1 / 31

Lesson 2.1

Chapter 2: Cells and Tissues. Lesson 2.1. Molecules of Life. Molecules of Life. An almost countless number of different types of molecules exists in the human body.

trilby
Download Presentation

Lesson 2.1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 2: Cells and Tissues Lesson 2.1 Molecules of Life

  2. Molecules of Life • An almost countless number of different types of molecules exists in the human body. • Biochemistry is the detailed study of the molecules of life, how they are made, how they interact, and how they are broken down. • Many chemicals important for life are organic molecules. Ex. Glucose (C6H12O6) • Organic molecules always contain carbonand hydrogen. • They usually contain oxygen, as well as nitrogen, phosphorous, sulfur, and other elements CHNOPS

  3. Molecules of Life • Major classes of large organic molecules in the body include: • Carbohydrates • Proteins • Lipids • Nucleic acids • Water*

  4. Carbohydrates • These are also known as saccharides, they are “sugar or starch” molecules • Simple carbohydrates • Glucose – circulates in the body • Complex carbohydrates • Glycogen (stored in animals) • The main functionof carbohydrates in the body is to serve as a source of chemical energy, or fuel. • The body can quickly utilize this fuel to make energy (ATP)

  5. Proteins • Proteins are large biological molecules made of chains of hundreds of amino acids. • There are 20 common amino acids, which are the building blocks of proteins • Amino acids are linked together by peptide bonds • Long chains of amino acids are called polypeptides

  6. Proteins • The structure and shape of a protein is organized into the following levels: • Primary – amino acid chain (polypeptide) • Secondary • Tertiary • Quaternary –2 or more polypeptides = protein

  7. Proteins • Proteins have many functions in the body including acting as: • Structural elements: collagen which gives strength to ligaments and tendons • Enzymes: salivary amylase found in saliva and breaks down carbohydrate molecules into smaller sugar molecules – accelerate biological reactions

  8. Lipids • Lipids are fats, oils and related molecules. • Fatty acids: • Key building blocks of other lipids. Hydrocarbon with carboxylic acid group. • Glycerides • Composed of a glycerol molecule (a simple sugar) with one, two, or three fatty acids attached, to make mono-, di-, and triglycerides • Glycerides are important energy storage molecules in the body.

  9. Lipids • Phospholipids • Are similar to glycerides with a hydrophilic phosphate head and a hydrophobic tail • As a result, phospholipids in a watery environment tend to form bilayers Ex. Cell membranes • Steroids • Have a structure different from other lipids • Have the same four-ring backbone but differ in the attached side groups • Three well-known steroid molecules—cholesterol, testosterone, and estrogen

  10. Nucleic Acids • Nucleic acids are key information-carrying molecules in cells. • They are chains (polymer) of nucleotides (subunits) • The two kinds of nucleic acids found in cells are: • Deoxyribonucleic acid (DNA ) • Ribonucleic acid (RNA) • messenger RNA (mRNA) • transfer RNA (tRNA) • ribosomal RNA (rRNA)

  11. Energy • Adenosine Triphosphate (ATP) • is a nucleotide composed of an adenine base, a sugar, and three phosphate groups. • This is an energy source used in many cellular processes

  12. Water* • Water makes up about two-thirds of the mass of the human body. • Hydrogen bonding • These are relatively weak bonds and are responsible for several biologically important properties of water such as solvent properties • Good solvent • The polar nature of water makes it a good solvent for many compounds. H2O

  13. Water • pH • A small fraction of water molecules in solution dissociate to make hydrogen ion (H+) plus hydroxide ion (OH-).

  14. Review and Assessment True or False? • Proteins are made up of fatty acids. 2. Glucose is a simple carbohydrate. 3. A steroid is a type of lipid. 4. A nucleic acid is a chain of amino acids. 5. Water has one hydrogen atom. FALSE TRUE TRUE FALSE FALSE

  15. Chapter 2: Cells and Tissues Lesson 2.2 Cells

  16. Anatomy and Physiology of Cells • The cells of the human body are surrounded by extracellular fluid, which is mostly water, and an extracellular matrix. • Plasma membrane makes up the shell of the cell • regulates the movement of material in and out of the cell • Cytoplasm • liquid inside the cell which contains the organelles • Nucleus • control center of cell

  17. Plasma Membrane Components • This is a phospholipid bilayer which contains cholesterol and a variety of proteins including channel proteins which allow water or small, charged particles such as sodium, to pass into or out of the cell.

  18. Membrane Transport • Membrane transport is the movement of substances across the plasma membrane which can occur on one of two ways: • Passive transport • Requires no energy • Usually involves diffusion – movement of a substance from an area of high to low concentration. • Active transport • Requires energy expenditure • Involves the movement of a substance from an area of low to high concentration • Sodium-potassium pump found in neuron membranes used to move Na+ out of the cell and K+ into the cell

  19. Cytoskeleton • The cytoskeleton strengthens and gives the cell its shape. • The cytoskeleton contains three types of long fibers: • Microfilaments: • the thinnest of these fibers, especially prominent in muscle cells. • Intermediate filaments: • give the cell strength to resist external pulling forces • Microtubules: • help to separate and organize chromosomes during cell division.

  20. Organelles in the Cytoskeleton

  21. Organelles in the Cytoskeleton • Microvilli • Finger-like extensions that increase the surface area of a cell. • Cilia • Hair-like projections that actively flex back and forth to move mucus or fluids across the outside of the cell • Centrioles • The centrioles help guide the movement and separation of chromosomes during cell division.

  22. Mitochondria and Energy • Mitochondria • Tubular- shaped structures in the cytoplasm of cells responsible for making ATP, the universal carrier of energy within cells • Powerhouses of the cell

  23. Golgi Apparatus • The Golgi is a set of membranous discs in the cytoplasm, usually between the endoplasmic reticulum and the plasma membrane of the cell. • Forms small vesicles used to package or move materials out of the cell.

  24. Ribosomes and Endoplasmic Reticulum • Ribosomes are very large enzymes that make polypeptides. • Endoplasmic reticulum (ER) is a network of membranes in the cytoplasm connected to the nuclear envelope • Rough ER has ribosomes attached to it and is a site for protein production and modification • Smooth ER has no ribosomes, it is a site where “replacement” membrane is made for the cell.

  25. The Nucleus • The nucleus is enclosed by nuclear envelope • Contains the cells genetic information – DNA, some RNA and proteins • The nucleolus is an area in the nucleus where ribosomal RNA is made and packaged

  26. DNA, RNA, and Proteins • The sequence of bases in DNA contains the information essential for making the RNA and Proteins needed for life. • The production of RNA from DNA is called transcription. • The production of Proteins from RNA is called translation.

  27. Life Cycle of a Cell • Most cells do not have a long life span • Intestinal cells have a life span of just 2 to 7 days. • Red blood cells live for about 120 days (4 months). • Many of the nerve cells in your brain, on the other hand, are as old as you are. • Cells must divide to make new cells for our bodies. • Interphase: the cell performs its usual functions and prepares for cell division. • The mitotic phase: cell divides into two identical daughter cells. • Mitosis is the division of the cell nucleus and chromosomes • prophase • metaphase • anaphase • telophase • Cytokinesis is the division of the cell cytoplasm, final step of cell division.

  28. Mitosis • Prophase • chromatin condenses into chromosomes, cell membrane breaks down • Metaphase • chromosomes line up in the center of the cell • Anaphase • centromeres are cut in half, sister chromatids pull toward centrioles • Telophase • chromosomes “decondense,” new nuclear membrane forms

  29. Mitosis

  30. Cancer • Cancer is the uncontrolled division and growth of abnormal cells. • grows too much • grows where it does not belong • does not die when it should • Cancer is caused by damage to a cell’s DNA molecules.

More Related