Enveloped viral membranes are generally (C)lipid bilayers with associated virus-specific (C)glycoproteins.
Viruses are intracellular parasites that hijack the cellular machinery for their own replication. Therefore, an essential step in the viral life cycle is the transfer of the viral genome into cells. Enveloped viruses (viruses with a lipid envelope) use a two-step process to release their genetic material into the cell.
It first binds to specific surface receptors on target cell membranes and then fuses with these. Viruses and cell membranes. This last step can occur at the cell surface or after internalization of the virus particle by endocytosis or another pathway (such as micropinocytosis).
Strikingly, the virus-cell-membrane fusion process proceeds along essentially the same intermediate steps as other membrane fusions that occur, for example, in vesicle fusion at neural synapses or cell-cell fusion in yeast mating. Fusogens, special viral proteins, facilitate the fusion of viruses and cell membranes.
Learn more about Virus here:
brainly.com/question/14281731
#SPJ4
Photosynthesis
During photosynthesis plants use up carbon dioxide and produce oxygen
Answer:
Option C, Intrapleural pressure is less than intrapulmonary pressure
Explanation:
During inspiration, the air enters the lungs due to lower pressure in the intrapulmonary or intra-alveolar than the atmospheric pressure. During quite respiration, the intrapulmonary pressure reduces to a pressure that is 3 mm Hg lower than that of atmospheric pressure. During quiet expiration, the intrapulmonary pressure rises up to a pressure that is 3 mm Hg higher than that of atmospheric pressure. This leads to lack of air in the intrapleural space thereby producing intrapleural pressure which is lesser than that of intrapulmonary pressure.
This difference in pressure (i.e higher pressure with in the lungs than the atmosphere) causes lungs to remain attached to the chest wall and hence looks inflated.
Hence, option C is correct
Answer:
c. the formation of bone from within fibrous membranes
Explanation:
On the basis of formation ossification process is divided into two types:
1) Endochondral ossification : The process by which bone is formed from haline cartilage.
2) Intramembranous ossification : The process by which bone is formed by replacing a fibrous membrane and not from cartilage. This type of ossification occurs as follows :
- An ossification center appears in the fibrous connective tissue membrane.
- Bone matrix is secreted within fibrous membrane
- Woven bone and periosteum forms.
- Bone collar of compact bone forms and red marrow appears.
Hence option c. the formation of bone from within fibrous membranes is the right option
Answer:
1. The difference between the normal hemoglobin protein DNA sequence and the sickle cell hemoglobin DNA sequence is a base to base shift, in this case adenine (GAG) to thymine (GTG).
2. The difference affects the amino acid sequence of the protein by replacing glutamic acid (Glu) with valine (Val).
Explanation:
In sickle cell anemia, a change in the DNA nucleotide sequence is observed, where adenine is substituted by thymine, whose expression is the change in the amino acid sequence of globine β, incorporating valine instead of glutamic acid. This represents a molecular mutation - point mutation - by subtitution, which corresponds to missense mutation.
<u>Normal hemoglobin protein in a RBC</u>
DNA CTG ACT CCT GAG GAG AAG TCT
Amino acids Leu Thr Pro Glu Glu Lys Ser
<u>Sickle cell hemoglobin protein in a RBC</u>
DNA CTG ACT CCT <em>GTG</em> GAG AAG TCT
Amino acids Leu Thr Pro <em>Val</em> Glu Lys Ser
When GAG is transcribed to mRNA, the CUC codon is obtained, which codes for glutamic acid. Thymine substitution causes the DNA sequence to change to GTG, which is transcribed as CAC, the codon that encodes the amino acid valine. The <u>change from glutamic acid to valine in β-globin causes an altered hemoglobin, giving the abnormal erythrocytes observed in sickle cell disease</u>.
