Chapter 03 _ Cells

Cells Chapter 3 Summary

Page 2: Learning Objectives

  • Cells and Movement of Substances Through Cell Membranes

    • Identify three major components of a cell.

    • Discuss the structure and function of the plasma membrane and cytoplasm.

    • List and discuss functions of primary cellular organelles.

    • Explain the structure and function of the nucleus.

    • Compare passive and active transport processes and their relation to diseases.

Page 3: Cells

  • Size and Shape

    • Human cells vary in size but are all microscopic.

    • Notable differences in cell shape.

Page 4: Cell Composition

  • Cytoplasm

    • Substance found only in cells.

    • Contains organelles, specialized structures within the cytoplasm.

    • Surrounded by a plasma membrane.

Page 5: Parts of the Cell

  • Plasma Membrane

    • Forms the outer boundary of the cell.

    • Composed of a phospholipid bilayer with proteins.

    • Selectively permeable.

Page 7: Cytoplasm

  • Internal Living Material

    • Fills space between plasma membrane and nucleus.

    • Contains numerous organelles.

Page 8: Cell Structure

  • Nucleus and Organelles

    • Key components include the nuclear envelope, nucleolus, and various organelles like mitochondria, Golgi apparatus, and lysosomes.

Page 9: Organelles: Ribosomes

  • Function

    • Manufacture enzymes and proteins.

    • Can be attached to rough ER or free in cytoplasm.

    • often called protein factories

Page 10: Organelles: Endoplasmic Reticulum (ER)

  • Network of interconnected sacs and canals

  • Transports substance through the cell’s fluid cytoplasm

  • Types

    • Rough ER: Collects, folds, and transports proteins.

    • Smooth ER: Synthesizes chemicals and makes new membranes.

Page 11: Organelles: Golgi Apparatus

  • Group of flattened sacs located near the nucleus.

  • Collects chemicals into vesicles that move from the smooth ER to the plasma membrane.

  • Functions as the cell's chemical processing and packaging center.

Page 13: Organelles: Mitochondria

  • Composed of inner and outer membranous sacs.

  • Involved in energy-releasing chemical reactions.

  • Contains one DNA molecule

Page 14: Organelles: Lysosomes

  • membranous- walled organelles

  • Contain digestive enzymes for breaking down waste.

  • Protective function against microbes (digests it)

  • previously thought to be involved in apoptosis (cell death)

Page 15: Organelles: Centrosome

  • Function

    • Microtubule-organizing center.

    • Contains centrioles that assist in cell reproduction.

Page 16: Organelles: Cell Extensions

  • Microvilli and Cilia

    • Microvilli: small, finger like extensions of the plasma membrane.

      • Increase surface area for absorption.

    • Cilia: fine, hairlike extension found on free or expose surfaces of some cells

      • Move in unison to propel substances.

Page 18: Organelles: Flagella

  • Single projections extending from the cell surface.

  • Much larger than cilia.

  • The "tails" of sperm cells are the only example of flagella in humans.

Page 20: Nucleus

  • Structure

    • Surrounded by a nuclear envelope with pores.

    • Made up of 2 separate membranes

    • Contains nucleolus and chromatin.

Page 21: Nucleus: Chromatin and Chromosomes

  • Function

    • Contains DNA, which controls cell functions.

    • DNA condenses into chromosomes during cell division.

    • Made up of nuclear envelope, nucleoplasm, nucleolus and chromatin granules

    • Each cell has 46 chromosomes in the nucleus

Page 22: Relation of Cell Structure and Function

  • Every human cell has a specific function.

  • Some functions help maintain the cell, while others regulate body processes.

  • Specialized functions vary based on the number and type of organelles in the cell.

Page 23: Movements of Substances: Cell Membranes

  • Passive Transport

    • Does not require energy; moves down a concentration gradient.

Page 24: Diffusion

  • Process

    • Substances scatter evenly in available space from high to low concentration.

Page 27: Osmosis and Dialysis

  • Definitions

    • Osmosis: Diffusion of water across a selectively permeable membrane.

    • Dialysis: Diffusion of solutes.

Page 30: Filtration

  • movement of water and solutes across a membrane driven by hydrostatic pressure.

  • plays a key role in urine formation

Page 31: Active Transport Processes

  • Occurs only living cells

    • Requires energy (ATP) to move substances against concentration gradients.

Page 32: Ion Pumps**

  • Protein complexes in the cell membrane

    • Uses ATP energy to move substance against their concentration gradients

    • collaborates ion pumps work with other carriers

Page 34: Phagocytosis and Pinocytosis

  • Active Transport Mechanisms

    • Phagocytosis: Engulfing particles (e.g., bacteria).

    • Pinocytosis: Incorporating fluids or dissolved substances.

Page 36: Cell Transport and Disease

  • Examples

    • Cystic fibrosis: Abnormal chloride ion transport.

    • Cholera: Causes severe diarrhea due to ion and water leakage.

Page 38: Learning Objectives Lesson 3.2

  • Cell Reproduction and Heredity

    • Compare DNA and RNA functions in protein synthesis.

    • Discuss stages of mitotic cell division.

Page 39: Cell Growth and Reproduction

  • DNA Structure

    • Double helix made of sugar, bases, and phosphate units.

Page 41: DNA

  • Genetic Code

    • Sequence of base pairs determines heredity and protein production.

Page 42: RNA Molecules and Protein Synthesis

  • Process

    • Genetic information transfers from nucleus to cytoplasm for protein synthesis.

Page 44: Transcription

  • Process

    • DNA separates to form mRNA, which directs protein synthesis.

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Page 45: Translation

  • Involves synthesis of proteins in cytoplasm by ribosomes

  • Requires use of information contained in mRNA

  • Codon: Series of three nucleotide bases that act as a code for a specific amino acid

Page 46: Protein Synthesis and Disease

  • Impact of Abnormal DNA

    • Can lead to diseases due to inherited or damaged DNA.

Page 47: Cell Life Cycle

  • Phases

    • Mitosis: Division of the nucleus and cytoplasm.

      • results in two daughter cells

    • Interphase: Period when the cell is not dividing.

    • DNA Replication- Each half of a DNA molecule becomes a complete molecule identical to the original; occurs before mitosis.

Page 49: Mitosis

  • Function

    • Distributes identical chromosomes to new cells, enabling reproduction and heredity.

Page 50: Prophase- First Stage

  • Chromosome Formation: Chromosomes, consisting of paired chromatids, appear.

  • Nuclear Envelope: Disappears, releasing the genetic material.

  • Spindle Fibers: Appear to assist in cell division.

  • Centrioles Movement: Centrioles move away from the nucleus.

  • Chromatin Organization: Chromatin granules become organized.

    • Chromatin granules are tiny, thread-like structures inside the nucleus made of DNA and proteins that contain the cell's genetic information

Page 51: Metaphase- Second Stage

  • Chromosomes align at the center of the cell

  • Spindle fibers attach to each chromatid

Page 52: Anaphase- Third Stage

  • Centromeres break apart.

  • Separated chromatids are now called chromosomes.

  • Chromosomes are pulled to opposite ends of the cell.

  • A cleavage furrow begins to form at the end of anaphase.

Page 53: Telophase- Fourth Stage

  • Cell division is completed

  • Nuclei reappear in the daughter cells.

  • Nuclear envelope and nucleoli reform

  • Cytoplasm divides (cytokinesis)

  • Daughter cells become fully functional.

Page 54: Changes in Cell Growth

  • Hypertrophy and Atrophy

    • Hypertrophy: Increase in cell size.

    • Atrophy: Decrease in cell size.

Page 55: Changes in Cell Reproduction

  • Hyperplasia: Increase in cell reproduction, leading to an increase in tissue size.

  • Anaplasia: Production of abnormal, undifferentiated cells.

Page 56: Cancer

  • Types

    • Abnormal cell reproduction leading to various cancers.