ACTIVITY 2 THE ANIMAL CELL Guide Questions: 1. Draw a human cheek cell observed under the HPO. Label the parts observed. 2. Not all structures known to be present in cells can be observed with your microscope. Refer to a diagram of a generalized cell in your textbook. List all these cell parts and give their corresponding functions. Nucleus – It is the most important part of this cell, and to all eukaryotic cells because it controls the center of the cell and contains genetic material or DNA necessary for cell division. Cytoplasm – It is the semifluid gel material outside the nucleus where organelles are placed. Cell Membrane – It is also called a plasma membrane or plasmalemma. A phospholipid bilayer consisting of hydrophilic heads and hydrophobic tails regulates what goes in and out of the cell. Golgi apparatus – This is also called the Golgi complex, consisting of membranous vesicles that store, modify, and package Endoplasmic Reticulum products, lipids, and proteins. The Golgi apparatus consists of two faces: the cis face, which receives the transport vesicles, and the trans face, which exudes or ships the secretory vesicles. Cytoskeleton – The cytoskeleton provides cell with an internal framework wherein it maintains the cell shape and support movements within the cells. There are three types of the cytoskeleton: Microfilaments that provide cell motility which are made up of actin monomers, Microtubules that move chromosomes during cell division which is made up of tubulin dimers, and Intermediate Filaments which aids the desmosome junction that resists cell stretching which are commonly made up of protein subunits of fibers. Smooth Endoplasmic Reticulum – It is the part of the endoplasmic reticulum that does contain ribosomes and is in charge of synthesizing lipids Rough Endoplasmic Reticulum – The part of the endoplasmic reticulum studded with ribosomes makes it the primary site of protein synthesis. Nucleolus – It is located inside the nucleus, contains DNA and ribosomal RNA, and is the ribosome factory of a cell. There are types of cells wherein the nucleus contains multiple nucleoli. Nuclear envelope – It is also called the nuclear membrane, which is a double phospholipid membrane that separates the nuclear contents from the cytoplasm and allows the exchange of materials with the rest of the cells. Microvilli – These are small finger-like projections of the cell surface produced by invaginations of the plasma membrane to increase the area of absorption and digestion of food and water molecules. Centriole – These are cell organelles that are not membrane-bound and contain centrioles necessary for the formation of the mitotic spindle during cell division. Mitochondria – These double membrane, self-replicating organelles are famously known as the cell's power house. They are responsible for synthesizing Adenosine Triphosphate by cellular respiration for cellular energy and process. Lysosome – These are enzyme-filled vesicles that bud from the Golgi complex responsible for digesting non-usable materials such as damaged organelles and engulfed bacteria. Their enzymes are so powerful that they could kill the cell that formed them through lysis which makes the ‘suicide bags’ of the cell. Ribosomes – They are commonly mistaken for organelles due to their significant function and their multiple quantities inside cells, but it is not because they don't have membranes that separate them from other organelles. 3. Define cell, tissue, organ and organ system. Cell - Cells are the smallest units of all living organisms and are the second in the level of structural organization. They are considered the basic unit of life which are made from specific molecules made of the simplest and first level of the structural ladder, the atoms. There are basically two types: animals and plants, but both have some common structures, compositions, and functions. However, cells vary widely in shape, size, and particular body roles. Tissue - There are living organisms that are only composed of a single cell; however, there is a vast number of complex organisms such as humans, plants, animals, and animals wherein specific groups of cells form together to make tissues. Considering cells the second, tissues come in the third level of the structural organization. There are four types of tissues in humans, and other multicellular complex animals play a definite but different role in the body. Organ - The organ is a structure composed of two or more tissue types that perform a specific function for the body. At this fourth level in the structural organization, extreme complex functions are possible. A damaged organ, to an extent, greatly affects the body's performance and could threaten a person's life wherein, sometimes, organ transplants could be a viable option. Organ System - An organ system, from the name itself, is a system of a group of organs that work together to accomplish a common purpose. Twelve organ systems in the human body have specific roles for digestion, reproduction, blood circulation, and many more. Moreover, specific organ systems are responsible for homeostatis which is the body’s ability to maintain stable internal conditions despite continuous changes happening in the environment or outside the body. Virtual Laboratory for Animal Cell Journal Questions: 1. How are cells similar to a factory or business? List five similarities. The cells are the basic unit of life, containing various cell organelles that are each specialized in a specific task. The cells operate similarly to how a factory would work. Here are five similarities between a cell and a factory: (1) Like a factory, the cell has a 'head office,' where all the data processing, checking, and transporting is handled. In the cell, the ‘head office’ is called the nucleus, where genetic material is processed, transported, and checked. (2) The cell's 'factory floor,' or where the cell's real work occurs, is in the cytoplasm. The cytoplasm is where all the workers or organelles are placed and collectively work to produce a product or perform a function that generally falls under production, maintenance, and energy transformation. (3) The cell's endoplasmic reticulum, which is involved in the synthesis of proteins, is similar to a factory conveyor belt. The endoplasmic reticulum helps transport materials within a cell like a conveyor belt. (4) A factory's finishing and packing room are equivalent to a cell's Golgi apparatus. After the ribosome finishes producing it in the endoplasmic reticulum, the protein must be prepared for usage or export. (5) Lastly, a cell must have an energy source, just like how a factory requires power to operate. The two organelles responsible for energy transformation are the mitochondria and the chloroplasts. Just like a power plant in a factory, these two organelles transform one form of energy into another. 2. How are animal and plant cells similar? How are they different? Explain. Plant and animal cells are quite similar since they are both eukaryotic cells. The nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes are only a few membrane-bound organelles that are present in both of them. The membrane, cytosol, and cytoskeletal components are also identical in both. In contrast to plant cells, animal cells do not have a cell wall. In terms of form, an animal cell is spherical (an irregular shape), but a plant cell is rectangular. Animal cells have one or more tiny vacuoles, but they are far smaller than plant cells, which have a single, massive central vacuole that can take up to 90% of the cell volume. All animal cells include centrioles, although only lower plant species have them in their cells. Animal cells lack the chloroplast, but plants have it, allowing them to produce their own sustenance. Animal and plant cells both include cytoplasm, ribosomes, mitochondria, endoplasmic reticulum, peroxisomes, the Golgi apparatus, microtubules or microfilaments, the nucleus, and cilia. Animal cells do not have parasites, however, plant cells do. Animal cells only have the plasma membrane, but plant cells both have a cell wall and a cell membrane. Both, but in some other cells, include flagella. Lysosomes are found in the cytoplasm of animal cells, but they are often not visible in plant cells. Animal cells have cilia, which are typically absent in plant cells. Animal and plant cells are both eukaryotic, which accounts for their striking similarity. Only a few membrane-bound organelles in both include the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes. Both also have an identical membrane, cytosol, and cytoskeletal components. 3. A solar cell is a device that collects energy from the sun to make electricity. What part of a plant cell is most similar to a solar cell? It would most likely be the chloroplast of a plant cell since chloroplasts also collect energy from the sun, but rather than making it into electricity, it converts the light energy into chemical energy. 4. Why is the nucleus considered to be the boss of the cell? The nucleus is one of the most essential components of eukaryotic cells, which is enclosed by the nuclear envelope and responsible for storing and processing genetic information. Thus, it is regarded to be the boss of the cell. It has all the information considering how the cell must properly function to sustain life. The nucleus has a unique role as well in managing cellular activities. It is necessarily comprised of deoxyribonucleic acid (DNA), the code for building the proteins that carry out all body functions. 5. Exploring the South American rain forest, a scientist discovers a mysterious organism and brings it back to the lab for further study. What cell characteristics should the scientist examine to tell whether the organism is an animal or plant? Why? The scientist should examine the presence of chloroplasts and cell walls in the mysterious organism found in the South American rainforest. The presence of chloroplasts connotates that the organism’s cell contains the organelle that absorbs sunlight energy to synthesize organic compounds from carbon dioxide and water. These chloroplasts can only be found in a plant cell. Thus, if it is present in the organism, the scientist can already conclude that the organism is a plant since animal cells do not contain chloroplasts for photosynthesis. Moreover, the presence of a cell wall can also be used as a reference. Animal cells only have a cell membrane but no cell wall, while in plant cells, the cell wall surrounds its cell membrane. REFERENCES A Busy Factory. (n.d.). http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Cells-abusy-factory.pdf Comparing the Cell to a Factory. (n.d.). https://mrbloch516.edublogs.org/files/2013/09/ComparingtheCelltoaFactoryReading1x7capx.pdf Diffen. (n.d.). Plant Cell vs. Animal Cell. Retrieved August 3, 2022, from https://www.diffen.com/difference/Animal_Cell_vs_Plant_Cell Kennedy, M. R. (2018). NUCLEUS is The Boss of the Cell. SlidePlayer. Retrieved August 2, 2022, from https://slideplayer.com/slide/13338401/ Khan Academy. (n.d.). Intro to photosynthesis (article). Khan Academy. Retrieved August 5, 2022, from https://www.khanacademy.org/science/ap-biology/cellularenergetics/photosynthesis/a/intro-to-photosynthesis Marieb, E. N., Whilhelm, P.B., & Mallatt, J.B. (2016). Human Anatomy 8th Edition. Pearson College Div. Retrieved August 3, 2022
