Biology Lesson 8.2 - Cell Structure

Vesicle

Store and move materials between cell organelles, as well as to and from the cell surface.

Lysosome

"Cleanup Crew" - Small organelles filled with enzymes. Break down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell. Also breakdown organelles that have outlived their usefulness. Perform the vital function of removing "junk" that might otherwise accumulate and clutter up the cell.

Vacuole

"Storage" - Large sac-like, membrane-enclosed structures that store materials like water, salts, proteins, and carbohydrates.

What are the 5 steps involved in Making Proteins?

(1) Proteins are assembled on ribosomes. (2) Proteins targeted for export to the cell membrane, or to specialized locations within the cell, complete their assembly on ribosomes bound to the rough endoplasmic reticulum. (3) Newly assembled proteins are carried from the rough endoplasmic reticulum to the Golgi apparatus in vesicles. (4) The Golgi Apparatus further modifies proteins before sorting and packaging them in membrane-bound vesicles. (Golgi Apparatus functions somewhat like a customization shop, where the finishing touches are put on proteins before they are ready to leave the "factory." (5) Vesicles from the Golgi Apparatus are shipped to their final destination in, or out of, the cell.

ORGANELLES THAT CAPTURE AND RELEASE ENERGY

** All living things require a source of energy, so energy conversion is one of the most important processes in the cell. ** Most cells are powered by food molecules that are built using energy that ultimately comes from sunlight.**

CELL BOUNDARIES

** Cell boundaries protect cell from the environment and serve as a barrier that keeps its products safe and secure until they are ready to be shipped out. ALL cells are surrounded by a barrier called the Cell Membrane. Many cells, including most prokaryotes, ALSO produce a strong supporting layer around the membrane known as the "Cell Wall."

ORGANELLES THAT STORE, CLEAN UP, AND SUPPORT

** Structures such as vacuoles, vesicles, lysosomes, and the cytoskeleton represent the cellular factory's STORAGE SPACE, CLEANUP CREW, and SUPPORT STRUCTURES. **

ORGANELLES THAT BUILD PROTEINS

**A big part of the cell is devoted to the production and distribution of proteins.**

Which types of cells have cell walls? Which cells do NOT have cell walls?

-Most prokaryotes have cell wall --Many eukaryotes, including PLANTS and FUNGI, also have cell wall --Animal cells do NOT have cell wall!

Cell membrane

ALL cells have cell membranes. The cell membrane regulates what enters and leaves the cell and also protects and supports the cell.

What is the function of a contractile vacuole?

Contractile vacuoles contract rhythmically to pump excess water out of the cell.

Cytoskeleton

Eukaryotic cells are given their shape and internal organization by a network of protein filaments known as the "cytoskeleton." The cytoskeleton helps the cell maintain its shape and is also involved in movement. Certain parts of the cytoskeleton also help transport materials between different parts of the cell, much like the conveyor belts that carry materials from one part of a factor to another.

Chloroplast

Found in PLANTS and some other organisms. Capture the energy from sunlight and convert it into chemical energy stored in food during photosynthesis. Biological equivalent of solar power plants!

Endoplasmic Reticulum

Internal membrane system contained in eukaryotic cells. Where lipids are synthesized, along with proteins and other materials that are exported from the cell.

Cell Wall

Lies just outside cell membrane. Main function is to support, shape, and protect the cell. Most cell walls are porous enough to allow water, oxygen, carbon dioxide, and certain other substances.

What is the main function of the cell wall?

Main function of the cell wall is to support, shape, and protect the cell.

Organelle

Major components of plant and animal eukaryotic cells - some of which are also found in prokaryotic cells. Act like specialized organs.

Mitochondria

Mitochondria convert the chemical energy stored in food molecules into compounds that are more convenient for the cell to use. Mitochondria are like "electric power plants" of the cell. Nearly all eukaryotic cells, including plants, contain mitochondria.

Selectively Permeable

Most cell membranes are "selectively permeable," meaning that some substances can pass across them and others cannot. Selectively permeable membranes are also called "semipermeable membranes."

Are cell walls porous?

Most cell walls are porous enough to allow water, oxygen, carbon dioxide, and certain other substances.

Lipid Bilayer

Part of the cell membrane. Gives cell membrane a flexible structure that forms a strong barrier between the cell and its surroundings.

What is the function of the plant cell's fluid-filled central vacuole?

Plant cell's fluid-filled central vacuole provides strength and support (rigidity).

5 Steps of making Proteins (condensed)

Protein on Ribosomes-- Rough ER---Golgi Apparatus---Cell-Membrane-bound vesicles--- Shipped to final location in, or out of, the cell.

Ribosomes

Proteins are assembled on ribosomes. Ribosomes are small particles of RNA and protein found throughout the cytoplasm in both eukaryotes and prokaryotes. Ribosomes produce proteins by following coded instructions that come from DNA.

Proteins - What do they do?

Proteins carry out many of the essential functions of living things, including the synthesis of other macromolecules such as lipids and carbohydrates.

Golgi Apparatus

Proteins produced in the rough ER move next to an organelle called the Golgi Apparatus. The Golgi Apparatus modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release from the cell.

Rough Endoplasmic Reticulum

Ribosomes are found on its surface (making it "rough") Proteins made on the Endoplasmic Reticulum include those that will be released, or secreted, from the cell; many membrane proteins; and proteins destined for other specialized locations within the cell.

Smooth Endoplasmic Reticulum

Ribosomes are not found on its surface ("smooth" surface). Many times, smooth ER contains collections of enzymes that perform specialized tasks, including the synthesis of lipids and the detoxification of drugs. Smooth ER also plays an important role in the synthesis of carbohydrates.

Cytoplasm

The portion of the cell outside the nucleus. The interior of a prokaryotic cell, which lacks a nucleus, is also referred to as the cytoplasm.