Structure, function, & growth of a cell

By Ms. Sommer

What is a cell?• A cell is the basic structural, functional, and biological unit of all

known living organisms. It is the smallest unit of life that is classified as a living thing and is often called the “building block of life””

• Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell.

• The cell was discovered by Robert Hooke in 1665

What’s the difference between prokaryotes and Eukaryotes• Prokaryotic cells were here first and for billions of years were the only

form of life on Earth. All prokaryotic organisms are unicellular

• Eukaryotic cells appeared on earth long after prokaryotic cells but they are much more advanced. Eukaryotic organisms unlike prokaryotic can be unicellular or multicellular

The Prokaryotic Cell .1-10um

Prokaryotes • Pro- means before, Karyote- means kernel• Prokaryotes do NOT have a nucleus so their genetic material is dispersed throughout

the cytoplasm• Single stranded DNA • No membrane bound organelles• They have a cell wall that helps separate the inside and outside of the cell.• Some prokaryotic cells have external whip-like flagella for movement or hair like pili

for adhesion• They are smaller than Eukaryotes and are unicellular• Contains 4 main parts: genetic information, cytoplasm, cell membranes, and

ribosomes

Eukaryotic Cell 10-100um

Eukaryotic cells• Eu- true Karyote-(kernel) nucleus • Eukaryotes are more advanced and bigger than prokaryotes. They are found in plants,

animals, protists, and fungi.• Eukaryotic cells are unicellular and multi-cellular• The cell is composed of 5 main parts: • 1. Cell Membrane-the semipermeable membrane surrounding the cytoplasm of a cell• 2. Cytoplasm-rich protein fluid with gel-like consistency that houses organelles• 3. Nucleus- “control center” of cell, houses DNA• 4. Ribosomes- Make proteins• 5. Membrane bound Organelles- small structures that carry out specific functions(little

organs) ex: Golgi, RER, SER, Mitochondria, etc

Reflect with a partner• Did the prokaryotic cell come before the Eukaryotic cell?

• What are some similarities between both cells?

• What are some differences?

• Usually found in the center of the cell • Contains the cells genetic (DNA) information • The nucleus houses DNA in 2 forms1. Chromatin- mass of DNA that condense to form chromosomes2. Chromosomes –structures that contain information to make new cells (looks like an X)• Also contains an organelle called the Nucleolus

that makes the cells ribosomes

Nucleus

Reflect with a partner • What does semi permeable mean? what does the cell membrane do?• What does the nucleus contain inside its organelle?• What does the mitochondria provide?

Ribosomes • Cells need to make proteins. Those proteins might be used as

enzymes or as support for other cell functions.• Ribosomes are the protein builders or the protein synthesizers for the

cell.

Rough Endoplasmic Reticulum (RER)

A network of interconnected membranes forming channels within the cell

Covered with ribosomes (causing the rough appearance ) which are in the process of synthesizing (producing) proteins for secretion (to leave organelle)

Reflect with a partner • What is the function of the Rough Endoplasmic Reticulum(RER)?• What are Ribosomes? • What is the function of the Golgi apparatus ?• What’s the difference between the RER and Golgi?

Cell Wall• The cell wall provides extra support for the cell and gives it a shape. • Cell walls are found in eukaryotic plant and prokaryotic cells• Cell walls are NOT found in Animal cells

Reflect with a partner • What do Lysosomes do?

• What is the responsibility of chloroplasts? Do humans have them?

• What does the cell wall provide for the plant cell?

Vacuole • Vacuoles are storage bubbles found in cells. They are found

in both animal and plant cells but are much larger in plant cells. Vacuoles store food, nutrients, and waste products so the rest of the cell is protected from contamination.

Flagella and Cilia • Flagella (long and moves side to side) and Cilia (shorter and there are

a lot move back and forth): • Both aid in movement

Cytoskeleton• The Cytoskeleton are fibers that run through the cytoplasm. They give

it rigidity but allows the cell to move• Microtubules are straight hollow tubes they are more rigid and keep the cell

organized• Microfilaments are thinner solid rods that allow the cell to move and change

shape when needed

Cytoplasm• They cytoplasm is the fluid that fills

the inside of the cell.- Cyto- cell, Plasm- fluid- A thick solution that fills each cell

and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. In eukaryotic cells, the cytoplasm includes all of the material inside the cell and outside of the nucleus- Acts like the “blood” by circulating

nutrients around the cell

Reflect with a partner • How do the organelles within the cell relate to the organs in our

body?

• List as many organelles that you can.

• Which organelles are located within the plant cell but not the animal cell?

Animal cell vs Plant cell

ANIMAL CELL • Cell membrane• Cytoplasm• Nucleus• Chromosomes• Mitochondria• Nuclear membrane • Small Vacuoles • Lysosomes- digestive enzyme• Centrioles- spindle fibers for cell division • Round shape cell

PLANT CELL • Cell wall- made of chitin or cellulose• Cell membrane • Cytoplasm • Nucleus• Chloroplasts-organelles contain chlorophyll that

capture sunlight to make glucose (energy)for cell• Large Central Vacuole-where water, food, and other

chemicals are stored• Mitochondria • Nuclear Membrane • Chromosomes• Box shaped cell

Animal Cell and Plant cell comparison 1

Animal cell and plant cell comparison 2

Animal Cell and Plant Cell differences

Reflect with a partner• What are some similarities between animal and plant cells?• What are some differences?