Biology Unit 1 Vocabulary and Concepts

A hypothesis is a testable explanation for an observation, phenomenon, or scientific problem that can be tested through experimentation. A scientific theory, on the other hand, is a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses. It is supported by a large body of evidence and has been repeatedly confirmed through experimentation and observation. A scientific law, however, is a statement based on repeated experimental observations that describes some aspect of the universe. It is a concise and universal description of a fundamental relationship in nature, often expressed mathematically.

A graph should include a title that describes the data being presented, labeled axes with units, data points plotted accurately, a key if multiple data sets are represented, and proper use of space so that the graph is easy to read and interpret.

The control group is the group of squirrels that received no compost.

<p>The experimental groups consist of the squirrels in Group A (3-month compost) and Group B (6-month compost).</p> Signup and view all the answers

<p>Lactase is a protein, and lactose is a carbohydrate.</p> Signup and view all the answers

<p>Enzymes speed up chemical reactions by lowering the activation energy needed for the reaction to occur. They do this by providing an alternative reaction pathway with a lower activation energy, which allows the reaction to proceed faster at a lower temperature. Enzymes are highly specific for the reactions they catalyze, binding to specific substrates and facilitating the formation of a transition state that promotes the reaction.</p> Signup and view all the answers

<p>The product that is missing from the equation is heat (energy).</p> Signup and view all the answers

<p>A. Housing DNA: Nucleus B. Cellular respiration: Mitochondria C. Photosynthesis: Chloroplast D. Organization and packaging of cellular materials: Golgi apparatus E. Digestion: Lysosomes F. Protein synthesis: Ribosomes</p> Signup and view all the answers

<p>A protein synthesized by ribosomes will be transported to the endoplasmic reticulum (ER), where it may undergo folding and modification. From the ER, the protein travels to the Golgi apparatus, where it may be further modified, packaged, and sorted into vesicles. These vesicles then move to the cell membrane, where they fuse with the membrane and release the protein outside the cell through exocytosis.</p> Signup and view all the answers

<p>Prokaryotic cells are simpler and smaller than eukaryotic cells. They lack a nucleus and other membrane-bound organelles. Their DNA is located in a region called the nucleoid. Prokaryotes are typically single-celled organisms, such as bacteria and archaea. Eukaryotic cells, on the other hand, have a nucleus that contains their DNA, as well as other membrane-bound organelles, such as mitochondria, chloroplasts, Golgi apparatus, and endoplasmic reticulum. Eukaryotes include all multicellular organisms, as well as some single-celled organisms, such as protists and fungi.</p> Signup and view all the answers

<p>A plant cell can be distinguished from an animal cell by the presence of a cell wall, chloroplasts, and a large central vacuole. The cell wall provides structural support and protection to the plant cell, chloroplasts are responsible for photosynthesis, and the central vacuole stores water and other nutrients.</p> Signup and view all the answers

<p>Active or passive transport? = Active transport requires energy, while passive transport does not.</p> Signup and view all the answers

<p>The cell in the middle (with H2O going both in and out of the cell) is isotonic, the cell on the left (with H2O going into the cell) is hypotonic, and the cell on the right (with H2O going out of the cell) is hypertonic. You can tell by the direction of the water flow in the diagram.</p> Signup and view all the answers

<p>Mitosis is a type of cell division that produces two daughter cells that are genetically identical to the parent cell. It is essential for growth, repair, and asexual reproduction. Three reasons why mitosis might occur are:</p> <ol> <li> <p><strong>Growth:</strong> Mitosis is responsible for increasing the number of cells in an organism, allowing it to grow and develop.</p> </li> <li> <p><strong>Repair:</strong> Mitosis is also used to repair damaged or worn-out tissues. When tissues are damaged, new cells are generated through mitosis to replace the lost or injured cells.</p> </li> <li> <p><strong>Asexual Reproduction:</strong> Some organisms, such as bacteria, reproduce asexually by mitosis, where a single parent cell divides into two identical daughter cells. This allows for rapid population growth.</p> </li> </ol> Signup and view all the answers

<p>Here are the definitions of some terms that students often use incorrectly in biology:</p> <p>• <strong>Centriole:</strong> A small, cylindrical organelle that is involved in the formation of microtubules and is found in animal cells. It is involved in the formation of spindle fibers during mitosis and meiosis. • <strong>Centromere:</strong> The constricted region of a chromosome where spindle fibers attach during cell division. • <strong>Chromatin:</strong> The uncondensed, thread-like form of DNA found in the nucleus during interphase. • <strong>Chromosome:</strong> A condensed, rod-shaped structure composed of DNA and proteins that carries genetic information. Chromosomes are visible during cell division. • <strong>Gene:</strong> A segment of DNA that codes for a specific protein or functional RNA molecule. • <strong>Cell Division:</strong> The process by which a parent cell divides into two or more daughter cells. There are two main types of cell division: mitosis and meiosis. • <strong>Binary Fission:</strong> A form of asexual reproduction in prokaryotic cells where a single parent cell divides into two identical daughter cells.</p> Signup and view all the answers

<p>Checkpoints are critical control points that regulate the progression of the cell cycle. They ensure that the cell only progresses to the next stage if the previous stage has been completed successfully and the conditions are favorable. They help to prevent errors in DNA replication and cell division, which could lead to cancer.</p> Signup and view all the answers

<p>Metaphase</p> Signup and view all the answers

<p>Anaphase</p> Signup and view all the answers

<p>Prophase.</p> Signup and view all the answers

<p>Cellular respiration occurs in the mitochondria of eukaryotic cells. Photosynthesis occurs in the chloroplasts of plant cells.</p> Signup and view all the answers

<p>Photosynthesis is an anabolic process, meaning it builds complex molecules from simpler ones. During photosynthesis, light energy is used to convert carbon dioxide and water into glucose, a complex carbohydrate. Cellular respiration is a catabolic process, meaning it breaks down complex molecules into simpler ones. In cellular respiration glucose is broken down to produce energy in the form of ATP. Photosynthesis and cellular respiration are connected because the products of photosynthesis (glucose and oxygen) are the reactants of cellular respiration.</p> Signup and view all the answers

<p>The part of cellular respiration that is also found in fermentation is glycolysis. Glycolysis is the initial stage of cellular respiration, where glucose is broken down into pyruvate. Fermentation is an anaerobic process that occurs in the absence of oxygen and uses only glycolysis to generate energy. The process of fermentation only produces 2 ATP molecules per glucose molecule. This is significantly less than the 36-38 ATP molecules produced by cellular respiration.</p> Signup and view all the answers

<p>ATP (adenosine triphosphate) is the primary energy currency of cells. It stores energy in the bonds between its phosphate groups. When a phosphate group is removed from ATP, energy is released, converting ATP to ADP (adenosine diphosphate). This energy can be used to power cellular processes, such as muscle contraction, protein synthesis, and active transport.</p> Signup and view all the answers