Eukaryotic Cell Structure 7.2 Biology Mr. Hines

Comparing the cell to a factory In order for a cell to maintain its internal environment (homeostasis), many things must go on. This is similar to a factory. Things come and go in and out of a factory in an orderly fashion. Things come and go in cells too, they are just very small.

Prokaryotic and Eukaryotic Cells Section 7-1 Cell membrane Cytoplasm Prokaryotic Cell Nucleus Eukaryotic Cell Organelles

There are many structures in cells which perform different tasks There are many structures in cells which perform different tasks. These structures are called organelles. Organelle - specialized structure that performs important cellular functions within a eukaryotic cell Cells are divided up into 2 main sections. a. cytoplasm - material inside the cell membrane—not including the nucleus b. nucleus - Control center of cell containing DNA

Nucleus The nucleus contains nearly all the cell’s DNA and with it the coded instructions for making proteins and other important molecules The nucleus is surrounded by a nuclear envelope composed of 2 membranes. The nuclear membrane contains thousands of pores which allow materials to flow in and out. The nucleus controls what goes on in the cell by sending chemical instructions through this membrane

The granular material inside of the nucleus is called chromatin The granular material inside of the nucleus is called chromatin. Chromatin is made of DNA wound around proteins. When the cell is about to divide, the chromatin coils up into chromosomes.

The nucleus also contains a smaller structure called the nucleolus. The nucleolus is a dense region where the assembly of ribosomes begins.

Ribosomes One of the most important functions in a cell is the production of proteins. Ribosomes are small particles of RNA and Protein. Ribsomes make proteins. They do this by following coded instructions from the nucleus (the boss) Ribsomes are found in the cytoplasm and on the Endoplasmic reticulum.

Endoplasmic Reticulum (ER) The endoplasmic reticulum is the site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell. There are 2 kinds of ER a. Smooth ER – does not have ribosomes b. Rough ER – does have ribosomes

When ribosomes located on the rough ER make protein, the proteins are moved inside to the ER where it is chemically modified and sent to its needed location. The smooth ER creates lipids for the cell membrane and detoxifies various chemicals.

Golgi Apparatus The golgi apparatus is composed of stacks of membranes. The function of the golgi apparatus is to modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.

Cytoskeleton Cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. The cytoskeleton is also involved in movement. There are 2 componets of the cytoskeleton Microtubules – hollow tubes made of proteins Microfiliments – threadlike structures made of protein Microtubles and microfiliments are used by microorganisms to move. (cilia and flagella)

Lysosomes Lysosomes are small organelles filled with enzymes (proteins) Lysosomes sort of clean up the cell. Lysosomes breakdown macromolecules such as carbohydrates, lipids, and proteins into their monomers so they can be reused somewhere else. Lysosomes will also disassemble organelles that are no longer useful to the cell.

Centrioles Centrioles are structures made of proteins that help control the process of cell division. Centrioles are not found in plant cells.

Mitochondria Mitochondria are located all over a cell’s cytoplasm. Mitochondria convert the chemical energy stored in carbohydrates into simple compounds so the energy can be used. Mitochondria is also called the “powerhouse” of the cell because it provides energy.

2 interesting facts. Where did you get your mitochondria? From mom or dad? When the sperm fertilizes the egg, the sperm cell donates only DNA and no mitochondria. Your mitochondria are all from mom 2. Mitochondria have their own DNA and can reproduce themselves. It is theorized that before the time of living cells, mitochondria existed alone

Figure 7-11 Cytoskeleton Cell membrane Endoplasmic reticulum Section 7-2 Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Mitochondrion

Plant cell organelles Plants have 2 organelles that are not found in animal cells. Chloroplasts Vacuole Cell Wall

Chloroplasts Chloroplasts are organelles that capture the energy from sunlight and covert it into chemical energy in a process called photosynthesis (create carbohydrates) Chloroplasts are located in the cytoplasm of plant cells, some protists, and some bacteria. Chloroplasts contain chlorophyll

1 interesting fact. Chloroplasts have their own DNA and can reproduce themselves. It is theorized that before the time of living cells, chloroplasts existed alone

Vacuoles Vacuoles are membrane bound organelles that store carbohydrates, proteins, salts, or water.

Figure 7-5 Plant and Animal Cells Section 7-2 Centrioles Nucleolus Nucleus Nuclear envelope Rough endoplasmic reticulum Golgi apparatus Smooth Mitochondrion Cell Membrane Ribosome (free) (attached) Animal Cell

Figure 7-5 Plant and Animal Cells Section 7-2 Nuclear envelope Ribosome (attached) (free) Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Nucleolus Golgi apparatus Mitochondrion Cell wall Cell Membrane Chloroplast Vacuole Plant Cell