Answer:
Some organs are both a source and sink. Leaves are sinks when growing and sources when photosynthesizing. Rhizomes are sinks when growing but become sources in the spring when they provide energy for new growth.
It can be either diffusion, osmosis or active transport. depending on what is transported and how in which net direction they're moving.
Answer:
Advantage of gene expression in prokaryotes is it occurs faster than in eukaryotes because transcription and translation occur simultaneously in the cytoplasm, and regulation occurs at the transcriptional level. Whereas disadvantage of gene expression in prokaryotes is that there is no post translational modification and low expression of genes.
Explanation:
Prokaryotic organisms are single-celled organisms that lack a cell nucleus, and their DNA therefore floats freely in the cell cytoplasm. To synthesize a protein, the processes of transcription and translation occur almost simultaneously. When the resulting protein is no longer needed, transcription stops. As a result, the primary method to control what type of protein and how much of each protein is expressed in a prokaryotic cell is the regulation of DNA transcription. All of the subsequent steps occur automatically. When more protein is required, more transcription occurs. Therefore, in prokaryotic cells, the control of gene expression is mostly at the transcriptional level. whereas in eukaryotes, the DNA is contained inside the cell’s nucleus and there it is transcribed into RNA. The newly synthesized RNA is then transported out of the nucleus into the cytoplasm, where ribosomes translate the RNA into protein. The processes of transcription and translation are physically separated by the nuclear membrane; transcription occurs only within the nucleus, and translation occurs only outside the nucleus in the cytoplasm.
Answer:
At the base of Actinopterygii
*This is a unique characteristic of this group.
Explanation:
A peculiar characteristic organ observed in ray-finned fish (as well as in Sarcopterygii, or lobe-finned fish) but not in cartilaginous fish like shark is the swim bladder.
This organ is often described to be a sac containing gas. It helps these set of fish adjust its buoyancy and its position in the water by regulating the concentration of gas present in it.
The swim bladder is formed as a pouch coming off the embryonic digestive tract, and in chondrosteans and holosteans, with a set of teleosts e.g. the eels, it maintains an open pathway to the esophagus. In majority of the bony fish, the swim bladder is totally sealed off, as gas levels in their swim bladder are regulated by producing gas into the bladder via a network of capillaries, the rete mirabile (Latin word for "marvelous net").
The swim bladder is homologous to the lungs of tetrapods. Since they are formed in the same vein. Few fishes that have an open swim bladder employs it as a breathing organ.
Answer:
The answer is insulin.
Explanation:
Pancreatic juice is an enzyme containing secretion produced by the pancreas into the small intestine. Enzymes in the pancreas help in digesting proteins, carbohydrates and fats. The constituent enzymes are as follows:
- Trypsinogen and Chymotrypsinogen: Precursors of the proteases, trypsin and chymotrypsin that digest proteins. They are released as precursors to protect the intestinal lining. Enterokinase, an enzyme secreted by small intestine's epithelial cells, activates these precursor.
- Lipase: Enzyme that digests lipids by hydrolysing triglycerides into 2-monoglyceride and two free fatty acids.
- Amylase that helps in digesting any left over carbohydrates and complex starch.
Insulin:
Insulin can never be part of pancreatic juice because it is a hormone, not an enzyme. Hormones are chemical messengers secreted only in blood. Insulin is a hormone secreted by the pancreas to lower blood glucose levels by binding to insulin receptors on cells and stimulating the intake of glucose through glucose transport channels (GLUTs) in the cell membrane.
