Cell
Life's fundamental structural and functional components are called cells. A cell consists of a membrane/plasma membrane, inside which the number of organelles is suspended in a thin liquid known as the cytosol. The cells are self-sufficient and self-sustaining. Nutrients are converted into energy, which is used for special functions and can be reproduced in the cell. Tissues have a variety of cell types that play different roles. For example – muscles, blood, etc. Organs are formed by combining various tissues.
For example – stomach, brain, etc. Organs of similar functions come together to form an organ system. Individuals' health is maintained by different organ systems as they interact with each other to maintain homeostasis.
Prokaryotic cells - Cell nuclei and other organelles that are connected by membranes are absent in prokaryotes. There are some multicellular prokaryotes, but most are unicellular
Eukaryotic cells - Eukaryotic cells have internal membranes and cytoskeletons that organize them into complex structures. The nucleus is a membrane-bound structure with a unique appearance.
Structure
The cytoplasm and cell organelles of humans and other animals share some structural features, despite their many differences: a cell membrane, a nucleus, and a cytoplasm. A red blood cell, on the other hand, has no nucleus when mature. The membrane surrounds the nucleus, cytoplasm, and organelles and forms the outer boundary of each cell.
Transport across the cell membrane
Blood and tissue fluid around living cells exchange substances constantly, allowing the cells to choose which substances to take in and which to excrete. Materials are moved into and out of cells via several different mechanisms of transport. Some of them are mentioned below.
Diffusion
In diffusion, molecules travel from greater concentration area to lower concentration area. Molecules are always in motion because they have free energy, which is why diffusion occurs.
Osmosis
Osmosis occurs when selectively permeable membranes allow water to diffuse through them.
Facilitated diffusion
Facilitated diffusion occurs when molecules move from a dense point to a less dense point through a membrane, but they need some help to do so. For example - Glucose is transported into most cells by glucose transporters, which can also be called carrier enzymes. Transporters in the membrane of the cell are proteins.
Active transport
Molecules traveling from an area of a lesser concentration to one of a greater concentration require ATP energy for movement. Active transport involves moving across concentration gradients.
Filtration
Energy is also needed for the filtration process, though this energy is not directly supplied by ATP. The mechanical pressure is the energy. A membrane is forced through a higher-pressure area to a lower-pressure area to filter water or dissolved materials.
Phagocytosis
There is a moving cell engulfing something here. For example – white blood cells engulfing bacteria.
Pinocytosis
Here, a stationary cell engulfs something. For example – kidney tubules cells reabsorbing small proteins.
There are several cell organelles in the cells with unique functions that are mentioned below:
Life's fundamental structural and functional components are called cells. A cell consists of a membrane/plasma membrane, inside which the number of organelles is suspended in a thin liquid known as the cytosol. The cells are self-sufficient and self-sustaining. Nutrients are converted into energy, which is used for special functions and can be reproduced in the cell. Tissues have a variety of cell types that play different roles. For example – muscles, blood, etc. Organs are formed by combining various tissues.
For example – stomach, brain, etc. Organs of similar functions come together to form an organ system. Individuals' health is maintained by different organ systems as they interact with each other to maintain homeostasis.
- Metabolism
- Reproduction
- Sensitivity to external and internal stimuli, for example, temperature change, pH change, and the number of nutrients present.
- The use of genes encoding enzymes and other proteins is made by messenger RNA intermediates as well as ribosomes.
Prokaryotic cells - Cell nuclei and other organelles that are connected by membranes are absent in prokaryotes. There are some multicellular prokaryotes, but most are unicellular
Eukaryotic cells - Eukaryotic cells have internal membranes and cytoskeletons that organize them into complex structures. The nucleus is a membrane-bound structure with a unique appearance.
Structure
The cytoplasm and cell organelles of humans and other animals share some structural features, despite their many differences: a cell membrane, a nucleus, and a cytoplasm. A red blood cell, on the other hand, has no nucleus when mature. The membrane surrounds the nucleus, cytoplasm, and organelles and forms the outer boundary of each cell.
Transport across the cell membrane
Blood and tissue fluid around living cells exchange substances constantly, allowing the cells to choose which substances to take in and which to excrete. Materials are moved into and out of cells via several different mechanisms of transport. Some of them are mentioned below.
Diffusion
In diffusion, molecules travel from greater concentration area to lower concentration area. Molecules are always in motion because they have free energy, which is why diffusion occurs.
Osmosis
Osmosis occurs when selectively permeable membranes allow water to diffuse through them.
Facilitated diffusion
Facilitated diffusion occurs when molecules move from a dense point to a less dense point through a membrane, but they need some help to do so. For example - Glucose is transported into most cells by glucose transporters, which can also be called carrier enzymes. Transporters in the membrane of the cell are proteins.
Active transport
Molecules traveling from an area of a lesser concentration to one of a greater concentration require ATP energy for movement. Active transport involves moving across concentration gradients.
Filtration
Energy is also needed for the filtration process, though this energy is not directly supplied by ATP. The mechanical pressure is the energy. A membrane is forced through a higher-pressure area to a lower-pressure area to filter water or dissolved materials.
Phagocytosis
There is a moving cell engulfing something here. For example – white blood cells engulfing bacteria.
Pinocytosis
Here, a stationary cell engulfs something. For example – kidney tubules cells reabsorbing small proteins.
There are several cell organelles in the cells with unique functions that are mentioned below:
- Endoplasmic reticulum - Materials are transported within the cell using this passageway. Lipid synthesis also takes place in the endoplasmic reticulum.
- Ribosomes – ribosomes are known as a site of protein synthesis.
- Golgi apparatus – it is a site of synthesis of carbohydrates.
- Mitochondria – site of ATP production.
- Lysosomes - Compose enzymes that digest ingested materials or damaged tissue
- Centrioles – are responsible for organizing the spindle fiber during cell division.
Get subject wise printable pdf documentsView Here
No comments:
Post a Comment
Please don't spam. Comments having links would not be published.