Biology chapter 7 - The cell membrane and transport

Describe surface-to-volume ratio regarding cell size and be able to tell why this is a limiting factor cell size.

The surface area to the volume ratio gets smaller as the cell gets larger. This is a limiting factor to cell size because if the cell grows past a certain size, not enough material can pass through the cell membrane fast enough to accommodate increased cellular volume.

Know active transport.

"Cell membrane pumps specifically sodium-potassium pumps, endocytosis and exocytosis" (Mrs. Burns)

What is the fluid mosaic model of the cell membrane? To what does fluid refer? To what does mosaic refer?

- "The fluid mosaic model explains various observations regarding the structure of functional cell membranes" (google) - Fluid: a substance that has no fixed shape and yields easily to external pressure; a gas or (especially) a liquid. - Mosaic: An individual (especially an animal) composed of cells of two genetically different types.

What is the purpose of exocytosis?

- "To expel material from the cell into the extracellular fluid." (google)

Know these other terms regarding passive transport: concentration gradient, equilibrium, hypotonic, hypertonic, isotonic, contractile vacuole (though it requires energy from the cell), turgor pressure, plasmolysis, cytolysis.

- C.G: "This is the process of particles, which is solutes, moving through a solution from an area with a higher number of particles to an area with a lower number of particles." (google) - Equilibrium: "The condition in which all acting influences are balanced or canceled by equal opposing forces, resulting in a stable system" (google) - Isotonic: Equal solute. No water gained or loss - "Contractile Vacuole: A membrane-enveloped cellular organelle, found in many microorganisms, that periodically expands, filling with water, and then contracts." (google) - Turgor Pressure: "Turgor pressure is the force within the cell that pushes the plasma membrane against the cell wall" (google) - Plasmolysis: "Plasmolysis is the process in which cells lose water in a hypertonic solution." (google) - Cytolysis: "The dissolution or disruption of cells, especially by an external agent." (google)

What additional structures are present in plant cells that are not found in animal cells, and what are their functions?

- Cell Wall: "The cell wall gives the cell strength and structure, and to filter molecules that pass in and out of the cell." (google) - Central vacuole: Holds material and waste. - Chloroplasts: "Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant." (google)

Know passive transport: diffusion, simple (or regular) diffusion, osmosis, facilitated diffusion.

- Passive Transport: "Passive transport is a movement of ions and other atomic or molecular substances across cell membranes without need of energy input." (google) - Simple Diffusion: "This is the unassisted passage of small, hydrophobic, nonpolar molecules from a higher concentration to a lower concentration." (google) - Osmosis: "A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane." (google) - Facilitated Diffusion: "Facilitated diffusion is the process of spontaneous passive transport of molecules or ions across a biological membrane via specific trans membrane integral proteins." (google)

Know the difference between prokaryotic and eukaryotic cells. Identify organisms that have each type.

- Prokaryotic: "A prokaryote is a unicellular organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle." (google) Organisms include: Bacteria, animals, plants. - Eukaryotic: "Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes." (google) Organisms include: Animal, sponge, fungus.

Describe homeostasis in unicellular and multicellular organisms.

- Unicellular: To maintain homeostasis, "unicellular organisms grow, respond to the environment, transform energy, and reproduce." (google) - Multicellular: These organisms "perform specialized tasks and communicate with one another in order to maintain homeostasis." (google)

For endocytosis: vesicle, pinocytosis, phagocytosis, phagocytes (like white blood cells).

- Vesicle: "Cells ingest fluid, molecules, and particles by endocytosis, in which localized regions of the plasma membrane invaginate and pinch off to form endocytic vesicles" (google) - Pinocytosis: "The ingestion of liquid into a cell by the budding of small vesicles from the cell membrane." (google) - Phagocytosis: This is the process by which a cell engulfs a solid particle to form an internal compartment known as a phagosome. Phagocytes: "These are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells." (google)

Name the five contributors to the discovery of the cell and know their individual contribution.

1. Anton Van Leeuwenhoek: Discovered bacteria called Animalcules. 2. Robert Hooke: Looked at cork under a microscope. He saw organisms and named them cells. 3. Matthias Schleiden: German botanist that discovered plant cells. 4. Theodore Schwann: German scientist who discovered all animals are mad of cells. 5. Ruldolf Virchow: German scientist who discovered all cells come cells that already exist.

Name the three basic parts of all cells and describe their function.

1. Plasma membrane: Protects a cell from its surroundings. 2. Region containing D.N.A: Gives instruction for development and function of all living things. 3. Cytoplasm: contains all organelles and cell parts.

Referring to any organism, why must homeostasis be maintained at the cellular level?

Can't have hormones without homeostasis. Cell would be unhealthy without homeostasis.

Describe what is meant by cell diversity and give examples. Why is cell diversity important regarding eukaryotic cells both when it comes to maintaining homeostasis and with function of the cell?

Cell diversity: Cells differ in size, shape and internal organization. Plants and animals have cell diversity. Because the cells need to be different sizes. If the cell was the same size for a whole animal, the animal would be deformed.

Be sure you can identify and describe what is going on in the pictures from 7.3 notes.

Done!

Identify the parts of the cell (the ones I asked you to know in your notes) and know their function.

Done.

Understand the comparison sheet between pro and eukaryotic cells, and between plant and animal cells.

Done.

Identify all of the parts of the plasma (cell) membrane and know the function of each: phospholipid bilayer, cholesterol, integral proteins (transport proteins, receptor proteins), peripheral proteins (cell-surface marker proteins, glycoprotein with its carbohydrate and protein portion).

Functions: - "Phospholipid bilayer: Phospholipids like to line up and arrange themselves into two parallel layers" (google) - Cholesterol: "This helps slightly immobilize the outer surface of the membrane and make it less soluble to very small water-soluble molecules that could otherwise pass through more easily." (google) - "Transport Proteins: This serves as a tunnel across the membrane into the cell." (google) - Receptor Proteins: "These proteins are used in inter cellular communication." (google) - Cell-Surface Marker Proteins: "These are expressed on the surface of cells that often conveniently serve as markers of specific cell types" (google) - "These function in the structure, reproduction, immune system, hormones, and protection of cells and organisms" (google) - Protein Portion: Must portion because if you have too many proteins, cell is not OK?

Identify the organization of complex living things from atom to organism.

Levels of organization: Atoms, molecules, organelles, cells, tissue, organs, organ systems, organism.