Cells Mrs. Reesse

Microscope The invention of the microscope made it possible for people to discover and learn about cells. A microscope is an instrument that makes small objects look larger.

Magnification The ability to make an object look larger than it is through the bending of light that passes through lenses.

Resolution Resolution is the ability to clearly distinguish the individual parts of an object.

ModernMicoscopes The light microscope. The common light microscope used in the laboratory is called a compound microscope because it contains two types of lenses that function to magnify an object. The more traditional form of electron microscope is the transmission electron microscope (TEM). To use this instrument, one places ultrathin slices of microorganisms or viruses on a wire grid and then stains them with gold or palladium before viewing. The densely coated parts of the specimen deflect the electron beam, and both dark and light areas show up on the image. The scanning electron microscope (SEM) is the more contemporary form electron microscope. Although this microscope gives lower magnifications than the TEM, the SEM permits three-dimensional views of microorganisms and other objects. Whole objects are used, and gold or palladium staining is employed.

What do all living things have in common? All living things are composed of cells.

What are cells? Cells are the basic unit of structure and function in organisms. Structure is how things are made. Function is the action, role, or duty that a particular cell performs. Organisms are living things.

Are all cells alike? No. There are many kinds of cells such as skin cells, nerve cells, sex cells, blood cells etc.

Do all cells have the same function? No. Cells have specialized jobs.

Structure and Function Nerve cells carry messages from one of the body to another.

Structure and Function

Structure and Function White blood cell fight against infections. There are multiple types of white blood cells.

Structure and Function Red blood cells carry oxygen to all cells in the body.

Sickle Cell-crescent shaped RBC

Structure and Function Muscle cells aid in movement

Who discovered cells? An English scientist named Robert Hooke was one of the first persons to view cells. He built a microscope and viewed cork cells which are part of the bark from oak trees. He saw thousands of tiny structures that looked like little rooms – he called them cells.

Cell Theory The cell theory was first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann. All organisms (bacteria, fungi, protists, plants, and animals) are composed of one or more cells. All cells come from preexisting cells. The cell is the most basic unit of life

Multi-cellular vs. Uni-cellular Some organisms are made of many cells (multi-cellular), like plants, animals and fungi; and some are made of just a single cell (unicellular), like protists and bacteria.

Comparison of Unicellular Organisms (PROTIST) STRUCTURE OF A BACTERIUM

Prokaryotes and Eukaryotes

Cell Organelles Organelles are the “little organs” inside of a cell that have specific structure and function and work together to keep the cell working properly.

Prokaryotes Prokaryotic cells lack a nucleus and membranous organelles. Example: bacteria

Eukaryotes Eukaryotic cells contain a membrane-bound nucleus and numerous membrane-enclosed organelles.

Cell

Plant Cell

Parts of the Cell Cell Membrane- In a plant, the next layer after the cell wall in the cell membrane. In animal cells, the cell membrane is the first layer. The function of the cell membrane is to control what can come in to the cell or go out from the cell. Food, oxygen, wastes, are all examples of substances that can go in and out of the cell via the cell membrane.

Cell Membrane

Parts of a Cell Nucleus- The nucleus is inside the cell (center) and it is the “brain” of the cell. It is where all of the cell’s activities are controlled. Inside the nucleus you find the cells DNA (genetic material).

Parts of a Cell Cytoplasm- The cytoplasm is a clear, thick, gel-like fluid. This fluid is always moving and this is where the rest of the cell’s organelles (little organs) are found.

Part of a Cell Mitochondria-This is the “power-house” of the cell. This is where most of the cell’s energy (ATP) is produced. Some cells (such as muscle cells) have multiple mitochondria.

Parts of the Cell Cell Wall- The cell wall is found ONLY in plants. The cell wall is made of tough yet flexible material called cellulose. The function of the cell wall is to protect and support the cell. Even though the cell wall is rigid, water and oxygen can still pass through easily.

Parts of a Cell Vacuoles- Round water filled sac floating in the cytoplasm. This is a storage area for the cell. It can store food, waster products, and water. If the vacuoles of a plant cell are not filled, the shape of the plant wilts.

Parts of a Cell (Plant Cells) Chloroplast- Plant organelles that capture energy from sunlight and use it to produce food for the cell (photosynthesis).

Levels of Organization Cells Tissue Organs Organ Systems Organism Tissue: A group of cells that perform a specialized function. Your body has tissues specialized for functions such as absorbing materials, transporting materials, and support. Organ: A group of tissues that perform a specialized function. The stomach, the heart, skin, bone….are all organs. Organ System: Digestive System, Circulatory System, Skeletal System, etc… Organism

but you will need to know it next year…. Other organelles that are in the cell but we DO NOT have to know this year… but you will need to know it next year….

Parts of a Cell Endoplasmic Reticulum- The ER is the passageway for moving proteins and other materials from one part of the cell to another.

Parts of a Cell Lysosomes- A lysosome is a small round structure that contains chemicals that break down large food, old cells, etc. Lysosomes are the clean-up crew. The lysosomes have a thick membrane that allows for the harch chemicals to stay inside.

Parts of a Cell Golgi Bodies- Golgi bodies can be thought of a mail room. They are flat sacs that store, package, and then “ship” out materials to other parts of the cell or even outside the cell.

Parts of a Cell Ribosomes- are like little factories that make proteins for the cells. Proteins are complex molecules that can carry out chemicals reactions, transmit signals, or provide structure and support for cells.