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.