Answer:
A
Explanation:
D) Examples of membrane proteins include ion channels, receptor proteins, and proteins that allow cells to connect to each other.
C) Almost every chemical reaction in a cell is catalyzed by a class of proteins called enzymes
B) Membrane proteins are the nanomachines that enable membranes to send and receive messages and to transport molecules into and out of cells and compartments.
A) Proteins that are anchored by dissolving in the bilayer core are said to be integral to the membrane. Lipids: Lipid-soluble substances (e.g. alcohol, chloroform) can dissolve into the bilayer and thus cross the membrane.
Answer:
A. Cholecalciferol, or vitamin D3, is necessary for the normal absorption of calcium and phosphate ions. Vitamin D3 is made by cells in the epidermis due to exposure to sunlight. Without enough exposure to sunlight, the body won't produce enough vitamin D3
Explanation:
Hydroxyapetite is the organic mineral in the bone that maintain the mechanical strengthening of the bone, by interacting with collagen fibres. Calcium and Phosphate ions are the two major components of this bone materials. Generally 90%of bone is calcium , while 80% is phosphate. Phosphate stimulate growth of Oesteocytes. And the latter is important for bone mineralization. Together they maintain bone mineralization and maintenance,thereby preventing bone resorption.
Absorption of Ca and P. into the blood stream to reach the bones cells is conducted by Vit D. Dietary supply is not the only route through which Vit D get to the blood stream. Exposure of the skin to UVB rays of the early morning sunlight is another route.
Vitamin D plays major role in absorption of Ca and P in the body.
Vit. D is naturally synthesized in humans when the skin is exposed to early morning sunlight (UVB). It is usually produce in inactive forms,and undergoes hydroxylation( i.e addition of hydroxyl group -OH) in the liver to be biologically active .
Its active forms acts on the epithelial cells of the intestinal wall to facilitate calcium absorption into the blood stream to reach the bone cells .it also stimulate absorption of Phosphate.
Since these two minerals ensures, mechanical strength, prevention of bone resorption, there availability in the bone must be maintained by Vit, D supply from exposure to sunlight.
,
Complete question: <em>"RNA plays important roles in many cellular processes, particularly those associated with protein synthesis: transcription, RNA processing, and translation. Drag the labels to the appropriate bins to identify the step in protein synthesis where each type of RNA first plays a role. If an RNA does not play a role in protein synthesis, drag it to the "not used in protein synthesis" bin.</em>
<em>1. transcription/RNA processing
</em>
<em>2. translation
</em>
<em>3. not used in protein synthesis
</em>
<em>a) snRNA
</em>
<em>b) tRNA
</em>
<em>c) mRNA
</em>
<em>d) RNA primers
</em>
<em>e) pre-mRNA
</em>
<em>f) rRNA</em>
Answer
1. transcription/RNA processing:
<em>a) snRNA</em>
<em>c) mRNA</em>
<em>e) pre-mRNA</em>
2. translation
<em>b) tRNA</em>
<em>f) rRNA</em>
3. not used in protein synthesis
<em>d) RNA primers</em>
Explanation:
There are many RNAs, each in charge of performing a different function.
- preRNA is the precursor of the mature mRNA. These molecules possess long intermediate sequences called introns that do not codify for proteins. It occurs a posttranscriptional modification that eliminates introns and makes the RNA to get mature as mRNA.
- snRNA means <em>"small nuclear RNA"</em>. These are small RNA molecules located in the nucleus and are implicated in the mRNA maturation process. They associate with proteins composing the small nuclear ribonucleoproteins, and their function is to contribute to the initial mARN processing that transcribes from DNA and that must maturate to be exported from the nucleus. These molecules eliminate the introns.
- mRNA means "<em>messenger RNA</em>". These molecules are carriers of the genetic information and are in charge of transporting it from the genome to the ribosomes. They are the mold for the new protein synthesis. Their nucleotide sequence is complementary with the nucleotide sequence of a particular DNA segment.
- rRNA means "<em>ribosomal RNA</em>". They are the principal ribosomal component. Ribosomes are constituted by two subunits. One of them is a big RNA molecule associated with about 20 proteins. The other subunit is composed of three RNA molecules associated with about 50 proteins.
- tRNA means "<em>transference RNA</em>". These molecules are in charge of transferring activated amino acids from the cytosol to the ribosomes where the new protein is being synthesized.
Protein synthesis is initiated when mRNA meets a free ribosome, the primary structure for protein synthesis. Ribosomes can be found in the rough endoplasmic reticulum or floating in the cytosol. They read the mRNA code and add the correct amino acid using transference RNA to build the protein.