Download Plant and Animal Cell

Cell Nucleus - Commanding the Cell
The cell nucleus acts like the brain of the cell
It helps control eating, movement, and reproduction
The nucleus is not always in the center of the cell
It will be a big dark spot somewhere in the middle of all of the cytoplasm (cytosol)
You probably won't find it near the edge of a cell because that might be a dangerous place for the nucleus to be
Cell Wall
Cell wall structure showing membrane and cell wall in a plant
Cell membranes surround every cell you will study
Cell walls made of cellulose are only found around plant cells and a few other organisms Cellulose is a specialized
sugar that is classified as a structural carbohydrate and not used for energy.
If a plant cell is like a water balloon, the cell wall is like a cardboard box that protects the balloon. While cell walls
protect the cells, they also allow plants to grow to great heights
You have a skeleton to hold you up. A 100-foot tall redwood tree does not It uses the strong cell walls to maintain its
shape. For overall support, dense cells in the core of the trunk can let a tree grow very high
Cell walls are slightly elastic for smaller plants, leaves, and thin branches.
Cell Membrane
Cell membrane is like a plastic bag
According to cell theory, cells are the main unit of organization in biology. Whether you are a single cell or a blue
whale with trillions of cells, you are still made of cells
All cells are contained by a cell membrane that keeps the pieces inside
When you think about a membrane, imagine it is like a big plastic bag with some tiny holes. That bag holds all of the
cell pieces and fluids inside the cell and keeps any nasty things outside the cell
The holes are there to let some things move in and out of the 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 might store large amounts of food, water or any variety of nutrients a cell might need to survive
They can even store waste products so the rest of the cell is protected from contamination Eventually, those waste
products would be sent out of the cell
When a plant cell has stopped growing, there is usually one very large vacuole. Sometimes that vacuole can take up
more than half of the cell's volume.
Vacuoles hold onto things that the cell might need, just like a backpack.
Cytoplasm
Cytoplasm is the fluid that fills a cell
Scientists used to call the fluid protoplasm. Early on, they didn't know about the many different types of fluids in the
cell.
There is special fluid in the mitochondria, endoplasmic reticulum, Golgi apparatus, and nucleus.
The only two 'plasms' left are cytoplasm (cytosol) and nucleoplasm (nucleus)
Each of those fluids has a very different composition
The cell organelles are suspended in the cytosol
The microfilaments and microtubules set up a "skeleton" of the cell and the cytosol fills the spaces
The cytoplasm has many different molecules dissolved in solution
You'll find enzymes, fatty acids, sugars, and amino acids that are used to keep the cell working.
Waste products are also dissolved before they are taken in by vacuoles or sent out of the cell
Chloroplast
Chloroplasts are the food producers of the cell
The organelles are only found in plant cells and some protists such as algae
Animal cells do not have chloroplasts
Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells
The entire process is called photosynthesis
It all depends on the little green chlorophyll molecules in each chloroplast
The oxygen released by the chloroplasts is the same oxygen you breathe every day.
They use oxygen in the process of releasing chemical energy from sugars
Endoplasmic Reticulum
Another organelle in the cell is the endoplasmic reticulum
The ER functions as a manufacturing and packaging system
It works closely with the Golgi apparatus, ribososmes, mRNA, and tRNA
The endoplasmic reticulum is a network of membranes found throughout the cell and connected to the nucleus
The membranes are slightly different from cell to cell and a cell’s function determines the size and structure of the ER
For example, some cells, such as prokaryotes or red blood cells, do not have an ER of any kind
Cells that synthesize and release a lot of proteins would need a large amount of ER
You might look at a cell from the pancreas or liver for good examples of cells with large ER structures.
Mitochondrion
Mitochondria are known as the powerhouses of the cell
They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy
rich molecules for the cell
The biochemical processes of the cell are known as cellular respiration
Many of the reactions involved in cellular respiration happen in the mitochondria
Mitochondria are the working organelles that keep the cell full of energy
Mitochondria are small organelles floating free throughout the cell
Some cells have several thousand mitochondria while others have none
Muscle cells need a lot of energy so they have loads of mitochondria. If a cell feels it is not getting enough energy to
survive
More mitochondria can be created Sometimes a mitochondria can grow larger or combine with other mitochondria
It all depends on the needs of the cell
lysosome
Lysosomes - Little Enzyme Packages
You will find organelles called lysosomes in nearly every animal-like eukaryotic cell
Lysosomes hold enzymes that were created by the cell
The purpose of the lysosome is to digest things
They might be used to digest food or break down the cell when it dies
A lysosome is basically a specialized vesicle that holds a variety of enzymes
The enzyme proteins are first created in the rough endoplasmic reticulum
Those proteins are packaged in a vesicle and sent to the Golgi apparatus
The Golgi then does its final work to create the digestive enzymes and pinches off a small, very specific vesicle
That vesicle is a lysosome
From there the lysosomes float in the cytoplasm until they are needed. Lysosomes are single-membrane organelles
Golgi body
Golgi Apparatus - Packing Things Up
The Golgi apparatus or Golgi complex is found in most cells
It is another packaging organelle like the endoplasmic reticulum (ER)
It was named after Camillo Golgi, an Italian biologist
While layers of membranes may look like the rough ER, they have a very different function
The Golgi apparatus gathers simple molecules and combines them to make molecules that are more complex
It then takes those big molecules, packages them in vesicles, and either stores them for later use or sends them out
of the cell
It is also the organelle that builds lysosomes (cell digestion machines)
Golgi complexes in the plant may also create complex sugars and send them off in secretory vesicles
The vesicles are created in the same way the ER does it
The vesicles are pinched off the membranes and float through the cell
The Golgi apparatus is a series of membranes shaped like pancakes
The single membrane is similar to the cell membrane in that it has two layers
Lysosome
Ribosomes - Protein Construction Teams
Cells need to make proteins
Enzymes made of proteins are used to help speed up biological processes. Other proteins support cell functions and
are found embedded in membranes
Proteins even make up most of your hair
When a cell needs to make proteins, it looks for ribosomes
Ribosomes are the protein builders or the protein synthesizers of the cell
They are like construction guys who connect one amino acid at a time and build long chains
Every cell needs ribosomes to manufacture proteins
Since there are no membrane-bound organelles in prokaryotes, the ribosomes float free in the cytosol
Ribosomes are found in many places around a eukaryotic cell
You might find them floating in the cytosol
Those floating ribosomes make proteins that will be used inside of the cell
Other ribosomes are found on the endoplasmic reticulum
Endoplasmic reticulum with attached ribosomes is called rough ER. It looks bumpy under a microscope
3 major differences between the plant and animal cell
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Animal cells do not have chloroplasts
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Only plant cells have a cell wall
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Vacuoles are way bigger in plant cells