Chapter 03 _ Cells
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.
Size and Shape
Human cells vary in size but are all microscopic.
Notable differences in cell shape.
Cytoplasm
Substance found only in cells.
Contains organelles, specialized structures within the cytoplasm.
Surrounded by a plasma membrane.
Plasma Membrane
Forms the outer boundary of the cell.
Composed of a phospholipid bilayer with proteins.
Selectively permeable.
Internal Living Material
Fills space between plasma membrane and nucleus.
Contains numerous organelles.
Nucleus and Organelles
Key components include the nuclear envelope, nucleolus, and various organelles like mitochondria, Golgi apparatus, and lysosomes.
Function
Manufacture enzymes and proteins.
Can be attached to rough ER or free in cytoplasm.
often called protein factories
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.
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.
Composed of inner and outer membranous sacs.
Involved in energy-releasing chemical reactions.
Contains one DNA molecule
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)
Function
Microtubule-organizing center.
Contains centrioles that assist in cell reproduction.
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.
Single projections extending from the cell surface.
Much larger than cilia.
The "tails" of sperm cells are the only example of flagella in humans.
Structure
Surrounded by a nuclear envelope with pores.
Made up of 2 separate membranes
Contains nucleolus and chromatin.
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
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.
Passive Transport
Does not require energy; moves down a concentration gradient.
Process
Substances scatter evenly in available space from high to low concentration.
Definitions
Osmosis: Diffusion of water across a selectively permeable membrane.
Dialysis: Diffusion of solutes.
movement of water and solutes across a membrane driven by hydrostatic pressure.
plays a key role in urine formation
Occurs only living cells
Requires energy (ATP) to move substances against concentration gradients.
Protein complexes in the cell membrane
Uses ATP energy to move substance against their concentration gradients
collaborates ion pumps work with other carriers
Active Transport Mechanisms
Phagocytosis: Engulfing particles (e.g., bacteria).
Pinocytosis: Incorporating fluids or dissolved substances.
Examples
Cystic fibrosis: Abnormal chloride ion transport.
Cholera: Causes severe diarrhea due to ion and water leakage.
Cell Reproduction and Heredity
Compare DNA and RNA functions in protein synthesis.
Discuss stages of mitotic cell division.
DNA Structure
Double helix made of sugar, bases, and phosphate units.
Genetic Code
Sequence of base pairs determines heredity and protein production.
Process
Genetic information transfers from nucleus to cytoplasm for protein synthesis.
Process
DNA separates to form mRNA, which directs protein synthesis.
/
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
Impact of Abnormal DNA
Can lead to diseases due to inherited or damaged DNA.
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.
Function
Distributes identical chromosomes to new cells, enabling reproduction and heredity.
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
Chromosomes align at the center of the cell
Spindle fibers attach to each chromatid
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.
Cell division is completed
Nuclei reappear in the daughter cells.
Nuclear envelope and nucleoli reform
Cytoplasm divides (cytokinesis)
Daughter cells become fully functional.
Hypertrophy and Atrophy
Hypertrophy: Increase in cell size.
Atrophy: Decrease in cell size.
Hyperplasia: Increase in cell reproduction, leading to an increase in tissue size.
Anaplasia: Production of abnormal, undifferentiated cells.
Types
Abnormal cell reproduction leading to various cancers.
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.
Size and Shape
Human cells vary in size but are all microscopic.
Notable differences in cell shape.
Cytoplasm
Substance found only in cells.
Contains organelles, specialized structures within the cytoplasm.
Surrounded by a plasma membrane.
Plasma Membrane
Forms the outer boundary of the cell.
Composed of a phospholipid bilayer with proteins.
Selectively permeable.
Internal Living Material
Fills space between plasma membrane and nucleus.
Contains numerous organelles.
Nucleus and Organelles
Key components include the nuclear envelope, nucleolus, and various organelles like mitochondria, Golgi apparatus, and lysosomes.
Function
Manufacture enzymes and proteins.
Can be attached to rough ER or free in cytoplasm.
often called protein factories
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.
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.
Composed of inner and outer membranous sacs.
Involved in energy-releasing chemical reactions.
Contains one DNA molecule
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)
Function
Microtubule-organizing center.
Contains centrioles that assist in cell reproduction.
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.
Single projections extending from the cell surface.
Much larger than cilia.
The "tails" of sperm cells are the only example of flagella in humans.
Structure
Surrounded by a nuclear envelope with pores.
Made up of 2 separate membranes
Contains nucleolus and chromatin.
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
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.
Passive Transport
Does not require energy; moves down a concentration gradient.
Process
Substances scatter evenly in available space from high to low concentration.
Definitions
Osmosis: Diffusion of water across a selectively permeable membrane.
Dialysis: Diffusion of solutes.
movement of water and solutes across a membrane driven by hydrostatic pressure.
plays a key role in urine formation
Occurs only living cells
Requires energy (ATP) to move substances against concentration gradients.
Protein complexes in the cell membrane
Uses ATP energy to move substance against their concentration gradients
collaborates ion pumps work with other carriers
Active Transport Mechanisms
Phagocytosis: Engulfing particles (e.g., bacteria).
Pinocytosis: Incorporating fluids or dissolved substances.
Examples
Cystic fibrosis: Abnormal chloride ion transport.
Cholera: Causes severe diarrhea due to ion and water leakage.
Cell Reproduction and Heredity
Compare DNA and RNA functions in protein synthesis.
Discuss stages of mitotic cell division.
DNA Structure
Double helix made of sugar, bases, and phosphate units.
Genetic Code
Sequence of base pairs determines heredity and protein production.
Process
Genetic information transfers from nucleus to cytoplasm for protein synthesis.
Process
DNA separates to form mRNA, which directs protein synthesis.
/
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
Impact of Abnormal DNA
Can lead to diseases due to inherited or damaged DNA.
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.
Function
Distributes identical chromosomes to new cells, enabling reproduction and heredity.
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
Chromosomes align at the center of the cell
Spindle fibers attach to each chromatid
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.
Cell division is completed
Nuclei reappear in the daughter cells.
Nuclear envelope and nucleoli reform
Cytoplasm divides (cytokinesis)
Daughter cells become fully functional.
Hypertrophy and Atrophy
Hypertrophy: Increase in cell size.
Atrophy: Decrease in cell size.
Hyperplasia: Increase in cell reproduction, leading to an increase in tissue size.
Anaplasia: Production of abnormal, undifferentiated cells.
Types
Abnormal cell reproduction leading to various cancers.
