Chemistry of Life (157 – 163)6.3

Cell ProcessesActive and Passive

Transport, Osmosis, Diffusion,

Exocytosis, and Endocytosis

pp. 155 – 156; 195 -2006.2, 8.1Hickox: Baker High School Biology

Objective 2.0: Describe cell processes necessary for achieving homeostasis, including active and passive transport, osmosis, diffusion, exocytosis, and endocytosis• Identifying functions of carbohydrates, lipids, proteins, and nucleic acids in cellular activities• Comparing the reaction of plant and animal cells in isotonic, hypotonic, and hypertonic solutions• Explaining how surface area, cell size, temperature, light, and pH affect cellular activities• Applying the concept of fluid pressure to biological systems

Examples: blood pressure, turgor pressure, bends, strokes

Core concept: Most cell functions involve chemical reactions. Food molecules taken into cells react to provide the chemical constituents needed to synthesize other molecules. There are four main biochemicals: Carbohydrates, Proteins, Lipids and Nucleic acids. Cells use carbohydrates to provide energy. Cells use proteins for cellular construction and repair, cellular chemical activities, and as a back-up energy source if carbohydrates are not available. Both breakdown and synthesis are made possible by a large set of protein catalysts, called enzymes. Cells use lipids for cell membrane construction. Cells use nucleic acids to store genetic information for protein synthesis.

Most cell functions involve chemical reactions. Food molecules taken into cells react to provide the chemical constituents needed to synthesize other molecules. There are four main biochemicals: Carbohydrates, Proteins, Lipids and Nucleic acids. Cells use carbohydrates to provide energy. Cells use proteins for cellular construction and repair, cellular chemical activities, and as a back-up energy source if carbohydrates are not available. Both breakdown and synthesis are made possible by a large set of protein catalysts, called enzymes. Cells use lipids for cell membrane construction. Cells use nucleic acids to store genetic information for protein synthesis.

Vocabulary• Carbohydrate• Nucleic Acid• Lipids• Proteins• Enzyme

Core concep: Cell membranes are selectively permeable. This gives them the ability to maintain cell homeostasis by regulating what enters and leaves the cell. The direction of water movement across the cell membrane depends on the relative concentrations of free water molecules in the cytoplasm and in the fluid outside the cell. Different kinds of cells have evolved different ways of dealing with hypertonic, hypotonic, and isotonic solutions. The cells of plants have rigid cell walls that keep the cells from expanding too much. Animal cells can avoid swelling by moving dissolved particles from the cytoplasm.

Cell membranes are selectively permeable. This gives them the ability to maintain cell homeostasis by regulating what enters and leaves the cell. The direction of water movement across the cell membrane depends on the relative concentrations of free water molecules in the cytoplasm and in the fluid outside the cell. Different kinds of cells have evolved different ways of dealing with hypertonic, hypotonic, and isotonic solutions. The cells of plants have rigid cell walls that keep the cells from expanding too much. Animal cells can avoid swelling by moving dissolved particles from the cytoplasm.

Vocabulary• Passive transport• Active transport• Endocytosis• Isotonic• Exocytosis• Diffusion• Hypotonic• Hypertonic• Homeostasis• Osmosis

Core Concept: Small cells function more efficiently than large cells. Small cells can exchange substances more readily than large cells because small objects have a higher surface-area-to-volume ratio than larger objects. Most cells function best within a narrow range of light, temperature and pH. At very low temperatures, reaction rates are too slow. Extremes of light, temperature and pH can irreversibly change the structure of most protein molecules. Vocabulary: pH, surface area, volume

Turgor pressure is the main pressure of the cell contents against the cell wall in plant cells and bacteria cells, determined by the water content. Blood pressure refers to the force exerted by circulating blood on the walls of blood vessels. High blood pressure can cause stroke.Breathing gas under pressure can present a myriad of possible medical problems. One of these is decompression sickness or "the bends," caused by breathing nitrogen or other gases under pressure, which are not metabolized by the body.

Vocabulary• Bends• Stroke Hickox: Baker High School Biology

Simple to Complex Life’s Levels of Organization

Our journey begins here, atoms like Hydrogen (H) and Oxygen (O)

1. Atoms come together to make up molecules like water, H2O.2. Molecules make up organelles.3. A group of organelles make up cells.

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4. Chemical Reactions

CO2 + H2O C6 H12 O6 + 02

REACTANTS

PRODUCT(S)

CHEMICAL EQUILIBRIUM

Sun

Acids and Bases5. Acids are substances that forms in water and

release hydrogen ions (H+).6. Bases are substances that either take up

hydrogen ions (H+) or release hydroxide ions (OH-).

7. pH measures how acidic or basic a solution is

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pH Scale

7. A pH scale is used to indicate how acid and basic of a solution.8. Ranges from 0-14• 7 = Neutral•>7 = Base•<7 = Acid

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pH Matters

pH is a measure of proton (hydrogen ion or

H+) concentration .

In biology, keeping H+ levels within a narrow

range is critically important.

Low pH = lots of H+s, high pH = few H+s.

A strong acid is pH of 2

A strong base is pH of 12

Diffusion

9. Diffusion is the net movement of particles from an area of higher

concentration to an area of lower concentration.

VIDEO FROM FILE

Diffusion continues until there is no concentration gradient!

What affects the speed of Diffusion?10. concentration: main factor, higher the more11. temperature: if temp. increase greater diffusion12. pressure: increasing pressure increases diffusion

no concentration gradient!

Dynamic equilibrium

Dynamic equilibrium

Osmosis

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Osmosis

13. Isotonic Solution - Solute and Solvent (water) concentrations both inside and outside the membrane are equal.

14. Hypotonic Solution - Solution with a lower concentration of solute than the solution on the other side of the membrane.– Cells placed in a hypotonic solution will swell.• Lysis

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Osmosis

15. Hypertonic Solution - Solution with a higher concentration of solute than the solution on the other side of the membrane.– Cells placed in a hypertonic solution will shrink.• Plasmolysis

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The results of diffusion (write into notes)

When a cell is in dynamic equilibrium with its environment, materials move into and out of the cell at equal rates. As a result, there is no net change in concentration inside or outside the cell.

Material moving out of cell equals material moving into cell

16. What type of osmosis is this?(Isotonic, hypotonic, or hypertonic)Does cell shrink, expand, or stay the same?

ISOTONIC

STAYS THESAME

17. What type of osmosis is this?(Isotonic, hypotonic, or hypertonic)Does cell shrink, expand, or stay the same?

HYPOTONIC

EXPANDS

18. What type of osmosis is this?(Isotonic, hypotonic, or hypertonic)Does cell shrink, expand, or stay the same?

HYPERTONIC

SHRINKS

Diffusion in Living Systems: the way cells move substances in and out of the cell

Osmosis is the diffusion of particles through a semi- permeable membrane.

IsotonicHypotonic Hypertonic

Review Quiz:OSMOSIS

20. ___________ is the diffusion of particles through a semi- permeable membrane. 21. __________________: movement of particles across cell membranes by diffusion or osmosis. The cell uses NO energy to move these particles22. ________________: the transport of materials against the gradient and this takes energy23, _________________: the pushing out of water in a plant cell

against the cell wall24. __________________: shrinking of cell due to water moving

out (dissolved solution outside cell high) 25._____________: swelling of a cell due to water moving in

26. ____________: concentrations inside and outside cell is balanced.

VIDEO FROM FILE

OSMOSIS

PASSIVE TRANSPORT

ACTIVE TRANSPORT

TURGOR PRESSURE

HYPERTONIC

HYPOTONIC

ISOTONIC

Biomolecule: Structures vary

amino acids

lipids

Three views of glucose, a common simple sugar.

RINGS

BUNCHED CHAINS

LONG CHAINS

Molecules of Life

Start with water, add lots of small carbon-containing molecules and …….

How do you build a cell?

Use these four major classes of biological molecules:Carbohydrate, lipid, protein, nucleic acid.

CarbohydratesCarbon, Hydrogen, and Oxygen

27. Carbohydrates are used for energy and to create structures.

28. The building blocks for carbohydrates are simple sugars.

Three views of glucose, a common simple sugar.

30. Lipids are large and are made mostly of carbon and hydrogen and small amounts of oxygen.

Fat

Phospholipid

Lipids are used by cells for energy storage, insulation, and protective coatings, such as in membranes.

Phospholipids Form Double-Layered Biological Membranes

Protein p. 66

32. Proteins are the key elements of life.

33. Proteins provide structure for tissue and organs and carry out cell metabolism. Provide the body with the ability to move muscles. They are needed to transport oxygen in the bloodstream.

34. Enzymes, a type of protein that change the speed of chemicals reactions in the body.

34a. An enzyme (p. 66) is a protein that enables other molecules to undergo chemical changes to form new products. Enzymes increase the speed of reactions that would otherwise proceed too slowly.

SubstrateActive site

Strands of the Protein Keratin Create Hair

Nucleotides are Chains of Linked Amino AcidsDNA and RNA

35. The building blocks of proteins are amino acids!

36. There are two kinds of nucleic acids, DNA and RNA. Both are

involved in the storage and flow of information from gene to gene

product.

39. Nucleotides Are the Monomers That Create Polymers of DNA and RNA

The small subunits that make up nucleic acids are nucleotides.

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DNA

Mader: Biology 8th Ed.

RNA