CytologyCytology

Biochemistry – Chap. 2Biochemistry – Chap. 2

Cell Biology – Chap. 3Cell Biology – Chap. 3

22

Learner Outcomes:Learner Outcomes: To describe the characteristics and identify the To describe the characteristics and identify the

monomers of lipids, proteins, carbohydrates, and monomers of lipids, proteins, carbohydrates, and nucleic acids and to define their role in nucleic acids and to define their role in biochemical processes.biochemical processes.

To analyze and explain the chemical reactions To analyze and explain the chemical reactions that provide energy for the body.that provide energy for the body.

To investigate and describe the integration of the To investigate and describe the integration of the chemical and physical properties that contribute chemical and physical properties that contribute to homeostasis in cells.to homeostasis in cells.

To compare the structures and functions of To compare the structures and functions of organelles within cells of the body.organelles within cells of the body.

To describe the processes involved in the cell To describe the processes involved in the cell cycle.cycle.

33

Importance of WaterImportance of Water

PropertiesProperties: :

It is polarIt is polar (H+ hydrogen ion & OH- (H+ hydrogen ion & OH- hydroxide ion)hydroxide ion)

Held together by Hydrogen BondsHeld together by Hydrogen Bonds

- relatively weak; can be broken - relatively weak; can be broken

easily.easily.

44

Characteristics of H2O- Why Characteristics of H2O- Why important in Living Systemsimportant in Living Systems

1. Universal solvent1. Universal solvent aids in ionization of salts and aids in ionization of salts and electrolytes within the body. electrolytes within the body. 2. Cohesive2. Cohesive allows blood vessels to be filled; allows blood vessels to be filled; even distribution throughout body.even distribution throughout body.3. High heat of vaporization3. High heat of vaporization resistant to change; helps maintainresistant to change; helps maintain homeostasis of body temp.homeostasis of body temp.

55

Acids & BasesAcids & Bases

AcidsAcids – dissociate in water; release – dissociate in water; release hydrogen ions (H+)hydrogen ions (H+)

Ex’s: lemon juice, hydrochloric Ex’s: lemon juice, hydrochloric

acid, coffee, tomatoes, vinegaracid, coffee, tomatoes, vinegar BasesBases – take up H+ ions or release – take up H+ ions or release

hydroxide ions (OH-). hydroxide ions (OH-).

Ex’s: milk of magnesia, ammoniaEx’s: milk of magnesia, ammonia

66

pH ScalepH Scale

77

pH of body fluids needs to be maintained pH of body fluids needs to be maintained within a narrow range, or health suffers. within a narrow range, or health suffers.

Ave. pH of blood is 7.4Ave. pH of blood is 7.4 BuffersBuffers are built-in mechanisms to prevent are built-in mechanisms to prevent

pH changes.pH changes.

chemicals or combos of that take up chemicals or combos of that take up excess H+ ions or hydroxide ions.excess H+ ions or hydroxide ions.

- ex: combo of carbonic acid (H2CO3) & - ex: combo of carbonic acid (H2CO3) & bicarbonate ion (HCO3) help maintain pH of bicarbonate ion (HCO3) help maintain pH of blood.blood.

Q: How does water play a role in this Q: How does water play a role in this process?process?

88

Cell Theory Review…Cell Theory Review…

All living things composed of 1 or All living things composed of 1 or more cells.more cells.

Cells are basic unit of structure and Cells are basic unit of structure and function for any living organism.function for any living organism.

Cells only arise from pre-existing Cells only arise from pre-existing cells.cells.

Theory of BIOGENESISTheory of BIOGENESIS

99

DNA limits cell sizeDNA limits cell size The cell cannot survive unless there is The cell cannot survive unless there is

enough DNA to support the protein enough DNA to support the protein needs of the cell.needs of the cell.

In many large cells, more than one In many large cells, more than one nucleus is present.nucleus is present.

Large amounts of DNA in many nuclei Large amounts of DNA in many nuclei ensure that cell activities are carried out ensure that cell activities are carried out quickly and efficiently.quickly and efficiently.

1010

Surface area-to-volume ratioSurface area-to-volume ratio

As a cell’s size increases, its volume As a cell’s size increases, its volume increases much faster than its surface increases much faster than its surface area.area.

Surface area = 6 mm2 Volume = 1 mm3

Surface area = 24 mm2 Volume = 8 mm3

1 mm 1 mm

1 mm

2 mm 2 mm

2 mm

4 mm 4 mm

4 mm

1111

Surface area = 6 mm2 Volume = 1 mm3

Surface area = 24 mm2 Volume = 8 mm3

1 mm 1 mm

1 mm

2 mm 2 mm

2 mm

4 mm 4 mm

4 mm

If cell size doubled, the cell would If cell size doubled, the cell would require eight times more nutrients and require eight times more nutrients and would have eight times more waste to would have eight times more waste to excrete.excrete.

Surface area-to-volume ratioSurface area-to-volume ratio

1212

Surface area-to-volume ratioSurface area-to-volume ratio

Surface area = 6 mm2 Volume = 1 mm3

Surface area = 24 mm2 Volume = 8 mm3

1 mm 1 mm

1 mm

2 mm 2 mm

2 mm

4 mm 4 mm

4 mm

The cell would either starve to death or The cell would either starve to death or be poisoned from the buildup of waste be poisoned from the buildup of waste products.products.

1313

Eukaryotic CellsEukaryotic Cells

With the exception of symbiotic and With the exception of symbiotic and parasitic relationships with bacteria, parasitic relationships with bacteria, all of the cells of our body are all of the cells of our body are eukaryotic.eukaryotic.

What does this mean?What does this mean?

1414

Eukaryotic CellsEukaryotic Cells

Plasma membranePlasma membrane Nucleus and NucleolusNucleus and Nucleolus Cytoplasm containing organellesCytoplasm containing organelles

Each of our bodies exhibits Each of our bodies exhibits specialization. The presence or specialization. The presence or absence of some organelles and their absence of some organelles and their arrangements vary dependant on the arrangements vary dependant on the needs of the cell.needs of the cell.

1515

Cellular OrganizationCellular Organization Organelles: Nucleus, Endoplasmic Organelles: Nucleus, Endoplasmic

Reticulum (Rough and Smooth), Golgi Reticulum (Rough and Smooth), Golgi Apparatus, Lysosome/Peroxisome, Apparatus, Lysosome/Peroxisome, Mitochondria, Vesicle, Ribosomes, Mitochondria, Vesicle, Ribosomes, Cytoskeleton, Cilia/Flagella.Cytoskeleton, Cilia/Flagella.

Create an analogy to explain the functions Create an analogy to explain the functions of each of these organelles. Be sure the of each of these organelles. Be sure the analogy theme you use is consistent and analogy theme you use is consistent and be ready to justify your explanations.be ready to justify your explanations.

Once your group has chosen your theme, Once your group has chosen your theme, be sure to tell me so no one else uses the be sure to tell me so no one else uses the same idea.same idea.

1616

Fig. 3.1aFig. 3.1a

1717

Fig. 3.2Fig. 3.2

1818

Fig. 3.3Fig. 3.3

1919

Fig. 3.4Fig. 3.4

2020

Fig. 3.5Fig. 3.5

2121

Fig. 3.6Fig. 3.6

2222

Fig. 3.1bFig. 3.1b

2323

End of Organelle Structure and End of Organelle Structure and FunctionFunction

2424

Cellular Membrane TransportCellular Membrane Transport

2525

Cellular Homeostasis – the plasma Cellular Homeostasis – the plasma membranemembrane

Semi-permeable or Selectively permeableSemi-permeable or Selectively permeable 2 methods used in crossing the membrane 2 methods used in crossing the membrane

– active and passive– active and passive Active transport requires the use of ATP. Active transport requires the use of ATP.

Which organelle provides this high-Which organelle provides this high-powered molecule for the cell?powered molecule for the cell?

Passive transport uses the principles of Passive transport uses the principles of diffusion to cross the membrane and does diffusion to cross the membrane and does not require the use of ATP.not require the use of ATP.

2626

Selectively Permeable MembraneSelectively Permeable Membrane

ININ OUTOUT

WaterWater CO2CO2

NutrientsNutrients Metabolic Metabolic nitrogenous wastesnitrogenous wastes

OxygenOxygen Products (proteins)Products (proteins)

HormonesHormones HormonesHormones

* Chemical composition & size determine if it goes in or out!

2727

DiffusionDiffusion

The random movement of molecules from The random movement of molecules from an area of high concentration to an area of an area of high concentration to an area of low concentration.low concentration.

The characteristics of the cell membrane The characteristics of the cell membrane allow for certain molecules to diffuse allow for certain molecules to diffuse across the membrane. across the membrane.

What are the characteristics of the cell What are the characteristics of the cell membrane? What molecules might be membrane? What molecules might be able to diffuse through it?able to diffuse through it?

2828

DiffusionDiffusion

Lipid membrane so – lipid-soluable Lipid membrane so – lipid-soluable materials.materials.

AlcoholsAlcoholsHormonesHormones

Very small molecules too.Very small molecules too.OxygenOxygenCarbon dioxideCarbon dioxideMany elementsMany elements

2929

OsmosisOsmosis Diffusion of water across a plasma membrane. Diffusion of water across a plasma membrane.

There must be a concentration gradient for this to There must be a concentration gradient for this to occur until dynamic equilibrium is met.occur until dynamic equilibrium is met.

Normally body fluids are Normally body fluids are isotonic isotonic – there is an – there is an equal concentration of solutes and solvent on equal concentration of solutes and solvent on both sides of the membrane.both sides of the membrane.

Hypotonic Hypotonic solutions cause cells to swell and go solutions cause cells to swell and go through lysis (burst).through lysis (burst).

HypertonicHypertonic solutions cause the cells to shrink and solutions cause the cells to shrink and crenate.crenate.

These changes are a result of These changes are a result of osmotic pressureosmotic pressure..

3030

Fig. 3.8aFig. 3.8a

3131

Fig. 3.8bFig. 3.8b

3232

Fig. 3.8cFig. 3.8c

3333

FiltrationFiltration

Diffusion aided by blood pressure.Diffusion aided by blood pressure. Occurs in the kidneys where blood is Occurs in the kidneys where blood is

filtered of nitrogenous waste.filtered of nitrogenous waste. Large substances stay behind the Large substances stay behind the

filtration membrane and smaller ones filtration membrane and smaller ones and water pass through.and water pass through.

3434

Facilitated TransportFacilitated Transport

Diffusion, from high to low Diffusion, from high to low concentration, using an integral concentration, using an integral protein carrier (examples: amino protein carrier (examples: amino acids or glucose).acids or glucose).

Movement includes attachment to Movement includes attachment to the protein embedded in the the protein embedded in the membrane. membrane.

3535

Active Transport Active Transport

Movement is against the Movement is against the concentration gradient (low to high concentration gradient (low to high concentration).concentration).

Requires a protein carrier and the Requires a protein carrier and the use of ATP. ATP is used by the use of ATP. ATP is used by the carrier to modify the shape of the carrier to modify the shape of the protein.protein.

Example: Sodium-Potassium Pump; Example: Sodium-Potassium Pump; endocytosis, exocytosis.endocytosis, exocytosis.

3636

Fig. 3.9Fig. 3.9

3737

EndocytosisEndocytosis

Also called phagocytosis or Also called phagocytosis or pinocytosis.pinocytosis.

Process in which a portion of the Process in which a portion of the plasma membrane invaginates to plasma membrane invaginates to engulf a substance and then pinches engulf a substance and then pinches off the membrane to form a vesicle.off the membrane to form a vesicle.

3838

ExocytosisExocytosis

A process where a vesicle fuses with A process where a vesicle fuses with the other plasma membrane as the other plasma membrane as secretion of the contents occur.secretion of the contents occur.

3939

End of Cell TransportEnd of Cell Transport

4040

Fig. 3.10Fig. 3.10

4141

Fig. 3.11Fig. 3.11

4242

Fig. 3.12Fig. 3.12

4343

Fig. 3.14Fig. 3.14

4444

Fig. 3.15Fig. 3.15

4545

Protein SynthesisProtein Synthesis

Transcription – synthesis of the Transcription – synthesis of the mRNA from the DNA in the nucleus.mRNA from the DNA in the nucleus.

RNA polymerase – enzyme that RNA polymerase – enzyme that assists in obtaining the genetic assists in obtaining the genetic information.information.

mRNA leaves the nucleus through mRNA leaves the nucleus through the nuclear pores of the envelope.the nuclear pores of the envelope.

4646

Fig. 3.13Fig. 3.13

4747

Protein SynthesisProtein Synthesis

Translation – occurs in the cytoplasm Translation – occurs in the cytoplasm associated with a ribosome (rRNA). associated with a ribosome (rRNA). The mRNA, tRNA, and rRNA all come The mRNA, tRNA, and rRNA all come together to bind the amino acids together to bind the amino acids together into the proper proteins as together into the proper proteins as dictated by the DNA.dictated by the DNA.

4848

4949

End of Protein Synthesis