Cell Structure and Function PDF

CELL Fundamental unit of life table of 01 Cell. 02 Types of cells: components. contents: 03 04 Structure and basic functions. Protein syn...

CELL Fundamental unit of life table of 01 Cell. 02 Types of cells: components. contents: 03 04 Structure and basic functions. Protein synthesis. 05 06 Energy supply. Cellular digestion. 07 08 Support and movement. Storage and transportation.  Cell All the characteristics shared by all living things- can be observed and are executed at the cellular level.  Cell Basic and fundamental unit of life, it possesses a highly organized structure that enables it to carry out its vital functions.  Prokaryotic Prokaryotic Dispersed genetic material Lack a defined nucleus in the cytoplasm. Plant Types Cellulose cell wall; chloroplasts and vacuoles. of Cells Animal Rigid cell wall; may have flagella. Eukaryotic Have a defined nucleus Protist They can have a cell wall, without differentiated tissues. Fungal Chitin Cell Wall; they are heterotrophs. Cellular metabolism occurs within membranous organelles. Organelles are small, specialized structures in cells which operate like organs by carrying out specific tasks. According to Campbell et al. (2003), one advantage of having organelles is that two different cellular activities that require different conditions can occur at the same time since they are carried out within different organelles.  Composed of several fundamental components Ribosome Rough endoplasmic Cell membrane Nucleus Golgi Apparatus reticulum. Lysosome and Mitochondria Chloroplasts peroxisome Centriole Microtubules Structure and basic functions These components work together to maintain cellular homeostasis and perform essential life activities.  Cell membrane The cell membrane surrounds the cell and is a selective barrier between the interior and the exterior. Its primary role lies in regulating the passage of substances, including nutrients and waste materials. Within it, specialized proteins play a crucial role in facilitating molecular transport and cellular communication.  Cell nucleus An organelle that houses DNA, located in the center of eukaryotic cells. Its primary function is to store and safeguard genetic information, controlling gene expression and DNA replication. It also contains the nucleolus, which is involved in ribosome synthesis.  Cytoplasm The cytoplasm is a gel-like matrix containing water, salts, proteins, and other molecules. It occupies the intracellular space between the cell membrane and the nucleus. It plays a crucial role in biochemical reactions, energy production, and substance transport. Essential for cellular metabolism, it provides structural support to the cell.  Manufacture Building and repairing cellular structures, regulating biological processes, and expressing specific characteristics of each organism.  Cell nucleus The nucleus is considered as the brain center of the eukaryotic cell as it controls most of the cell’s metabolic activities. It contains the DNA (deoxyribonucleic acid), the cell’s hereditary blueprint and holds the key codes for making proteins and other important molecules. It also contains the nucleolus, which is involved in ribosome synthesis. Other structures found in the nucleus are: Chromatin and chromosomes – the granular material within the nucleus. It consists of DNA bound to protein. When a cell divides, the chromatin condenses to chromosomes, distinct, thread-like structures containing the genetic information that is passed from one generation to the next. Nucleolus – organelle where the manufacture or synthesis of ribosomes start. Nuclear envelope – Just like the cell membrane, the nuclear envelope is a double membrane layer that is semi-permeable. It regulates the entry and exit of materials within the nucleus.  Ribosome Ribosomes are essential organelles for cellular functioning and survival. They synthesize proteins using the genetic information from messenger RNA (mRNA), which is crucial for cellular structure, function, and regulation. Ribosomes are located in the cytoplasm and the rough endoplasmic reticulum. Ribosomes found attached to the endoplasmic reticulum are responsible for making proteins that will be transported out of the cell. Endoplasmic reticulum A network of interconnected membranes that extends from the nuclear membrane to the cell membrane. It plays a fundamental role in the transport, processing, and distribution of proteins and lipids within the cell. There are two main types of ER: The Rough Endoplasmic Reticulum (RER) is studded with ribosomes and is involved in the synthesis and modification of proteins. It makes membranes which serves as vesicles for export outside ER. The Smooth Endoplasmic Reticulum (SER) specializes in lipid synthesis, carbohydrate metabolism, and detoxification.  Golgi apparatus Key in the processing and packaging of proteins and lipids produced in the endoplasmic reticulum. It synthesizes carbohydrates and lipoproteins and is essential for maintaining the cell's internal balance and facilitating communication with the outside. Composed of a series of flattened sacs called cisternae, it acts as the 'shipping center' of the cell, sorting and packaging proteins into vesicles for transport and distribution. breakdown  Lysosomes Peroxisomes They contain enzymes that They contain digestive enzymes degrade hydrogen peroxide and that break down molecules and toxic compounds, thereby unwanted cellular materials. protecting the cell from oxidative damage. They facilitate cellular digestion, Additionally, they play a role in by disposing of waste, recycling the synthesis and degradation of nutrients, and defending against lipids and bile acids, regulating pathogenic invasions. lipid metabolism and overall homeostasis.  Vacuoles Vacuoles – are also membranous sacs that are larger than vesicles. They have variety of functions like storage of food, important molecules and certain enzymes. In plants, a central large vacuole is clearly seen. Since plant cells do not have lysosomes, the vacuole can serve as a large digestive bag, or it can serve as storage of vital chemicals needed by the cell. In protists, such as in Paramecium found in fresh waters, they have contractile vacuoles that get rid of excess water in the cell. All the organelles discussed above – nucleus, ribosomes, ER, Golgi body, lysosomes and vacuoles- constitute a cytoplasmic network that is called the endomembrane system. These organelles work together in the synthesis, storage, and export of important molecules.  Energy Processing To carry out vital functions and necessary metabolic processes essential for the proper functioning of the cell and/or organism.  Mitochondria Considered as the “powerhouse of the cell” because this is where cellular respiration takes place. Cellular respiration is an energy conversion process where chemical energy stored in food molecules such as sugars is converted to another form of chemical energy in ATP (adenosine triphosphate) molecules. ATP is the direct source of energy for cells during their metabolic activities.  Chloroplasts Exclusive to plant cells and photosynthetic organisms, chloroplasts carry out photosynthesis, converting solar energy into chemical energy. During photosynthesis, they synthesize glucose and other organic compounds using carbon dioxide and water, releasing oxygen as a byproduct. They are responsible for the crucial production of oxygen that sustains the planet.  Support and Movement Maintaining cellular shape, enabling cellular movement and division, are essential for its functioning and survival.  Cytoskeleton It is composed of protein filaments (microtubules, microfilaments, and intermediate filaments) and provides support and enables movement in eukaryotic cells. Its specific functions encompass stability, intracellular transport, and contraction. Furthermore, it regulates cellular shape and plays a role in division, migration, and communication. Three main kinds of fibers make up the cytoskeleton; a. the microtubules - are hollow tubes of protein that maintain cell shape and can serve as tracks along which organelles can move, just like in the case of centrioles. Centrioles, which are only present in animal cells, aid in cell division by serving as guides to the movement of chromosomes when cells divide. Microtubules are also the main components of cilia and flagella. b. the microfilaments – mainly composed of actin, which are primarily responsible for muscle contraction c. the intermediate filaments - help provide structure to the nuclear envelope and anchor organelles. They are made of fibrous proteins and have a rope-like structure. They serve mainly as reinforcing rods for bearing tension but also help anchor certain organelles. These four general categories of organelles emphasize that different parts of the cell form an integrated team and that properties of life at the cellular level emerge from the coordinated functions of the team members. Needless to say, the coordinated actions of cellular organelles underlie most of the emergent properties of life like cell movement.  Vesicles and endosomes Membranous vesicles that transport specific materials between organelles and the cell membrane. Vesicles: They transport materials from the endoplasmic reticulum and the Golgi apparatus to other destinations. Endosomes: They capture and distribute materials for degradation, recycling, or their incorporation into metabolic pathways. Think about the organelles found in a cell, from the nucleus, to the smooth and rough ER, Golgi bodies, lysosomes, ribosomes, chloroplasts, mitochondria, cytoskeleton, vacuoles and the cell membrane. Each of these organelles perform an amazing job that keeps you and I alive! Which one do you think has the most amazing job? Write an appreciation poem, or letter, or a short comic strip, or just a doodle for one of the organelles in your cell. Make sure to mention the important function of the organelle that, to you, makes it amazing. And do not forget that this is an appreciation activity! Thank you! Any questions?