A procaryotic cell has five essential structural components: a nucleoid (DNA), ribosomes, cell membrane, cell wall, and some sort of surface layer, which may or may not be an inherent part of the wall.
Answer:
B
Explanation:
Both of the original DNA strands act as templates during replication. This option is correct.
Answer:
Consumer is a category that belongs within the food chain of an ecosystem. It refers predominantly to animals.
Consumers are unable to make their own energy, and instead rely on the consumption and digestion of producers or other consumers, or both, to survive.
Explanation:
Answer:
The type of mutation that occurs when in the DNA strand there is a change from guanine to cytosine is a nonsense mutation, since the triplet that should encode the amino acid encodes a stop codon and the protein cannot be completely synthesized.
Explanation:
The nonsense mutation consists of a change in one of the bases of the stranded DNA, which is transcribed into an altered mRNA, producing a stop codon, instead of an amino acid.
In the table it is observed that the CCA codon is a stop codon that cuts off the protein synthesis prematurely, leaving it incomplete and probably non-functional.
Sometimes this type of mutation can alter the sequence of amino acids but the protein may be complete enough to partially fulfill its function.
Answer:
a. osteoblasts
b. osteoid
Explanation:
Osteoblasts are the fundamental cell of bone tissue. They are the cells that synthesize the bone matrix called osteoid from which it is made from the skeleton of bone fish, to the skeleton of humans. Since the bone skeleton is an evolutionary paraphiletic characteristic (it is present in several taxonomic groups that have evolved from the same ancestor).
Osteoblasts are responsible for the development and growth of bones during the juvenile stage of individuals and are also responsible for maintaining adult bone and regenerating bone when it breaks.
Osteogenesis is the process of differentiation of osteoblasts. The cells from which osteoblasts differ are called osteoprogenitors. The differentiation of osteoprogenitor cells, which come from the mesoderm, periosteum or bone marrow, is induced by growth factors called bone morphogenetic proteins (BMPs), capable of inducing the growth of bone, cartilage or connective tissue. When an osteoprogenitor cell receives a BMP signal, it quickly begins to express the genes to generate collagen, osteonectin and alkaline phosphatase, among other compounds necessary for bone growth. When the bone grows, it ends up wrapping some of the osteoblasts and they lose their ability to replicate, at that time they are dedicated to bone maintenance and not to their synthesis and are called osteocytes.
