Objectives 7.2Cell Structure

-Describe the structure and function of the cell nucleus.

-Describe the roles of the organelles.

-Describe the function of the cell membrane.

Lesson Overview Cell Structure

Cell Organization

Many cellular structures act as if they are specialized organs. These structures are known as organelles or “little organs.”

Lesson Overview Cell Structure

The Nucleus

The nucleus is the control center of the cell.

The nucleus contains nearly all the cell’s DNA .

Lesson Overview Cell Structure

Vacuoles

Many cells contain structures called vacuoles that store water, salts, proteins and carbohydrates.

Lesson Overview Cell Structure

Lysosomes

Lysosomes are small organelles filled with digestive enzymes that function as the cell’s cleanup crew.

Lesson Overview Cell Structure

The Cytoskeleton

Eukaryotic cells are given their shape and internal organization by a network of protein filaments known as the cytoskeleton.

Lesson Overview Cell Structure

Centrioles

Centrioles are located near the nucleus and help to organize cell division.

Centrioles are not found in plant cells.

Lesson Overview Cell Structure

Ribosomes

Ribosomes produce proteins, some are found in the cytoplasm others are attached to the rough ER.

Lesson Overview Cell Structure

Endoplasmic Reticulum

The rough endoplasmic reticulum, or rough ER, is involved in the synthesis of proteins.

The smooth endoplasmic reticulum, or smooth ER, has no ribosomes on its surface. The smooth ER is involved in the synthesis of membrane lipids and detoxification of drugs.

Lesson Overview Cell Structure

The Golgi apparatus modifies, sorts and packages proteins and other materials from the ER for storage in the cell or release outside the cell. It is like the UPS of the cell, where items are packaged and shipped.

Golgi Apparatus

Lesson Overview Cell Structure

Chloroplasts

Plants and other photosynthetic organisms contain chloroplasts.

Chloroplasts are the biological equivalents of solar panels. They capture the energy from sunlight and convert it into energy in a process called photosynthesis.

Lesson Overview Cell Structure

Mitochondria Nearly all eukaryotic cells, including plants, contain mitochondria.

Mitochondria are the power house of the cell. They convert the chemical energy stored in food into ATP (ENERGY!).

The mitochondria is also unique because it has its own DNA, which came from the ovum, or egg, and therefore came directly from your MOM!

Lesson Overview Cell Structure

Cellular Boundaries

Cells are surrounded by a barrier known as the cell membrane.

Many cells, including most prokaryotes, also produce a strong supporting layer around the membrane known as a cell wall.

Lesson Overview Cell Structure

Cell Walls

The main function of the cell wall is to provide support and protection for the cell. Prokaryotes, plants, algae, fungi have them.

Animal cells do not have cell walls.

Lesson Overview Cell Structure

Cell Membranes

All cells contain a cell membrane that regulates what enters and leaves the cell and also protects and supports the cell.

The composition of nearly all cell membranes is a double-layered sheet called a lipid bilayer.

The cell membrane is selectively permeable (only let’s certain things in).

Lesson Overview Cell Structure

The Lipid Bilayer

The fatty acid portions of such a lipid are hydrophobic, or “water-hating,”

while the opposite end of the molecule is hydrophilic, or “water-loving.”

Lesson Overview Cell Structure

True or False

Prokaryotic and eukaryotic cells are surrounded by a thin, flexible barrier called a cell membrane. _________________________

Flagella made up of microtubules help organize cell division. _________________________

Ribosomes that synthesize proteins are found on the smooth endoplasmic reticulum. _________________________

Plant cells have chloroplasts but not mitochondria. _________________________

Lesson Overview Cell Structure

Answers

Prokaryotic and eukaryotic cells are surrounded by a thin, flexible barrier called a cell membrane.True

Flagella made up of microtubules help organize cell division. False, centrioles

Ribosomes that synthesize proteins are found on the smooth endoplasmic reticulum. False, rough

Plant cells have chloroplasts but not mitochondria. False, and