in "Kaplan AP Biology" and "The Internet for Cellular and Molecular Biologists." our editorial process Regina Bailey Updated July 10, 2019 Biology is a wondrous science that inspires us to discover more about the world around us. While science may not have the answers to every question, some biology questions are answerable. Have you ever wondered why DNA is twisted or why some sounds make your skin crawl? Discover answers to these and other intriguing biology questions. Why Is DNA Twisted? KTSDESIGN/Getty Images DNA is known for its familiar twisted shape. This shape is often described as a spiral staircase or twisted ladder. DNA is a nucleic acid with three main components: nitrogenous bases, deoxyribose sugars, and phosphate molecules. Interactions between water and the molecules that compose DNA cause this nucleic acid to take on a twisted shape. This shape aids in the packing of DNA into chromatin fibers, which condense to form chromosomes. The helical shape of DNA also makes DNA replication and protein synthesis possible. When necessary, the double helix unwinds and opens to allow DNA to be copied. Why Do Certain Sounds Make Your Skin Crawl? Nails scraping against a chalkboard is one of ten most hated sounds. Tamara Staples/Stone/Getty Images Nails on a chalkboard, squealing brakes, or a crying baby are all sounds that can make one's skin crawl. Why does this happen? The answer involves how the brain processes sound. When we detect a sound, sound waves travel to our ears and the sound energy is converted to nerve impulses. These impulses travel to the auditory cortex of the brain's temporal lobes for processing. Another brain structure, the amygdala, heightens our perception of the sound and associates it with a particular emotion, such as fear or unpleasantness. These emotions can elicit a physical response to certain sounds, such as goose bumps or a sensation that something is crawling over your skin. What Are the Differences Between Eukaryotic and Prokaryotic Cells? Pseudomonas Bacteria. SCIEPRO/Science Photo Library/Getty Images The primary characteristic that differentiates eukaryotic cells from prokaryotic cells is the cell nucleus. Eukaryotic cells have a nucleus that is surrounded by a membrane, which separates the DNA within from the cytoplasm and other organelles. Prokaryotic cells do not have a true nucleus in that the nucleus is not surrounded by a membrane. Prokaryotic DNA is located in an area of the cytoplasm called the nucleoid region. Prokaryotic cells are typically much smaller and less complex than eukaryotic cells. Examples of eukaryotic organisms include animals, plants, fungi and protists (ex. algae). How Are Fingerprints Formed? Andrey Prokhorov/E+/Getty Image Fingerprints are patterns of ridges that form on our fingers, palms, toes, and feet. Fingerprints are unique, even among identical twins. They are formed while we are in our mother's womb and are influenced by several factors. These factors include genetic makeup, position in the womb, amniotic fluid flow, and umbilical cord length. Fingerprints are formed in the innermost layer of the epidermis known as the basal cell layer. Rapid cell growth in the basal cell layer causes this layer to fold and form various patterns. What Are the Differences Between Bacteria and Viruses? Influenza virus particle. CDC/Frederick Murphy While both bacteria and viruses are capable of making us sick, they are very different microbes. Bacteria are living organisms that produce energy and are capable of independent reproduction. Viruses are not cells but particles of DNA or RNA encased within a protective shell. They do not possess all of the characteristics of living organisms. Viruses must rely on other organisms in order to reproduce because they do not possess the organelles needed to replicate. Bacteria are typically larger than viruses and susceptible to antibiotics. Antibiotics do not work against viruses and viral infections. Why Do Women Typically Live Longer Than Men? Women on average live anywhere from 5 to 7 years longer than men. B2M Productions/Digital Vision/Getty Images In almost every culture, women usually outlive men. While several factors can influence the life expectancy differences between men and women, genetic makeup is considered to be the major reason women live longer than men. Mitochondrial DNA mutations cause males to age faster than females. Since mitochondrial DNA is only inherited from mothers, mutations that occur in female mitochondrial genes are monitored to filter out dangerous mutations. Male mitochondrial genes are not monitored so the mutations accumulate over time. What Are the Differences Between Plant and Animal Cells? Encyclopaedia Britannica/UIG/Getty Images Animal cells and plant cells are both eukaryotic cells with a number of common characteristics. These cells also differ in a number of characteristics such as size, shape, energy storage, growth, and organelles. Structures found in plant cells and not animal cells include a cell wall, plastids, and plasmodesmata. Centrioles and lysosomes are structures that are found in animal cells but not usually in plant cells. While plants are capable of generating their own food through photosynthesis, animals must obtain nutrition through ingestion or absorption. Is the 5-second Rule True or a Myth? Is it okay to apply the 5-second rule to foods that fall on the floor? Studies suggest that there is some truth to the 5-second rule. David Woolley/Digital Vision/Getty Images The 5-second rule is based on the theory that food that has been dropped on the floor for a brief period of time does not pick up many germs and is safe to eat. This theory is somewhat true in that the less time food is in contact with a surface, the fewer bacteria are transferred to the food. Several factors play a role in the level of contamination that may occur once food has been dropped on the floor or another surface. These factors include the texture of the food (soft, sticky, etc.) and the type of surface (tile, carpet, etc.) involved. It is always best to avoid eating food that has a high risk of contamination, such as food that has been dropped in the trash. What Are the Differences Between Mitosis and Meiosis? Dividing Cell in Mitosis. Dr. Lothar Schermelleh/Science Photo Library/Getty Images Mitosis and meiosis are cell division processes that involve the division of a diploid cell. Mitosis is the process by which somatic cells (body cells) reproduce. Two identical daughter cells are produced as a result of mitosis. Meiosis is the process by which gametes (sex cells) are formed. This two-part cell division process produces four daughter cells that are haploid. In sexual reproduction, the haploid sex cells unite during fertilization to form a diploid cell. What Happens When Lightning Strikes You? A cloud-to-ground lightning strike originating from higher based cloud structure. Lightning penetrates a low level cloud before reaching earth. NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL) Lightning is a powerful force that can cause serious injury to those that are unfortunate enough to be hit by it. There are five ways in which individuals may be hit by lightning. These types of strikes include a direct strike, side flash, ground current strike, conduction strike, and a streamer strike. Some of these strikes are more serious than others but all involve electrical current traveling through the body. This current moves over the skin or through the cardiovascular system and nervous system causing serious damage to vital organs. What Is the Purpose of Bodily Functions? Baby Yawning. Multi-bits/The Image Bank/Getty Images Have you ever wondered why we yawn, burp, sneeze, or cough? Some bodily functions are the result of voluntary actions controlled by the individual, while others are involuntary and not under the control of the individual. Yawning, for example, is a reflex response that occurs when a person is tired or bored. Though the reasons for yawning are not fully understood, studies indicate that it helps to cool the brain. What Are the Different Types of Plant Growth? The main stages in the germination of a plant seed. In the third image, the root grows downwards in response to gravity, while in the fourth image the embryonic shoot (plumule) grows up against gravity. Power and Syred/Science Photo Library/Getty Images Have you ever noticed how plants grow toward different types of stimuli? Growth of a plant in the direction of a stimulus is called plant tropism. Some of these stimuli include light, gravity, water, and touch. Other types of plant tropisms include growth in the direction of chemical signals (chemotropism) and growth in response to heat or temperature changes (thermotropism).