Biology Midterm Ch. 7

• Hooke-discovered dead plant cells on a cork
• Schleiden-concluded all plants made of cells
• Schwann-concluded all animals made of cells
• Virchow-all cells come from existing cells

• All living things are composed of cells
• Cells are the basic units of structure and function in living things.
• New cells are produced form existing cells.

• Prokaryotic cells have genetic material that is not contained in a nucleus. They don't have a nucleus at all. Some contain internal membranes, less complicated that eukaryotes. Bacteria are prokaryotes.
• Eukaryotic cells contain a nucleus in which their genetic material is separated from the rest of the cell. Some are multicellular, some are unicellular. Plants, animals, fungi, and protists are eukaryotes.

cell membrane

• 1. Nuclear Envelope
• 2. Ribosome (free)
• 3. Ribosome (attached)
• 4. Golgi Apparatus
• 5. Mitochondrion
• 6. Vacuole
• 7. Chloroplast
• 8. Cell membrane
• 9. Cell Wall
• 10. Rough E.R. (Blue part)
• 11. Smooth E.R. (Yellow part)
• 12. Nucleus
• 13. Nucleolus

• 1. Smooth E.R. (Blue part)
• 2. Ribosome (free)
• 3. Cell membrane
• 4. Ribosome (attached)
• 5. Golgi Apparatus
• 6. Mitochondrion
• 7. Centrioles
• 8. Rough E.R. (yellow part)
• 9. Nuclear Envelope
• 10. Nucleus
• 11. Nucleolus

Another name for a cell, because many of these strutures act as if they are sepcialized organs. "little organs"

Cytoplasm is the jelly-like substance. It is the portion of the cell outside of the nucleus, but inside the cell membrane.

The nucleus controls most cell processes and contains the hereditary information of DNA. The nucleus contains nearly all the cell's DNA and with it the coded instructions for makeing proteins and other important molecules. It is only found in eukaryotic cells.

The nucleus is sorrounded by a nuclear envelope composed of two membranes. It is dotted with thousands of nuclear pores, which allow material to move into and out of the nucleus. It is found only in eukaryotic cells.

The granular material in the nucleus is chromatin. It consists of DNA bound to protein. Most of the time, it is spread throughout the nucleus.

When a cell divides, chromatin condenses to form chromosomes. These distinct, threadlike structures contain the genetic information that is passed from one generation of cells to the next.

A small, dense region found inside the nucleus. it is where the assembly of ribosomes begins.

Proteins are assembled on ribosomes. Ribosomes are small particles of RNA and protein found throughout the cytoplasm. They produce proteins by following coded instructions that come from the nucleus. They can also be found attached to the rough Endoplasmic Reticulum.

The endoplasmic reticulum (E.R.) synthesizes proteins for export from the cell. The rough E.R. gets its name for the rough appearance of ribosomes on its surface. The E.R. is the site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell. The portion of the E.R. involved in the synthesis of proteins is the rough E.R. The other portion of the E.R., the smooth E.R., is smooth because ribosomes are not attached to it. In many cells, the smooth E.R. contains collections of enzymes that perform specialized tasks.

The function of the Golgi apparatus is to modify, sort, and package proteins and other marterials from the E.R. for storage in the cell or secretion outside the cell.

Lysosomes are small organelles filled with enzymes. One function of lysosomes is the digestion of lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell.

Vacuoles store materials such as water, salts, proteins, and carbohydrates.

Mitochondria are organelles that convert the chemical energy stored in food compounds that are more convenient for the cell to use.

Chloroplasts, only found in plant cells, are organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis.

mitochondria and chloroplasts

The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. It is also involved in movement.

they are hollow structures made of proteins that play critical roles in maintaining cell shape.

located near the nucleus and help to organize cell division. They are not found in plant cells.

all cells are sorrounded by a thin, flexible barrier known as the cell membrane. The cell membrane regulates what enters and leaves the cell and also provides protection and support.

The composition of nearly all cell membranes is a double-layered sheet called a lipid bilayer. It gives the cell membranes a flexible structure that forms a strong barrier between the cell and its sorroundings. The lipid bilayer has proteins embedded in it and carbohydrates attached to the proteins. The proteins act as channels and pumps. The carbohydrates act like chemical identification cards.

• 1. Outside of cell
• 2. Proteins
• 34. Carbohydrate chains
• 4. Cell membrane
• 5. Inside of cell (cytoplasm)
• 6. Protein channel
• 7. Lipid Bilayer

Found mostly in plant cells, many cells also produce a strong supporting layer around the membrane known as a cell wall. The main function of the cell wall is to provide support and protection for the cell. They are made from fibers from the carbohydrate and protein. It is also made from cellulose and tough carbohydrate fibers.

liquid

It means certain materials can pass through it. Liquids pass through the cell wall. Carbon Dioxide, Water, and Oxygen can pass through.

• Solute: substances dissolved in a solution.
• Solvent: substances a solute is dissolved in to form a solution

The mass of solute in a given volume of solution.

• 1. 4g/L
• 2. 2g/L
• 3. First one by 2g/L

constantly

A process (does not require energy) in which the particles tend to move from an area of high concentration to an area of low concentration. Because diffusion depends on random particle movements, substances diffuse across membranes without requiring the cell to use energy.

It is the ability of a substance to be able to diffuse across a membrane. Permeability depends on the size, shape, and charge of a particle.

equilibrium

When is everything is the same throughout the solution. The solution is evenly distributed.

proteins

The diffusion of water through a selectively permeable membrane. Water passes easily through most membranes.

isotonic

Hypertonic

Hypotonic

Movement of specific molecules across cell membranes through protein channels. Involves help of protein channels. Can't be isotonic. Not requiring energy. Still diffusion. High concentration to low concentration.

Energy-requiring process that moves material across a cell membrane against a concentration difference. Requires energy. Low concentration to High concentration.

Small molecules and ions are carried across membranes by proteins in the membrane that act as pumps. (different from channels) Requires energy. Low concentration to high concentration.

"cell eating" Extensions of cytoplasm sorround a particle and package it in a vacuole. Used for solid materials. Requires energy.

Tiny pockets form along the cell membrane, fill w/ liquid, and pinch off to form vacuoles with in the cell. Used for liquid materials. Requires energy.

endocytosis

The membrane of the vacuole sorrounding the material fuses with the cell membrane, forcing the contents out of the cell.

Larger molecules are taken into the cell by means of the cell membrane folding around and engulfing the membrane.