Structure and Function of Cells

Prokaryotes Prokaryotes lack a nucleus and nuclear membrane. All prokaryotic organisms are unicellular. They don't ever become multicellular organisms. They lack some organelles such as mitochondria and chloroplast. Instead proteins attach to a cell envelope. Some organisms from Protista are prokaryotes.

Eukaryotes Eukaryotic cells contain a nucleus. These cells are 10 times as large than prokaryotic cells. These contain many organelles. Eukaryotic organisms make up multicellular organisms.

Prokaryotes and Eukaryotes compared

Unicellular organisms and Cells A unicellular organism is an organism made up of only one cell. Examples include bacteria and plankton. Bacteria are the most common unicellular organisms. Organelles function to produce energy, build and transport needed materials, and store and recycle wastes. All cells need energy to function. Oxygen is required for energy to be produced. Energy is produced through a process called cell respiration. All living things are composed of cells, Cells are the basic units of structure and function in living things. All cells are made from other cells. There are three types of cells plant, animal, and specialized.

Organelles

Cell types Plant cell Specialized cell

Specialized cells Specialized cells are cells that were made to perform a specific function. An example a nerve cells.

Cell Wall Cell walls are present in plant cells only. The cell wall surrounds the cell membrane. The cell wall is made of a tough and flexible material called glucose. The cell wall also protects and supports the cell. Some materials can pass through such as water and oxygen.

Cell Membrane In a plant cell the cell membrane regulates the materials that enter and leave the cell. Since animal cells lack a cell wall the cell membrane also separates the cytoplasm from the outside environment, the cell membrane also performs the functions listed above. Some materials such as water and air can also pass through.

Lysosomes The lysosomes exist in both plant and animal cells. The lysosomes use digestive enzymes to break down the food, worn out pieces of the cell, and destroy viruses. Different enzymes break down different materials. The PH scale is a scale that measures how acidic or basic a substance is. A lysosome uses 4.5 PH to function. Without Enzymes cells couldn’t break down food!!!

Nucleus Animal Cells: Contained in almost all animal cells. Direct cell's activities. Deoxyribonucleic acid (DNA) is stored in the chromatin, also RNA or Ribonucleic acid. RNA helps break down proteins. Contains chromatin which instructs the cells functions. Plant Cells: Contained in all plant cells. Directs all of the cells activities including reproduction. Contains chromatin the instructions for life. Also contains DNA and RNA.

Vacuole Vacuoles appear in both plant and animal cells. Vacuoles hold water, food, waste products, and other materials.

Mitochondria The Mitochondria are the power plants of the cells. The mitochondria appear in both plant and animal cells. These organelles produce most of the cell’s energy. They’re rod shaped.

Cytoplasm Cytoplasm is the area between the cell membrane and the nucleus. It contains a gel-like fluid in which many different organelles are found. Cytoplasm Contains Ribonucleic acid (RNA) which helps produce proteins.

Nucleolus The nucleolus is located inside a cell’s nucleus. The nucleolus is where ribosomes are made.

Ribosomes Ribosomes are present in both plant and animal cell. The ribosomes function is to produce proteins. Ribosomes are either attached to the endoplasmic reticulum or they float free within the cytoplasm.

Golgi body The golgi bodies appear in both plant and animal cells. They assist in transportation of materials throughout the cell.

Endoplasmic Reticulum The endoplasmic reticulum appears in both plant and animal cells. The endoplasmic reticulum moves materials throughout the cell, such as proteins.

Chloroplast This organelle is only in plant cells. They gather energy from sunlight and use it to produce food through photosynthesis.

Food The cells get food in different ways. The cells of an autotroph would get their food by making it, possibly through photosynthesis. Photosynthesis is a process in autotrophs in which chloroplast use sunlight to make their own food. Some unicellular organisms will find their own. In a multicellular organism food is distributed by specialized cells throughout the body.

Movement Movement varies from species to species. But some unicellular organisms use flagella or a whip like projectile to propel themselves forward. Some organisms use pseudopods or temporary bulges to move.

Reproduction Cells reproduce in different ways. Some will split in half and give an exact copy of the parent. Others will mutate and change. Binary fission is a form of reproduction in which the cell’s DNA is replicated to its children, this is commonly used by unicellular organisms.

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