The Cell and its functions :The Cell and its functions Mercedes Gonzalez


Objectives :Objectives Identify organic compounds and their functions Identify inorganic compounds and their functions Identify and discuss the parts of the cell Discuss the functions of the cell and its parts


Facts :Facts The cell is the basic unit of structure and function of all living things Humans contain 60 to 100 trillion cells The human body has numerous types of cells, each specialized in performing particular functions. Cell structure is directly related to its function.


Protoplasm :Protoplasm A colloidal structure composed of water and of organic & inorganic materials, which form the living cell The protoplasm contains 70 – 85% water.


Organic compounds found in protoplasm(Organic compounds are substances which contain carbon) :Organic compounds found in protoplasm(Organic compounds are substances which contain carbon) The four major classes of organic compounds found in cells include: Proteins- They are found in all parts of the cell. Their functions include: assisting in growth, constructing new tissues & repairing injured or worn-out tissues. Amino acids are the building blocks of proteins. Enzymes are an important group of proteins that act as an organic catalyst. (They control the chemical reactions that occur) Lipids – They function in storing energy, insulating our bodies from the cold, assisting with the digestive process & helping to lubricate the joints


Organic compounds found in protoplasm(Organic compounds are substances which contain carbon) :Organic compounds found in protoplasm(Organic compounds are substances which contain carbon) Carbohydrates- Major source of cell energy, and they are predominately located in the liver and muscles. Nucleic Acids- The largest known organic molecules, and they are composed of thousands of smaller subunits called nucleotides. There are two types of nitrogenous bases which contribute to the composition of nucleic acids: Purines – adenine (A) or guanine (G) Pyrimidines – cytosine (C), thymine (T) or uracil (U) The Nucleic Acids include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)


Inorganic compounds found in the protoplasm :Inorganic compounds found in the protoplasm Inorganic substances are essential for cell life. Potassium (K) inside the cell prevents it from collapsing Sodium (Na) outside the cell prevents the cell from bursting.


Cell StructureThe basic cell structure of human cells: a cell membrane, cytoplasm and organelles.All human cells except mature red blood cells have a nucleus. :Cell StructureThe basic cell structure of human cells: a cell membrane, cytoplasm and organelles.All human cells except mature red blood cells have a nucleus. Cell membrane- Also called plasma membranes, and functions to separate the cell’s interior from its exterior surroundings. It is composed of lipids and proteins arranged in a double layer. The cell membrane is selectively semi-permeable. Cytoplasm – Watery solution found between the nucleus and cell membrane. Chemical reactions, such as protein synthesis and cellular respiration take place in the cytoplasm. Catabolism- process of converting a complex substance into a simpler substance. Anabolism – the building up of a body’s substance.


Organelles :Organelles Structures located within the cytoplasm that help the cell function Centrioles – A pair of cylindrical organelles contained in a circular body named the centrosome. Their function is to organize the spindle fibers during cell mitosis


Organelles :Organelles Endoplasmic reticulum (ER) – tubular network that extends from the nuclear membrane to the cell membrane; and assists in channeling proteins & lipids into and out of the nucleus. Rough ER – Has numerous ribosomes attached to its outer surface, giving it a rough appearance. Found in cells that actively secrete proteins (endocrine & exocrine glands) Smooth ER – Does not have ribosomes attached to it. The site for enzyme reactions in steroid hormone production and inactivation.


Organelles :Organelles Mitochondria- “Powerhouse” of the cell. Aerobic (oxygen-requiring) reactions of cell respiration take place here. The mitochondria contains enzymes that assist in breaking down carbohydrates, fat, and proteins into energy, that are stored in the cell as ATP. Golgi Apparatus- Organelle that synthesizes carbohydrates The carbohydrates are combined with proteins and are concentrated & packaged for secretion from the cell These organelles are most abundant in the gastric gland cells, salivary glands & pancreatic glands.


Organelles :Organelles Lysosomes – Organelles that assist in digesting old, worn-out cell parts, dead cells, bacteria, and foreign materials. The Nucleus – The central core of the cell. It controls metabolism, it stores and processes genetic information, and it controls protein synthesis. The nuclear membrane surrounds the nucleus, which has openings through which substances can travel from cytoplasm to nucleus or vice versa. DNA and proteins are contained within the nucleus.


Nucleus :Nucleus Chromatin - composed of long thin strands of DNA contains instructions that control cell metabolism and heredity Nucleolus - Spherical body in the cell nucleus that holds nuclear RNA. Instructions in DNA are copied here - works with ribosomes in the synthesis of protein


RNA :RNA There are 3 varieties of RNA: Messenger RNA (m-RNA) – RNA that binds amino acids to ribosomes during protein synthesis. Transfer RNA (t-RNA)- RNA that carries amino acids to ribosomes for assisting in protein synthesis Ribosomal RNA (r-RNA) – assists in the linking of the messenger RNA to the ribosome.


Chromosomes & Genes :Chromosomes & Genes Chromosomes - The linear thread of a cell nucleus. They contain DNA, which makes up genes, our hereditary blueprint. The normal number of chromosomes for humans is 46 (diploid – 2n) Gene – The basic unit of heredity which has a specific location on a chromosome.


Summary :Summary The protoplasm contains organic and inorganic compounds. Organic compounds denote chemical substances which contain carbon (proteins, carbohydrates, nucleic acids, and lipids) Inorganic compounds in the cell are sodium and potassium, and they are essential for cell life. A cell membrane, cytoplasm and organelles, are the basic structures of a human cell. All human cells except mature red blood cells have a nucleus. Organelles are structures located within the cytoplasm that help the cell function. DNA is the carrier of genetic material in the cell. RNA controls protein synthesis and there are 3 types: m-RNA, t-RNA, and r-RNA The parts of a cell are: Cell membrane - Golgi Apparatus Cytoplasm - Lysosomes Centrioles - Nucleus Endoplasmic Reticulum (rough & smooth) Mitochondria


References :References Brown, Terry. "Cell Structure and Processes." 1999. 29 Sep 2008 Forshier, Steve. Essentials of Radiation Biology and Protection. Canada: Delmar, Thomson Learning, 2002 Martini, Frederic H.. Fundamentals of Anatomy & Physiology. 7th. San Francisco: Pearson Benjamin Cummings, 2006.


Questions :Questions 1. (True or False) Humans contain 60 to 100 million cells. False 2. The four major classes of organic compounds found in cells include: ________, lipids, carbohydrates, and nucleic acids. proteins 3. (True or False) Potassium & sodium are inorganic substances that are essential to cell life. True


Slide 20:4. What are the two types of Endoplasmic Reticulum? smooth and rough 5. Which structure produces ATP? a. cytoplasm c. mitochondria b. nucleus d. Golgi apparatus C. 6. The mitochondria is also known as the ________ of the cell. powerhouse 7. Which of the following is a function of the nucleus? a. control metabolism c. store & process genetic information b. control protein synthesis d. all of the above D.


Slide 21:8. _______ are organelles that assist in digesting old, worn-out cell parts, dead cells, bacteria, and foreign materials. a. Proteins c. Mitochondria b. Lysomomes d. Ribosomes B. 9. The _______ is the basic unit of heredity. gene 10. ___________ inside the cell prevents it from collapsing, while __________ outside the cell prevents the cell from bursting. a. Potassium, sodium b. Sodium, potassium


Answers :Answers False Proteins True Smooth ER & rough ER C Powerhouse D B Gene A