Answer:
The cell membrane is semi-permeable. It allows some molecules to enter easily inside the cell whereas some molecules are blocked from entering the cell.
Small, polar molecules and hydrophobic molecules enter easily through the cell membrane. But large molecules and ions cannot easily move inside the cell membrane.
A hydrophilic substance like the substance L mentioned in the question enters the cell membrane through the help of carrier proteins. The substance attached to the large protein might enter through active or passive diffusion but it can only enter the cell by attaching to carrier proteins.
Answer:
<em>The correct option is A) they are all classified as pure substances.</em>
Explanation:
Pure air is a term which is used to described air which is free from pollutants or other contaminants. All the substance from which air is made are considered as pure substances. Hence, option A is correct.
Other options, like option C, is false because the components of the air are no chemically bonded to one another. They exist freely. Options D is false because not all the components of air can be classified as an element. For example, carbon dioxide is not an element.
Answer:
Prokaryotes do not have introns, eukaryotes have introns
Explanation:
Prokaryotes do not have introns, eukaryotes do. Introns are regions of DNA that are transcribed but not part of the final protein. They interrupt exons, which are the coding parts of the gene. These are only present in eukaryotes.
Introns need to be removed before the mRNA can be translated into the protein sequence. This occurs by a process called splicing. The splicing machinery binds the junction between introns and exons and excises the intron. The exons are then fused together to create the mRNA.
Other processing steps occur to the eukaryotic pre mRNA to prevent it from being degraded in the cell. This includes adding a cap to the 5' end of the protein, and adding a poly A tail to the 3' end. One these steps are complete, the eukaryotic mRNA is complete.
The prokaryotic mRNA undergoes transcription and translation simultaneously because it doesn't require these processing steps.
Explanation:
Hey there! Carbohydrates are one of four macromolecules. Carbohydrates provide short-term energy. Glucose, sucrose, starch, cellulose, chitin all belong to Carbohydrates. Carbohydrates are often referred to as saccharides and form ring structures. All Carbohydrates names end with "ose".
Carbohydrates Elements: Carbon, Hydrogen, and Oxygen - ratio 1:2:1 CHO
Carbohydrates Monomers: Monosaccharides (one sugar)
Carbohydrates Polymers: Polysaccharides and Disaccharides
Carbohydrates Functions: Store energy; provide structural support
Carbohydrates Examples: Bread, pasta, grains
~I hope I helped you :)~
