Biology Quiz PDF

**1. When you look at an unknown cell under the microscope, you noticed the presence of a cell wall and membrane-bound organelles. You conclude that the cell is a/an \_\_\_\_\_\_** a animal cell b\. bacterial cell **c. plant cell** d\. virus **2. The chlorophyll is found in the \_\_\_\_\_\_ of...

**1. When you look at an unknown cell under the microscope, you noticed the presence of a cell wall and membrane-bound organelles. You conclude that the cell is a/an \_\_\_\_\_\_** a animal cell b\. bacterial cell **c. plant cell** d\. virus **2. The chlorophyll is found in the \_\_\_\_\_\_ of a plant cell.** a\. cristae b\. cytoplasm c\. stroma **d. thylakoid membrane** **3. Melanin in the skin is a protein produced by cells called melanocytes. You would expect melanocytes to have higher than usual number of \_\_\_\_\_\_\_\_\_.** a\. Golgi apparatus b\. lysosomes **C ribosomes** d\. vesicles **4. Your heart muscle cells beat in a coordinated fashion every minute. The cell junctions that best facilitate this are \_\_\_\_\_\_\_.** a\. adhesion junctions b\. extracellular matrix **C. gap junctions** d\. tight junctions **5. Which microscope will you use to examine living cells lining your respiratory tract to determine if the cilia are effective in driving the dirt and mucus away from your lungs?** **a. light microscope to observe whole living cells** b\. confocal microscope to observe whole cells without slicing them c\. scanning electron microscope to reveal structures on cell surfaces d\. transmission electron microscope to reveal a very high magnification **6. Which of the following cell structures is exclusively related to prokaryotic cells?** a\. chromosomes **b. nucleoid** c\. nucleus d\. ribosomes **7. The endomembrane system includes all of the following cell structures except \_\_\_\_\_\_\_\_.** a\. endoplasmic reticulum b\. Golgi apparatus **c. peroxisome** d\. vesicle **8. The cells present in sebaceous glands that produce oil for your hair contain a lot of \_\_\_\_\_\_\_.** a\. lysosome b\. central vacuole c\. rough endoplasmic reticulum **d. smooth endoplasmic reticulum** **9. The organelle involved in the detoxification of alcohol is \_\_\_\_\_\_.** a\. lysosome b\. ribosome c\. peroxisome **d. smooth endoplasmic reticulum** **10. Researches on infertility in men with reduced sperm motility may be associated with exposure to environmental factors such as \_\_\_\_\_\_\_\_.** a\. genetically-modified food b\. overexposure to ultraviolet rays C. carcinogenic substances in street foods **d. hormone-like chemicals in the environment** **1. Nucleus** - **Description**: Large, membrane-bound organelle containing the cell\'s genetic material (DNA). - **Function**: Controls cellular activities by regulating gene expression and mediating the replication of DNA during the cell cycle. - **Association**: Associated with DNA replication, RNA transcription, and ribosome production. **2. Nucleolus** - **Description**: Dense region inside the nucleus. - **Function**: Produces ribosomal RNA (rRNA) and assembles ribosomes. - **Association**: Works closely with the nucleus and ribosomes in protein synthesis. **3. Ribosomes** - **Description**: Small structures either floating freely in the cytoplasm or attached to the endoplasmic reticulum. - **Function**: Translate mRNA into proteins by linking amino acids together. - **Association**: Works in protein synthesis and is associated with the rough endoplasmic reticulum and the cytoplasm. **4. Endoplasmic Reticulum (ER)** - **Rough ER** - **Description**: Network of membranous tubules with ribosomes attached. - **Function**: Protein synthesis and modification. - **Association**: Works with ribosomes and the Golgi apparatus to process and transport proteins. - **Smooth ER** - **Description**: Membranous tubules without ribosomes. - **Function**: Lipid synthesis, detoxification, and calcium storage. - **Association**: Associated with lipid metabolism, and detoxification processes, particularly in liver cells. **5. Golgi Apparatus** - **Description**: Stacks of flattened membrane-bound sacs. - **Function**: Modifies, sorts, and packages proteins and lipids for transport within or outside of the cell. - **Association**: Works with the ER and vesicles for protein and lipid transport. **6. Lysosomes** - **Description**: Membrane-bound vesicles containing digestive enzymes. - **Function**: Breaks down waste materials, damaged organelles, and macromolecules. - **Association**: Works in cellular digestion and is involved in autophagy (self-digestion of organelles) and immune responses. **7. Peroxisomes** - **Description**: Membrane-bound organelles containing oxidative enzymes. - **Function**: Breaks down fatty acids and detoxifies harmful substances like hydrogen peroxide. - **Association**: Involved in lipid metabolism and detoxification. **8. Mitochondria** - **Description**: Double-membrane-bound organelle with its own DNA. - **Function**: Produces energy (ATP) through cellular respiration. - **Association**: Essential for energy production; associated with the process of oxidative phosphorylation and ATP generation. **9. Chloroplasts (Plant Cells Only)** - **Description**: Double-membrane-bound organelle with chlorophyll, found in plant cells. - **Function**: Converts light energy into chemical energy via photosynthesis. - **Association**: Associated with energy production in plant cells and works in the light-dependent and light-independent reactions of photosynthesis. **10. Vacuole** - **Description**: Large, membrane-bound sac, prominent in plant cells. - **Function**: Stores nutrients, waste products, and helps maintain turgor pressure in plant cells. - **Association**: Works with the plant cell wall to maintain cell structure and water balance. **11. Cytoskeleton** - **Microfilaments (Actin Filaments)** - **Description**: Thin fibers composed of actin proteins. - **Function**: Maintains cell shape, enables cell movement, and supports intracellular transport. - **Association**: Associated with cell movement, division, and muscle contraction. - **Intermediate Filaments** - **Description**: Fibrous proteins that provide structural support. - **Function**: Provides mechanical support to the cell. - **Association**: Helps maintain cell integrity. - **Microtubules** - **Description**: Hollow tubes made of tubulin proteins. - **Function**: Involved in cell division (spindle fibers) and intracellular transport of organelles. - **Association**: Essential for cell division, vesicle transport, and forming the structure of cilia and flagella. **12. Centrosome** - **Description**: A region near the nucleus that contains the centrioles (in animal cells). - **Function**: Organizes microtubules and regulates the cell cycle during mitosis and meiosis. - **Association**: Works with microtubules in cell division. **13. Cilia and Flagella** - **Description**: Hair-like structures on the cell surface (cilia are short and numerous; flagella are longer and fewer). - **Function**: Involved in movement of the cell or fluids over the cell surface. - **Association**: Work with microtubules and motor proteins for locomotion and fluid movement. **14. Cell Membrane (Plasma Membrane)** - **Description**: Phospholipid bilayer with embedded proteins. - **Function**: Regulates the movement of substances in and out of the cell, provides structural support, and allows cell communication. - **Association**: Involved in transport, signaling, and maintaining homeostasis. **15. Cell Wall (Plant Cells Only)** - **Description**: Rigid outer layer made of cellulose (in plants). - **Function**: Provides protection, structural support, and helps maintain cell shape. - **Association**: Works with the vacuole in maintaining turgor pressure and overall cell rigidity. **16. Cytoplasm** - **Description**: Jelly-like substance within the cell membrane that contains organelles. - **Function**: Provides a medium for biochemical reactions and supports organelles. - **Association**: Facilitates interactions between organelles and is the site of many metabolic processes. These organelles work together to maintain cell life, control energy usage, facilitate growth, and respond to environmental changes. The **nucleus**, **ER**, **Golgi apparatus**, and **ribosomes** are heavily involved in protein production, while **mitochondria** and **chloroplasts** (in plants) are central to energy metabolism. The **cytoskeleton** provides structural integrity, and the **cell membrane** controls communication and transport with the outside environment. **Plant vs. Animal Cells (Focusing on Chloroplasts and Mitochondria)** **Similarities:** - **Eukaryotic cells**: Both plant and animal cells have membrane-bound organelles. - **Mitochondria**: Present in both, they generate ATP through cellular respiration. **Differences:** 1. **Cell Wall**: - **Plant cells** have a rigid **cell wall**; **animal cells** do not. 2. **Chloroplasts**: - Found only in **plant cells**; they carry out **photosynthesis** (converting sunlight to glucose). 3. **Shape**: - **Plant cells** are rectangular due to their cell wall; **animal cells** are more flexible. 4. **Vacuole**: - **Plant cells** have a large **central vacuole**; **animal cells** have smaller ones. **Chloroplasts (in Plant Cells):** - **Function**: Convert sunlight into glucose via photosynthesis. - **Structure**: Contain **thylakoids** (where light reactions occur) and **stroma** (where the Calvin cycle occurs). **Mitochondria (in Both Cell Types):** - **Function**: Generate ATP through **cellular respiration**. - **Structure**: Have a double membrane, with inner folds called **cristae** and a central matrix. **Chloroplasts and Mitochondria Relationship:** - **Chloroplasts** produce glucose in plants, while **mitochondria** break it down in both plant and animal cells to release energy. - Both likely evolved from ancient prokaryotes (endosymbiosis theory). **CHARACTERISTICS OF CELLS:** **1. Structural Organization:** **Cell Membrane:** A protective barrier that controls the movement of substances in and out of the cell. **Cytoplasm:** Jelly-like fluid where cellular processes occur. **Nucleus (in eukaryotic cells):** Contains DNA and controls cellular activities. **Organelles:** Specialized structures (e.g., mitochondria, ribosomes) that perform specific functions within the cell. **2. Reproduction:** **Mitosis:** Process by which a single cell divides to produce two identical daughter cells (asexual reproduction in eukaryotes). **Meiosis:** Produces gametes (sperm and egg cells) for sexual reproduction in multicellular organisms. **Binary Fission:** Reproduction method in prokaryotes (bacteria). **3. Metabolism:** Cells carry out chemical reactions (metabolism) to maintain life, including converting nutrients into energy (ATP). **Mitochondria (in eukaryotic cells)** are the main organelles involved in energy production. **4. Growth and Development:** Cells grow by increasing in size and mass. They also develop by undergoing differentiation (in multicellular organisms), where they take on specialized functions. **5. Response to Stimuli:** Cells can respond to changes in their environment (e.g., temperature, chemicals). Specialized cells, like neurons, transmit signals in response to stimuli. **6. Homeostasis:** Cells maintain a stable internal environment (balance of pH, temperature, and ion concentrations). **7. Genetic Material:** All cells contain DNA that carries the genetic instructions for the development, functioning, and reproduction of organisms. **8. Types of Cells:** **Prokaryotic Cells:** Simpler, without a nucleus (e.g., bacteria). **Eukaryotic Cells:** More complex, with a nucleus and organelles (e.g., plant and animal cells). These characteristics define the basic unit of life, whether it is a simple prokaryotic cell or a complex eukaryotic cell. Lesson 2.1 The Cell and Its Beginning Earliest Microscopic Observations ================================= **Robert Hooke** (1635-1703) - An English Scientist - He devised one of the earliest microscopes that can magnify every sort of material he can find at that time. - His most commemorative work came from a thin slice of cork from a bark of an oak tree; described as a honeycomb. - He called these as "cellulae" means "small room" because of the empty barren rooms, where monks spent most of their time. - He drew what he observed and his drawings were collected in a manuscript called "Micrographia". - He was first to be credited in publishing of seeing a cell in 1666, but he cannot fully define what he saw. - Those hollow chambers drawn by Hooke were actually not living. **Antonie van Leeuwenhoek** (1632- 1723) - A Dutch naturalist First to study magnified cells. - He devised his own microscope to study biological specimens. - First invention: Simple Microscope - He used his skill to devise more than 500 lenses during his lifetime in which one of his lenses was able to magnify 270 times. - He was able to make thousands of observations of microscopic objects and specimens in his time. - He can observe even microscopic things that were moving in the pond water. - He called as "animalcules" means - He was the first to observe living cells. The Cell Theory =============== - Focused his interests in the study of plant cells. They all confirmed that cells are fundamental units of life and that the bodies of living organisms are made up of cells. **Rudolf Carl Virchow** - German physician - All cells come from other cells through the process of cell division Summarized of Cell Theory ========================= 1. All organisms are composed one or more cells. 2. Cells are the smallest and basic units of structure and function in organisms. 3. Cells arise only from previously existing cells. - Life originated as primitive cells from inorganic and organic molecules in Earth's prebiotic oceans. - The hypothesis is known as the organic chemical evolution. **Aleksandr Oparin** -- proposed that organic molecules might have been assembled in Earth's primitive atmosphere in the presence of strong energy. **Stanley Miller** -- designed an experiment to test Oparin's hypothesis by placing a mixture of inorganic compounds in a closed system, resembling a strong reducing atmosphere of the primitive Earth. - This states that the first forms of true living cells have evolved from protocells, that are hypothesized to have been formed by the polymerization of organic molecules in heated rocks or in a clay. Lesson 2.2 The Invisible World Through the Lens of a Microscope --------------------------------------------------------------- - **1600s** -- Microscopes were invented - **Hooke's crude microscope** allowed him to observe a thin slice of cork reveal a lot about little boxes now called as cell walls. - Leeuwenhoek observed what he called **animalcules** known today as **single-celled organisms** called **protozoa.** - **17^th^ century**: invent light microscopes that allowed humans - **1930s**: invent electron microscope - **Micrograph**: to produce image as well as the magnification value of the image. - **Magnification:** measure of optical instruments for an object to appear larger than its actual size. - **Resolution**: clarity of an image - Most common type in school laboratories: **Light Microscope** - Most common type in advanced research laboratories: **electron** **microscope** 1. **[Common Microscope]** -- commonly used in schools 2. **[Simple Microscope]** -- examine cells and sections of tissues with the use of sunlight or artificial light. 3. **[Stereomicroscope]** -- examine the external structures of a specimen (insects). 4. **[Phase-contrast Microscope]** -- examine highly transparent objects (unstained cells). 5. **[Electron Microscope]** -- streams of electrons to enlarge objects. 6. **[Transmission Electron] [Microscope]** -- study internal structures of cells. 7. **[Scanning Electron Microscope]** -- examine the three-dimensional surface structures of objects 8. **[Fluorescent Microscope]** -- stained with fluorescent dyes that glow in the dark. 9. **[Fluorescence Microscopy]** -- location of certain organelles or substance inside the cell. ### 10. Confocal Scanning