Grade 9 Biology Quiz Questions And Answers

Explanation
In photosynthesis, the term "photo" is derived from the Greek word for light. Photosynthesis is a complex process carried out by plants, algae, and certain bacteria, where light energy is captured and utilized to convert carbon dioxide and water into glucose and oxygen. Light plays a central role in the initial phase, where pigments such as chlorophyll absorb light energy during the photochemical reactions, initiating the conversion of light energy into chemical energy stored in glucose molecules. The prefix "photo-" in photosynthesis emphasizes the essential role of light in driving this vital biological process.

Explanation
Root hair cells are specialized structures found in the roots of plants. Their main function is to absorb water and essential nutrients, such as minerals, from the soil. These cells have tiny hair-like structures called root hairs, which greatly increase their surface area. This adaptation allows them to efficiently absorb water and minerals through osmosis and active transport processes. The absorbed water is crucial for maintaining turgor pressure in plant cells and facilitating nutrient uptake for growth and metabolic processes. Thus, root hair cells play a vital role in ensuring plants receive the necessary resources for their survival and development.

Explanation
The total magnification of a microscope is calculated by multiplying the magnification of the ocular lens (eyepiece) by the magnification of the objective lens. In this case, if the ocular lens has a magnification of 10 times and the objective lens has a magnification of 20 times:

Total Magnification = Ocular Lens Magnification × Objective Lens Magnification
                  = 10 × 20
                  = 200

So, the total magnification of the microscope would be 200 times.

Explanation
DNA, or deoxyribonucleic acid, carries the genetic instructions that organisms need to grow, develop, and function. It is a molecule that contains information encoded in its structure, which determines the traits and characteristics of living things. DNA is composed of two strands that coil around each other to form a double helix. Each strand is made up of simpler units called nucleotides, which consist of a sugar (deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The sequence of these bases in DNA determines the genetic code that directs the synthesis of proteins and regulates cellular processes in organisms.

Explanation
Plants have vascular bundles that contain two types of vascular tissues: phloem and xylem. These tissues are like the veins and arteries in human bodies, but they serve different functions. Xylem tissue carries water and minerals absorbed from the soil up through the plant to its leaves and other parts. Phloem tissue transports glucose and other nutrients produced during photosynthesis from the leaves to other parts of the plant for growth and energy. Together, these vascular tissues form a network that supports the plant's structure and allows it to transport essential substances needed for survival and growth.

Explanation
The four bases that make up the genetic code of DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). These bases are the building blocks that form the rungs of the DNA double helix. Adenine pairs with thymine, and guanine pairs with cytosine, forming stable base pairs that hold the two strands of DNA together. The sequence of these bases along the DNA molecule encodes genetic information that determines an organism's traits and functions. This genetic code is essential for processes like protein synthesis and inheritance, making it crucial for the functioning and development of all living organisms.

Explanation
Photosynthesis is the process by which plants convert sunlight into energy. It occurs in the chloroplasts, which contain chlorophyll, the pigment responsible for capturing sunlight. The chloroplasts are found in the cells of the plant's leaves, where they absorb light energy and use it to convert carbon dioxide and water into glucose and oxygen. The nucleus is responsible for controlling the cell's activities, the vacuole stores water and other substances, and the mitochondria produce energy through cellular respiration. Therefore, the correct answer is chloroplasts/chlorophyll.

Explanation
DNA contains the instructions, or code, that cells use to make proteins. Proteins are essential molecules that perform a wide variety of functions in cells, tissues, and organs. The process of making proteins from DNA involves several steps: first, DNA is transcribed into messenger RNA (mRNA), which carries the genetic code from the nucleus to the ribosomes in the cell cytoplasm. Then, the mRNA is translated at the ribosomes, where transfer RNA (tRNA) molecules bring specific amino acids in the correct sequence according to the mRNA code. This sequence of amino acids forms a protein, which can have structural, enzymatic, or regulatory roles within the cell and organism.

Explanation
Animal cells have a nucleus, cytoplasm, and mitochondria. The nucleus is the control center of the cell, containing the genetic material and regulating cell activities. Cytoplasm is a gel-like substance that fills the cell, providing a medium for cellular processes. Mitochondria are the powerhouse of the cell, responsible for generating energy through cellular respiration. Chloroplasts are not present in animal cells, as they are responsible for photosynthesis in plant cells. Cell walls are also absent in animal cells, as they have a cell membrane.

Explanation
The statement is incorrect. Animals without backbones are called invertebrates, not vertebrates. Vertebrates are animals that have a backbone or spinal column.

Explanation
Seeds need water, warmth, and oxygen to germinate. Water is essential for the activation of enzymes that initiate germination. Warmth provides the necessary temperature for the enzymatic reactions to occur. Oxygen is required for respiration, which provides energy for the germination process. Light, although important for the growth of the seedling after germination, is not necessary for the actual germination process itself.

Explanation
Biology is the study of life. It focuses on understanding living organisms, their structure, function, growth, evolution, and interactions with their environment. Biologists explore the diversity of life forms—from microscopic bacteria to complex plants and animals—and investigate how organisms function at various levels, from cells to ecosystems. By studying biology, scientists seek to uncover the principles and processes that govern life, including genetics, physiology, ecology, and behavior. This knowledge is crucial for advancements in medicine, agriculture, conservation, and understanding the natural world around us. Thus, biology plays a fundamental role in shaping our understanding of life on Earth.

Explanation
The nucleus is the control center of a cell, housing the cell’s genetic material (DNA). It is surrounded by a double membrane called the nuclear envelope, which protects the DNA and regulates what enters and exits the nucleus. The nucleus orchestrates cell activities by directing protein synthesis and cell division. It contains the nucleolus, where ribosomal RNA is produced. Understanding the nucleus is essential for grasping how cells function, replicate, and respond to their environment. It plays a critical role in heredity and the regulation of cellular processes.

Explanation
Lipids are biomolecules primarily used for long-term energy storage in the body. They are fats and oils, composed mainly of fatty acids and glycerol. Lipids store more energy per gram than carbohydrates or proteins, making them efficient for long-term energy reserves. They also play vital roles in forming cell membranes, providing insulation, and protecting organs. Understanding lipids is crucial in biology because they are essential for energy balance, cellular structure, and metabolic processes. Their unique properties make them a key component in the storage and utilization of energy within the body.