CELLS The basic living, structural, and functional unit of all organisms.

The four principle parts of a generalized animal cell and their functions. Nucleus – “Control Center of the Cell” Nucleus – “Control Center of the Cell” Cytosol – intracellular fluid Cytosol – intracellular fluid Organelles – “elle = small or tiny building blocks of the cell” Organelles – “elle = small or tiny building blocks of the cell” Cell (Plasma) Membrane Cell (Plasma) Membrane  - selective permeability

Basic Cell

Basic Cell Structures

DRAW ME

Nucleus The “control center” of the cell The “control center” of the cell Usually the largest structure in the cell Usually the largest structure in the cell Contains genetic information Contains genetic information Controls cellular function and structure Controls cellular function and structure

Nucleus Nuclear Membrane Nuclear Membrane Nucleoplasm Nucleoplasm Nucleolus Nucleolus –site of ribosome synthesis Genetic Material DNA Genetic Material DNA –Chromatin contains DNA in thread-like form (cell is not dividing) –Chromosomes contains DNA in short, rod-like structures (cell is reproducing)

Cell Nucleus

Cytosol Cytosol Cytosol The semi-fluid component of cytoplasm or intracellular fluid The semi-fluid component of cytoplasm or intracellular fluid 75% - 95% water 75% - 95% water May contain organelles, large carbohydrates, fat, and protein molecules May contain organelles, large carbohydrates, fat, and protein molecules

Organelles Specialized structures and portions of the cell with characteristic shapes that assume specific roles: Specialized structures and portions of the cell with characteristic shapes that assume specific roles: –growth –repair –maintenance –control of cellular functions

cell membrane. The Cell (Plasma) Membrane The Cell (Plasma) Membrane –Thin structure that separates the internal cellular (intracellular) components from the external environment.

Cell Membrane

structure and function of the cell membrane. Cell Membrane Structure Cell Membrane Structure Phospholipid bilayer Phospholipid bilayer Hydrophilic phosphoric heads face outward Hydrophilic phosphoric heads face outward Hydrophobic fatty acid tails face inward Hydrophobic fatty acid tails face inward Carbohydrates assist in cell identification/communication Carbohydrates assist in cell identification/communication Cholesterol increases strength of cell membrane Cholesterol increases strength of cell membrane

structure and function of the cell membrane. (cell membrane proteins) Integral Proteins are proteins imbedded in the phospholipid bilayer Integral Proteins are proteins imbedded in the phospholipid bilayer –gates or channels are transport proteins –receptor sites for hormones –enzymes –cellular identity markers Peripheral Proteins are loosely bound to plasma membrane Peripheral Proteins are loosely bound to plasma membrane –function not completely understood

Cell Membrane Structures

Cell Membrane Proteins

selectively permeable membrane and factors which influence permeability. Cell Membrane Function Cell Membrane Function Flexible boundary Flexible boundary Facilitates contact with other cells and environment Facilitates contact with other cells and environment Receptor sites - hormones, enzymes, neurotransmitters, nutrients, antibodies Receptor sites - hormones, enzymes, neurotransmitters, nutrients, antibodies Selectively permeable - mediates entrance and exit of material into and out of cell. Selectively permeable - mediates entrance and exit of material into and out of cell.

selectively permeable membrane and factors which influence permeability. Size of molecules Size of molecules Solubility in lipids Solubility in lipids Charge on ions Charge on ions Presence of carrier molecules Presence of carrier molecules

Movement Across the Cell Membrane

intracellular and extracellular fluid in terms of location and composition. Intracellular Fluid-inside the cell Intracellular Fluid-inside the cell Fluid found in living cells Fluid found in living cells Comprises > 66% of body’s total water Comprises > 66% of body’s total water Mostly water Mostly water –may also contain potassium, phosphates, magnesium, chloride, and other ions

intracellular and extracellular fluid in terms of location and composition. Extracellular fluid Extracellular fluid –Fluid found in the microscopic spaces between cells Plasma Plasma –Extracellular fluid within blood vessels

cellular transport processes and classify them as active or passive. Passive Processes Passive Processes –No energy expenditure –Moves down a concentration gradient –High →low concentration Active Processes Active Processes –Requires energy expenditure –Moves against a concentration gradient –Low → high concentration –May utilize 40% of cells ATP supply

Movement Across the Cell Membrane

cellular transport processes Diffusion Diffusion Facilitated Diffusion Facilitated Diffusion Osmosis Osmosis Dialysis Dialysis Filtration Filtration

Diffusion The movement of molecules from a higher concentration to a lower concentration. Does not require energy. The movement of molecules from a higher concentration to a lower concentration. Does not require energy. Ex: perfume, electrolytes Ex: perfume, electrolytes

Facilitated Diffusion Facilitated diffusion is the process of diffusion through the protein channels of the cell membrane. Facilitated diffusion is the process of diffusion through the protein channels of the cell membrane. Ex: glucose Ex: glucose

Facilitated Diffusion

Dialysis Dialysis is the diffusion of excessive particles, waste, and water through a selectively permeable membrane. Dialysis is the diffusion of excessive particles, waste, and water through a selectively permeable membrane. Example: Kidney dialysis Example: Kidney dialysis

Filtration Filtration is the process of removing particles from a solution by allowing the liquid and substances less than 10,000 Daltons to pass through a membrane. Sugar and amino acid monomers are about 100 Daltons. It is influenced by gravity and hydrostatic pressure. Filtration is the process of removing particles from a solution by allowing the liquid and substances less than 10,000 Daltons to pass through a membrane. Sugar and amino acid monomers are about 100 Daltons. It is influenced by gravity and hydrostatic pressure. Example: Filtration in the glomerulus of the kidney nephron. Example: Filtration in the glomerulus of the kidney nephron.

cellular transport processes and active or passive. 1. Endocytosis occurs when the molecules are too big to enter the cell by diffusion or active transport, a vesicle is formed from the cell membrane. 1. Endocytosis occurs when the molecules are too big to enter the cell by diffusion or active transport, a vesicle is formed from the cell membrane. Example: Phagocytosis or cell eating. Example: Phagocytosis or cell eating.

cellular transport processes and active or passive. 2. Exocytosis 2. Exocytosis Any remaining particles from phagocytosis may be expelled from the cell when the vesicle joins with the cell membrane and the contents are removed from the cell. Any remaining particles from phagocytosis may be expelled from the cell when the vesicle joins with the cell membrane and the contents are removed from the cell.

Endocytosis and Exocytosis

cellular transport processes and as active or passive. Active Transport Active Transport –Uses energy –Ions move against a concentration gradient Na+/K+ pump Na+/K+ pump –Estimated 40% ATP use in the body Cytosis (Bulk Transport) Cytosis (Bulk Transport) –Endocytosis Phagocytosis - cell eatingPhagocytosis - cell eating Pinocytosis - cell drinkingPinocytosis - cell drinking Receptor mediated endocytosisReceptor mediated endocytosis –Exocytosis

Na+/K+ Pump

Osmosis Isotonic Solutions Isotonic Solutions Hypotonic Solutions Hypotonic Solutions Hypertonic Solutions Hypertonic Solutions

Osmosis the spontaneous net movement of solvent molecules through a semi- permeable membrane into a region of higher solute concentration, the spontaneous net movement of solvent molecules through a semi- permeable membrane into a region of higher solute concentration, Occurs in the direction that tends to equalize the solute concentrations on the two sides. Occurs in the direction that tends to equalize the solute concentrations on the two sides.

Osmosis

Isotonic solution two solutions having the same osmotic pressure across a semipermeable membrane two solutions having the same osmotic pressure across a semipermeable membrane

Hypertonic solution type of solution that has a greater concentration of solutes on the outside of a cell when compared with the inside of a cell. type of solution that has a greater concentration of solutes on the outside of a cell when compared with the inside of a cell.

Hypotonic solution any solution that has a lower osmotic pressure than another solution. any solution that has a lower osmotic pressure than another solution. In the biological fields, this generally refers to In the biological fields, this generally refers to –a solution that has less solute and more water than another solution

Tonic Solutions

Inside the Nucleus Nucleolus Nucleolus –Site of ribosome production (rRNA) ribosomal ribonucleic acid. DNA DNA –Double stranded helix of genetic material inside the nucleus. RNA RNA –Single stranded genetic material produced in the nucleus and exits through nuclear pores. –(mRNA, tRNA, rRNA)

Inside the Nucleus Chromosome Chromosome –tightly packed DNA prior to cell division. Chromatin Chromatin –(thread-like) loosely packed DNA. Gene Gene –a segment of DNA that codes for a protein.

Cell Nucleus

Organelles Specialized structures and portions of the cell with characteristic shapes that assume specific roles: Specialized structures and portions of the cell with characteristic shapes that assume specific roles: –growth –repair –maintenance –control of cellular functions

Organelles and Structures Ribosomes Ribosomes Endoplasmic Reticulum Endoplasmic Reticulum Golgi Complex Golgi Complex Mitochondria Mitochondria Lysosomes Lysosomes Peroxisomes Peroxisomes Microfilaments Microtubules Centrioles Centrosomes Flagella Cilia Microvilli Vacuoles

Ribosomes Appear as small, round, granular structures within the cell Appear as small, round, granular structures within the cell Sites of protein synthesis by assembling the amino acids in the correct order. Sites of protein synthesis by assembling the amino acids in the correct order. Made up of special type of RNA called ribosomal RNA (rRNA) Made up of special type of RNA called ribosomal RNA (rRNA)

Endoplasmic Reticulum Double membranous channels which are continuous with the nuclear membrane Double membranous channels which are continuous with the nuclear membrane Granular (Rough) Endoplasmic Reticulum Granular (Rough) Endoplasmic Reticulum –studded with ribosomes –site of protein synthesis Agranular (Smooth) Agranular (Smooth) Endoplasmic Reticulum Endoplasmic Reticulum –free of ribosomes –site of lipid synthesis

Functions of Endoplasmic Reticulum Mechanical support and distribution of cytoplasm Mechanical support and distribution of cytoplasm Surface area for chemical reactions Surface area for chemical reactions Intracellular transport system Intracellular transport system Storage of synthesized molecules Storage of synthesized molecules Protein (RER) synthesis Protein (RER) synthesis Lipid (SER) synthesis Lipid (SER) synthesis Detoxification of certain molecules Detoxification of certain molecules Release of calcium ions in muscles Release of calcium ions in muscles

Golgi complex (apparatus) Processes, packages, sorts, and delivers proteins to various parts of the cell Processes, packages, sorts, and delivers proteins to various parts of the cell Secretion of lipid molecules for transport around the cell Secretion of lipid molecules for transport around the cell Form lysosomes from the trans face Form lysosomes from the trans face Flattened membranous sacs (4 - 8) stacked upon one another

Vesicles (Vacuoles) Fluid and product filled organelles enclosed by a lipid bilayer membrane Fluid and product filled organelles enclosed by a lipid bilayer membrane Varied storage functions are for metabolism (digested cellular food or water), transport, enzymes, and chemical RXN. Varied storage functions are for metabolism (digested cellular food or water), transport, enzymes, and chemical RXN.

Lysosomes Nicknamed “suicide packets” Nicknamed “suicide packets” Small membrane enclosed spheres of digestive enzymes Small membrane enclosed spheres of digestive enzymes Intracellular digestion Intracellular digestion –Autophagy is the process by which old worn out organelles are digested –Autolysis is the process by which lysosomes digest themselves

Peroxisomes Similar to lysosomes but much smaller Similar to lysosomes but much smaller Usually found in the liver and kidney Usually found in the liver and kidney Must have metabolic oxygen present to function properly Must have metabolic oxygen present to function properly Role in detoxifying molecules (alcohol) Role in detoxifying molecules (alcohol) Break down fatty acids through beta- oxidation. Break down fatty acids through beta- oxidation.

Mitochondria Powerhouse of the cell Powerhouse of the cell Small, spherical or rod-shaped structures Small, spherical or rod-shaped structures Sites of cellular respiration Sites of cellular respiration –conversion of glucose and lipids to ATP –aerobic energy metabolism –Krebs cycle/TCA cycle/citric acid cycle –Mitochondrial Electron Transport

Mitochondria

The Cytoskeleton Complex internal structure of cytoplasm that consists of small lattice-like or web-like structures Complex internal structure of cytoplasm that consists of small lattice-like or web-like structures Provides support and maintains shape of the cell Provides support and maintains shape of the cell Provides organization for chemical reactions Provides organization for chemical reactions Assists in transport of substances through the cytosol Assists in transport of substances through the cytosol

Structures of the Cytoskeleton Microfilaments are rod-like, variable length - Actin and Myosin in muscles Microfilaments are rod-like, variable length - Actin and Myosin in muscles Microtubules are straight cylindrical structures Microtubules are straight cylindrical structures Intermediate Filaments provide structural support and framework Intermediate Filaments provide structural support and framework Microfilaments, Microtubules, and Intermediate Filaments make up the Microtrabecular Lattice Microfilaments, Microtubules, and Intermediate Filaments make up the Microtrabecular Lattice

Cytoskeleton Structures

Centrosome/Centriole Centrosome -Dense area of spherical cytoplasm generally located near the nucleus Centrioles -A pair of cylindrical structures located within the centrosome which serves as center of chromosome movement during cell division (mitosis)

Modifications of the Plasma Membrane Microvilli (#7) Microvilli (#7) –folds in the cell membrane –increase surface area for absorption of nutrients –Digestive System Cilia (#9) Cilia (#9) –slender projections of the cell membrane –move substances across surface of the cell –Trachea and Fallopian Tubes Flagellum (#8) Flagellum (#8) –single whip-like projection –used for cellular locomotion –Male sperm

Flagellum/Cilium

3.08 Compare and contrast mitosis and meiosis. Cell Division is a process by which cells reproduce themselves resulting in increased number of cells or HYPERPLASIA. Cell Division is a process by which cells reproduce themselves resulting in increased number of cells or HYPERPLASIA. Nuclear Division Nuclear Division –Somatic cell nuclear division (MITOSIS) –Sex cell nuclear division (MEIOSIS) Cytoplasmic Division - Cytokinesis Cytoplasmic Division - Cytokinesis

Results of Mitosis Mitosis is the formation of two new daughter cells with identical genetic make up of parent cell.

Mitosis Overview

Interphase metabolic phase - between cell division metabolic phase - between cell division replication of chromosomes replication of chromosomes replication of centrioles replication of centrioles time - highly variable from: time - highly variable from: –non existent –years normally about 18 to 24 hours normally about 18 to 24 hours

Meiosis mechanism by which sperm and egg cells are produced mechanism by which sperm and egg cells are produced results in the production of sex cells GAMETES results in the production of sex cells GAMETES –Ovary ---> Oogenesis ---> Ovum –Testes ---> Spermatogenesis ---> Sperm union and fusion of gametes is called fertilization union and fusion of gametes is called fertilization cell produced by fertilization - Zygote cell produced by fertilization - Zygote

Cytokinesis division of the cytoplasm