What are you made of? The building blocks inside you
Cells are the basic unit of structure and function inside living things.
The longest cells in the human body are the motor neurons. They can be up to 4.5 feet (1.37 meters) long and run from the lower spinal cord to the big toe.
The longest living cells in the body are brain cells which can live an entire lifetime.
15 million blood cells are produced and destroyed in the human body every second.
Plant Cell Animal Cell Cells are very complicated cities in action, with many organelles that have jobs to perform within the cell. Let’s go inside the cell to see these mini-cities in action…..
To enter the cell, we must pass through the cell membrane. In a city, the cell membrane is like the city limits. The cell membrane is made of lipids (fats).
But it’s not as easy as just taking a road into the city by crossing over an imaginary border. The cell membrane is semi-permeable. It allows some substances in, but keeps other substances out. What do you think the cell membrane would need to let in? What would it need to keep out? Pores are the channels that allows things in and out of the cell. What are the pores like in a city?
Once inside the cell we head to the control center of the cell, the nucleus. It is the largest organelle of the cell. In order to get into the nucleus, we need to pass through the pores in the nuclear membrane. These pores allow substances to go into and out of the nucleus. What would the nucleus, nuclear membrane and nuclear pores be like in the city?
If we were to go even deeper into the nucleus of the cell, opening up the chromatin, we would see the DNA helix (spiral staircase). It contains 3 billion letter codes that serve two main purposes: Codes for making offspring (reproduction), and Codes for the cell to do its job, whether it’s a red blood cell, muscle cell, etc. What would the chromatin and DNA be like in a city?
The nucleus also contains the nucleolus, which makes ribosomes for the cell. Ribosomes are important for making protein for the cell, so that new organelles can be made when the old ones die. What are the nucleolus and ribosomes like in a city?
After the ribosomes are made in nucleolus, they travel through pores in the nuclear membrane to the endoplasmic reticulum. The ribosomes will attach to the endoplasmic reticulum, which acts like a series of passageways throughout the cell. What is the endoplasmic reticulum like in the city?
While in the endoplasmic reticulum, the ribosomes begin to make proteins, if the large and small subunits are attached.
After the proteins are made in the ribosomes, the Golgi body is responsible for sorting and correctly shipping the proteins. If the Golgi body makes a mistake in shipping the proteins to the wrong place, certain functions in the cell may stop, and new organelles won’t be produced to replace old, worn out organelles. Camillo Golgi, an Italian physician, was the first person to describe this organelle in the cell. What is the Golgi body like in the city?
But none of this work could be done in the cell without the mitochondria. The mitochondria transforms the food (sugars) you eat and the oxygen you breathe into energy for the cell. Different cells have different amounts of mitochondria, because they have different needs for energy. For example, muscle cells can have thousands of mitochondria. What is like the mitochondria in the city?
The cytoplasm is the gel-like atmosphere inside the cell, and is composed of mostly water. All the organelles float in the cytoplasm. What is the cytoplasm like in the city?
Both plant and animal cells have vacuoles. These organelles store food, water, and waste for the cell. However, the vacuoles of plant cells are much larger to provide pressure in the plant so that it does not wilt. What is the vacuole like in the city?
Both plant and animal cells contain lysosomes, which clean up the cell of dead, worn out organelles. What is the lysosome like in the city?
Plant cells have organelles that animal cells do not have. One example is the chloroplast. It is in this organelle where photosynthesis takes place, the process where plant cells convert electromagnetic energy from the sun to chemical energy (food - glucose).
In addition to cell membranes, plant cells also have cell walls. The cell wall is an extra layer that provides protection and support for plants.
Paramecium Animal cells have an organelle that plant cells do not have. It is cilia, a form of locomotion resembling tiny hairs that act like legs so that one-celled animals can move in their environment to find food. Why don’t plant cells need cilia?
What are some similarities and differences between plant and animal cells? Think of organelles and functions. Plant Both Animal
All cells need to carry out functions, and a few of the functions are listed below. Think about what organelles in the cell take part in performing these jobs in the cell, and write those in the boxes. Reproduction Growth of new organelles Make energy Performing a job Clean-up