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Proteins make up about 50-60% of the dry mass of a cell. They are composed of subunits of amino acids attached to one another by peptide bond (-CONH2).
Proteins have five major roles in the cells: receptors (hormones), enzymes, structural materials, channels and pumps.
Common examples of proteins related to function on cells:
1. Receptors of neurotransmitters (cholinergic receptors receive acetylcholine molecules) in synapses of neuronal system.
2. Enzymes catalyzing the breaking down of neurotransmitters, such as cholinesterase enzyme.
3. Structural materials like cytoskeleton and its filaments.
4. Channel proteins such as Na+ channels which is voltage-gated.
5. Pumps or ATPase pumps such as Ca2+ pumps in sarcoplasmic reticulum of muscle cells
Receptor proteins are usually in the form of glycoprotein are found within the cell membrane as a way to receive information from hormones or other chemicals. When bounded to the substance, the protein receptor initiates an avalanche of reactions within the target cells usually to carry out cellular activities. Example insulin secreted during high blood glucose levels targets the liver and muscle cells to increase their permeability to glucose, increase the metabolic activity of the body and increase rate of conversion of glucose into glycogen. Glucagon is the opposite and is secreted by cells during hypoglycemia (low blood glucose level) so that cells limit the expenditure of glucose as well as increase conversion of glycogen into glucose to level up the blood glucose level.
In the cell, there are three types of protein bound to the cell membrane. These are the transmembrane proteins, integral proteins, and the peripheral proteins.
Transport of substances across membranes (into or out of the cells) is a function of proteins. For transport, the integral (also called intrinsinc) proteins are used. Intrinsinc prteins are classified as carrier proteins and channel proteins.
Transport of substances across the cell membrane is mediated by these intrinsinc proteins. Channel protein are selective transporters that do not require energy for transport of substances across the membrane, the may be gated channels (requiring external stimulation for opening). Carrier channels require energy or an electrochemical gradient for movement of substances in and out of the cell.
Proteins can also are the skeleton of the cells, known as the cytoskeleton. Cytoskeleton is made up of three types of filaments. Filaments of cells are:
1. microfilaments are made up of actin protein (used in muscular contraction),
2. microtubules are made of tubulin protein (confers motility to cells ex. bacterial cells),
3. intermediate filaments are made of several stable proteins.
Functions of cell filaments (cytoskeleton):
(i) gives cells its characteristic shape (animal cells)
(ii) as anchorage for the cell membrane
(iii) determine distribution of the cell organelles
(iv) confer motility to certain cells.
Wiki User
∙ 11y ago
Wiki User
∙ 12y agolots of stuff! channel proteins are used in membranes, DNA is wound round histomes (proteins) ribosomes are made of proteins, just so much stuff
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What are two ways in which cells use the energy provited by ATP?
Cells use the energy from ATP for active transport and protein synthesis.
Essential nutrient used to build and repair body cells and cells?
I am pretty sure that it is protein. Protein help build and repair muscle and tissue.
What is the site of protein synthesis in plant cells?
The site of protein synthesis in plant cells is the ribosome. When the proteins are manufactured, they will be stored in the vacuoles.
Why are cells called protein factory?
Because cells produce a lot of protein to build new cells, and to perform certain functions, and to repair damaged tissues.
Which is the process by which a protein is constructed in the cytoplasm of eukaryotic cells?
Proteins are one of the four major biomolecules in the body. The process by which a protein is constructed in the cytoplasm of eukaryotic cells is called protein synthesis.
Blood cells that use protein to capture and carry oxygen is?
Blood cells use a protein called hemoglobin to capture oxygen.
Cells use and to make protein?
Amino Acids?
How cells use protein?
They help the body to grow
When do cells make protein molecules?
Cells use genes to make proteins for critical jobs like carrying oxygen and contracting muscles. This is called protein synthesis.
What will protein do for your body?
Protein helps to repair damaged cells and build new cells in place of the dead ones. Body builders use proteins to build up extra cells than actually needed.
Do animal cells have a protein coat?
No, animal cells do not have a protein coat. Only viruses have a protein coat.
Is protein animal cells or plant cells?
All cells have protein, though animal cells typically have more as a percentage of their mass.
Would you find protein inside cells or cells inside protein?
Proteins are found in cells. Proteins are a macromolecule.
What is the protein synthesizer in all cells?
It is done differently in prokaryotic and eukaryotic cells.Prokaryotic cells just build proteins in their cytoplasm.Eukaryotic cells use organelles called ribosomes.
Do animal cells have protein coat?
No they do not have a protein coat
Are cells a type of protein?
No, cells are composed of all macromolecules: proteins, lipids, carbohydrates, and nucleic acids. Cells definitely contain protein in the membranes and organelles, but they're not wholly made up of protein or are a type of protein.
What are two ways in which cells use the energy provited by ATP?
Cells use the energy from ATP for active transport and protein synthesis.
