cells 1 Flashcards
(6 cards)
cells
cells are the structural and functional unit of the body,cells of physical structure and functions make up tissues.
-cells carry out the metabolic reactions to stay alive and divide to repair tissues
-when cells make tissues each tissue has a diffrent job.
-cells vary from small one cell organisms called aneobas and complex multicellular organs.
The human body has atleast 50 to 100 trillion of these building blocks.
cell theory
A cell is the basic structural and functional unit of living organisms. So, when you define cell properties, you are in fact defining the properties of life.
The activity of an organism depends on the collective activities of its cells.
According to the principle of complementarity, the activities of cells are dictated by their structure (anatomy), which determines function (physiology).
Continuity of life has a cellular basis. In other words, cells come from cells.
Cells Dictate Life
Cells are the fundamental unit of life, meaning everything that happens in the body—growth, movement, repair, etc.—starts at the cellular level. The way cells are structured (their form) and the way they function (their behavior) directly impacts the overall health and function of the body.
Homeostasis and Its Importance
Cells work hard to maintain homeostasis, which is the ability to maintain a stable internal environment despite changes in the external environment. For example, even if the temperature outside changes, the cells inside your body work to keep your internal temperature stable, usually around 98.6°F (37°C).
Loss of Homeostasis Leads to Disease
If something disrupts this balance—such as injury, infection, or environmental stress—it can cause cells to lose their ability to maintain homeostasis. Once this happens, the normal functions of cells are disrupted, and this leads to diseases. For instance:
If cells in the lungs lose their ability to maintain homeostasis, you could get conditions like asthma or pneumonia.
If cells in the pancreas can’t regulate blood sugar properly, diabetes could develop.
Despite the vast diversity of cells and their specialized functions in different organs and systems, all cells share a basic chemical composition. and cells are 60 percent water thats why we need water.
Generlized cells
Even though no cell is exactly the same,there are some things that cells all have.
Generly a cell will have three similar things: plasma membrane,nucleous and cytoplasma.
The nucleous is in the middle and is surrounded by a semifluid called cytoplasma which is encased by somethong called plasma membrane.
plasma membrane
The plasma membrane (also known as the cell membrane or cytoplasmic membrane) is the outer boundary of the cell. It has several important roles:
Fragile & Transparent: It’s a thin, flexible, and transparent barrier that surrounds the cell.
Containment: It holds the cell’s contents (like the nucleus, cytoplasm, and organelles) inside the cell and helps maintain the cell’s structure.
Protection: The plasma membrane protects the cell from its surrounding environment (like the interstitial fluid outside the cell in tissues), making sure the inside stays balanced and functional.
The plasma membrane has phospholipid heads, with tails touching tail to tail.
The plasma membrane also has cholesterol for sturdiness and flexibility.
It also contains proteins for responsiveness, channels, and carrier proteins. More on that next flashcard.
plasma membrane phopholipids
phospholipids are the core structure of the plasma membrane. The polar “heads” of the phospholipid molecules are hydrophilic (“water loving”) and are attracted to waterthe main component of both the intracellular and extracellular fluids,and so they lie on both the inner and outer surfaces of the membrane. Their nonpolar fatty acid “tails,” being hydrophobic (“water fearing”), avoid water and line up in the center (interior) of the membrane.
this part is explaining how the plasma membrane keeps the cell from breaking.
Phospholipids can rearrange themselves when the membrane is damaged, thanks to their self-orienting property. This happens because their hydrophilic heads are attracted to water (on the outside and inside of the cell), while their hydrophobic tails avoid water and stay tucked in the middle.
The hydrophobic tails create a barrier in the center of the membrane, which makes it relatively impermeable to water-soluble molecules. This helps maintain homeostasis by only allowing certain substances—like oxygen or carbon dioxide—to pass through easily.
Cholesterol adds stability by stiffening the membrane just enough, while still keeping it flexible. It prevents the membrane from becoming too soft or too rigid.
plasma membrane protien
Enzymes: Some proteins act as enzymes, which help speed up chemical reactions in the cell.
Receptors: Some proteins stick out of the cell to act as receptors for hormones or other chemical messengers. For example, if you get burned on the stove, proteins play a big role in receiving that signal and triggering a response.
Binding Sites: Certain proteins act as binding sites, helping to anchor the cell to other structures in the body. This helps form tissues or body parts.
Transport Proteins: Some proteins move across the membrane and are involved in transport, helping to move things in and out of the cell. These proteins are responsible for moving nutrients and other molecules that cannot pass through the phospholipid bilayer.
Channels and Carriers: Some proteins have tiny channels that allow water and small molecules to pass through the membrane. Other proteins act as carriers, meaning they bind to a substance and help move it across the membrane.
Glycocalyx: Many of these proteins have sugar molecules attached to them on the outside part of the membrane, creating a sugar coating on the cell called the glycocalyx. This plays a crucial role in cell recognition. Each cell has a unique set of glycoproteins and glycolipids in its glycocalyx, which helps the body distinguish its own cells from foreign cells, like bacteria or viruses.
