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Chapter 3 Cells and Tissue.

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1 Chapter 3 Cells and Tissue

2 Learning Objectives Identify and discuss the basic structure and function of the three major components of a cell. List and briefly discuss the functions of the primary cellular organelles. Compare the major passive and active transport processes that act to move substances through cell membranes.

3 Learning Objectives (cont’d.)
Compare and discuss DNA and RNA and their function in protein synthesis. Discuss the stages of mitosis and explain the importance of cellular reproduction.

4 Learning Objectives (cont’d.)
Explain how epithelial tissue is grouped according to shape and arrangement of cells. List and briefly discuss the major types of connective and muscle tissue. List the three structural components of a neuron.

5 Chapter 3 Lesson 3.1

6 Size and Shape Composition Human cells vary considerably in size.
All are microscopic. Cells differ notably in shape. Cytoplasm contains specialized organelles surrounded by a plasma membrane. Composition Cytoplasm contains specialized organelles. Plasma membrane surrounds each cell. Organization of cytoplasmic substances is important for life. The small, circular body called the nucleus is inside the cell. An ovum has a diameter of 150 micrometers. A red blood cell has a diameter of 7.5 micrometer. What are some of the shapes of different cell types?

7 Composition General Characteristics of the cell
Ask students to cite the functions of specific cell parts. What are the three parts of a cell?

8 Parts of the Cell Plasma membrane forms outer boundary of cell
only 7 nm (3/10,000,000 of an inch) thick thin two-layered membrane of phospholipids containing proteins form the framework of the plasma membrane is selectively permeable Cytoplasm internal living material of cells organelles—small structures that make up most of the cytoplasm Ribosomes: may attach to rough endoplasmic reticulum (ER) or lie free in cytoplasm. What is cholesterol, and what is its function? What are some of the other functions of the plasma membrane?

9 Parts of the Cell (cont’d.)
Endoplasmic reticulum (ER) network of connecting sacs and canals carries substances through cytoplasm Golgi apparatus group of flattened sacs stacked on one another near nucleus Mitochondria composed of inner and outer membranes each contains one DNA molecule What are the two types of ER? How do they function?

10 Parts of the Cell (cont’d.)
Lysosomes membranous-walled organelles contain digestive enzymes Centrioles paired organelles fine tubules that lie at right angles to each other near the nucleus Cilia fine hairlike extensions found on free or exposed surfaces of some cells Flagellum single projection extending from cell surfaces much larger than cilia Describe the protective function of lysosomes. What is the role that centrioles play during cell division?

11 Parts of the Cell (cont’d.)
Nucleus controls every organelle in the cytoplasm, along with cell reproduction contains the genetic code component structures include nuclear envelope, nucleoplasm, and chromatin granules What is the genetic code?

12 Relationship of Cell Structure and Function
Regulation of life processes. Survival of species through reproduction of the individual. Relationship of structure to function is apparent in number and type of organelles seen in different cells. What are some examples of specialized organelles?

13 Movement of Substances Through Cell Membranes
Passive transport processes processes do not require added energy and result in movement “down a concentration gradient” types of passive transport include: diffusion osmosis dialysis filtration What are the two transport processes for moving substances into and out of cells? How are they different?

14 Movement of Substances Through Cell Membranes (cont’d.)
Passive Transport Processes To form urine in the kidney, wastes are filtered out of the blood into the kidney tubules because of differences in hydrostatic pressure.

15 Movement of Substances Through Cell Membranes (cont’d.)
Passive transport processes Diffusion Substances scatter themselves evenly throughout an available space. It is unnecessary to add energy to the system. Movement is from high to low concentration. Osmosis and dialysis are specialized examples of diffusion. What are osmosis and dialysis? What are solutes?

16 Movement of Substances Through Cell Membranes (cont’d.)
Passive transport processes Filtration Movement of water and solutes through a membrane because of a greater pushing force on one side of the membrane than on the other. This force is called hydrostatic pressure. Responsible for urine formation. Give some additional examples of filtration.

17 Movement of Substances Through Cell Membranes (cont’d.)
Active transport processes occurs only in living cells movement of substances is “ against/up the concentration gradient” requires energy from adenosine triphosphate (ATP) What is adenosine triphosphate (ATP)?

18 Movement of Substances Through Cell Membranes (cont’d.)
Active Transport Processes

19 Movement of Substances Through Cell Membranes (cont’d.)
Active transport processes Ion pumps An ion pump is protein complex in cell membrane called a carrier. Ion pumps use energy from ATP to move substances across cell membranes against their concentration gradients Phagocytosis and Pinocytosis Both are active transport mechanisms because they require cell energy. Phagocytosis is a protective mechanism often used to destroy bacteria. Pinocytosis is used to incorporate fluids or dissolved substances into cells.

20 Chapter 3 Lesson 3.2

21 Cell Reproduction Mitosis
the process of cell reproduction, one cell divides to become two cells. tied closely to the production of proteins What molecules play a crucial role in protein synthesis and mitosis? (DNA and RNA)

22 Cell Reproduction (cont’d.)
DNA Molecule and Genetic Information Chromosomes are composed largely of DNA. DNA shaped like a long, narrow spiral staircase. Each step in the DNA ladder consists of pair of bases. Only two combinations of bases will occur A-T or C-G. Called complementary base pairing. What are the components of DNA? (Sugar, phosphate, nitrogen bases) What are the base pairs? (adenine–thymine and guanine-cytosine)

23 Genetic Code DNA Molecule and Genetic Information
Genes dictate formation of enzymes and other proteins by ribosomes. Although the types of base pairs in all chromosomes are the same, the sequence varies. Each gene directs the synthesis of a specific protein. Genetic code—the storage of information in each gene How many chromosomes are in human body cells? (46)

24 Genetic Code (cont’d.) RNA Molecules and Protein Synthesis
Ribonucleic acid (RNA) transfers genetic information from the nucleus to the cytoplasm. RNA is made up of: sugar: ribose phosphate nitrogen bases: cytosine, guanine, adenine, uracil Where does protein synthesis occur?

25 Genetic Code (cont’d.) RNA Molecules and Protein Synthesis
Transcription Double-stranded DNA separates to form messenger RNA (mRNA). Each strand of mRNA duplicates a particular gene (base-pair sequence) from a segment of DNA. mRNA molecules pass from the nucleus to the cytoplasm where they direct protein synthesis in ribosomes and ER.

26 Genetic Code (cont’d.) Translation
Involves synthesis of proteins in cytoplasm by ribosome Requires use of information contained in mRNA to direct the choice and sequencing of the building blocks called amino acids As amino acids are assembled into proper sequence, a protein strand forms. What happens after the protein strand is formed?

27 Genetic Code (cont’d.) Protein synthesis
Go through the steps of transcription and translation as shown in the figure.

28 Cell Division Reproduction of cell by division of the nucleus (mitosis) and the cytoplasm DNA Replication Process by which each half of a DNA molecule becomes a whole molecule identical to the original DNA molecule Happens before mitosis What is interphase?

29 Cell Division (cont’d.)
Mitosis Process in cell division in which identical chromosomes (DNA molecules) to each new cell are formed when the original cell divides Enables cells to reproduce their own kind Name the four stages of mitosis. (prophase, metaphase, anaphase, telophase)

30 Stages of Mitosis Prophase—first stage
Chromatin granules become organized. Chromosomes (pairs of linked chromatids) appear. Chromatids are held together by beadlike structure called centromere. Centrioles move away from each other. Spindle fibers form between centrioles. Nuclear envelope disappears, freeing genetic material.

31 Stages of Mitosis (cont’d.)
Metaphase—second stage Nuclear envelope and nucleolus have disappeared. Chromosomes align across center of cell. Spindle fibers attach themselves to each chromatid. What do spindle fibers resemble?

32 Stages of Mitosis (cont’d.)
Anaphase—third phase Centromeres break apart. Separated chromatids are now called chromosomes once again. Chromosomes are pulled to opposite ends of cell. Cleavage furrow develops at end of anaphase. Beginning to divide cell into two daughter cells Daughter cells have identical genetic characteristics. Each may later undergo mitosis.

33 Stages of Mitosis (cont’d.)
Telophase—fourth stage Cell division is completed. Nuclei appear in daughter cells. Nuclear envelope and nucleoli appear. Cytoplasm and organelles divide equally. Daughter cells become fully functional. What are the results of cell division? Discuss neoplasm

34 Chapter 3 Lesson 3.3 Epithelial Tissue types

35 Tissues Epithelial tissue Covers body and lines body cavities
Cells packed closely together with little matrix Classified by shape and arrangement of cells Epithelial tissue types simple squamous epithelium single layer of very thin, irregularly shaped cells transport is function (such as absorption of oxygen into blood) located in alveoli of lungs, lining of blood, and lymphatic vessels stratified squamous epithelium several layers of closely packed cells protection is primary function What are the four shapes of epithelial cells? In what ways can they be arranged?

36 Tissues (cont’d.) Epithelial tissue types Simple columnar epithelium
Single layer of tall, narrow cells Contain mucus-producing goblet cells Stratified transitional epithelium Up to 10 layers of roughly cuboidal-shaped cells that distort to squamous shape when stretched Functions as protection Found in body areas subject to stress and that stretch, such as urinary bladder Pseudostratified epithelium Single layer of tall cells that wedge together to appear as if there are two or more layers Simple cuboidal epithelium Form tubules specialized for secretory activity Usually form clusters called glands What is the special function of simple columnar epithelium? Where can these cells be found?

37 Tissues (cont’d.) Classification of epithelial tissues

38 Tissues (cont’d.) Connective tissue Most abundant tissue in body
Most widely distributed tissue in body Multiple types, appearances, and functions Relatively few cells in intercellular matrix Types Areolar—glue that holds organs together Adipose (fat)—lipid storage is primary function Fibrous—consists of strong, white collagen fibers Where is connective tissue found?

39 Tissues (cont’d.) Connective tissue types
Bone—matrix is hard and calcified Forms structural building blocks called osteons Function in support and protection, stores calcium Cartilage—chondrocyte is cell type Differs from bone because its matrix has the consistency of a firm plastic or gristle-like gel Blood and Hemopoietic Blood—matrix is fluid Hemopoietic—bloodlike connective tissue found in marrow cavities Osteons are also called Haversian systems. What is the function of hemopoietic tissue?

40 Tissues (cont’d.) Muscle tissue Types
Skeletal—also called striated or voluntary attaches to bones control is voluntary striations apparent when viewed under a microscope Describe the structure and distinctive traits of skeletal muscle cells.

41 Tissues (cont’d.) Muscle tissue types
Cardiac—also called striated involuntary produces regular, involuntary contractions of cardiac muscle to produce heartbeat has faint cross striations and thicker dark bands called intercalated disks Smooth—also called visceral involuntary control appears smooth; without cross striations has only one nucleus per fiber forms walls of blood vessels, hollow organs such as intestines and other tube-shaped structures Give some examples of smooth muscles. (digestive tract, respiratory tubes)

42 Tissues (cont’d.) Nervous tissue
Provides rapid communication between body structures and control of body functions Example is spinal cord tissue Consists of two cell types: neuron and glia Glia (neuroglia)—supportive and connecting cells Neurons—conducting cell Give a general description of a neuron. What does an axon do? What does a dendrite do?

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