Answer:
D
Explanation:
When a substance moves from low to high concentration it is moving against its concentration gradient, which requires more energy.
A. It depends on where it is moving, not the substance
OB. This is describing diffusion
OC. Does not require energy, it is passive transport through a semi-permeable membrane
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.
Answer: c. Transition Reaction
Explanation:
During the transition reaction, Acetyl-CoA is formed and connects the first stage of glycolysis with the Krebs Cycle (Citric Acid Cycle). In the presence of oxygen, pyruvate enters the mitochondria and is oxidized to form a compound of 2 carbon, acetate, with energy and CO2 release. During this process, the acetate binds to a coenzyme(coenzyme A (CoA)) - forming the acetyl-coenzyme A.
The 3 steps:
1. pyruvate is oxidized and forms acetate with liberation of CO2;
2. the energy released in the oxidation of pyruvate is stored in the reduction reaction of NAD+ to NADH + H+
3. The acetate molecule combines with coenzyme A to form acetyl-coenzyme A.
The process of turning off and on of genes is known as gene regulation.
Explanation:
When the gene is turned on, it instructs the cells to construct a particular protein. The proteins are the molecules that build your body with collagen, tendons, and bones or keratin in your hair.
The gene regulatory proteins allow the individual genes of an organism to be turned on or off . in different cell types there are different selections of gene regulatory proteins. The patterns of the gene expression gives each cell its unique characteristics.
Each cell produces or turns on only a fraction of its genes. the remaining genes are repressed or turned off. this process is known as gene regulation. The signals from the environment or from other cells activate proteins called transcription factors.
Lysosomes are subcallular organelles which perform many important cellular functions